[MRCA] T-195B and volts

[DSP3]

The high B+ is not critical to the radio, nor especially to the servo 
system.  That said, with the two systems I work with, the input voltage 
is set at 28.7 volts.  If you take a very close look at the A and B 
models, many of the nomenclature tag appears to say 29 volts!.. 
something like that.....   On one of the ones I had, it was imperative 
to run at least 28.6 volts for the autotune to actually settle.  I am 
unsure of the total reason but the book clearly states that the two 
pairs of matched diodes in the servo discriminators should be changes 
every 60 hours of operation.  That seems a bit short but that's what it 
says.  The original diodes are germanium and perhaps that's a clue to 
the low longevity in that circuit.  Also, the sampling choppers can go 
bad\.  I still have a few of them I bought.  They go in the T-195 and, I 
understand, in the ARC-38 (sic) and others.


Jeep K3HVG



On 9/26/2015 8:22 AM, Robert Newberry wrote:
>
> On the AM net this morning, I was given the advice of how important 28 
> volts DC input is with regards to autotune.
>
> Currently I am using a external HV supply that will not quite make 
> 1000 volts. We are using current limiting because if you use the solid 
> state one the current will destroy the supply. I am still using DC 
> input with a variable supply to run the low voltage section which has 
> tested out OK.
>
> Does anyone know if I can't get exactly 1000 volts will that affect 
> autotune?
>
> I suppose at a minimum I can use the external supply until I find 
> whatever is drawing so much current.
>
> Thank you
>
> N1XBM
> Apparare Scientor
> Paratus Communicare
> Allstar Node # 27086, 41540, 41812, 42086
>

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