TI-58 fault - repairable?

[Garth Wilson]

My first suspicion would be a shorted capacitor, followed by a bad IC.  I think it's pretty unlikely that a diode or transistor would go bad without being abused.

(08-23-2023 10:25 PM)teenix Wrote:  A bit off topic, but I always wondered why, on circuit boards of this era, the protective coating always has a bubbled effect on the traces.

It was common to put the solder plating on the copper before applying the soldermask; so when things were soldered, solder would run down under the trace.  Today it's normal to do soldermask over bare copper (SMOBC), before solder-plating the pads.