Mechanics and Electronics ME2000V User guide

ME2000-V

2M LINEAR AMPLIFIER 19’’ BOX

GS35B

Mechanics & Electronics Inc. Hungary

Draskovits Gábor HA1YA Szombathely, Kárpáti K. u. 43. H-9700

e-mail [email protected] [email protected]

1

CONTENT

1.0 General overview................................................................. 2

2.0 Specifications......................................................................4

3.0 Technical description.......................................................... 5

3./a Front Panel...........................................................................6

3./b Rear Panel............................................................................8

4.0 Installation ...........................................................................9

5.0 Troubleshooting ................................................................ 10

6.0 Drawings ............................................................................13

2

ATTENTION!

Please read this manual carefully before operating the equipment!
The Linear Amplifier is easy to use, and damages can be avoided by following the
instructions stated below. Incorrect use may cause the loss of warranty.

1.0 G E N E R A L O V E R W I E W

The Linear Amplifier is produced by M+E Mechanics & Electronics Inc.
During the design of the ME series , the main point was to construct Linear Amplifiers for HF, VHF,
and UHF amateur bands with similar mechanical measures and appearance ,using ceramic v alves
easily available on the market.

The ME2000-V series utilises the advantages of the ceramic valve GS35B, and considering the
power output and price, is a worthy competitor of similar equipment on the market.
The Amplifiers are protected by modern cir cuits,- specially designed and used only by our
company,- providing a very high level of protection. With their low input power and high efficiency
they fulfil the requirement of an improved amateur station.
To use the Amplifier with satisfaction and utilising all it’s advantages , please read the following
general instructions carefully:

1.1 Do not use higher driving power as given in the instruction manual. During SSB transmission the
‘MIC GAIN’ control of the TCVR is not fit for the TCVR is regularly activating the protection of the
Linear.
In case of lately designed equipment the output power of the TCVR is control of the radio.

1.2 The SWR protection of the Linear is inactive during STBY mode.
In case the VSWR > 1:2 in QRO mode, the protection is active.

1.3 The required power supply is 230V 50/60 Hz or 400V 50/60 Hz between two phase

according to the EU standard. Verify that the rating of the line fuses located in the rear panel of
power supply in fuse holders is suitable for the AC line voltage you will be using. The fuse
should be the glass cartridge slo-blow type. The rating should be 20 Ampere by 230V AC, 16
Ampere by 400 V AC.

1.4 The Amplifier is constructed with a forced air cooling. Free air movement has to be provided and

considered during positioning.
Do not operate the Amplifier in excessively warm locations or near heating vents or radiators.
Be sure air can circulate freely around and through the Amplifier cabinet, and can provide an
unobstructed air inlet for the internal cooli ng fan. Do not place any books, magazines, manuals,
or equipment that will impede the free flow of air near the sides and the hot air exhaust holes
located on the top of the cabinet. The internal fan allows an air flow of approximately
200m3/hours. The exhaust air becomes quite warm at high power levels. Do not position any
heat-sensitive objects in the exhaust airflow path.

3

1.5 The PA is constructed with the following protection circuits and useful features:

-

Heat up time checking circuit

-

Protection circuits (Ia, Ig1,temperature, SWR>3)

-

Cooling fan 230V 60W

-

Function and status indicator LEDs (6 pcs)

-

4KVA transformer

-

OPTO coupled PTT switch

-

Built in I/O coax relays

4

2.0 S P E C I F I C A T I O N S

ME2000-V

Frequency coverage 144-146MHz

Operating modes ALL mode

Output Power 2000 W pep CW/SSB

Driving Power 0-120W MAX

Input VSWR max 1:1.5

In/Out impedance 50 Ohm

Valve(s) GS35B

T/R System opto 12V/8mA OPEN COLL. OK

Harmonic supression >50dB at 1500W RF out

Intermodulation >35dB at 1500W RF out

Protection Ia >1.0A

Ig1 > 360mA
VSWR > 3

Dimension 19X14X14 coll

Weight 22kg

5

3.0 TECHNICAL DESCRIPTION

1. GENERAL

RF deck of this amplifier is built in aluminium compartment wich must be
electrically tight to avoid RF radiation. RF radiation will decrase output power
and can cause self oscillation of the transmitter chain as well as a healt risk.
The PA we can built in 19’’ “box” version.

