HP-65 goes on hold after reading a card

[Kostas Kritsilas]

(11-30-2020 03:34 AM)teenix Wrote:  

(11-30-2020 02:25 AM)Kostas Kritsilas Wrote:  I don't believe that the person attempting the repairs used an oscilloscope, as his background is in chemical engineering. He said he did inspect all the traces going into and out of the card reader ICs under magnification, and said they were fine, and verified them with a multi-meter.

He had some spare HP-65 card reader parts, and said that he tried to repair the unit with them, but then found out that the spare units themselves were bad. he also said that he would be putting his own spare HP-65s up on eBay as non-working units. he also said that the HP-67 heads are better in this regard, as they use a thicker, better insulated wiring between the board and PCB.

This is all I have on the repair process. The statements about the read/write head being bad, whether it was the leads going to the head, or the head itself, came from the person attempting to repair the unit. I can forward the relevant emails in direct messages if anybody would like to see them.

What a shame the parts were unusable.

Without an oscilloscope check, it would be hard to define where the problem might be.

On reflection, I guess it is hard to test a card write because you cannot read it back again unless you have access to another 65.

cheers

Tony

He did have a working HP-65, with which he used to verify that my card reader was bad, and his own HP-65 spare card reader parts were bad as well. I don't think he was aware that the HP-67 read/write heads are interchangeable with the HP-65 read/write heads. He did say that he could not repair the HP-65 read/write heads as their wires were, to quote him "hair thin" and he did not have the soldering skill to attempt that. He did say that he would not be working on HP-65 card readers any more, and that the read/write heads on the HP-67, because they were larger in diameter, were a lot more reliable, and easier to work on.

I think I am hijacking Alberto and Edouardo's thread, so I think I should stop posting about my HP-65 issues. If anybody would like to discuss this in further detail, please direct message me, and I will give you any information that I can.