Need to add a question to a thread.

[Pommie]

I need to add a question to this thread but it's locked!!!! I'd need to spend an hour (or two) reiterating the said thread for my question to make any sense. Can we stop locking threads?

Mike.

 

[atferrari]

For a thread where I was really interested to post a question, I asked JimB to unlock it.

Worked OK.

 

[Nigel Goodwin]

I need to add a question to this thread but it's locked!!!! I'd need to spend an hour (or two) reiterating the said thread for my question to make any sense. Can we stop locking threads?

Mike.

Sorry for the slow reply - but unused threads now lock automatically after a certain time, to prevent people posting in them as has happened in the past.

If you want to post (properly) in one, PM a mod and we'll unlock it for you, as atferrari said.

 

[Pommie]

Actually, it's you I need to ask the question of. Do you know if a schematic is available for that circuit? I used it as a battery charger and accidentally connected a 12V battery with the wrong polarity and something broke.

Mike.

 

[Nigel Goodwin]

Actually, it's you I need to ask the question of. Do you know if a schematic is available for that circuit? I used it as a battery charger and accidentally connected a 12V battery with the wrong polarity and something broke.

Mike.

I was never able to find one, and I looked before I started tracing the voltage setting part of the circuit out. However, the secondary side of a switch-mode regulator is pretty simple - and reverse connecting a battery to the output would presumably blow the rectifier diode, or something in series with it.

So I would check the diode, failing that look for a choke in the feed from it?. If not, then draw out the secondary part, there's not much of it.

Simple ohms tests should be helpful as well - you'd expect the negative side of the diode to read low to the negative output, and the positive side of the diode to read low to the positive output.

Just remembered - I've got one sat nearby. As I suspected, it reads under an ohm from the two outputs to the diode, and there's a choke in the positive lead, with electrolytics to negative from either side. The diode would still be my first bet.