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Old 20th Mar 2017, 2:49 pm   #45
Damo666
Hexode
 
Join Date: Jan 2010
Location: Blackburn, Lancashire, UK.
Posts: 399
Default Re: Harvard H407 CB RX audio problem

Jeremy,

When I was testing the voltage of pin 7, I found I was getting fluctuations in voltage readings like yours when I was using the chassis as the negative. However, I was getting different but solid readings when I was using transformer cans as the negative test point, if that makes sense? I found this odd, as the transformer cans are still connected to ground - unless my DMM is prone to slight RFI?

Anyway, in a nutshell, it seems that the dropping voltage of pin 7 on mine is presumably something to do with my problem - because your readings are constant as opposed to dropping.

I've ordered some 100uF Cap's, because they're handy & I have none, so I'll replace this one connected to pin 7 when I get them - as maybe the cap is leaky?

I'll hold off on the LA123O as you've all suggested & take things slow - besides, it's been pretty quiet on the CB these last couple of days, and no strong signals have been apparent which I really need.
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