[YoungSC]

I have finished building my Bugle and I am only just hearing sound through my speakers with full volume on my amp (albeit 2W worth).

I haven't cleaned the board as you can see from this picture:



There is no DC voltage across + and - at the output sockets (if that is what I should be looking for). I am using rechargeable batteries which put out 8.4V.  They are reading above 9V when charged though.

I have measured the following for the opamps (opamp 1 being the closest to the switch).  Looking at the numbers, I would guess that Opamp 2 is stuffed, but I'm a 'paint by numbers' electronics guy.  Would it be the opamp, or could it be related to a bad solder joint?

Opamp1
Pins against ground
1 0V
2 0V
3 0V
4 -9.5V
5 0V
6 0V
7 0V
8 9.6V

Opamp2
Pins against ground
1 -7.2V
2 -6.1V
3 -6.3V
4 -9.4V
5 -6.2V
6 -6.1V
7 -7.2V
8 -7.0V

Opamp3
Pins against ground
1 0V
2 0V
3 0V
4 -9.4V
5 0V
6 0V
7 0V
8 9.5V

[hagtech]

Don't worry about the cleaning, it's overrated.  Besides, if you have to change something...

The soldering looks fine.  Double check resistor values.  Are opamps inbackwards?  Get power to the board first.  Each opamp should have same voltage on pin 8 and same for pin 4.

jh

[YoungSC]

Thanks Jim,

I was stuck on the faulty opamp idea, I checked the resistor values and they were all good, then I noticed the joint on pin 8 of opamp 2 was dodgy.  You can't really see it on the photo due to the angle I took it.  There was a blob sitting on the end of the pin, but wasn't actually attached to the board.

The bugle is playing now and sounds great!!

Thanks for a great well priced product.

Simon

[Folsom]

If you want to make sure there are no issues with cleaning without cleaning just use a knife to cut the resin down to the PCB (does not really require any real scratching). This works well for SOIC type things.