HP-32E with errors ...

[ThomasF]

(04-29-2021 06:35 PM)PANAMATIK Wrote:  interestingy I have the HP-32 ROMs here in my spare parts box, because I upgraded my HP-32E to an HP-32E SPICE LP. Possibly your calculator could be repaired by them.

Bernhard

Late update!

I contacted Bernhard who sent me a set of ROMs from a HP-32E, and I managed to fix the faulty calculator into a working one!

When I started, I had a failing 32E (selftest reported Error 9), and this device had two chips installed (there a 3 possible chip positions, and I number them 1-3 with 1 being closest to the display):

1: 1MA1 0209
2: (empty)
3: 1MA 304

   

The chips I got from Bernhard was the following:
(Note that I didn't know the original position of these)

a: 1MA1 0009 (ROM)
b: 1MA1 0010 (ROM)
c: 00031 80008 (RAM)

The donor was a HP-32E which was enhanced with his HP-32E SPICE LP circuit making the ROMs superflous). In a second 32E Bernhard had the following chips (similar to mine):

a: 1MA1 0209 (ROM combined with RAM)
b: 1MA1 0010 (ROM)

So, I first replaced my chip 1MA 304 with the 1MA1 0010, but I couldn't see any changes after that, the calculator worked just as before, with the same faults.
Then I also replaced my 1MA1 0209 with the 1MA1 0009 and that made all the difference (I thought!).
After this step, the calulator now contained the following:

1: 1MA1 0009
2: (empty)
3: 1MA1 0010

The selftest passed, and everything looked ok, but it wasn't ... the RAM was of course missing (so STO/RCL/Sigma+ etc didn't work) as the 0009 is only ROM - no RAM - compared to the 0209 chip.

I then tried the following combination:

1: 1MA1 0009
2: 00031 80008 (RAM)
3: 1MA1 0010

   

Then I was back where I started! Selftest didn't pass, and it worked even worse then before (failing SIN/COS etc which worked before).

So, as a final step I swapped the RAM and ROM chip to the following order (as proposed by Bernhard ):

1: 00031 80008 (RAM)
2: 1MA1 0009 (ROM)
3: 1MA1 0010 (ROM)

And finally - the HP-32E was restored to a completly working condition! Selftest passing, and memory works as expected.

   

My conlusion is that the original 1MA1 0209 in my device was failing, but if it was the RAM or ROM-part I don't know (I suspect the ROM since STO/RCL etc was working ok). A bit strange that the device was failing when the RAM was positioned in port 2, since I was told that the order shouldn't matter - at least not for E-versions (in C-versions the order is important), but apparently the order is important even here.

So again a big thanks to Bernhard at Panamatik to help me (again) restore a classic LED HP calculator back to life!

Hope someone find this information helpful - and that there are help to get when restoring the old beautiful devices!

Cheers,
Thomas