PHILIPS GRANADA D16VP2 PHILIPS, D22VP3 PHILIPS, D26TP2 PHILIPS PHILIPS G20657, G20C655, G22C566, G22C567, G22C569, G22C655, G22C657, G22C660, G22C661, G22C662, G22C663, G22C664, G22C665, G22C666, G22C667, G22C700, G22C701, G22C702, G22C703, G22C705, G22C706, G22C707, G22C708, G26C672, G26C674 PYE CT420, CT450, CT451, CT452, CT453, CT454, CT455, CT456, CT457, CT462, CT464, CT467, CT474, CT480, CT481, CT483, CT484, CT492, CT493, CT494 Service manual & schematics
FIELD SERVICE INFORMATION
FOR THE
'Gll' Chassis
727 17608 (Revised)
CONTENTS
TEXT
| Sec | tion | Page No. |
|---|---|---|
| Α | INTRODUCTION | 2 |
| В | CHASSIS SPECIFICATION | 2 |
| С | USE OF THE CIRCUIT DIAGRAMS | 5 2-3 |
| D | SAFETY NOTES | 3-4 |
| Е | SERVICING NOTES | 4-5 |
| F | PRESET ADJUSTMENTS | 7-9 |
| G | CONVERGENCE CORRECTION AN | ID |
| PURITY ADJUSTMENTS | 9-12 | |
| Η | GREY SCALE TRACKING | 12 |
| J | DECODER ALIGNMENT | 15-17 |
| Κ | I.F. ALIGNMENT | 17 |
| SPARE PARTS LIST | in pocket |
ILLUSTRATIONS
| rig. n | 0. | ray | e 1v0. | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| _ | MAIN CIRCUIT DIAGRA | M | •• | •• | ••• | • • | •• | •• | •• | •• | • • | In po | cket |
| 1 | Timebase, decoder and | I.F. panel | s — sł | owing | g layc | out of | preset | t adju | stmer | nts etc | ). | 6 | |
| 2 | Layout of preset adjustr | nents on | rear c | of chas | sis | •• | 8 | ||||||
| 3 | Power supply panel, sho | wing pro | eset ad | ljustm | nent a | nd te | st poir | nt | •• | •• | 8 | ||
| 4 | Waveform at TP3 | •• | •• | •• | •• | •• | 9 | ||||||
| 5 | Deflection assembly and | d multi-p | ole un | it | 10 | ||||||||
| 6 | Receiver screen, showin | ig areas X | Kand` | Y (pur | ity ac | ljustm | ent) | •• | 11 | ||||
| 7 | Dynamic correction adju | ustments | - | ' | 13 | ||||||||
| 8 | Decoder panel, showing | layout c | of aligi | nment | pres | ets etc | . | •• | 14 | ||||
| 9 | Burst waveform | •• | • • | 15 | |||||||||
| 10 | Filter circuit for oscillos | cope co | nnecti | on | •• | 15 | |||||||
| 11 | Decoder alignment way | eforms | • • | 16 | |||||||||
| 12 | Block diagram | •• | 1 | 18-19 | |||||||||
| 13 | Power supply panel circ | uit diagr | am (B | Y01/B | Y02/H | HU01/ | HU02 | versio | ons) | 20 | |||
| 14 | Power supply panel - c | omponer | nt vièv | v (BYC | )2/HU | 102 ve | rsions | ) | 21 | ||||
| 15 | Line scan panel circuit d | liagram ( | BY02/ | BY03 / | HU02 | 2/HU0 | 3 vers | íons) | 22 | ||||
| 16 | Line scan panel — comp | onent vie | w (B | (02/B | Y03/H | Ú02/ | HU03 v | versio | ns) | 23 | |||
| 17 | Timebase panel — comp | onent vi | ew (B | 400/H | UOÓ V | ersio | ns) | , | 24 | ||||
| 18 | Timebase panel circuit o | liagram ( | BA00/ | HU00 | versi | ons) | 25 | ||||||
| 19 | Deflection assembly with | ring diag | ram | 26 | |||||||||
| 20 | Dynamic correction pan | el — con | nonei | nt viev | w (BY | 00/HL | J00 ve | rsions | s) | 27 | |||
| 21 | Dynamic correction pan | el (BY00 | HUO | versi | ons) a | and de | flection | on as | sembl | v circ | uit dia | gram | 28 |
| 22 | C B T base nanel — con | nonent | view ( | BY00/ | BY01 | /BY02 | vers | ions) | , | .g. a | 29 | ||
| 23 | C B T and base nanel ci | rcuit dia | aram | BY00 | /BY01 | BYO | 2/HU0 | 2 vers | sions) | •• | •• | •• | 30 |
| 24 | Decoder napel — compo | nent vie | 00/RA | 01/H | ersion | e) | , | •• | •• | •• | 31 | ||
| 25 | Decoder panel circuit di | agram (I | versid | ne) | •• | •• | •• | •• | 32 | ||||
| 25 | Mains input panel — co | mpopent | VEISI | 51137 | •• | •• | •• | •• | •• | 33 | |||
| 20 | Mains input panel oirou | it diagra | v16vv | •• | •• | •• | •• | • • | •• | •• | •• | •• | 33 |
| 22 | I E panel - component | 100/H |
areior |
(e) |
•• | •• | •• | •• | •• | •• | 34 | ||
| 20 | I.F. panel — component | ne) | 13) | •• | •• | •• | •• | •• | 35 | ||||
| 20 | Wayoforme 1 19 | II (BA00/ | 1000 | vei 310 | 115/ | •• | •• | •• | • • | •• | •• | •• | 26 |
| 30 | Waveforms 20 20 | • • | •• | •• | •• | •• | •• | •• | •• | •• | •• | •• | 30 |
| 31 | •• | •• | •• | •• | •• | •• | •• | • • | •• | • • | •• | 3/ | |
|
3Z
22 |
•• | •• | •• | •• | •• | •• | •• | •• | •• | •• | •• |
აი
აი |
|
| বর | •• | • • | • • | •• | • | • • | •• | • • | •• | •• | •• | - 29 |
Philips Service 604 Purley Way, Waddon, Croydon, CR9 4DR
Telephone: 01-686 0505
Telex: 262308
0---- M--
A-INTRODUCTION
The 'G11' series all solid-state colour television chassis is designed for both colour and monochrome reception on 625 lines U.H.F. The 110° deflection 20AX picture tube is inherently self-converging and has "quick-vision" guns to provide a viewable picture within about five seconds of switching on.
Most of the circuitry is accommodated on five main printed panels (line scan, power supply, timebase, decoder and I.F.) which are vertically mounted on two sub-chassis. These sub-chassis are pivot-mounted and can be hinged open from the main chassis frame, giving easy access to both sides of the panels. To open out a sub-chassis "door", it is first necessary to release its securing clip at the top and remove a transit screw (if fitted) at the bottom. If lifted slightly, the sub-chassis will then be free to open out, and it will lock in the half open or fully open positions as required. Any of the main panels may be unclipped and removed from the receiver after unplugging the appropriate connectors.
