STE 32MHz PLUG IN BOOSTER (again) 2021 variation

[HigashiJun]

Had some time today to continue my repair:

FDC.jpeg (410.25 KiB) Viewed 6298 times

As I wrote before, the PCB was really butchered by the previous owner (please guys, if you do not know what you are doing, just stop)...

I cannot go further today as I have no more rivets. I have ordered some from the Netherlands and they should arrive soon.

I just hope to finish this tedious job ASAP.

[HigashiJun]

And here is the other side of the motherboard:

FDC 2.jpeg (283.25 KiB) Viewed 6289 times

Cheers.

[tzok]

It looks nice, but I'm afraid, these areas may cause problems:

Clipboard-1.jpg (410.24 KiB) Viewed 6271 times

[HigashiJun]

It looks nice, but I'm afraid, these areas may cause problems:
Clipboard-1.jpg

No worries, they will not...

Everything is checked for continuity and shorts, and so far so good.

[exxos]

I think I agree with @tzok on this .. Overlapping copper on tracks like that isn't a good idea. It will likely come back to haunt you.

It may just be easier to find another STE. Or the way to repair such things , would really be to use thin wire and solder to the tracks and run the wires though the holes so you can solder them.. but such extensive repairs I don't think is a good idea anyway... But also note one side of the connector is all GND's, so you don't really need to do every single one.

[HigashiJun]

I would probably have serious doubts and agree with both of you if such a repair was my first time.

Even if the rivet is overlapping the track, it does not go under the PCB coating - but is just laying on it - and is then perfectly insulated from the copper layer.

And of course, to prevent shorts on the most butchered spots, I use my digital microscope to check if the coating is not damaged. If it is, I then cover the damaged area with epoxy before setting the rivet in place.

I could also use thin wire to have the job done and just do one ground instead of all, but as I like neat repairs, I cannot help myself to fine tune my work...

[exxos]

Even if the rivet is overlapping the track, it does not go under the PCB coating - but is just laying on it - and is then perfectly insulated from the copper layer.

In theory yes.. and maybe even for a short time.. but I have done this type of "trick" many times in the past, and even on brand new PCB's, solder over the mask seems to always manage to short out eventually. So you should never assume the insulation will "protect" you from shorts.. its not reliable..

[HigashiJun]

I never assume prior to trying.

I have more than 3 retro computers repaired that way and they are still working good for more than 8 years.

[tzok]

Even if the rivet is overlapping the track, it does not go under the PCB coating - but is just laying on it - and is then perfectly insulated from the copper layer.

I'm not suggesting shorts, but measure the capacitance. You're basically adding a few dozen pF between GND and each line.

[HigashiJun]

I partially agree on that point.

It might be an issue as well it might not...

Capacitance could wreak havoc on digital and analog signals under certain circumstances, where parallel length of traces, distance between these traces, trace thickness and so on are involved.

And I am not pretty sure the FDC meets the above mentioned circumstances.