HP-65 card reader repair - can't write card, but can read

[jay]

(10-06-2016 05:58 AM)Geoff Quickfall Wrote:  Okay!

Can you test the card in another hp65?

Did you check the current draw on the motor when adjusting the motor -or- did you try the hit and miss card read write then turn the eccentric. The second method is more time consuming. There may be a very narrow range of read and write on the eccentric adjustment.

Other factors, motor speed, magnetized head, dirty head, bad card.

Clear the program memory, run a blank card through to write a blank card. Then switch to run mode and insert the card. Still blinking?

I don't have another unit to test the card.

I tried both the current draw and the trial and error method, though admittedly my adjustment steps were quite coarse. I read that the ideal motor current with the card stalled is 180 +/- 20 mA, but couldn't get the current to go below ~320 mA in that condition. I get ~120 mA with no card, and ~220 mA while the card is running through. Does that indicate that I may have compressed the o-rings too much when installing them such that the OD is too large? What is the correct OD?

I just tried writing and reading a card after clearing the program memory, and I still get a blinking display.

Thanks for the help. Your insulation coupler tips were very helpful.