Fixing a HP34C

[teenix]

I don't think the components are missing, other power modules, that I have seen, do not have them either. They may have been installed but were considered redundant by the engineers.

Because of the original solderless construction, there could be open circuits causing the failure especially if the spongy layer has collapsed over the years. This provides the pressure to hold the integrated circuits connected to the flexible circuit film. The same applies for the display module.

Upon re-assembly, you would have to check all the connections to see if power and signal paths are still valid. This could only be accomplished with an oscilloscope. Without one you could only apply pressure to the circuit board in the hope that it springs back into life.

Having said all that, there could be failed components causing the issue.

Solderless assembly was probably seen as an innovative design back in the day, but over time maybe not so good, hence latter models were back to using solder again.

I have seen examples where the parts have been soldered to the film layer, but you would have to be careful not to overheat it.

Here is a service file for E series calculators.

cheers

Tony