Amp died after shipping -- anything easy that might be wrong?

[herbu]

So, it worked once.

My first guess would be the trace repairs. Soldering weakened a trace, and it opened again. See if you can follow the repaired trace(s) to PTH vias, and solder your jumper wires there.

 

[Jeff Potter]

What if I re-test all the continuity for my repairs? Actually, I think I've already done that, but I could doublecheck. If I have continuity shouldn't that indicate a good enough repair?

 

[TLS Guy]

What if I re-test all the continuity for my repairs? Actually, I think I've already done that, but I could doublecheck. If I have continuity shouldn't that indicate a good enough repair?

Continuity is only one side of the equation. You also need to check for shorts and inadvertent cross linkages at the repairs.

 

[Jeff Potter]

Thanks for the help!

So, it kinda seems that I now have these cross-linkages you mention. Rats! I just did a further continuity check and ... I'm getting continuity across traces. These are thin traces close together in the same area. Disaster?

My repairs visually look totally clean and not at all touching or impacting other traces. Did my iron-heat do something?

If a trace looks to start in one place and end in another, without any branches, shouldn't it stand alone as a circuit? I'm certainly no expert as to how they can function. Maybe a component is linking them together. ?

I have taken my exacto knife and run it along both sides of each repair, just in case, and I've tried to clean off all flux. I only used a smear of flux and have used alcohol to clean it off.

 

[herbu]

I'm getting continuity across traces. These are thin traces close together in the same area. Disaster?

Likely not as designed. Can't say if disaster, failure or no effect.

My repairs visually look totally clean and not at all touching or impacting other traces.

Did you examine under a microscope? Tiny hairline shorts can be impossible to see w/ the naked eye.

If a trace looks to start in one place and end in another, without any branches, shouldn't it stand alone as a circuit?

Not necessarily. Could be a component, or could be a bottom or sub-layer on the circuit board. Many have multiple layers, like a club sandwich, and you cannot see where they go.

 

[TLS Guy]

Thanks for the help!

So, it kinda seems that I now have these cross-linkages you mention. Rats! I just did a further continuity check and ... I'm getting continuity across traces. These are thin traces close together in the same area. Disaster?

My repairs visually look totally clean and not at all touching or impacting other traces. Did my iron-heat do something?

If a trace looks to start in one place and end in another, without any branches, shouldn't it stand alone as a circuit? I'm certainly no expert as to how they can function. Maybe a component is linking them together. ?

I have taken my exacto knife and run it along both sides of each repair, just in case, and I've tried to clean off all flux. I only used a smear of flux and have used alcohol to clean it off.

I see you have already tested the unit and it did not work properly, so I suspect you have now done more damage.

I did download all the circuits and board layouts from Hi-Fi Engine. You can register and get them as well. This will help to see if you repaired the boards correctly.

This is the problem of advising people with repairs who only have a volt meter. Part of the basics is having a Variac so that when bringing up a device for the first time you can do it gently and spot problems hopefully before they do more damage.

I have to say that your unit is likely now a boat anchor.