Spice dilema

[Michael de Estrada]

I have a complete set of the HP Spice calculators, including duplicates of the HP-32E and HP-37E. All of them were in good working condition until recently when my HP-33E would not turn on and I could not recharge the battery. Upon inspection, it became apparent that one of the contacts for the charger had corroded and broken off, so that the battery could not be recharged inside the calculator. This has happened before, and the solution is to simply charge the battery in a different calculator and then transfer it to this calculator, or to simply use regular non-rechargeable batteries. I tried this, but still no success. I then connected my regulated DC power supply to the contacts, but still no luck. Next, I disassembled the calculator and cleaned the switch contacts just to see if that was the problem, but again no luck. Looking closely at the battery contact circuit board it appears that corrosion has extended into the ribbon circuit in the area where it attaches to the battery contacts, such that electrons are not getting from the battery contacts to the main circuit board, and this is not something that is repairable.

OK, so here is my dilema. Do I take one of my good HP-37E units and swap the IC chips with those from my defunct HP-33E, so that I can have one working sample of each ? Or do leave things the way they are now, since I have a perfectly good working HP-33C, which is the same calculator as the HP-33E, except for the additional convenience of continuous memory ? For those of you unfamiliar with the construction of the Spice series, at least the early generation ones, the IC chips and LED array are just press fit into the circuit board without any soldering, so that it is very easy to change them out. I would rather keep the extra HP-37E for future use if something goes awry with my HP-33C, HP-34C or HP-38C, but it just bothers me knowing that I don’t have a good working sample of each model in the Spice series.

[AndiGer]

Try this
http://www.keesvandersanden.nl/calculato...pair_1.php
Andi

[Michael de Estrada]

(01-11-2018 05:43 PM)AndiGer Wrote:  Try this
http://www.keesvandersanden.nl/calculato...pair_1.php
Andi

Thanks for the suggestion, but after taking my unit apart it looks like the soldering skills required are well beyond my ability. So, I have simply transfered the IC chips from my HP-33E to the good connector assembly from my extra HP-37E and put it back together with the same keyboard. It is now working perfectly, and I now have a good spare keyboard, LED array and case back with door. So now my collection of Spice calculators is again complete with at least one working sample of each model. I still have two working samples of the HP-32E and HP-38C.

[Michael de Estrada]

Spice collection update:

The second HP-37E is working again, thanks to another battery contact to power circuit board assembly that I forgot about having in my spare parts drawer. The battery contacts are completely gone, but there is still enough conductive material to make it work with the help of some metal strips wedged between the battery terminals and the contacts. I’m using regular AA alkaline batteries, which result in a tight fit to maintain good electrical continuity. When I turned the calculator on I remembered that a jumper on the power circuit board had been cut, which changes the radix symbol from a period (.) to a comma (,). The thousands separator is now a period, instead of a comma.

So my working Spice collection is now eleven, including two each of the HP-32E, HP-37E and HP-38C.