I need an HP-65 & HP-45 circuit boards

[teenix]

Off hand it seems like some part of the ROM has failed. This seems more probable due the incorrect result from the diagnostics program which should have finished with all LED segments lit up (all 8's and the 2 neg signs).

If so, then a repair seems unlikely without some spares to try out. A shame that you now cannot know if it worked before starting the recondition.

I would have a close look at the soldering and circuit traces around the ROM chips. If you have a voltmeter, check the supply rails. If one is low (or high) then it may interfere with correct operation.

As a last resort, Harald probably still has Classic replacement CPU boards available for the 45 and I have 65 replacement CPU boards available.

cheers

Tony

(03-23-2020 06:25 AM)JohnRausch Wrote:  45 is board definitely dead.

65 freezes on trig functions and providing bad f-key results from bottom row. INT results in no change, though the display make a change like it is working. Tested in other 65s, same results. Contacts cleaned. 18A diagnostic ends with full display of zeros with minus sign.

Any tips for a fix for the 65 I could try. It's an otherwise excellent calculator. Silly me did a complete recondition before testing the board. Early 1333A 0574. I would like to get it working.

I've been quiet since way back in the 65 Notes era (member #88, good friend of Dean Lampman) days when I was doing a lot of 65/67/41 coding, This virus has me reconditioning machines again. The 65 is my favorite. Something very special about it. Perhaps forgoing a new car when it came out!

Sent a 65 and pack card images to Willy Kunz who writes incredible emulators for IOS. I encouraged him to write a 65 and sent him a working 65 because you must have one to include and understand all of its quirks.

Learning more and more about what makes an excellent recondition. The old "repair" articles on this site are long surpassed.

Having fun and have several parts. Ask. Also making what I think are better AAA battery packs. not more functional, but better cosmetically. Not selling them yet, if ever. Very easy to make

But if you have either of those circuit boards or a totally trash 45 or 65 with all else not worth messing with, let me know -- or maybe an answer to that bottom row and 3rd from the bottom giving crap results.

Nice to see familiar names.