TF930 & TF960
3GHz & 6GHz Universal Counters
SERVICE GUIDE
1
Table of Contents
Specifications 2
Safety 5
General 6
Frequency Calibration 7
C Input Threshold Adjustment 8
Diagnostic Notes 9
Battery replacement 11
Parts List 12
2
Specifications
Input Specifications
Input A
Configurable options
Input coupling:
Input impedance:
Attenuation:
Active edge:
Low pass filter:
Trigger threshold:
AC or DC
1MΩ or 50Ω
1:1 or 5:1
Rising or falling, or width high or low
Filter In (~50kHz cut-off) or Out
Var iable thr es hold for both DC and AC coupling
Input Impedance:
1MΩ//25pF (DC or AC coupled)
or 50Ω nominal (AC coupled only).
Frequency Range:
< 0.001Hz to >125MHz (1MΩ, DC coupled).
< 30Hz to >125MHz (1MΩ, AC coupled).
< 500kHz to > 125MHz (50Ω, AC coupled).
Trigger Threshold:
DC coupled:
AC coupled:
0 to 2V (1:1 attenuation) or 0 to 10V (5: 1 at tenuation).
Average ± 50mV (1:1 attenuation) or ± 250mV (5:1 a ttenuation).
Sensitivity: Sinewave - 15mVrms 30Hz to 100MHz, 25mV to 125MHz
at optimum threshold adjustment .
Input B
Input Impedance:
50Ω nominal (AC coupled).
Frequency Range: < 80MHz to >3GHz.
Sensitivity: 12mV
rms 80MHz to 2GHz, 25mVrms to 2.5GHz, 50mVrms to 3GHz.
Maximum Input Signal: < 0dBm recommended, +13dBm (1V
rms) maximum.
Input C (fitted to TF960 only)
Input Impedance:
50Ω nominal (AC coupled) in-band. 250kΩ at DC.
Frequency Range: < 2GHz to >6GHz (typically 1.8GHz to 7.5GHz).
Sensitivity: 25mV
rms (–19dBm) 2GHz to 6GHz.
Maximum Input Signal: < +16dBm (1.5Vrms) recommended. Damage level +25dBm (4V
rms).
External Reference Input
Input Impedance:
>100kΩ, AC coupled.
Frequency: 10MHz.
Signal Level:
TTL, 3V
pp
to 5Vpp CMOS or 1 to 2Vrms sinewave.
Maximum Input Voltage
Inputs A, B, C, and
External Reference:
30VDC; 30Vrms 50/60Hz with respect to earth gr ound
Note that the inputs will not be damaged if subjected to an acc idental short-term connection to a 50/60Hz
line voltage not exceeding 250V
rms, or 250V DC.
3
Timebase
Measurement Clock: 50MHz.
Internal Reference oscillator: 10MHz TCXO with electronic calibration adjustment.
Oscillator Temperature Stability: Better than ± 1ppm over rated temper at ure range.
Initial Oscillator Adjustment Error: < ± 0.2ppm at 21ºC.
Oscillator Ageing Rate: < ± 1ppm first year.
Calibration adjustment range: > ± 8ppm.
Measurement Functions
Frequency (Inputs A, B or C)
A Input Frequency Range:
< 0.001Hz (DC coupled) to >125MHz
B input Frequency Range:
80MHz to >3000MHz.
C input Frequency Range:
<2Ghz to >6GHz.
Resolution:
up to 10 digits (see below) or 0.001Hz
Period (Inputs A, B or C)
A Input Period Range:
8ns to 1000s (DC coupled)
B input Period Range:
0.333ns to 12.5ns
C input Period Range:
0.166ns to 0.5ns
Resolution: up to 10 digits (see below)
Pulse Width Modes (Input A only)
Functions:
Width high or low, ratio H:L (high time to low time) or duty cycle.
Pulse Width Range:
40ns to 1000s
Averaging:
Automatic within measurement time selected, up t o 50 pulses.
Resolution: 20ns for one pulse; up to 1ns or 10 digits with multiple pulse
averaging. 0.01% for Ratio H:L and Duty Cycle.
Total Count (Input A only)
Count range:
1 to 9 999 999 999
Minimum pulse width:
8ns
Frequency Ratio B:A
Resolution: Equal to the resolution of the two frequency measurements.