2. INPUT CIRCUIT

Tube is driven in catode over T filter. The input resistance of tube is about 40
Ohm.
The input circuit is working between 144-146 MHz without extarnal tuning. The
input SWR is better than 1:1.5 in this segment.

3. OUTPUT CIRCUIT

Output resonator is based on W6PO design. Tuning for resonance should be
done by changing length of two resonators rather than increasing C5 tuning
capacitor. The output capacitor value is about 3-4 pF.
Tune is very easy to maximum output .

4. COOLING

Cold air inlet is located in to input conpartment. We can deliver the PA with
internal or external fan.
Air flows trought over the catode box and across the tube body and anode
cooling fins. Hot air outlet is located above the tube anode cooling fins. The
protection circuit will work over 75 degree air temperature.

5. TUNING THE AMPLIFIER

Tuning the input resonance circuit should be done using VSWR meter
connected between driver and input. Output coupling capacitor should be set as
on the schematic to about 4pF.
Output you can indicate across the built iin LED bargraph power meter.
Before any high voltage will applied to the tube, tube should be run on heater for
several hours especially if the tube wasn’t use for long time. From this point of
time, cooling must be operational.
Having heater voltage connected to the tube without adequate cooling will
damage the tube.
The anode voltage should be applied /from your external high voltage supply ME
3000-S/ and idle conditions of the amplifier checked. Push the PTT and you can
see about 100mA on left meter. When you have more than this value, you can
adjust for this value with P7 poti on Zener PCB. /On case you use home brew
HV supply with lower or larger Ua voltage than 3500V. /Max Ua 3.6KV! /

6

3/a FRONT PANEL

1. POWER ON

Main switch of the equipment is on the power supply (ME3000-S).

2. ON LED
The LED indicator glows when the Linear is switched on. Doesn’t lit in case the
24V DC – supply for the protection circuits and antenna switch - is missing.

3. OVR LED
The blinking LED indicates the active stage of the protection circuit. The
protection might be active due to overdrive, IG1 higher as specified, SWR > 3,
or any other case. (See specifications)
If the protection is active, the TCVR power by-pass the PA. To reset the
protection release the STBY switch, than push it again(OPR). The reason of the
trouble has to be cleared first.

4

.

AIR LED

The indicator glows while transmitting and the T/R relay is switched on. Without
driving power the Ip bargraph indicates the idle current of the PA.

5. OPR LED
Glows when the PA is ready for transmission. During heating up period, when
the LED doesn’t lit, the driving is blocked. The stby time is > 120 sec.The
vacuum relay in PS switching the HV to PA,when OPR LED is lit.

6

.

WAIT LED

Blinking during the heating up period, indicating that the heating is in progress.
Required time is >120 sec, when the light goes out and the OPR led lit up.

7. QRO LED

Indicates the high power mode of the PA. Can be activated by the STBY/OPR
switch. In case the OPR mode is not active, only the TCVR power will on the
aerial. (Small PWR STBY mode)

7. HV PUSHBUTTON

When you push this button you can see the anode voltage on Ip/HV bargraph.

Multiplay the scale with 2. (full scale is 6kV).

8. TMP PUSHBUTTON

Normally you can see on the Ig1/TMP bargraph the current of the grid1(Ig1).
When you push this button you can check the actual outlet air temperature on
this scale.

9.

OPR/STBY SWITCH

The PA can be driven only if this switch is on OPR, otherwise the TCVR power
by passes the PA.(STBY)
In case the overload protection is active, release the STBY switch and push it
again to reset the protection circuit. (OPR)

7

10.

RF FORWARD POWER BARGRAPH

Indicate RF output power in KW.

11.

REFLECTED POWER BARGRAPH

Indicate the reflected power in Watts.

12. Ig1/TMP BARGRAPH

Indicate grid 1 current, when you push the TMP pushbutton indicate the outlet air temperature in oC.

13.

Ip/Ua BARGRAPH

Indicate the Ia current,when you push the HV pushbutton indicate the Ua voltage in KV.(Please multiplay the scale with x2)

14

. TUNE KNOB

Use for tuning the PA. Tune for max. output power.

