System 11 MPU corrosion repair

[arakissun]

I will try ti save this board for a customer.
Very very bad one.
Let's see what will happen.
Several pictures of the progress.

1-phase-all holes one by one cleaned with cutter knife very carefully.Checked every trace and all of them are OK.
2-phase-reflow all holes.
3-phase-made this beautiful holes.
This was the hardest work.

Next it to replace all elements again near the corrosion area,upper left corner and some of 2n6427 transistors because they are corroded too and the elements around Timer 555.

 

[arakissun]

What are all these "B" elements?

 

[arakissun]

Now it's done.It left to put new sockets and new ICs.

 

[arakissun]

Almost finish.
Several components left to be put.

 

[PBrookfield]

Spectacular clean up job on a very, VERY corroded board, very nice work.

Adding sockets for ALL of the ICs is a very classy touch. I hope you're getting adequate compensation for this!

C43 down in the corner looks like it'll need to be soldered on the backside of the board - no trace left on the through hole and the via itself is probably totally gone - thankfully it doesn't have any traces on the component side to have to jumper. But something tells me you're several steps ahead of me

 

[arakissun]

Thank you.
Yeah C43 will be solder from backside and it's traces are from backside so no worries for this.

 

[arakissun]

What type are the capacitors C41-C48.
I can see them from the manual 47pfd,50v,axial,but they look like Resistors.
When I was in the electronic shop,they told me that never saw capacitors like these green one.
Can I put from this type?The shop offered me these

 

[PBrookfield]

They're just ceramic capacitors - some of the older ceramic types that are in axial packages look like resistors. Virtually never see them anymore and I think it's because they indeed just look like resistors, so it was confusing.

Nothing wrong with using the normal ceramic ones like those you pictured.

 

[arakissun]

Thank you for the help.

 

[arakissun]

Finally PIAs arrived before several days.Put them.Run the board and everything works.
I'm very happy and the customer too.And he paid me good too.
This was my biggest corrosion project.Usually I don't like this type of fix but because in my country these boards cannot be found anywhere and usually the customers don't want to pay worldwide packages I need to fix them.