[MRCA] T-195/GRC-19 parts/accessories wanted

[WA5CAB at cs.com]

Well, open mouth...

The full title is "MODIFICATION OF TRANSMITTER, RADIO T-195B/GRC-19 TO 
PREVENT FAILURE OF SWITCHING TRANSISTORS AND DIODES IN HIGH AND LOW VOLTAGE POWER 
SUPPLIES AND EXHAUST BLOWER ASSEMBLY, TO PROVIDE INCREASED GRID DRIVE TO THE 
POWER AMPLIFIER STAGE, AND TO REDUCE THE FAILURE RATE OF TUBE TYPE 5763".

The switching transistors in the two PSU's were replaced with Motorola 
2N630's (also germanium, though).  The rectifiers were replaced with 1N2616.  The 
three tuning coil cores in Z105, 106 and 110 were replaced with higher Q ones.  
The capacitor across the input to the blower was replaced with a higher value 
one.  Q608 was replaced with 2N335 and a spike supression zener diode network 
added.  The dynamotor (sic) fuse was changed from 30 to 25 amperes.  The 
compete MWO kit ran to 25 line items and besides the semiconduction components 
included wire, lugs, clamps, threaded hardware, fuses, decals and sleeving.  
Everything but the decals and the cores could probably be sourced from surplus 
dealers or substituted with even newer components.  Priority of the MWO is NORMAL. 
 Depots shipping transmitters that hadn't had the MWO performed were only 
required to include the kit.



In a message dated 2/10/2008 11:36:48 PM Central Standard Time, 
ross at hypertools.com writes: 
> Robert -
> 
>   Re the T-195 MWO -  what did the switching transistor mod entail?
> 
> Dave Ross    N7EPI
> 
> 
> 
> WA5CAB at cs.com wrote:
> >The full long-number manual set C/O:
> >
> >TM 11-5820-335-10
> >TM 11-5820-335-20
> >TM 11-5820-335-20P
> >TM 11-5820-335-35
> >TM 11-5820-335-35P
> >MWO 11-5820-335-35/1 (mod to prevent failure of switching transistors).

Robert & Susan Downs - Houston
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