[MRCA] T-195

[D. Platt]

Both the HV and multi-voltage low-voltage solid-state power supplies are 
virtually unobtanium.  The last sets of these I got were from Baran's 
Surplus in PA, some 8 years ago.  The Baranosky brothers were the best 
source for years.  I have talked to them and they are "looking".  To 
date, no news of any kind from them.  The power supplies were 
manufactured by Victoreen, only, I believe.  These are the same folks 
that made all kinds of radiac sensors for OCDM and the military.  They 
are form/fit/function for the original dynamotors.  Several of the main 
repair issues are the potting of some portions of the units, the use of 
wholly obsolete germanium transistors, and some very small transformers 
that are not "standard" by any sort of imagination.  According to 
friends who used to work at the depot on PA that handled the GRC-19 
radio sets, the power supplies worked very well... while they worked.   
I particularly like them as the inrush current drops from about 70 amps 
down to the steady-state current of about 30A, on transmit. Also, poor 
old K2 doesn't burn up as quickly.   The saving grace is that the 400 Hz 
requirement (28v) is not too awfully bad.  As I recall, I'll have to 
look at the books again, it drives the blowers in late units (?) and the 
servo system in all units.  I don't think it5 stars out as 115v, 
though.  Again, I'm doing this, with trepidation, and not pulling out 
the TM.  Once the T-195 is going, they do sound nice.  Oh yeah, one more 
thing... if your servo system seems sluggish and/or won't settle 
properly, one of the things to replace.. replace are the two sets of 
discriminator diodes in the servo chain.  The TM says to change these 
matched diode sets (in pairs) every 60 hours of operation.  That seems 
excessive but on one of my systems, it made all the difference in the 
world.  The diodes have to be subbed, of course, but no real issue.  If 
anyone wants to know, I'll look in the my logistics department and see 
what I came up with from Mouser.  Also, I do have some spare  6.3v 400Hz 
servo choppers that go in the T-195 and the ARC-38 radio sets. I am not 
an expert or such.. just had some experience with mine........

Regards

Jeep - K3HVG