Apart from the five main panels there are three smaller printed panels (mains input, dynamic correction and C.R.T. base). These smaller panels are easily detachable and may be withdrawn to the extent of their connecting leads in order to gain access for component changing. If necessary, the connecting leads may be unplugged, enabling the panels to be removed from the receiver
The main chassis is pivoted at the bottom and after removing the two moulded retaining clips at the top it may be lowered through about 30° to gain access to the deflection coil assembly etc. The top and bottom chassis supporting brackets are adjustable to accommodate different cabinet sizes.
B -CHASSIS SPECIFICATION
| Mains supply | 240 volts, 50Hz, a.c. only | |||||
|---|---|---|---|---|---|---|
| Mains consumption | 145 watts nominal (155 watts max.) | |||||
| System | 625 lines, U.H.F., P.A.L. colour | |||||
| Tuner unit | U.H.F., capacitance diode tuning | |||||
| E.H.T. | 25kV | |||||
| Loudspeaker impedance | 25 ohms | |||||
| Sound output | 2.5 watts | |||||
| Intermediate frequencies | Vision, 39.5 MHz | |||||
| Sound, 33.5 MHz | ||||||
| Picture tube | 20AX in-line system | |||||
For the remainder of the specification (e.g. cabinet dimensions etc.) refer to the supplementary service information for the model in question.
Trade Descriptions Acts
Products offered for sale may differ from those described or illustrated in this Service Information due to later production changes in specifications, components or place of manufacture. The contents of this Service Information are therefore not to be treated as representations as to the current availability of products as described or as to products actually offered for sale.
C-USE OF THE CIRCUIT DIAGRAMS
1. Main circuit diagram
The main circuit diagram of the 'G11' chassis is provided on the large separate sheet accompanying this manual. Different background colours have been used to identify those parts of the circuit which are located on the major printed circuit panels. For example, the decoder panel section of the circuit is blue, the line scan panel section is mauve and so on. Minor units and cabinet mounted items are not coloured.
In order to keep the main circuit diagram applicable to different models, some parts (such as the programme selector unit) which may vary from model to model are shown in a simplified form. For full details of such items, reference should be made to the supplementary service information for the model in question.
In order to keep the main circuit diagram to a reasonable size, the internal details of circuit units and integrated circuits are omitted. To distinguish circuit units from integrated circuits their outlines are drawn differently (dotted lines and solid lines respectively). Where it has been found impracticable to show connections
between various parts of the main circuit, an arrow with an identifying letter A, B, C, etc. is shown which lines up with a corresponding arrow and letter at the point of connection.
2. Individual circuit diagrams
Individual circuit diagrams for each panel and unit are provided in this service manual in order to supplement the main circuit diagram. The internal details of the circuit units and integrated circuits which were omitted from the main diagram are shown in the individual circuits; the I.C.s being represented in block diagram form.
As far as possible, the layout of each individual circuit has been kept similar to the corresponding part of the main circuit diagram. Engineers can therefore turn from one to the other without the difficulty of interpreting a different layout. The major individual circuits have background colours to match the corresponding parts of the main circuit diagram.
3. H.T. and L.T. supply lines
The chassis has several H.T. and L.T. d.c. supply lines and on the circuit diagrams these are labelled H.T.1, L.T.1 and so on. The following table lists all the supply lines, giving their origins and nominal voltages :-
| Supply line | Origin | Nominal voltage |
|---|---|---|
| H.T.1 | Power supply panel | 156V stabilised |
| H.T.2 | H.T.1 via R4079 | 125V |
| Н.Т.З | Line output stage | 165V |
| H.T.4 | Line output stage | 800V |
| L.T.1 | Line output stage | 16V |
| L.T.2 | L.T.1 via IC5073 | 12V stabilised |
| L.T.3 | Line output stage | 37V |
| L.T.4 | Line output stage | 37V |
4. Component and plug/socket identification system
In order to identify a particular component in the circuit with its position in the receiver, a coding system for component numbers is used. For instance, any component with a 5000 number is
| Position | Position number group | Panel or unit prefix |
|---|---|---|
| Chassis mounted components (e.g. backplate isolator) | 1200—1299 | 12 |
| Mains input panel | 1300—1399 | 13 |
| Line output transistor and heatsink assembly | 1400—1499 | 14 |
| Dynamic correction panel | 15001599 | 15 |
| C.R.T. base panel | 1600—1699 | 16 |
| Customer controls | 1700—1799 | 17 |
| Cabinet assembly (e.g. C.R.T., def. coils, speaker etc.) | 18001899 | 18 |
| Programme selector unit | 1900—1999 | 19 |
| 20002499 | 2 | |
| I C s on timebase panel | 2500-2599 | |
| Line scan panel | 3000—3199 | 3 |
| Power supply panel | 40004999 | 4 |
| LE panel | 5000—5999 | 5 |
| U.H.F. tuner unit | 53005399 | |
| Vision selectivity and gain unit | 5400—5499 | _ |
| ,, ,, LC.s external to circuit units | 55005599 | |
| Vision detector unit | 5600—5699 | |
| Decoder panel | 60006599 | 6 |
| Luminance/chrominance control unit | 6200—6299 | |
| ,, ,, LCs external to Lum/chroma control unit | 6500-6599 |
located on the I.F. panel, and a component with a 2000 number will be found on the timebase panel.
A coding system is also used for the multi-way sockets. Taking the decoder panel as a first example; the wiring to this panel terminates in five sockets. These are given letter identifications from A to E. The prefix number for the decoder panel is then added before the letter, giving 6A, 6B, 6C etc. A contact number is then added after the letter so that 6A4 for example, denotes contact 4 of socket A on the decoder panel.
Taking the line scan panel as a second example; there are five sockets here and these are given the letters A to E. The prefix for the line scan panel (3) is then added to the letters, thereby distinguishing sockets A, B, C etc. on the line scan panel from sockets A, B, C on any of the other panels. The contact number is added after the letter, as already described, so that the reference 3D2 for example, denotes contact 2 of socket D on the line scan panel.
It will be noted that, in some instances, two or more sockets engage with a single fixed plug. In view of this, the identification letter always applies to the socket, since the plug is effectively two or more connectors in one, and therefore cannot be identified by a single letter.
Single lead connectors are denoted by the letter X where the lead joins different panels or units, or the letters PC where both ends of the lead are on the same panel or unit, e.g. PC2—the colour killer link.
The above table gives the full coding system for component numbers and also the panel or unit prefixes as used for connectors.
D-SAFETY NOTES
1. Safety standard
The 'G11' series of receivers are designed and manufactured to comply with the British Standard for Safety, BS415. Engineers should always ensure that maintenance and repairs uphold the original performance and safety standards, taking particular care that safety hazards are not introduced by the inadvertent or deliberate 'defeat' of any mechanical or electrical safety feature.
2. Safety components (
The receiver contains certain components which have been specially chosen to ensure safety under both normal and fault conditions. These components are identified in this service infor-
mation and also in the receiver itself, by the safety symbol . Should a safety component need to be replaced, it is essential to use a component of the identical type (see spare parts lists) which must be mounted in exactly the same manner.
