IBM 5150 - MDA - Parallel port Error 432

[tradde]

Nice work.

 

[modem7]

And all is good again.

Excellent.

I never did find the fault under the IC’s , possibly just some flux or solder flash, or something inside the board layers…

It won't be flux. My understanding is that deteriorated flux stil has a high resistance (only affecting high resistance/impedance circuitry.)

A nice new bodge wire, yellow for consistency. A bit thicker.

Regarding the IBM-fitted yellow wires. Looking at the end of one of the wires, could it be that some of the patch wire fitting was being done by someone in on 'work experience'.

 

[T-R-A]

Looking at the end of one of the wires, could it be that some of the patch wire fitting was being done by someone in on 'work experience'.

View attachment 1254381

Indeed. No one with real experience would leave that much bare wire over a trace (much less 3 of them) and put the run-wire that close to another pin. Vibration would eventually take a toll.

 

[fdiskitup]

I think they were just slinging them out as fast as they could make them back in 1982… next on the list: model F keyboard foam. Not looking forward to this.