15. FAULT LEDs

You can check one or more LED-s blinking on case overload. You can check what cause of the problem. There is not LED display for RF overdriving, on this case only the OVR LED is blinking.

8

3/b REAR PANEL

1. Remote connector

Connecting with short cable to ME3000-S power supply.

2. FAN 1

Cooling fan for the RF tube (230V/AC,60W,200m3/h)

3. PTT

Connection for SEND relay contact of your transceiver. The relays are closed
by earth connection. Low voltage, low current opto entry. Fit for open collector
control well (24V 10mA).

Use external sequencer unit for long life of coaxial relays!

5. INP
Input connection for the driver TCVR. 50 Ohm.

6. OUT
Aerial connection 50 Ohm (“N” or 7/16”connector).

7. GND
Ground connection.

8. 5PIN tuchel connector ( option if you want, you can order)

Connect to external units, preamplifier, etc….You can use free relay contacts of
relays for external units.

9

4.0 INSTALLATION

4.1 Connect your TCVR to the Linear using a short, 50 Ohm coaxial cable.

4.2 Connect your TCVR ground giving socket to the PTT RCA connector on the rear

panel of the Linear, using a screened cable.
In case your TCVR has an open collector PA controll output, you can use it
without difficulties. The input of the PA PTT is 24V 10mA.

4.3 Connect your aerial to the OUT connector of the Linear. VSWR must be better

than 1:2.

4.4 Using a flexible cable at least 6mm2, connect your PA to a suitable grounding

point and to the grounding point of the transceiver, and to ME3000-S HV power
supply.

4.5 Connect the power cord to the mains and switch on the equipment (ME3000-S).

Check before the exact input voltage of the ME3000-S (230 or 400V AC!). The
ON LED glows and the WAIT LED start blinking for a period of abt. 180 sec,
during the heating period. Set the OPR/STBY switch to STBY.
The readiness of the Linear is indicated by the OPR LED. If the PA was out of
use for a longer period (2-3 month), it would be advisable to keep the PA heated
without driving for a few hours. The control unit will switch the high voltage to
linear, when the OPR LED lit. The vacuum relay can switch the HV only on case
if you connected the HV cable to linear!

4.6 Switch the OPR/STBY switch to OPR. Using the tuning mode of the TCVR (CW)

or give small driving power to reach 300-400 mA indication on the IP bargraph.
With the Tune knob tune the Linear to reach maximum output power on RF out
bargraph. Increase the driving power until maximum anode current, than carry
out fine tuning using the Tune knob again. In case a 50 Ohm aerial, the power
meter will indicate the output power exactly. On reflected power bargraph you
can check the reflected power of your antenna.
Check the Ig1 current, if everything is right you can start the work. After the
some minutes, when the PA will reach the working temperature tune for the
peak output again with TUNE knob.

.

.

REMEMBER THIS AMPLIFIER DOES NOT REQUIRE TO MUCH DRIVE POWER.
SO START WITH LOW DRIVE POWER, AND THEN TUNE TO RESONANCE AS
OUTLINED ABOVE. OTHERWISE, ARCING MAY OCCUR INSIDE YOUR
AMPLIFIER.
NEVER RUN YOUR AMPLIFIER FOR ANY SUSTAINED PERIOD WITH A SCREEN
CURRENT READING GREATER THAN SPECIFIED. IF YOU DO, POSSIBLE
DAMAGE AND FAILURE OF THE TUBE(S) WILL RESULT, AND THEY WILL NOT
BE COVERED BY WARRANTY!

10

5.0 TROUBLESHOOTING

Malfunctions are mostly due to improper handling, overload or similar reason.

5.1Do not use higher input power as stated in the specification. The grid protector

circuit will usually safe the power valves, but OVERLOAD alarm will appear
regularly. This may happening often in SSB mode, especially in case of old
transceivers, when the output power in SSB mode is not adjustable. The ‘MIC
GAIN’ knob is not fit for power reduction!

5.2 INPUT SWR

The input SWR of the Linear is < 1:1,2.
A well adjusted TCVR will tolerate these values without any trouble.

5.3 OUTPUT SWR

The protection of the Linear will block the transmission in case the SWR of the
aerial exceed 1:2.

5.4 FAILURES

¾

The PA not turn on, nothing happens ON switch is pushed.



