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

[Garret Scott]

Mike,

 

Thank you for the advice.  I will check voltages and the IF transformers.  Another MRCA member (Robert Downs) suggested that the IF transformers, specifically on the F series radios are the single most common failure.  I will know later today when I dig back in.   

 

As it is, it seems that nothing at will get through the IF section, and I mean nothing.  So it makes sense that it could be the IF transformers.   

 

I again appreciate all of the help.  Will let you know how it turns out and if it’s caps or transformers, and if I manage to repair or salvage one. 

 

I’m really hoping to have at least one BC-611 working for our upcoming Secret City Festival WWII reenactment and Amateur Radio Special Event Station, as all of these are crystalled up on 3885, and we plan to operate there with an SCR-284/BC-654, TBX-8 and a SCR-694/BC-1306. 

 

Thanks,

Garret

W8BUG

 

 

 

From: Mike Feher [mailto:n4fs at eozinc.com] 
Sent: Saturday, May 20, 2017 9:20 PM
To: 'Garret Scott' <scottgs at bellsouth.net>; 'Mrca Mailing List' <MRCA at mailman.qth.net>
Subject: RE: [MRCA] BC-611 (SCR-536) Restoration - Experience/Advice Needed

 

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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