3. Live chassis
WARNING: If the receiver is operated on "raw" (non-isolated) mains, the chassis will be at approximately half mains potential. This applies whether the mains lead is connected in accordance with its colour code or not. In view of this it is recommended that a mains isolating transformer (rated at not less than 500VA) should be used for the receiver supply when servicing.
Never connect earthed test equipment to any part of the receiver (other than the aerial socket) unless the receiver mains supply is isolated.
4. X-ray radiation warning
The voltage and currents on the cathode ray tube are higher in a colour receiver than in a monochrome type, and, as a result, the X-rays will have greater penetrating power and will be present in larger quantities. In practice, this means that suitable protection has to be built into a receiver in order to reduce the radiation hazard to an acceptable level. It is important that personnel involved in installation and servicing should be aware of any possible dangers. The radiation problems are confined to X-rays generated by the cathode ray tube. During development of the 'G11' series colour television chassis, special attention has been given to these points. With the back-plate removed, no significant radiation is present, and therefore the maximum dose rate is much less than the accepted danger level. This low level of radiation is due to :---
- (i) The absorbing power of the glass in the cathode ray tube.
- (ii) The C.R.T. internal metal shield provided for magnetic screening.
Any increase in H.T. voltage would cause the E.H.T. voltage to rise, resulting in possible forward X-ray radiation from the C.R.T. face. An over-voltage protection circuit has therefore been incorporated on the power supply panel. This protection circuit is formed by the gas-filled glow-switch GS4038 in series with the thermal fuse R4067 the latter being a wire-wound resistor with "spring-off" contacts which are normally soldered together.
If the H.T. voltage rises above about 195-205 volts due to a fault in the receiver, the glow-switch will "strike" and operate so as to connect R4067 between the H.T. line and chassis. The glowswitch will then open and close alternately (assuming that the over-voltage condition persists) until the heat dissipated by R4067 melts the solder holding its "spring-off" contacts. The contacts will then open, breaking the H.T. feed to the receiver.
If R4067 operates, it should be reset (after clearing fault) by resoldering the "spring-off" contacts using 60/40 grade solder.
NEVER ATTEMPT TO OVERRIDE OR DISABLE THE OVER-VOLTAGE PROTECTION CIRCUIT.
5. Discharging and handling the C.R.T.
The C.R.T. final anode will store an E.H.T. charge for some time after the receiver is switched off. Before handling the C.R.T. (or the E.H.T. lead), it will be necessary to discharge the C.R.T. to avoid electric shock.
The only safe method of doing this is to discharge the E.H.T. terminal of the C.R.T. to the braiding which earths the tube's external aquadag coating, using a suitably insulated lead and probe. Connect the earth end of the lead first.
DAMAGE TO SEMICONDUCTOR DEVICES MAY RESULT IF THE C.R.T. IS DISCHARGED TO THE METAL CHASSIS FRAME (OR ANY PART OF THE RECEIVER OTHER THAN THE TUBE AQUADAG).
THE C.R.T. CONTAINS A HIGH VACUUM AND THEREFORE IT MUST BE HANDLED WITH EXTREME CARE, TAKING ALL APPROPRIATE SAFETY PRECAUTIONS, INCLUDING THE WEARING OF SUITABLE EYE PROTECTION.
6. Measuring voltages on the power supply panel
Care should be taken when measuring voltages in the trigger pulse phase control stage (T4045) since the use of a low impedance meter can cause an undesirable temporary rise in H.T. voltage. A 20kΩ/V meter (e.g. AVO 8) is satisfactory, but avoid using ranges below 25V. Alternatively, use a high impedance electronic type meter.
7. C.R.T. base panel cover
High voltages are present on the C.R.T. base panel when the receiver is operating. In order to protect service engineers from electric shock (particularly while adjusting the G2 controls) a moulded insulating cover is clipped over the print side of the panel. This cover may be removed if it becomes necessary to gain access to the print side of the panel, but it is important to ensure that it is refitted afterwards.
E-SERVICING NOTES
1. The aerial system
The aerial chosen for use with the receiver should be for the correct group of U.H.F. channels applicable to the area in which the receiver is being installed. It must also be capable of supplying a good signal, free from noise and multi-path reflections.
2. Plugs and sockets
A socket can be identified as the connector which contains the female contacts and may be found either in a fixed position or on a fly-lead; similarly a plug contains the pins. Most sockets have pin numbers moulded in the plastic housing. Some of the plugs
Sockets should never be removed from the plugs by pulling on the leads, since this practice may result in connections being damaged.
3. Test points
A number of test points are provided, chiefly to facilitate adjustments. Each test point is identified on the printed panel by a number with the prefix TP, e.g. TP1, TP2, TP3, etc. The test points are similarly indicated on the circuit diagrams etc. The following table lists all the test points :--
| Test point | Location | Circuit position |
|---|---|---|
| TP1 | Power supply panel | H.T.1 line (FS4037) |
| TP2 | Decoder panel | pin 4 U6200 |
| ТРЗ | Decoder panel | pin 8 U6200 |
| TP4 | Decoder panel | pin 5, IC6520 |
| TP5 | Decoder panel | pin 9, IC6520 |
| TP6 | Decoder panel | L.T.2 line |
| TP7 | Decoder panel | junct. R6074/R6075 |
| TP8 | Decoder panel | junct. R6072/R6106 |
| ТР9 | Decoder panel | pin 17, U6200 |
| TP10 | Decoder panel | pin 13, IC6520 |
| TP11 | Decoder panel | pin 14, IC6520 |
4. Fly-leads PC1 and PC2
These fly-leads are located on the decoder panel and are provided to facilitate servicing and adjustment operations. The fly-lead PC2 should be connected to pin 'a' for normal operation. To disable (override) the colour killer, unplug PC2. To remove colour connect PC2 to position 'b'. To remove the luminance signal unplug the fly-lead PC1.
5. Connecting test equipment
Refer to the "Live chassis" warning in the Safety Notes (Section D) before connecting any test equipment.
'Earth' connections for test equipment must be made as close as practicable to the part of the circuit under investigation. Failure to observe this precaution may result in misleading results and/or damage to semiconductors. To give an example, when measuring voltages around the field deflection integrated circuit (IC2520), the negative meter lead must be connected to the print 'earth' for this I.C. (as close as possible to pin 1) and NOT to the metal chassis frame.
Caution: Most semiconductor heat sinks are above chassis potential and therefore cannot be used as 'earthing' points for test equipment.
6. Thermal fuses R4067 ($, R5046 ($)
R4067 is dealt with in Section D, note 4.
R5046 is a thermal fuse of the wirewound resistor type with "spring-off" contacts. It is located on the I.F. panel and its function is to protect certain parts of the receiver against the effects of excessive current consumption in the sound output stage. If R5046 operates, it should be reset (after clearing fault) by resoldering the "spring-off" part to the end of the resistor lead-out wire using 60/40 grade solder.