If the ratio exceeds ten digits, displays six digits plus exponent.
Measurement Time
Selectable as 100s, 10s, 1s or 0.3s. The instrument displays the average value of the input
signal over the measurement time selected, updated every 2s, 1s, 0.5s or 0.3s respectively. The
hardware captures the count values and continues measuring without any dead time.
Resolution
The displayed resolution depends upon measurement time and input f r equency. The basic
resolution of period is 8 digits for every 2 seconds of m easur ement time. Frequency resolution is
the reciprocal of period resolution. Usable resolution can be r educed by noise at low fr equencies.
Accuracy
Measurement accuracy is timebase accuracy + measurement resolut ion + 2 c ounts.
4
Operating Facilities
Noise Filter (Input A only)
The Filter key controls a low pass filter, with a cut-off frequency of about 50kHz, to assist in
obtaining stable readings at low frequencies.
Hold
Pressing the Hold key will hold the current measured value in the display, with the Hold indicator
on, until the Hold key is pressed again. The measurement continues in the bac kground when
Hold is on. A long press on the Hold key clears old data and restarts the measurement.
Intelligent Power Switching
The unit automatically selects the best available power source of AC adaptor, USB or battery.
Intelligent switching avoids discharging the batter y overnight when operated from externally
switched AC power.
A press-to-measure facility allows a quick measurement to be made by pressing a function select
key which will power the instrument up in the corresponding function. The instrument will
automatically switch off 15 seconds after the last key-press.
Remote Control
All capabilities can be controlled remotely and measur em ents r ead t hr ough a USB port.
The instrument can be powered (but the battery cannot be charged) by the USB host.
Interface: Serial port emulation over USB.
Current consumption: < 100mA (<5mA if AC adaptor power is present)
Command set: Instrument specific. TF830 and TF930 compatible.
Power Requirements
The instrument has fixed internal rechargeable batteries and is supplied with a universal voltage
external mains adaptor with interchangeable UK, Euro, Australian and US power connectors.
Battery Type: Three 2500mAh NiMH cells.
Battery Operating Life: Typically 24 hours
Low Battery Indicator: ‘Lo Bat' shows in display when approximately 10% of battery life remains.
Recharge Time: < 4 hours
Adaptor Supply range: 85 to 240V, 50 or 60 Hz,
Power consumption: 5W max at DC input to unit; 15VA max at AC adaptor input (charging).
General
Display: 10 digit LCD, 12.5mm high (0.5”). Annunciators show input
configuration, operating m ode, m eas ur em ent units and gate time.
Operating Range: +5°C t o + 40° C, 20% to 80% RH
Storage Range:
–20°C to +60°C
Environmental: Indoor use at altitudes up to 2000m, Pollution Degree 2
Size: 260mm(W) x 88mm(H) x 235mm(D)
Weight: 1050 gms (plus 170 gms AC adaptor)
Electrical Safety: Complies with EN61010-1
EMC: Complies with EN61326
5
Safety
Universal Counter
This instrument is Safety Class III acc or ding to IEC classification and has been designed to meet
the requirements of EN61010-1 (Safety Requirements for Electrical Equipment for Measurement,
Control and Laboratory Use).
This instrument has been tested in accordance with EN61010-1 and has been supplied in a safe
condition. This instruction manual contains some information and warnings which have to be
followed by the user to ensure safe operation and to retain the inst r um ent in a safe condition.
This instrument has been designed for indoor use in a Pollution Degree 2 environment in the
temperature range 5°C to 40°C, 20% - 80% RH (non-condensing). It m ay occasionally be
subjected to temperatures bet ween +5° and -10° C without deg r adation of its safety. Do not
operate while condensation is present.
Use of this instrument in a manner not s pecified by these instructions may impair the safety
protection provided.
WARNING!
All accessible parts will be at the same voltage as the outer of the signal input sockets. I n
particular, note that the shell of the USB connector is galvanically connected to the body of the
N-type and BNC inputs and will therefore be at earth ground potential when the USB port is
connected to a desktop PC. However, to maintain user safety under all other circumstances it is
essential that no input is connected to a voltage above 30Vdc or 30Vrms with respect to earth
ground
which is the limit of Safe Extra Low Voltage (SELV) by IEC definition. Note that
although the inputs will withstand short-term accidental connection to an AC line voltage up to
250Vrms, 50/60Hz, users will be at risk if the instrument 'ground' is connected to such hazardous
voltages.
