Mechanics & Electronics ME2000-V User manual

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] [e-mail]

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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

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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 valves
easily available on the market.
The ME2000-V utilise the advantages of the ceramic valve, and considering the power output and
price, is a worthy competitor of similar equipment on the market.
The Amplifiers are protected by modern circuits,-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.
1.3The 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, 12
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 cooling 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.

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1.5 The PA is constructed with the following protection circuits and useful features:
-Heat up time checking circuit (3 min)
-Protection circuits (Ia, Ig1, temperature, SWR>3,overdrive)
-Cooling fans (2 pcs)
-Function and status indicator LEDs (6 pcs)
-4KVA transformer
-OPTO coupled PTT switch
-Built in I/O coax relays
-External HV power supply

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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

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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 health risk.
We can build normal 19’’ “box” version the line ME2000-V.
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
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 in power meter. /FWD knob in/ The
output is 3KW in right end of the meter. /10x scale/ All was made by the factory /
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.
Next 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! /

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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
15V 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 du 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 button, than push it again. 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 PLATE meter indicates the base 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 about 120 sec.
6. WAIT LED
Blinking during the heating up period, indicating that the heating is in
progress. Required time is abt. 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 push-
button below. In case the mode is not active, only the TCVR power is on the
aerial. (Small PWR STBY mode)
8. Ua PUSHBUTTON
Selects the anode voltage (kV) indication on the POWER meter using the
PLATE scale. There is only one way selection between Ua -Ig2 pushbuttons.
9. Ig1
The current of the grid (Ig1) can be checked. Current limit is 350 mA, when the
protection is activated.

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10. FWD
Output power indication. Use for tuning the Linear. The indication calibrated for
50 ohm aerial impedance.
At other values the accuracy may be +-10%.
11. REV
Will indicate the relative reflected power on the right side meter. Helps to check
the aerial.
12. Ig2
Only in case the PA constructed with tetrode! The concerning grid current can
be checked. Inactive in case the PA built with triode.
13. STBY
The PA can be driven only if the button is pushed, otherwise the TCVR power
by-passes the PA. In case the overload protection is active, release the button
and push it again.
14. PLATE meter
Indicates always the anode current of the PA. The green mark is the limit for the
idle current, while the red shows the maximum allowable current.
15. POWER meter
Multifunctional meter. Forward or reflected power, anode voltage or grid
current indications can be selected.
16. TUNE knob
Tuning knob of the anode cavity. Used for tuning the PA.

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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)
3. PTT
Connection for PTT RCA. The relays are closed by earth connection. Low
voltage, low current opto entry. Fit for open collector control a well (24V 10mA).
5. INP
Input connection for the driver TCVR. 50 Ohm (“N” or 7/16’’ connector).
6. OUT
Aerial connection 50 Ohm (“N” or 7/16”connector).
7. GND
Ground connection.

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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 socket on the rear
panel of the Linear, using a screened cable.
In case your TCVR has an open collector PA controller output, you can use it
without difficulties. The input of the PA PTT is 24V 10mA.
4.3 Connect your aerial to the OUT socket 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.
4.5 Connect the power cord to the mains and switch on the equipment (ME3000-S).
The ON LED glows and the WAIT led start blinking for a period of abt. 120 sec,
during the heating period.
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.
4.6 Using the tuning mode of the TCVR (CW) give driving power to reach 300-400
mA indication on the PLATE meter. Push the FWD button and using the Tune
knob tune the Linear to reach maximum output power indication. 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.
REMEMBER THIS AMPLIFIER DOES NOT REQUIRE 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!
4.7 Check the grid current using the Ig1 push-button. Reduce the driving power or
make fine tuning in case the grid current would exceed THE SPECIFIED VALUE!
4.8 During SSB transmission the peak power of the TCVR may exceed the allowed
maximum driving power of the transceiver! Use The POWER knob on the TCVR
in this case.

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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!
5.2INPUT SWR
The input SWR of the Linear is < 1:1,2.
A well adjusted TCVR will tolerate these values without any trouble.
5.3OUTPUT SWR
The protection of the Linear will block the transmission in case the SWR of the
aerial exceed 1:2.
5.4 FAILURES
¾The PA not turn on, nothing happens ON switch is pushed.
External AC wiring, fuse or circuit breaker may be open.
Any connector is not in place -cover safety interlock open.
Fuse F1, F2, F3, F4 open or missing -check fuses with an ohmmeter.
(ME3000-S power supply)
¾The PA turns on but no HV is indicated by the level meter.
Possible HV circuit fault.
HV sampling resistor in power supply damaged. (ME3000-S power
supply)
¾No idle current when you push the PTT (about 100 mA on meter).
Not Ua voltage. Check the protection resistor on power supply.
Check the Q1 (BD249C transistor on control board).
¾The 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).
¾You can indicate normal Ia current on meter when drive PA but no output
power.
Check the output coaxial relay.

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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 prot ective
features of the third protective conductor in the power cord by using a two conductor 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 coppe r wire
and pipe clamps.
It is best to ground all equipment to one point at the operating position and then ground this
point as described above.

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5.7 SAFETY INTERLOCK SWITCH
While the Amplifier's top cover is in place, the interlock switch closes to allow AC line voltage
to reach the power transformer. When the top cover is removed, the interlock switch opens and
disconnects the line 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.