7. Replacing semiconductor devices
General
When replacing any semiconductor device which uses a heat sink, a coating of heat sink compound should be applied to the thermal contact surface of the device before it is clamped to the heat sink. In some cases, an insulating pad is fitted between the device and its heat sink. This pad must be correctly refitted when replacing the device.
When fitting a new integrated circuit, care should be taken to ensure that it is inserted into the panel the correct way round, i.e. with the indicating notch on the I.C. adjacent to hole 1 on the printed panel.
Replacing the field integrated circuit (IC2520)
- (a) Disengage both ends of the curved spring clip from the heat sink.
- (b) Unsolder the two heat sink tag connections from the printed panel and remove the heat sink.
- (c) Gently ease the I.C. out of its holder by pulling the spring clip.
- (d) When fitting the new I.C., a coating of heat sink compound should be applied to its thermal contact surface before refitting the heat sink. Ensure that the I.C. is fitted the correct way round, i.e. with the notched end nearest the field output filter coil (L2092).
- (e) After clipping the heat sink into position again, resolder its tags to the printed panel.
Replacing the line output transistor (T1401)
- (a) Remove the line output transistor heat sink assembly from the chassis by removing the two fixing screws and unplugging the connector 3E.
- (b) Unsolder the capacitor and leads (note lead colours) from the base and emitter pins of the line output transistor, then remove the insulating plate. Remove the transistor from the heat sink (two screws).
- (c) Alternative types of line output transistor may be used in production, giving rise to a situation where the fixing lugs of the replacement transistor may be a different thickness to those of the criginal. In this event, it will be necessary to add (or omit) washers under the heads of the fixing screws when fitting the new transistor in order to accommodate any difference in thickness. Heat sink compound must be used when fitting the new transistor.
- (d) Refit the insulating plate over the base and emitter pins of the transistor, then resolder the capacitor and leads.
- (e) Finally, refit the heat sink assembly to the chassis and plug in the connector 3E.
- 8. Removing and replacing the deflection coil assembly and multi-pole unit (see Fig. 5)
- (a) Hinge open the two sub-chassis "doors" to their fullest extent (not necessary if the multi-pole unit only is being removed).
- (b) Unplug the C.R.T. base panel from the tube
- (c) Release the multi-pole unit by rotating its clamp ring fully anti-clockwise. Remove the unit from the tube neck.
- (d) The screw clamping the deflection coil assembly will now be visible. Slacken this screw.
- (e) Unplug the deflection coil wiring from the dynamic correction panel (socket 15A).
- (f) Withdraw the deflection coils, turning them to clear the chassis frame.
- (g) When refitting the deflection coils, ensure that the datum mark on the top of the coil housing is in line with the datum mark moulded on the C.R.T. and that the housing is pushed firmly and squarely against the centring ridge on the C.R.T. cone before tightening the clamp screw.
- (h) Refit the multi-pole unit with its triangular datum pointer at the top, ensuring that the two moulded locating projections on the multi-pole unit are felt to engage in the correspond ing recesses in the deflection coil assembly moulding. Secure the multi-pole unit by rotating its clamping ring clockwise.
- (j) Reconnect the deflection coil wiring and the C.R.T. base panel.
- (k) It will now be necessary to adjust the picture rotation (see Section F) and the convergence correction and purity (see Section G).
9. Circuit units
The receiver contains four signal processing circuit units as follows:-
- (a) U.H.F. tuner unit (U5300)
- (b) Vision selectivity and gain unit (U5400)
- (c) Vision detector unit (U5600)
- (d) Luminance/chrominance control unit (U6200)
(a), (b) and (c) incorporate adjustable tuned circuits which are pre-aligned during manufacture. THE ALIGNMENT OF THESE UNITS MUST NOT BE DISTURBED. If a replacement unit is fitted, no alignment will be required.
(d) incorporates only one adjustment, the preset brightness control (R6212) which, if necessary, should be adjusted as described in Section F.
It is generally recommended that if a fault occurs in a circuit unit, then the entire unit should be replaced (particularly in the case of the U.H.F. tuner unit). In some instances, it may be possible to effect a repair by replacing a transistor or I.C. for example, but engineers are advised that the majority of circuit unit components are not normally available separately. If replacement components are fitted, ensure that their leads are cut short after soldering to prevent them touching the screening can.
After replacing the luminance/chrominance control unit (U6200) (or the integrated circuit within it), it is advisable to realign the decoder (see Section J) in order to maintain optimum performance.
Avoid obstructing the square ventilation holes in the vision detector unit (U5600). Do not interchange the screening cans of circuit units.
10. Coding of panels and units
Most of the panels and units are coded with a BA, BY or HU number, relating to production changes. This number will be found on a label attached to the unit. A higher number does not necessarily indicate a later assembly.
When servicing a panel or unit, check the BA/BY/HU number and refer to the appropriate illustrations, together with any information in the text relating to the BA/BY/HU code.
F --- PRESET ADJUSTMENTS
1. Set H.T.1 (R4042), see Fig. 3
Set R4042 to its mid-position then connect the receiver to a 240V a.c. supply having a rating of at least 500VA. Tune the receiver to a transmission then switch off all three guns of the C.R.T. (gun switches located on C.R.T. base panel). Connect a d.c. voltmeter between chassis and TP1 (on the power supply panel). Adjust R4042 for a reading of 156 volts then switch on all the C.R.T. guns.
2. Field hold (R2045), see Fig. 1
Tune the receiver to a transmission. Adjust R2045 to the centre of its "hold" range.
3. Line hold (R2002), see Fig. 1
Tune the receiver to a transmission. Temporarily remove the video input to the timebase panel by connecting a shorting link across C2043 (field and line sync. will now be lost). Adjust R2002 for minimum line slip then remove the shorting link. The picture should lock.
4. Picture rotation, see Fig. 5
- (a) Lower the chassis to gain access to the deflection coil assembly. Check that the datum mark on the top of the deflection coil housing is in line with the datum mark moulded on the C.R.T. and adjust if necessary (see Servicing Note 8).
- (b) Tune the receiver to a cross-hatch pattern from a pattern generator. Free the deflection yoke in its housing by pulling the two clamp levers fully back towards the rear of the receiver.
- (c) Hold the yoke at point B and rotate it within its housing until the central horizontal line of the cross-hatch is correctly orientated.
- (d) Adjust the raster shape magnet lever so that the central horizontal line of the cross-hatch is straight.
- (e) If necessary, repeat steps (c) and (d) until the central horizontal line is both straight and level. After adjustment, secure the yoke by pushing the two clamp levers forward again, then return the chassis to its normal position.
5. Line linearity (L1501), see Fig. 2
Tune the receiver to a test-card transmission or a suitable display from a pattern generator. Adjust the rotatable magnet of L1501 using a strift (2.4mm) square-ended non-metallic tool for optimum line linearity.
6. Height (R2058), field linearity (R2052), see Fig. 1
Tune the receiver to a test-card transmission or a suitable display from a pattern generator. Adjust R2058 and R2052 in conjunction with one another to obtain correct height and optimum field linearity consistent with satisfactory vertical centring of the picture.
