27-05-2011, 01:58 PM
The anode voltage on the tuning indicator is, or was until things went wrong, 26V between stations and 96V on a strong one.
You're obviously right about the capacitors in test leads, Steve; I'd mistakenly thought that the 100µF one already fitted to the output would do the same job.
I don't have an isolating transformer but this wouldn't have protected me in this case anyway as I got the shock by touching both the tip and ring of the 3.5mm jack plug - the shape of the scar on my finger confirms this. It was also handy that it's got a pair of 10 kΩ stereo to mono mixing resistors in. I'm just pleased I didn't manage to connect it.
I've just been having another look but can't see anything shorting. The test lamp lights briefly, then goes out but as the set finishes warming-up it comes back on dimly as the voltage appears on the PU input. I'm loathe to risk leaving it on for long as I don't now what harm it's doing.
I'll keep looking as it's too easy to not end up being able to see the wood for the trees. It's so annoying as it was working fine, apart from VHF, until I put it back in the cabinet. At least if I knew what I'd done I'd have an idea of what to do about it and even if it was irreparable would have learnt a lesson for the future.
Joe
You're obviously right about the capacitors in test leads, Steve; I'd mistakenly thought that the 100µF one already fitted to the output would do the same job.
I don't have an isolating transformer but this wouldn't have protected me in this case anyway as I got the shock by touching both the tip and ring of the 3.5mm jack plug - the shape of the scar on my finger confirms this. It was also handy that it's got a pair of 10 kΩ stereo to mono mixing resistors in. I'm just pleased I didn't manage to connect it.
I've just been having another look but can't see anything shorting. The test lamp lights briefly, then goes out but as the set finishes warming-up it comes back on dimly as the voltage appears on the PU input. I'm loathe to risk leaving it on for long as I don't now what harm it's doing.
I'll keep looking as it's too easy to not end up being able to see the wood for the trees. It's so annoying as it was working fine, apart from VHF, until I put it back in the cabinet. At least if I knew what I'd done I'd have an idea of what to do about it and even if it was irreparable would have learnt a lesson for the future.
Joe
