|(RF-5031 drives 10221-6100) RF-3230||1,000
MT-6233 (low profile)
MT-6378 Ant Siting
GRC-193B(V)3 Marine Corps
|TM 11-5820-1045-20P||TM 11-5820-1045-40P||TM 11-5820-1045-34|
|AM-6545A RF Amp
|CU-2064 Ant Cplr
|CU-2064A Ant Cplr|
|AM-6879 Audio Amp/RTTY
|Coupler to the Back for use
with Whip antenna on Jeep.
|M151, M151A1 or M151A2 (CJ5 Jeep)||Army Utility Truck 1/4 Ton||Mk-2461/GRC-193A||5820-01-189-9795||TM 11-2300-475-13&P-3|
|M151, M151A1 or M151A2 (CJ5 Jeep)||Marine Corp Utility Truck 1/4 Ton||p/n: 755017C9000 (14304)
|M998, M1038 HMMWV||1
M1008A1 CUCV (Wiki)
||Cargo Truck 1-1/4 Ton, 4x4||MK-2462/GRC-193A||5820-01-189-9794||TM 11-2300-475-13&P-1|
|M1009 CUCV (Wiki)
||Cargo Truck 3/4 Ton, 4x4||MK-2544/GRC-193A
||Cargo Truck 1 1/4 Ton, 6x6||Mk-2458/GRC-193A||5820-01-189-9796||TM 11-2300-475-13&P-4|
|M113A1 APC & Carrier Command Post - M577A1||Full Tracked||Mk-2460/GRC-193A||5820-01-189-9798||TM 11-2300-475-13&P-6|
MT-6232, AM-6879, RT-1209
||Package 61 lbs.
||Packing 10 lbs
||Package 101.2 lbs.
packing 7.2 lbs.
At power on there is beeping in the loudspeaker and the Tune light is on
as everything warms up.
Pressing the FAN/Lamp Test button turns on the fans and all 6 Test Lamps light.
After about a minute the beeping stops and the RDY and TUN lights are on.
Unit warmed up and ready.
|Pressing the mike PTT
starts the tune operation and XMT & TUN are on
this lasts only about 5 to 10 seconds.
TUN and PA Fault lights are on and there a lot of beeping.
PP-6224 is running at about 4 amps.
most likley cause of the problem is a poor electrical
connection. See Hints and
Tips: What Goes Wrong
PU4 AM-6545 Top Inside
||AM-6545 Inside Lid
and reinstalling the 6 PCBs (1A1 to 1A6) and the tank
assembly (1A8) did not solve the problem.
The tank assembly does NOT move when tune is under way so maybe the servo (1A5) circuit has a problem.
|Main Test Points
||1A8 Tank Assembly
|Prior to making the meter
readings I noticed that a nut holding a white wire from
the transformer had been melted,probably by a short to
ground. What is the function of that wire?
|Aapped Nut photo taken
after removing 1A13 HV module.
|The 1A5 Servo pwb test
to open the 1A13 HV module and see what burned up.
It was R12 1 Ohm 1/2 Watt in series with the emitter of Q1
(2N3055). The collector is tied to the +26.5 buss
and R12 is in series with the HV Start pin M on the
|Input Voltage Regulator
There are a number of places where the main input power supply has been used like an arc welder. Two of the 2N3055 cans have holes and the bracket and a number of strike markes. You can also see this in the first
top inside view above (Fig PU4)
These three 2N3055 transistors are:
Q3 - 19V regulator pass transistor (2 holes)
Q4 - Filament regulator for V1 (1 hole)
Q5 - Filament regulator for V2 (no holes)
As the final power tubes age they have lower gain and that lets the plate voltage rise. When the plate voltage gets high enough an arc from the plate to other parts of the tube (including the cathode/filaments) burns out the tubes and the circuitry associated with the power tubes.
If the power amp had received regular maintenance where the plate voltage was kept adjusted there would not have been a arc over.
But this seems to be a common problem with high power RF amps.
Eimac app note 17 recommends adding a resistor in series with all the high voltage terminals to limit the energy in any arc to 4 Joules.
Replacement tube ideas (may require different filament voltage or mechanical heat sinking:
Y621B (stock tubes no longer available)
8873 (replacement, but different filament voltage)
3CX-800A7 - 3CPX-800A7
|Note the DC input
connector, J3, has a central threaded hole, not the
common DC input connector male threaded post.
See the CX-4721 cable photos.
This is the same DC Input connector as used on the GRC-106. A cable with a mating connector is the CX-10071/U, but is has bare wires at the other end for connection to a battery.
A & B = + 26.5 VDC
C & D = Ground
The meter can read 11 different things depending on an internal switch setting.
(J3 or J4)
To get access to the solder lugs:
Remove top and bottom clamp rings using special spanner tool.
Pull center locking assembly out.
The stock wiring of the CX-4721 is:
Liquid Wrench helped in getting the old cable out of the connector shell and free up the brass ferrel that the nut compresses.
Removed the old yellow label since the new shrink tube would not pass over it.
|On the PP-6224 two rear output connectors (J3 or J4) A = Gound, B= +28 VDC. Pins C and D are not used.|
This is the new GRC-193 DC power cable made to be driven by the PP-6224 or any other Mil Vehicle 4-socket source.
|Top showing Dogs.
The outside dogs are clamps but the
inside dogs are fixed. Tere is provision for 4 dogs at the left, why?
|Side View of RF Amp and
The CU-2064 has 5" spacing on the other side instead of 6-1/4".
|Top & Back with
center Dogs positioned correctly.
MT-6378/GRC-193A Mount, Remote Siting Lowered Position
This base is the AB-652.
What's needed to convert to the AT-1011 mast elements?
Ans: The Witch's Hat AT-1011 base.
||Equip 1 - Jack No.
||Equip 2 - Jack No.|
||Audio to Amp-Speaker
||RT Interface cable
||low level RF to/from Pwr
||Control to/from Pwr Amp
75501780714 Mfg 14304, Ends: P1 & P2
Note the P2 end has a mangled connector nut.
Wiggling had no effect.
||Control to/from Ant
||RF to/from Ant Coupler
||HV Conn on Ant Coupler to
||Conn: SM-C-S029 I 2
||Coax to 50 Ohm Ant
||DC power input
[an error occurred while processing this directive] page created 5 Dec 2011.