East-west shaping, centre (R2137) East-west shaping, corner (R2123) see Fig. 1
Tune the receiver to a test-card transmission or a cross-hatch display from a pattern generator. Set R2123 to its fully anti-
clockwise position (viewed from the component side of the panel). Adjust R2137 to straighten the vertical lines at the edges of the screen. Adjust R2123 to straighten the vertical lines in the corners of the screen, re-adjusting R2137 as necessary to maintain overall straightness.
8. Width (R2133), see Fig. 1
Tune the receiver to a test-card transmission or a suitable display from a pattern generator. Adjust R2133 so that the picture just overlaps the sides of the screen.
9. Line phase (R2025), see Fig. 1
Tune the receiver to a test-card transmission or a pattern generator providing a suitable display for horizontal centring adjustment. Adjust R2025 to centre the picture horizontally within the screen
10. Focus (U3158), see Fig. 2
Tune the receiver to a test-card transmission or a pattern generator display incorporating definition lines. Adjust the brightness and contrast controls to a slightly higher than normal setting. Adjust the control knob of the focus unit U315E for best definition of the verticals in the outer areas of the picture.
11. Preset saturation (R6012), see Fig. 1
Note : The decoder alignment must be correct before carrying out this adjustment.
Tune the receiver to a colour transmission. Set the contrast and brightness controls for a normal picture. Set the customer's colour control to maximum then adjust R6012 to obtain slightly over-saturated colours. Finally, check that a reasonable range of colour saturation is obtainable with the customer's colour control.
12. A.G.C. crossover (R5013), see Fig. 1
Tune the receiver to a known noise-free picture (preferably a test-card transmission or a suitable display from a pattern generator). Turn R5013 slowly clockwise (viewed from the component side of the panel) until "noise" just begins to show on the picture* then "back-off" the control tc a position just past the point where the picture becomes free of noise.
*If the signal strength is very high, the picture may become overl oaded and/or unstable (instead of noisy) as the control is turned clockwise, in which case the aerial input must be attenuated before the A.G.C. crossover can be adjusted. Remove the attenuation after adjusting.
13. Preset brightness (R6212), see Fig. 1
The preferred adjustment procedure is given in Method A. If an oscilloscope is not available, then Method B should be employed, but the result obtained will be less precise.
Method A
- (a) Tune the receiver to a transmission. Connect the fly-lead PC2 (on the decoder panel) to pin 'b' to remove the colour. Unplug the fly-lead PC1 (on the decoder panel) to remove the luminance signal.
- (b) Set the contrast control to its mid-position.
(Continued on Page Nine)
Fig. 3-Power supply panel, showing preset edjustment and test point
Page Eight
- (c) Connect a d.c. voltmeter between chassis and TP2 (on the decoder panel). Adjust the customer's brightness control for a meter reading of 1.35 volts. The customer's brightness control must then be left undisturbed until the following steps (d) and (e) have been completed.
- (d) Connect an oscilloscope to TP3 (on the decoder panel) with the screening of the 'scope lead connected to the screening can of the luminance/chrominance control unit (U6200). Adjust the 'scope to display the line rate waveform.
- (e) Adjust R6212 (accessible through hole in end of U6200 screening can) to give a 200mV difference between the black level and the blanking level, as shown in Fig. 4.
- (f) After adjustment, reconnect PC1 and reconnect PC2 to pin 'a'.
Method B
- (a) Tune the receiver to a transmission. Connect the fly-lead PC2 (on the decoder panel) to pin 'b' to remove the colour. Unplug the fly-lead PC1 (on the decoder panel) to remove the luminance signal.
- (b) Set the contrast control to its mid-position.
- (c) Connect a d.c. voltmeter between chassis and TP2 (on the decoder panel). Adjust the customer's brightness control for a meter reading of 1.35 volts. The customer's brightness control must then be left undisturbed until the following step (d) has been completed.
- (d) Reconnect the voltmeter (250V d.c. range) between chassis and pin 13 of the C.R.T. (red cathode). Adjust R6212 (accessible through hole in end of U6200 screening can) for a meter reading of 140 volts.
- (e) After adjustment, reconnect PC1 and reconnect PC2 to pin 'a'.
G-CONVERGENCE CORRECTION AND PURITY ADJUSTMENTS
Notes
- (a) The adjustments described in this section are carried out during manufacture of the receiver, and no subsequent adjustments are normally required unless the C.R.T., deflection coils, multi-pole unit or dynamic correction components have been changed.
- (b) Before attempting the following adjustments, ensure that all the preset adjustments in Section F have been completed.
- (c) The adjustments should be carried out in subdued lighting conditions.
(d) The receiver is fitted with an automatic degaussing circuit which operates each time the receiver is switched on from cold. However, if the C.R.T. and/or associated metal parts have been subjected to extra strong magnetic fields, it may be necessary to pass an external degaussing coil across the C.R.T. face and in each corner before correction/purity adjustments are carried out.
At no time whilst using an external degaussing coil should it be allowed to come closer to the face of the C.R.T. than is necessary for complete degaussing, otherwise permanent damage may be caused to the shadowmask plate inside the tube.
(e) For optimum results, the pattern generator used for checking and adjusting the static and dynamic correction should provide a correctly centred cross-hatch pattern, i.e. the centre vertical line and centre horizontal line should intersect in the centre of the screen.
Static correction adjustments (see Fig. 5 for layout of controls)
The receiver must be allowed to warm up for at least one hour before commencing the static correction adjustments. During this warm-up period a picture or reasonably bright raster should be displayed to enable the C.R.T. shadowmask to reach its normal operating temperature.
- Tune the receiver to a cross-hatch pattern from a pattern generator. Adjust the receiver controls for a medium brightness display.
- Set all six control levers of the multi-pole unit to their midpositions (i.e. vertical, with the four upper levers in the "12 o'clock" position and the two lower levers in the "6 o'clock" position. Switch off the green gun of the C.R.T. (gun switches located on C.R.T. base panel).
- 3. Set the four-pole field strength lever against either of its limit stops. (This lever should now be in approximately the "10 o'clock" or "2 o'clock" position).
- 4. By means of the four-pole field direction lever, bring red and blue together, along either a vertical or a horizontal crosshatch line in the centre of the screen.
- 5. By simultaneous adjustment of both the four-pole levers (strength and direction), keep red and blue superimposed in one direction (as obtained in step 4) while bringing them together in the other direction. The red and blue cross-hatch patterns should now be completely superimposed in the centre of the screen.
- 6. Switch on the green gun. Set the six-pole field strength lever against either of its limit stops. (This lever should now be in approximately the "10 o'clock" or "2 o'clock" position).
- 7. By means of the six-pole field direction lever, bring the red/ blue and green together along either a vertical or a horizontal cross-hatch line in the centre of the screen.
- 8. By simultaneous adjustment of both the six-pole levers (strength and direction), keep the red/blue and green superimposed in one direction (as obtained in step 7) while bringing them together in the other direction. The red, blue and green cross-hatch patterns should now be completely superimposed in the centre of the screen.
- 9. Adjust the raster shape magnet lever so that the most central horizontal line of the cross-hatch is straight.
