Need advice - Corrosion spots on PCB

[BesaMoogie]

Hi,
I`ve found some corrosion spots on the PCB of one of my 2 channel Dual Rectifiers. I made some pictures of it and would like to ask, what some of you guys think of it.

The spots are on the bottom side of the PCB and seem to be related to the channel cloning and bias switch. I measured the traces affected from it and they have connection.
However, sometimes I think, the amp changes it`s tone after like 20min of playing. Wether this is related to the corrosion or not I can`t tell.

I was trying to locate the affected traces on the schematics but I have problems cause all of the parts that are connected to them are difficult to identify. The labels on the PCB are mostly under the parts.

So what do you think, just leave it? Or make new connections?

 

[mcstinger]

It is flux leftover after resoldering job. You can remove it with isopropyl alcohol. However, I would be very careful the dissolved flux does not get into the contacts, connectors etc.

 

[BesaMoogie]

It is flux leftover after resoldering job. You can remove it with isopropyl alcohol. However, I would be very careful the dissolved flux does not get into the contacts, connectors etc.

Are you sure about this? I am not talking about the yellowish stuff. Here are some marks on the pictures of what I mean.

 

[mcstinger]

Ahh, this seems like the board was repaired. Doesn't look like corrosion to me. Not sure from pics.

 

[Geo]

I would say, if it's working, leave it alone.

 

[BesaMoogie]

Ahh, this seems like the board was repaired. Doesn't look like corrosion to me. Not sure from pics.

I was thinking for a moment that maybe someone was using a dremel or something similar to do this, but I`m not sure.

 

[BesaMoogie]

I would say, if it's working, leave it alone.

It looks like it does. But than again, I witnessed some tone change after like 20min and as far as I remember, the bias was constant when I monitored it.

 

[Geo]

It looks like it does. But than again, I witnessed some tone change after like 20min and as far as I remember, the bias was constant when I monitored it.

Could be tube or cap related.