The instrument shall be disconnected f r om all voltage sources before it is opened for any
adjustment, replacement, m aint enance or repair. Any adjustment, maintenance and repair of the
opened instrument under voltage shall be avoided as far as possible and, if inevitable, shall be
carried out only by a skilled person who is aware of the hazard involved.
Do not wet the instrument when cleaning it.
The following symbols are used on the instrument and in this manual.
Adaptor/Charger
The adaptor/charger supplied has a universal input voltage rating of 100-240VAC, 50/60Hz. It is
a Class II (double insulated) device, fully approved to EN 60950-1 (2001), UL 60950 (UL listing
E138754) and AS/NZS CISPR:2002 (C-Tick).
Use ONLY the AC adaptor /charger provided by TTi with the instrument.
Use of any other power source may damage the unit and will void the
warranty.
Direct Current
CAUTION – ref er t o ac com panying documentation.
Damage to the instrument may occur if these precautions are ignored.
meaning that the marked t er m inal is connect ed to accessible
conductive parts.
6
General
Service Handling Precautions
Service work or calibration should only be carried out by skilled engineers using high quality test
equipment. If the user is in any doubt as to his c om pet enc e t o carry out the work, the instrument
should be returned to the manufacturer or their agent overseas for the work to be carried out.
This simplified service guide only details the routine calibration procedure and the dismantling of
the instrument to PCB assembly level. If a PCB assembly is suspected as being faulty it should
be returned to the manufact ur er or t heir agents overseas for repair or replacement. The Parts
List gives the part numbers of each PCB assembly, together with the mechanical parts and
fasteners that can be easily replaced by the user.
Dismantling the instrument
Note that calibration of the oscillator frequency does not require the instr um ent to be opened.
Refer to the procedure in the next section.
1. Disconnect the instrument from all input s ignals, the USB connection and the AC adaptor.
2. Unclip the front bezel by gently pulling the centre of each long edge up and forward.
3. The case halves are held together by 4 plastic push-ri vets.
4. Lift off the case upper, leaving the front and rear panels in the base of the unit.
The instrument can be operated in this condition for fault diagnosis. If adjustment of the C
input threshold setting is all that is requir ed, no further dismantling is necessary.
5. Otherwise, disconnect the ribbon cable from t he r ear of the Main (front panel) PCB.
6. Before removing the rear panel or the Batter y/USB PCB, note t he posit ion of the
grounding spring attached to the USB socket. The PCB is attached to the case lower with
4 screws. To avoid short-circuiting the batteries, do not place this PCB on a conducting
surface. When reassembling, take care not t o damage the USB spring.
7. To remove the Main PCB from the front panel, first pull the knob off its shaft, lift the Front
Panel assembly from the base of the unit and lay it face down on a soft surface to avoid
damaging the LCD. Keeping the metal panel flat and upside down, remove the screws
holding the PCB to the front panel and lift it off, leaving t he loose keycaps in the metal
panel. Collect and store the keycaps for reassembly.
8. The C input PCB may be separated from the Main PCB by removing the nut from t he N type connector and pulling the PCB backwards off the connecting pins. O n reassembly,
align these pins carefully. The washer fits between the flange of the N-type connector and
the rear of the Main PCB. Retighten the nut firmly, to put the washer under compression.
9. Reassemble in the reverse order. Take care when reassembling the Main PCB to the
metal front panel that all of the keycaps are cor r ec t ly aligned. Connect the ribbon cable
and test the unit for correc t oper ation before reassembling the case.
Use the blade of a small screwdriver to remove
the snap-lock rivets as follows:
First, ease out the head of the rivet using a f ine
screwdriver blade under the edge of the head
(Fig.a). W ith the rivet head fully out, the body
of the rivet can now be eased out with the
screwdriver blade and removed completely
(Fig.b). To re-ass emble, fully re-inser t the body
of the rivet then push in the head to lock it.
7
Frequency Calibration
Equipment Required.
A Standard Frequency Source with accuracy ±0.05ppm or better at a frequency of 5MHz or
10MHz. Ideally use a 10MHz Rubidium source. The procedure below assumes 10MHz.
TF930 and TF960 Reference Oscillator Specification.
Temperatur e coefficient:
± 1 ppm over the full operating temper ature range.