The purity must now be adjusted (see page 11).
Page Ten
Purity adjustment (see Fig. 5 for layout of controls)
The purity adjustment procedure must be carried out with the C.R.T. shadowmask cool. The receiver must therefore be switched off and allowed to cool down for 10–15 minutes before adjusting. When the receiver is switched on again, the brightness and contrast settings must be kept low throughout the purity adjustment procedure to avoid heating of the shadowmask by high beam current. Once the purity has been adjusted with the shadowmask cool, it will then automatically remain correct throughout the normal range of operating temperatures.
- Keeping the brightness and contrast settings low (see note above), tune the receiver to a transmission (alternatively, leave tuned to the cross-hatch pattern previously used for static correction adjustments). Remove colour (if any) by connecting the fly-lead PC2 (on the decoder panel) to pin 'b'. Remove the luminance signal by unplugging the fly-lead PC1 (on the decoder panel). Lower the chassis to gain access to the deflection coil assembly.
- 2. Switch off the green and blue guns of the C.R.T. (gun switches located on C.R.T. base panel).
- 3. Adjust the brightness control (and, if necessary, the red G2 control on the C.R.T. base panel) to obtain a low brightness level of the raster.
- 4. Free the deflection yoke in its housing by pulling the two clamp levers back to their intermediate position (not fully back). This permits axial movement of the deflection yoke whilst preventing unwanted rotation.
- 5. Set the deflection yoke fully forward in its housing by rotating the yoke axial position control fully clockwise. Observe the areas X and Y on the screen (see Fig. 6), disregarding the appearance of the rest of the screen. If the areas X and Y are impure (bluish and greenish), follow the adjustment method A. If the areas X and Y are not impure (i.e. if they are red), set the deflection yoke fully backward in its housing by rotating the yoke axial position control fully anti-clockwise, then follow the adjustment method B.
Fig. 6—Receiver screen, showing areas X and Y
Method A—starting with the deflection yoke fully forward (nearest screen)
Adjust the colour purity lever to equalise the degree of impurity in the areas X and Y. Disregard the appearance of the rest of the screen at this stage.
- 7. Gradually rotate the yoke axial position control anti-clockwise while at the same time re-adjusting the colour purity lever to keep the degree of impurity in the areas X and Y always equal. The impurities in the areas X and Y will diminish as the yoke is moved backward and will disappear together provided the colour purity lever is being correctly re-adjusted as just described.
- 8. When the areas X and Y have become a pure red, check the purity over the whole of the screen. If necessary, move the yoke further back (without adjusting the colour purity lever), stopping as soon as the entire screen becomes a pure red. The final position of the yoke must be as far forward as possible, consistent with good overall purity.
- 9. Switch off the red gun and switch on the green gun. If necessary, adjust the green G2 control to obtain a low brightness level. Check that the entire screen is a pure green.
- 10. Switch off the green gun and switch on the blue gun. If necessary, adjust the blue G2 control to obtain a low brightness level. Check that the entire screen is a pure blue.
Note: If necessary, move the deflection yoke a little further back to obtain optimum purity during steps 9 and 10 above. Do not move the yoke further back than is absolutely necessary.
- 11. Switch on all three guns. Secure the deflection yoke in its housing by pushing the two clamp levers fully forward. Reconnect the fly-lead PC1 and reconnect the fly-lead PC2 to pin 'a'. If the setting of any of the G2 controls was altered during purity adjustment, it will now be necessary to adjust the grey scale tracking (see Section H).
- 12. After completing the purity adjustments, tune the receiver to a cross-hatch pattern from a pattern generator and check that the static correction is satisfactory (i.e. red, blue and green cross-hatch lines superimposed in the centre of the screen). If necessary, make small adjustments to the fourpole and/or six-pole field levers as described under the heading "Static correction adjustments".
Method B-starting with the deflection yoke fully back (away from screen)
- 6. Adjust the colour purity lever to equalise the degree of impurity in the areas X and Y. Disregard the appearance of the rest of the screen at this stage.
- 7. Gradually rotate the yoke axial position control clockwise while at the same time re-adjusting the colour purity lever to keep the degree of impurity in the areas X and Y always equal. The impurities in the areas X and Y will diminish as the yoke is moved forward and will disappear together provided the colour purity lever is being correctly re-adjusted as just described.
- 8. When the areas X and Y have become a pure red, move the yoke further forward (without adjusting the colour purity lever), while observing the entire screen area. As the yoke is moved forward, the whole of the screen should become a pure red. Continue moving the yoke forward until impurities just begin to re-appear, then move the yoke back just sufficiently to restore the pure red raster. The final position of the yoke must be as far forward as possible consistent with good overall purity.
The remainder of Method B is the same as steps 9–12 of Method A which must now be carried out.
Dynamic correction adjustments
The receiver must be allowed to warm up for at least one hour before commencing the dynamic correction adjustments. During this warm-up period a picture or reasonably bright raster should be displayed to enable the C.R.T. shadowmask to reach its normal operating temperature.
Caution: Some parts of the circuitry on the dynamic correction panel operate at high potential. Use a non-metallic trimming tool for adjustments.
- Tune the receiver to a cross-hatch pattern from a pattern generator. Adjust the receiver controls for a medium brightness display. Check that the static correction is satisfactory (i.e. red, blue and green cross-hatch lines superimposed in the centre of the screen). If necessary, make small adjustments to the four-pole and/or the six-pole field levers as described under the heading "Static correction adjustments". Good static adjustment must be achieved before commencing the dynamic correction adjustments.
- 2. Switch off the green gun of the C.R.T. (gun switch located on C.R.T. base panel).
- 3 Adjust the core of the line symmetry control (L1504) to superimpose the red and blue vertical cross-hatch lines at the ends of the horizontal axis of the screen (see Fig. 7a).
- 4. 22 inch receivers
Set the field symmetry parabola control (R1539) fully clockwise (viewed from the print side of the panel). Adjust the field symmetry tilt control (R1541) to superimpose the red and blue central vertical lines (see Fig. 7b). If necessary, slightly "back-off" R1539 from its fully clockwise position to obtain optimum results.
26 inch receivers
Adjust the field symmetry tilt control (R1541) in conjunction with the field symmetry parabola control (R1539) to superimpose the red and blue central vertical lines (see Figs. 7b and 7c).
- Unplug PC3. Adjust the core of the line balance control (L1516) to remove "crossover" of the red and blue central horizontal lines, leaving only "parabola" error (see Fig. 7d (before adjustment) and Fig. 7e (after adjustment)).
- Connect the twist compensation plug (PC3) to positions 'a', 'b' and 'c' in turn and leave it in the position which gives optimum coincidence of the ends of the red and blue central horizontal lines (see Fig. 7e).
Note: Plug PC3 has two positions 'b'—these are electrically the same.
Adjust the field balance-top control (R1528) to superimpose the red and blue horizontal lines at the top of the vertical axis of the screen (see Fig. 7f).
8. Adjust the field balance-bottom control (R1529) to superimpose the red and blue horizontal lines at the bottom of the vertical axis of the screen (see Fig. 7g). Finally, switch on the green gun.
