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Re: Letting the smoke out

 

Trace the track from IRF drain through L8 I am willing to bet L8 is fried or track burnt.
If your 10A fuse blew then the PCB tracks didn't have a chance!

From the drain to the power pin at PA power 1 should show 0 Ohms. In your case it wont
and you could friend what has fried. It could even be the 2 pin power connector wire.

Good luck
Raj, vu2zap



At 17-03-2017, you wrote:

I received my BITX40 kit and wired it up on my workbench. The receiver worked well and I made three QSOs before disassembling it to install in a homemade case. While reassembling the IRF150 tab shorted to the case? with the power on. This blew the 10 amp fuse on my 13.7 volt power source and literally produced smoke from around C157. Fortunately the receiver still functions but I get no transmit power out. It appears that C157 was not damaged and it is not shorted. I checked L8 and T7 for continuity and they seemed OK. I replaced the IRF150.

What I see now:

0.17 A draw on receive, rises to 0.29 A when PTT pushed but goes no higher

about 9 volts on the drain of the IRF150, drops to 0.0 volts when PTT pushed, speaking into mike causes slight negative voltage (-0.15V)

Any suggestions on what (and how) to check next?

??? Thanks
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