Ageing (first year):
± 1 ppm.
Initial accuracy:
± 0.2ppm (at 23ºC) when new.
Recommended recalibration accuracy:
±0.05ppm
Initial Set-up.
Place the unit in the controlled temperature calibration environment and switch on, r unning from
its batteries. The Bat annunciator should show. Allow at least 30 minutes t o ac hieve temper at ure
equilibrium.
If Lo Bat is shown, connect the mains power unit and allow the unit to charge, which may take up
to four hours. Wait a further one hour after char ging completes to allow any internal temperature
rise to dissipate.
Manual Reference Oscillator Frequency calibration.
Connect the standard frequency signal to t he A input.
If the unit is on, press Operate to switch it off.
Hold down the Input A/B key and press Operate.
Release Operate when the display appears, then release Input A/B; the display should show
Cal ? Y n.
Press the left hand Measurement Time key to select Yes.
An annunciator C should be flashing in the display.
In calibrate mode an extra digit of resolut ion is shown (to speed t he process), but note that the
last digit may be in error by more than one count.
Select 50Ω Impedance (with the default AC Coupling) and centre the Threshold control at the
AC marker. The display should show the frequency of the standard source, s ubj ec t t o any precalibration inaccuracy.
If the reference signal is large it may be necessary to select the 5:1 attenuator.
The calibration setting is adjusted by pressing t he Frequency and Period keys.
The Frequency key raises the oscillator frequenc y and makes the displayed value lower.
The Period key lowers the oscillator frequency and makes the displayed value higher.
The amount of adjustment for each press depends on the Measurement Time setting.
With 0.3s M easur ement Time selected, note the difference between the reading and
10.00000MHz and press either the Frequency or Period key to get a closer r es ult . Each step
moves the oscillator by about 0.2ppm (2Hz at 10MHz). Repeat as needed, aiming to be within
about 4Hz, then move to the next step.
Set the Measurement Time to 1s and repeat the process. The adjustment per step is now a
decade smaller and multiple presses may be needed. The measurement restarts aft er eac h set
of key presses. It will take a few seconds f or t he reading to stabilise because of the settling t ime
of a filter on the control voltage. Aim to be within about 0.5Hz and then move to the next step.
Set the Measurement Time to 10s and wait for the measurem ent t o c om plet e (Measure stops
flashing and an extra digit appears). Check that the reading is within ±0.05ppm (0.5Hz), m aking
further adjustment if needed (waiting for Measure to stop flashing after each adjustment). Each
key press moves the oscillator about 0.002ppm (2 counts in the last digit).
Although the calibration value can be set to this precision, this is mor e acc ur at e than is
necessary, considering the medium term stability of the osc illator. The initial accuracy is specified
at ±0.2ppm on despatch from the factory, but after a unit has aged for a year or more, it is
8
reasonable to set the calibration value to within ±0.05ppm. This is typical of the variation over
normal room temperature chang es dur ing the course of a day.
Finally, press and hold down the Width key for a few seconds to store the c alibrat ion value in
EEPROM.
Hold the key down until the C annunciator stops flashing and stays off.
Note: To exit calibration without saving the new value, simply press Operate to switch off.
Press Operate to switch the unit off, wait a few seconds and then press it again to turn the unit
back on.
Select 50Ω Impedance (and if necessary 5:1 attenuator). Set the Measurement Time to 10s.
Check that the reading is the same ( within 1 count) t o pr ove that the new calibration value has
been stored.
If desired, set the Measurem ent Time to 100s, and ( after Measure stops flashing) record the
final reading.
C Input Threshold Adjustment
Introduction
The prescaler used in the C input will self-oscillate if no signal is applied. To avoid distracting the
user a signal level detector circuit senses the absence of a useable input signal and disables the
divider to show 0.0 on the display. There is a preset adj us t m ent in this circuit, which might
possibly drift with time. If the threshold is too low, then the unit will show a random count around
7GHz whenever the C input is selected without a signal. If the threshold is set too high, then the
usable sensitivity of the input is impaired.
Equipment required
2 to 6GHz signal generator with reasonably accurate calibrated level around 5 to 15mV.
A microwave grade N-type to N-type coaxial lead. (Do not use a BNC type with adapters).