H-GREY SCALE TRACKING
(see Figs. 1 and 2 for layout of controls)
The grey scale tracking adjustments should be carried out in subdued lighting conditions.
Dark grey tones
- 1. Tune the receiver to a stationary picture, preferably a test-card transmission or a pattern generator display incorporating a "staircase" grey-scale pattern.
- 2. Connect the fly-lead PC2 (on the decoder panel) to pin 'b' to remove the colour (if any). Unplug the fly-lead PC1 (on the decoder panel) to remove the luminance signal.
- Connect a d.c. voltmeter between chassis and TP2 on the decoder panel. Adjust the brightness control for a meter reading of 1.35 volts. The brightness control must then be left undisturbed during the following steps 4, 5 and 6.
- 4. Switch off the green and blue guns of the C.R.T. (leaving red on). Adjust the red G2 control to obtain a barely visible red raster.
- 5. Switch off the red gun and switch on the green gun. Adjust the green G2 control to obtain a barely visible green raster.
- 6. Switch off the green gun and switch on the blue gun. Adjust the blue G2 control to obtain a barely visible blue raster.
- Switch on all three guns and restore the luminance signal by reconnecting PC1. Check that the picture has good neutral grey tones. If necessary, slightly re-adjust the blue G2 control and/or the green G2 control to obtain correct grey tones. (Do not re-adjust the red G2 control.) Finally, restore the colour by reconnecting PC2 to pin 'a'.
White tone
The controls for setting the "white tone" in the grey scale tracking procedure are accurately adjusted during manufacture of the receiver. The following instruction is given for guidance only, since it is necessary to use special equipment to obtain precise results.
Tune the receiver to a pattern generator and display a pattern containing a large area of white. Alternatively, tune to a transmission containing an area of white, e.g. test-card F. Adjust the green drive control (R6094) and/or the blue drive control (R6106) to obtain a neutral white.
J-DECODER ALIGNMENT
(see Fig. 8 for layout of controls etc.)
Introduction
Three methods of decoder alignment are described. Method A can be performed using any good pattern generator with a standard colour bar output (or a colour bar test transmission) in conjunction with an oscilloscope display. Methods B and C use a Philips pattern generator (type PM5506, PM5508 or PM5509). Each of these generators provide special test patterns to enable decoder alignment to be performed using the receiver screen as an indicator, therefore Methods B and C will generally prove quicker and more convenient than Method A. Many of the decoder preset adjustments are inter-dependent.
Many of the decoder preset adjustments are inter-dependent, therefore when any decoder re-alignment is required it is recommended that the entire procedure for the chosen method is carried out in the sequence given.
Before commencing decoder alignment, engineers should ensure that all other preset adjustments are correctly set, including the grey scale tracking.
Method A
Eauipment reauired
Pattern generator with standard colour bar output (not required if transmitted colour bars are available)
Oscilloscope with high impedance (10MQ) probe
D.C. voltmeter (0–10V) 100nF capacitor 270pF capacitor 100pF capacitor 90kΩ resistor (e.g. 68kΩ and 22kΩ resistors in series) 10kΩ resistor 6k8Ω resistor (optional) Shorting link Trmming tools
Procedure
- 1. Connect the receiver to the pattern generator and display standard colour bars. (Alternatively, tune the receiver to a standard colour bar test transmission). Adjust the contrast and brightness controls to a normal viewing level.
- Set the customer's colour control to its mid-position. If the setting of the preset saturation control R6012 has been disturbed (or if this control has been replaced) it should be readjusted to its mid-position.
- 3. Unplug the fly-lead PC2 to disable the colour killer. Unplug the fly-lead PC1 to remove the luminance signal.
- Connect a 100nF capacitor (with leads as short as possible) between TP4 and chassis. Connect a 90kΩ resistor between TP4 and TP6. Connect a shorting link between TP10 and TP11. The colours will now be out of lock.
- Adjust the A.C.C. level control R6058 to give a moderate level of colour saturation on the receiver screen. (This is a temporary setting of R6058 to prevent over-loading during the initial stages of alignment and is different to the final setting which is made in step 8 of the alignment procedure).
- 6. Adjust the reference oscillator trimmer C6045 for minimum colour slip (colour bars almost stationary) then remove the shorting link from TP10/TP11.
7. Adjust the d.c. balance control R6068 for minimum colour slip (colour bars almost stationary).
Note: The receiver takes a few seconds to respond to adjustment of R6068.
If this is found to be a disadvantage, the time taken to respond can be shortened by connecting a 6k8Ω resistor across C6060. Remove the 6k8Ω resistor after adjusting R6068.
- 8. Connect the d.c. voltmeter between TP5 and chassis. Adjust the A.C.C. level control R6058 for a meter reading of 4.0 volts then disconnect the meter.
- 9. Disconnect the 100nF capacitor and 90kΩ resistor. The colours should lock. Reconnect PC2 to pin 'a' (leave PC1 disconnected).
- Connect the oscilloscope to TP4 via a high impedance (10MΩ) probe. Adjust the 'scope to display the burst signal (see Fig. 9). Adjust the A.C.C. gain control R6054 for a burst amplitude of 1.5 volts peak-to-peak, then disconnect the 'scope.
Fig. 9—Burst waveform
- 11. Temporarily convert the decoder to "simple PAL" operation by connecting a shorting link across L6016.
- 12. Connect the oscilloscope to TP8. To reduce the effect of H.F noise (e.g. 4.43MHz subcarrier) on the display, the 'scope connection should be made via the filter circuit shown in Fig. 10. This filter circuit should be used for all 'scope connections in the remainder of the alignment procedure
Fig. 10—Filter circuit for oscilloscope connection
Fig. 11—Decoder alignment waveforms
- 13 Ensure that the customer's colour control is still set to its midposition. Set the brightness control to maximum to reduce "crushing" of the waveform. Switch off all three guns of the C.R.T. to prevent beam current limiter operation (gun switches located on C.R.T. base panel). Adjust the contrast control to approximately 1/2 of its maximum setting.
- 14. Adjust the 'scope to display the line-rate waveform at TP8 in such a way that two consecutive lines are superimposed on the 'scope screen, then adjust the core of the burst phase coil L6039 for optimum coincidence of the "double pictures" seen on the 'scope—see Figs. 11A (before adjustment) and 11B (after adjustment).
- 15. Transfer the 'scope connection to TP7. Adjust the 'scope to display the line-rate waveform at TP7 in such a way that two consecutive lines are superimposed on the 'scope screen, then adjust the quadrature control R6042 for optimum coincidence of the "double pictures" seen on the 'scope—see Figs. 11C (before adjustment) and 11D (after adjustment). If more than a small adjustment of R6042 was required, reconnect the 'scope to TP8 and repeat steps 14 and 15.
- 16. Remove the shorting link from L6016.
- 17. With the 'scope still connected to TP7, adjust the cores of the PAL-D matrix phase coils L6016 and L6021 for optimum
coincidence of the "double pictures" seen on the 'scope—see Figs. 11E (before adjustment) and 11F (after adjustment.) These coils should be adjusted alternately in small steps in such a way that when the adjustments are completed, the cores are both at approximately the same position in their formers.
