Re: 7B50 - No Trace


Ozan
 

On Mon, Nov 15, 2021 at 01:55 PM, n4buq wrote:
I think I discovered where R394 and C395 are. They're in plain sight just on
the other side of a metal shield - just across from R264. The parts layout
image labels those as R265 and C264; however there are no such parts (at least
not that I can find) in the parts list and I could not find those numbers on
the schematic either.
Good detective work.

In any case, R394 measures 65 ohms so I'll be looking to replace that. I
probably should replace the electrolytics in the decoupling section just for
good measure.
Although I agree R394 looks a little too high and changing it should help, it is unlikely the root cause of the fault you are seeing.

Your measurement of voltage difference between bottom of R264 and base of Q266 needs another look. We don't expect so much DC drop across L267. Another data point is voltage across CR262 was 0.249V and voltage across R267 is 0.47V that again says there is some DC drop across L267.
Ozan

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