Procedure
To adjust the s et ting, first dismantle the unit to the stage of removing the top cover. Identify the C
input PCB, the variable adjustment, a two pin link LK1 and a surface m ount LED near the link.
With no signal applied, switch the unit on and s elect t he C input. If 0.0 is displayed, short
together the two pins of LK1. The unstable count should appear; if not, then there is a fault
present.
Apply a CW signal at 3GHz and a level of 6mV. Using a suitable trimming tool, turn the variable
adjustment clockwise until the LED lights (and a count appears on t he display). Then turn t he
variable adjustment slowly anti-clockwise until the LED just extinguishes.
Increase the signal generator level until the LED lights and a count shows; t his should be before
12mV. The count should be cor r ec t by 15mV. Decrease the signal generator level to 4mV and
check that the LED extinguishes and the display shows 0.0. Check at ot her frequencies across
the range 2 to 6GHz that the LED remains off at a signal level of 4mV.
Note
This is a general purpose setting which will achieve rated sensitivity, but at some frequenc ies t he
level detector will permit a count with a signal level below that needed to produce a correct count.
Some customers may prefer a higher threshold setting, so that a count does not s how until it is
correct. This setting can be perf or m ed at the customer ’s prefer red frequency, but this may
possibly mean that the unit does not meet its sensitivity specification at other frequencies.
9
Diagnostic Notes
This instrument uses many small surfac e m ount components in critical high frequency circuits.
Component level fault finding and repair is not possible and service is normally perform ed by
identifying the faulty PCB assembly and returning it to the manufacturer or t heir field service
agent for repair or replacement. The only field repair possible is the replacement of the
rechargeable battery cells. The following notes are intended to help in identifying which of the
PCBs is faulty.
AC Adaptor
The output voltage of the adaptor can be checked with a DVM: the outer sleeve is the negative
terminal and the voltage should be around 5.2 to 5.3V.
Initial Checks
First check that all keys are f r ee t o operate; if any one is stuck down, then the unit cannot
correctly identify keystrokes.
Now remove the top cover of the instrument as described up to s t ep 4 of the disassembly
procedure above.
First try disconnecting and then reconnecting t he r ibbon cable from the back of t he main PCB.
Inspect the insulation displacement connectors and check they are clamped together tight ly. If
intermittency is suspected, remove the Charger PCB and check the solder joints on the transition
header.
Otherwise, identify the faulty subsystem by checking t he following items in order.
Batteries
Measure the voltage of each cell; they should be similar and between 1.0V (discharged) and
1.45V (fully charged). If any cell delivers below 0.5V it is probably damaged and all three cells
must be replaced, either by field repair (see below) or service exchange.
There is a self resetting fuse in series with the battery. This component is a last resort prot ection
against fire and any failure indicates that another major fault has occurred.
Note in particular that this component MUST NOT be hand soldered as that will
almost certainly cause an internal short circuit which would negate the protection.
If the cells are charged, but t he unit will not func t ion t hen t he fault is almost certainly on the main
PCB. To check, use a DVM to measure the batt er y voltage on the charger PCB between the test
points T0V (to the right of the USB socket) and TV (in front of the large gold area on the PCB).
Then measure the voltage on the main PCB between T0V (in the bottom left hand corner) and
the hole for pin 1 of the unfitted power socket on the right hand edge of the PCB. If the sam e
voltage is present here, then the fault lies on the Main PCB.
Battery Charger
Connect the AC adaptor to the unit and switch it on. Check that the input voltage appears
between the test point T0V (to the right of t he USB socket) and the input to D2 on the rear-most
of the three gold heatsink areas.
There is a 2A surface mount fuse in the input circuit to this point. The AC adaptor supplied with
the instrument does not have sufficient current capacity to blow this fuse, so if it is open circuit
this indicates that an incorrect AC adaptor has been attached to the unit. Major consequential
damage should be assumed, so replace the whole PCB; do not just replace t he fuse.
If the battery voltage is below about 3.3V the charger should start autom at ically, and the yellow
lamp should show on the panel. The charger may also be started by pressing SW1 on the PCB.
If the charger is active, it will be possible to feel t hat D2 and Q 1 are warm within a few minutes. If
the charger is running but the lamp is not s howing then t he fault might be in the drive circuit, the
ribbon cable connections or the LED itself.
