[Milsurplus] BC-611 power inverters

[WA5CAB@cs.com]

Perry, Dennis, et al,

The Litrico converters are a bit difficult to bench test because of the load 
sensing circuit that turns them on and off with the antenna operated switch.  
I built up a special thin bottom cover with meter leads run out for test 
purposes.

Although it's possible that you got a bad one, I've had about a dozen through 
here and all worked, although the B+ did vary somewhat from unit to unit.

However, as supplied, they do not in fact work in the late BC-611-F (with the 
thick bottom cover) nor in the BC-721.  Reason #1 is that the A and B sides 
are rigidly attached to each other (unlike two individual batteries which can 
float up and down independently).  The late -F and BC-721 bottom covers have s
olid fixed-length posts for the battery contacts, and whichever one touches 
first pushes the converter down and it never touches the other contact.  Even in 
the early -F and earlier models, you may have to "tune" the brass or phosphor 
bronze contact leaves for satisfactory operation.

Plus for some reason the B side has a brass strip attached which fouls the 
mic/earphone terminal board.  I asked about why it was there but never really 
got an answer.  I think it was a quick fix for a length error in the design.  I 
had the B+ end cap off of one once (it came off by itself and the owner sent 
it to me to fix) and if length or relative location in space was the reason for 
the brass strip, I would have built up the B+ contact with a brass rivet or 
screw + necessary spacers.

Anyway, I concluded that a suitable fix to make them work with the late -F 
and 721 would be to remove the brass strip, somehow remove the A+ and B+ end 
caps and install spring loaded contacts as are used elsewhere on the thick bottom 
covers.  Or less desirable for several reasons replace the solid posts with 
spring loaded ones.

In a message dated 1/6/2004 1:29:04 PM Central Standard Time, w8au@sssnet.com 
writes: 
> What type '611's are you using them in?
> 
> I ordered four of those from Carmello Litrico a few years back,
> and none worked in my BC-611F's.   I even test rigged them
> on the bench and could not get them to work.
> 
> I sent them back and since Italy wanted import duty on them
> Carmello did not claim them and they were sent back to me.  :-)
> 
> I then sent them back a second time, marked "junk parts" and then
> went thru OK.
> 
> Carmello sent three of the originals back saying they were good, and
> one NEW one that he replaced.
> 
> Still, none worked.   The "replaced" one did sputter a little and put out
> about 15 volts on the test bench.... and then stopped.
> 
> So, I'm back to just building my own batteries with 12 Nine Volters....
> 

73
Robert Downs - Houston
<http://www.wa5cab.com> (Web Store)
<wa5cab@cs.com> (Primary email)
<wa5cab@houston.rr.com> (Backup email)


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