Spice Low Power

[PANAMATIK]

(10-10-2019 03:12 AM)jjohnson873 Wrote:  Bernhart...I'll dig up the pics on the ribbon cable and post it.
As far as the clamshell construction....it was a poor choice IMHO, for HP to use this construction. Before you reassemble the IC's into the clamshell use DEOXIT GOLD to coat the pads of the pc board where the ICs leads contact. One of the challenges is the coplanarity of the IC leads. If one lead gets "lifted" or isn't coplanar with the rest of the leads, you'll have a lead that isn't in contact with the pc board and then your HP-34 won't be electrically functional.

I totally agree with the above. The grooves are the logical consequence of the plastic deformation of the board material with time and reason for bad contacts. Also oxidation is a problem. sometimes I had a black color coating (sulfid) on the pads. I used a drill with metal brush to clean the contacts, but very careful to not destroy the contacts.

The SPICE LP prototype boards are ordered and will arrive soon. Then I can check the contact behaviour. In my test calculator I have already put some solder to the pads for fixing the prototype wires, which also eliminates the grooves. I think this could possibly also a solution for repairing solderless boards without the LP.

Bernhard