HP-65 goes on hold after reading a card

[albertofenini]

Hi Tony
this is what we tested :

Storage Register : these all works well
Yesterday it was me using them wrongly
You can store in any of the 1 to 9 registers, you can recall the values, and you can do storage register arithmetic as well

Writing a program : we followed the example on the quick reference guide,
LBL E ENTER ENTER x x RTN, and it works, we even wrote it on a card,
turned off the unit, read it from the card and it worked, it was also read from
other units with no problems, I would say that the card reader works fine ...

Standard Pac programs : some programs like Day of the Week, Temp Conversion, Weight conversion are read with no problem and run, most like the Diagnostic don't
This behavior is consistent also using other Standard Pacs

Then, we have put into this assembly one known working hybrid board and everything worked perfectly, no problems at all
I would say the card reader and the led/keys boards are ok.

On the opposite, we have put this hybrid board in another unit and all the wrong behaviors were exactly repeated

I would say that the problem is within the logic board at this point ...

Could it be a ROM/RAM problem or one of the chips inside the Hybrid is failing ?
We have a set of the ROMs, would you suggest to try to replace them ?
All, one in particular ?

Thanks for help !!!

(11-15-2020 03:40 AM)teenix Wrote:  

(11-15-2020 12:13 AM)albertofenini Wrote:  Hi everyone

this is a unit that we restored a while ago but never truly tested
Few days ago we replaced a coil following the advice of Teenix (thanks for help !) and fixed an issue that was causing the G segment to be always off (the related coil was open)

We discovered that when a card is read, a steady 0.00 appears, but when we try to execute the loaded program, the unit goes in a non responsive status.

With the diagnostic card, to name one, it happens just hitting the R/S key in order to start the test
With the Temperature Conversion, to name another, you can input a value and it locks immediately after that

When used for standard operations it works with no problem

I may be wrong but with a number on the screen just typed, pressing STO will make
a .00 appears after the digit, but then pressing RCL won't recall the number.

Thanks for any idea you may want to share in roder to possibly fix it
Let us know if we can upload anything that can be of help

Take care !

My emulator shows the entered number plus [00] on the display after STO is pressed if FIX 2 is selected.

Are you pressing (say) STO 5, then use RCL 5 to recall it.

Can you write a program and switch to RUN mode and execute it? Does it read with a known good CPU board?

If so, then problem could be the card reader, the CRC chip in the hybrid, the usual copper traces, connection from card reader to CPU board etc.

I guess invalid data could be read from the card which confuses the CPU board when the code tries to run.

cheers

Tony