I had soldered this up yesterday and had used a ceramic 4ohm / 5 W resistor for R8 along with a 5W speaker. The board was working fine without any problems.
My son accidentally pulled the universal power supply lead out from the adapter and when he put it back in he reversed the polarity.
It now doesnt work.
I’m getting a constant voltage across the LS of around 8v, before it was fluctuating. I’ve checked the diodes and they are working. There is also quite a bit of heat at the IC.
I’m thinking the most probable thing is the Op-Amp has blown. Are there any other checks I can perform or should I just order another IC. It is the LM324N.
I’m going to use this as part of an alarm circuit not a toy.
Thanks
LM324 is definately defective and should be replaced.
Possibly, T1 is also defective.
[quote=“VEL417”]LM324 is definately defective and should be replaced.
Possibly, T1 is also defective.[/quote]
Thanks. Cheap enough to replace. I have ordered some IC’s and will try from there. All good fun
[quote=“postmaster-general”][quote=“VEL417”]LM324 is definately defective and should be replaced.
Possibly, T1 is also defective.[/quote]
Thanks. Cheap enough to replace. I have ordered some IC’s and will try from there. All good fun[/quote]
IC replaced, works fine now. Thanks, very kind of you to help.