[Premium-Rx] Racal 6793 problem

[C. van Ravenswaaij]

Hi all,

Problem found and solved. Big thanks to Dan AC6AO/G3NCR for thinking 
along with me on solving this issue.
It turned out to be a faulty tantalum C, but not on board A4, but board 
A5 which was fed through A4.

73, Cornel

Op 21-5-2016 om 17:57 schreef C. van Ravenswaaij:
> Hi all,
>
> I have a Racal RA6793-2C with a problem.
> A while ago I switch the receiver on and within a few second I smelled 
> a burning odor. Quickly turned the receiver off.
> After opening the receiver, tried another startup, same smell, but now 
> with smoke coming off of board A4. It looked like tantalum C93 was the 
> culprit.
> To be sure, I replaced all tantalum and regular electrolytic C's on 
> board A4.
> Then checked all supply voltages, they were ok.
>
> Another start of the receiver gave the same smell again. Coil L4 was 
> becoming very hot. This coil is in the 15 V line and seems to draw too 
> much current.
>
> Can somebody give me a clue where to look next?
>
> 73, Cornel
> PA3BTS
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