[Milsurplus] AN/URM25-J

[WA5CAB at cs.com]

To the best of my knowledge, no one has ever turned up a manual on the 
AN/URM-25J (SG-85C).  However, I do have the NAVSHIPS manual covering 
AN/URM-25D, G and H.  And the SG-85B/URM-25D used in AN/URM-25H has an oscillator 
filament regulator board added that is not in the first two versions.  The two 
diodes are 1N540's.  The two capacitors are 2200 uf 10 VDCW.  The two 
resistors are 15 ohm 5W.  And the zener is a 1N3998A 6.2V.  Probably the same 
board.  What other differences there are in the SG-85C I couldn't say.

In a message dated 12/03/2013 19:43:24 PM Central Standard Time, 
mark.richards at massmicro.com writes: 
> Among the pile of Dyna-Swill I find two URM25 signal generators. Needing 
> the services of one I find that neither of these has any RF output 
> although both show meter indication that they are generating.
> 
> One unit is marked SG85/URM-25D on both the case and the front panel.
> 
> The other is marked SG85C/URM-25D on the front panel and AN/URM25J on 
> the case.
> 
> I find in BAMA the manuals for the 25D, but not the 25J.
> 
> And these units are slightly different.  The 25J has an extra phenolic 
> board on which are mounted 2 capacitors, 2 rectifier diodes, and a Zener 
> diode.  The zener looks to be fried.
> 
> Perhaps I should quit while ahead.. or maybe someone knows the mysteries 
> of the 25J?
> 
> /K1MGY

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480