10
If a charge terminat ion fault is suspected, return the char ger PCB for replacement as it is not
safe to have the batteries continuously charged. There are four different charge t er m inat ion
circuits and an immediate recharge prevention circuit: do not at tempt diagnosis.
USB faults
Use the AC adaptor to power the unit while attempting to diagnose USB problems.
Many USB problems are actually PC configuration issues. The interface device on the charger
PCB is a USB to serial converter: remote control messag es ar e s ent t o the main system
processor on the Main PCB through an internal serial link. The counter appears as a COM port t o
the PC; this is not a “virtual” COM port it is a real one that happens to be connected by a USB
cable. Port properties such as the baud rate m ust be correctly configured from the PC end of the
link (details are in the User Manual).
The COM port number allocated is chosen automatically during the driver installation. The BIOS
of some older computers prevents proper operation of a USB connected port if the number
allocated is COM3 or COM4; if this happens, use Device Manager to manually configure it to
COM5 or higher. Note also that some old PC software will not communicate with ports above
COM15.
The interface device on the Charger PCB is responsible for the USB enumeration. If the PC
cannot detect the counter as a USB device, then the fault lies here. The switching logic will not
take power from the USB unless the port has been proper ly enumerat ed by the host PC.
If the PC can detect the USB device, but func t ional cont r ol of the counter is not possible then
(provided the baud rate etc. are correct ly conf igured) the fault lies with the processor on the Main
PCB, or possibly on the interconnection between.
Note that changing the USB/Charger PCB wil l change t he instrument’s USB serial number,
so it will appear t o be a di fferent unit to any PC, which will seek to reinstall the drivers.
Functional Faults
If there is a fault in any aspect of the operation of the A or B inputs, then the Main PCB should be
returned for repair or replacement.
For a TF960, if operation of the A and B inputs is correct, but the C input is faulty, then further
checks may be carried out to determine the locat ion. It may also be worth checking the soldering
on the interconnections.
Switch on the unit and select the C input.
Note: if the unit has been dismantled and t he Main PCB is hanging loose, take care not to
accidentally press one of the keys and change the operating m ode while handling the board.
With no signal applied to t he C input, s hor t together the two pins of LK1 on the C input PCB. An
unstable count (broadly in the region of 7GHz) should appear on the display.
If a count appears, then the cir cuits on t he Main PCB are funct ioning correctly and the fault lies
on the C input PCB. It is possible that the signal detector threshold setting is incorrect. I f suitable
test equipment is available, attempt the t hr eshold setting procedure below. Otherwise return the
C input PCB for replacement.
If no count appears, then ret ur n both PCBs for repair or replacement.
11
Battery replacement
The battery consists of three 2.5Ah NiMH cells. They are conservatively constructed and should
provide hundreds of charge-discharg e cycles. Extended st or age or use in high temperature
environments may reduce cell life. If it appears that t he disc har ge time has reduced significantly,
or if the cell voltages have become mismatched, then the cells may be replaced.
Replace all three cells simultaneously, using new cells of the same make and type.
Use only A or AF size 2.5Ah NiMH (Nickel Metal Hydride) rechargeable cells.
Do not use AA size cells. Do not use Nickel Cadmium cells.
Remove the top cover of the instrument and disconnect t he r ibbon cable from the rear of t he
Main PCB. Disconnect the AC adaptor.
Remove the old cells from the unit by cutting the tag s at tached t o the battery and then the tiewraps holding them to the PCB. Cut the tags; do not attem pt to unsolder them. Tape up the cells
to avoid accidental short circuits and dispose of safely.
Do not incinerate the cells, or place them with domestic waste.
Dispose of them in accordanc e with local regulat ions and facilities.
These cells are recyclable.
Early units may be fitted with cells having tags with connecting holes; these are attached to the
PCB with lengths of wire. Current production cells have tags without holes. These are attached
using standard 0.025” square connecting posts tak en from a SIL pin header. Clean up the
connections and fit new posts if required.
Note that there is a thermistor near t he c ent r e c ell which is used by the charger c irc uit t o sense
its temperature. Place a small amount of heatsink compound over the thermistor to ensure good
thermal conductivity.
Place the cells on the PCB, making sure that t hey are all corr ect ly oriented ( they all point in the
same direction) and that the tags are aligned with the correct connecting pads. Secure the cells
to the PCB with tie-wraps (only sufficiently tight to hold the cells – do not bend the PCB).