- 18. Connect a 270pF capacitor between pin 11 of U6200 and chassis. Adjust the PAL-D matrix amplitude control R6019 for optimum coincidence of the "double pictures" seen on the 'scope—see Figs. 11E (before adjustment) and 11F (after adjustment), then disconnect the 270pF capacitor. If more than a small adjustment of R6019 was required, repeat steps 17 and 18. Disconnect the 'scope and 'scope filter circuit after the adjustments have been completed.
- 19. Switch on all three C.R.T. guns and reconnect PC1.
- 20. Tune the receiver to a colour transmission. Adjust the contrast and brightness controls to a normal viewing level. Set the customer's colour control to maximum, then adjust the preset saturation control R6012 to obtain slightly oversaturated colours. Finally, check that a reasonable range of colour saturation is obtainable with the customer's colour control.
Method B
Equipment required
Philips pattern generator type PM5506 or PM5508 Oscilloscope with high impedance (10MΩ) probe C IIII D.C. voltmeter (0–10V) 100nF capacitor 90kΩ resistor (e.g. 68kΩ and 22kΩ resistors in series) 6k8Ω resistor (optional) Shorting link Trimming tools
Procedure
Steps 1–10 of Method B are the same as steps 1–10 of Method A. The remainder of Method B is as follows :---
- 11. Reconnect PC1. Switch the generator to the "DELAY" pattern. Adjust the customer's brightness, contrast and colour controls to display the pattern at a satisfactory viewing level.
- 12. Adjust the PAL-D matrix amplitude control R6019 for minimum "venetian blind" effect in bar 3. (Ignore the overall colour of bar 3)
- 13. Adjust the cores of the PAL-D matrix phase coils L6016 and 16021 for minimum "venetian blind" effect in bar 2. (Ignore the overall colour of bar 2). These cores should be adjusted alternately in small steps in such a way that when the adjustments are completed, the cores are both at approximately the same positions in their formers. If necessary, repeat steps 12 and 12 for optimum results
- 14. Switch the generator to the "PHASE" pattern. Adjust the core of the burst phase coil L6039 to obtain the same colour in the upper and lower halves of bar 3 (magenta).
- 15 Adjust the quadrature control R6042 to obtain the s colour and brightness in the upper and lower halves of har ? (green). If necessary, repeat steps 14 and 15 for optimum results.
- 16. Adjust the preset saturation control R6012 as described in step 20 of Method A.
Method C
Equipment required
Philips pattern generator type PM5509 Oscilloscope with high impedance (10MΩ) probe D.C. voltmeter (0-10V) 100nF capacitor 90kΩ resistor (e.g. 68kΩ and 22kΩ resistors in series) 6k8Ω resistor (optional) Shorting link Trimming tool
Steps 1-10 of Method C are the same as steps 1-10 of Method A.
Note: The colour "BAR" pattern provided by the Philips PM5509 generator normally has a white reference section across the lower part of the display. If desired, the pattern may be changed to full length colour bars by making a simple internal adjustment to the generator (refer to the generator handbook for details), but either version of the "BAR" display is suitable for steps 1–10.
The remainder of Method C is as follows:------------------------------------
- 11. Reconnect PC1. Switch the generator to the "DEM" pattern. Adjust the customer's brightness, contrast and colour controls to display the pattern at a satisfactory viewing level.
- 12. Adjust the PAL-D matrix amplitude control R6019 for minimum "venetian blind" effect in bar 3. (Ignore the overall colour of bar 3).
- 13. Adjust the cores of the PAL-D matrix phase coils L6016 and L6021 for minimum "venetian blind" effect in bars 1 and 4. (Ignore the overall colours of the bars). These cores should be adjusted alternately in small steps in such a way that when the adjustments are completed, the cores are both at about the same positions in their formers. If necessary, repeat steps 12 and 13 for optimum results.
- 14. Adjust the core of the burst phase coil L6039 until bar 3 is a neutral grey (i.e. the same as the lower reference part of the test pattern).
- 15. Adjust the quadrature control R6042 until bar 4 is a neutral grey (i.e. the same as the lower reference part of the test pattern). If necessary, repeat steps 14 and 15 for optimum
- 16 Adjust the preset saturation control R6012 as described in step 20 of Method A.
Each individual circuit unit on the I.F. panel is pre-aligned during manufacture using special equipment. If a replacement unit or tuner is fitted no alignment will be required. Engineers are advised not to disturb the trimming of R.F. or I.F. circuits (except the sound guadrature coil L5025 which, if necessary, may be adjusted as described below).
Sound guadrature (L5025)
- Tune the receiver to a test transmission (or pattern generator signal) with sine-wave sound modulation (i.e. continuous audio tone).
- (b) Connect an oscilloscope across the loudspeaker and adjust the 'scope to display the audio waveform. (If preferred, a 25Ω 2 watt resistor may be temporarily connected in place of the loudspeaker as a dummy load)
- (c) Adjust the volume control of the receiver for a waveform amplitude of approximately 4 volts peak-to-peak (this corresponds to a moderate sound level thus avoiding any wave-form distortion due to overloading).
- (d) Adjust the core of the sound quadrature coil L5025 for adjust the core of the sound quadratic con Leoco of the sound quadratic con Leoco of the sine-wave seen on the scope.
- (e) If more than a slight adjustment of L5025 was required repeat steps (c) and (d).
Page Nineteen
Page Twenty
Fig. 13-Power supply panel (BY01/BY02/HU01/HU02 versions)
On some panels 132 is type 206099 On some panels R51 is 100Ω
Fig. 14—Power supply panel — component view (BY02/HU02 versions) On BY00 panels, a four-diode encapsulation (D4005) is used in place of D4091-94 and R4015/17 are omitted.
On BY01/HU01 panels, R4015/17 are mounted on L4009.
Page Twenty-one
Page Twenty-two
Fig. 15 Line scan panel (BY0/BY03/HU02/HU03 versions)
Page Twent
On some panels a Ferrox bead (FX64) is added on the apode lead of D63.
Fig. 18 - Timebase panel (BA00/
panel (8A00/HU00 versions)
Fig. 21—Dynamic correction panel (BY00/HU00 versions) and deflection assembly
Fig. 21—Dynamic correction panel (BY00/HU00 versions) and deflection assembly
Fig. 22-C.R.T. base panel - component view (BY00/BY01/BY02/HU02 versions)
Fig. 23—C.R.T. and base panel (BY00/BY01/BY02/HU02 versions)
Page Thirty-one
Fig. 25 - Decoder panel (BAC
(BA00/BA01/HU01 versions)
On BA01/HU01 panels a 1k Ω resistor (R22) is added between pin 4 of IC 510 and pin 3 of plug 5Z. This provides interstation sound muting on certain models with remote control.
Fig. 29 - I.F. panel (B.
Page Thirty-five
Fig. 31 — Waveforms 20 — 39
Fig. 32 — Waveforms 40 — 59
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