External AC wiring, fuse or circuit breaker may be open.



Amplifier power cable not in place - cover safety interlock open.



Fuse F1, F2, F3, F4 open or missing - check fuses with an ohmmeter.
(ME3000-S power supply)

¾

The PA turns on but no HV is indicated by the multimeter LED bargraph.



Possible HV circuit fault.



HV sampling resistor or HV fuses in power supply damaged. (ME3000-

S power supply)

¾

No idle current when you push the PTT (about 100 mA on meter).



Not Ua voltage. Check the protection resistor in PS or FUSE on HV

PCB.
Check the Q1 (BD249C transistor on control board).
The vacuum relay switch the HV to PA after the heating period(OPR
ON)

¾

The base current is too low or too high.



Check the control PCB board. Check the Q1 (BD249C transistor and

the zener stabilizer circuit PCB, you can set the needed value with poti

on zener PCB).Check both transistors on zener PCB.

¾

You can indicate normal Ia current on meter when drive PA but no output
power.



Check the output coaxial relay.

11

5.5 LIMITED WARRANTY
The M+E

Mechanics & Electronics

will warrant that the equipment will perform
substantially in accordance with the written materials for a period of 12 month
from the date of receipt and will be free from defects in material and
workmanship under normal use. This Limited Warranty is void if failure of the
equipment has resulted from accident or misapplication, any kind of
modification done, overvoltage, shipping, and in case the damage of the power
valves.
Warranty repairs done only on the base of the M+E

Mechanics & Electronics

.

Return cost will be covered by the owner.

5.6 ALWAYS THINK - SAFETY

THIS LINEAR AMPLIFIER DESCRIBED IN THIS MANUAL CONTAINS VOLTAGE HAZARDOUS TO
HUMAN LIFE AND SAFETY WHICH IS CAPABLE OF INFLICTING PERSONAL INJURY. NEVER
OPERATE THE AMPLIFIER WITH THE TOP COVER REMOVED AND THE TOP COVER SAFETY
SWITCH DEFEATED. BEFORE REMOVING THE TOP COVER MAKE SURE THE AC LINE POWER
CORD HAS BEEN DISCONNECTED FROM THE AC POWER SOURCE. ALLOW A MINIMUM OF 5
MINUTES TO ELAPSE BEFORE REMOVING THE TOP COVER AFTER POWER HAS BEEN
REMOVED. THIS IS NECESSARY TO ALLOW THE PLATE VOLTAGE FILTER CAPACITORS TO
BLEED DOWN TO A SAFE LEVEL.

Before operating this unit ensure that the protection conductor (green/yellow wire) is connected
to the ground (earth) protective conductor of the power outlet. Do not defeat the protective
features of the third protective conductor in the power cord by using a two conduct or extension
cord or a three-prong/two-prong adapter.

Before operating this unit:

1. Ensure that the instrument is configured to operate on the voltage available at the power
source. (See Installation Section)

2. Ensure that the proper fuses are in place in the amplifier's AC line fuse holders located
on the rear panel.

3. Ensure that all other devices connected to or in proximity to this amplifier are properly
grounded or connected to the protective third-wire earth ground.

If at any time the amplifier shows visible damage, has sustained stress, emits a foul smell,
fails to operate satisfactorily, it should not be used until its performance has been checked
by qualified service personnel.

Connect a good earth or water pipe ground to the ground post on the rear of the Amplifier. Use
the heaviest and shortest connection possible. Before you use a water pipe ground, inspect the
connections around your water meter and make sure that no plastic or rubber hose
connections are used. These connections interrupt the continuity to the water supply line.
Install a jumper around any insulating water connectors you may find. Use heavy copper wire
and pipe clamps.
It is best to ground all equipment to one point at the operating p osition and then ground this
point as described above.

12

5.7 SAFETY INTERLOCK SWITCH

While the Amplifier's top cover is in place, the interlock switch closes to allo w AC line voltage to reach
the power transformer. When the top cover is removed, the interlock switch opens and disconnects the
li

ne voltage. This does not discharge the bank of power supply filter capacitors. Be sure to allow the
filter capacitors to discharge before you touch anything inside the Amplifier. You can select the High
Voltage function of the Multimeter to check the high voltage potential.