Finally wrap the tags around the 0.025” square posts and solder as quick ly as possible. It is
important not to overheat the seals of t he c ell.
As quickly as possible, confirm the polarities by using a DVM to check that the voltage between
the test points T0V (to the right of the USB socket) and TV (in front of the large gold heatsink
area) is equal to the sum of t he cell voltages – it s hould be between 3V and 4V.
Reattach the ribbon cable to the Main PCB. The unit should now be functional.
Attach the AC adaptor and provide power; it the cell voltages are low charging will start
automatically, in which case wait a few minutes until the cells are charged past the threshold.
Test the charge termination circuits as follows:
Press SW1 to start charging, then brief ly short LK1: c har ging should stop.
Press SW1 again, then briefly short LK2: charging should st op.
Place a shorting link across LK3 (to run the timer at test speed)
Note the time and press SW1 to start charging; char ging should stop in 45 to 55 secs.
Wait a further 60 secs t hen pr es s SW1 again; charging should not restart.
Disconnect the AC power and remove the test link across LK3. If any of these test fail, return the
PCB for repair or replacement.
Re-apply power, press SW1 and m onit or the first charging cycle by watching the yellow charge
indicator on the front panel. Charging m ust automatically stop within four hours. At the end of the
charging cycle check that the cell voltages are eq ual within ±50mV and that the temperature of
the three cells feels similar to the touch.
If charging does not aut om at ically stop, then it should be assumed that the old cells were
destroyed by a faulty charging circuit and the whole PCB should be returned f or r epair.
12
Parts List
Part Number
Description
Position
Common Items
51151-0820
AC ADAPTOR UNIV 5.2V/1A DC
(WI TH CONNECTORS)
44813-0410
PCB ASSEMBLY – CHARGER & USB - TF
(COMPLETE W ITH 10W CABL E)
20010-0258
RIVET SNAPLOK 3.6Dx2.7-3.6L G REY
FOR CASE
20010-0259
RIVET, SCREW TYPE
FOR FEET
20073-9801
SCREW No. 4x1/4 Plastite
CHARGER PCB TO CASE
20234-0100
SCREW M3x6 C/W WASHER
MAIN PCB TO FRONT PANEL
20662-0590
FOOT - BLACK RBS-1 - S/ADHESIVE
33143-0310
FOOT PLAIN (ROUND) BENCH CASE 2
33143-0320
FOOT BAIL HOUSING BENCH CASE 2
33143-0330
FOOT TILT BAIL BENCH CASE 2
31711-0210
BEZEL - BENCH CASE 2
33536-4380
CASE UPPER BENCH CASE 2
33536-4390
CASE LOWER BENCH CASE 2
33331-9790
REAR PANEL
37113-2183
KEYCAP 8X6MM GREY3 TF
37151-0483
KNOB 21MM D-SHAFT GREY3
38611-0010
COLLAR – BNC – FOAM
20653-0204
CABLE TIE 100 x 2.5mm
FOR BATTERIES
22010-0500
BATTERY 1.2V2.5Ah NiMH AF TAG
35358-0580
EARTHING SPRING USB
SUPPLIED W ITH CHARGER PCB
48511-1110CD
CD – UNIVERSAL PRODUCT DAT A
INCLUDES USB DRIVERS
TF930 Items
33331-4690
FRONT PANEL – TF930
33331-9780
OVERLAY – FRONT PANEL – TF930
44813-0400
PCB ASSEMBLY – MAIN – TF930
48581-1400
INSTRUCTION BOOK TF930
TF960 Items
33331-1690
FRONT PANEL – TF960
33331-1700
OVERLAY – FRONT PANEL TF960
44813-0430
PCB ASSEMBLY – MAIN – TF960
44813-0440
PCB ASSEMBLY – INPUT C – TF960
48581-1440
INSTRUCTION BOOK TF960
Thurlby Thandar Instruments
Ltd
.
Glebe Road • Huntingdon • Cambridgeshire • PE29 7DR • England (United Kingdom
)
Telephone: +44 (0)1480 412451 • Fax: +44 (0)1480 450409
International web site:
www
.aimt t i.com • UK web site:
www
.aimt t i.co.uk
Email: info@aimt t i.com
Aim Instruments and Thurlby Thandar Instruments Book Part No. 48581-1450 Issue 1
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