[MRCA] BC-611 (SCR-536) Restoration - Experience/Advice Needed

[Mike Feher]

Garret –

 

I have restored numerous 611s a long time ago. With most of them I found leaky plate to grid capacitors. All the circuits are very high impedance to preserve battery life, so, even a meg of leakage in a cap is too much and drives the following grid positive. Make voltage measurements with a high impedance volt meter. I also found a couple where the IF transformers were defective to corrosion of the fine leads in the coils. Fortunately with careful work and still good eyes I was able to repair them all. Hope these tips help. 73 – Mike  

 

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell, NJ, 07731

848-245-9115

 

From: MRCA [mailto:mrca-bounces at mailman.qth.net] On Behalf Of Garret Scott
Sent: Saturday, May 20, 2017 4:56 PM
To: 'Mrca Mailing List'
Subject: [MRCA] BC-611 (SCR-536) Restoration - Experience/Advice Needed

 

I’m starting on restoration of several BC-611F’s.   

 

Any advice from someone who’s actually done it?   

 

I’ve googled it, and come up with nothing, other than the TM and a post on how to make a battery.   

 

All of these are Mid 1945 Galvin production, appear completely original, no LSD overhauls or any other sign of repair since originally manufactured. 


So far, all appear to be mostly inoperative in the same way.  i.e. , there is some white noise in the earpiece, the LO is running on freq., but the IF seems pretty much dead.  Injection of 455Kcs does nothing unless I pound the detector grid with lots it.  AF amp seems to have some reasonable gain.  

 

I have not checked nor replaced any caps, although I see a few micamolds in there, so am naturally suspect, and will be replacing them.  

 

Thanks,

Garret

W8BUG

 



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