HP82240a self test

[mendesp]

Hello,
When I do a self test on my hp82240a printer, the characters print correctly but the message BAD INT appears at the end of the test. Could someone please tell me what this is about?
On the other hand, my printer continues to work without a problem with an H42s or a DM42.
Thanks for your help.

[rprosperi]

Though I don't know what that means, where is that printed with respect to the battery strength status, above it, below it, in lieu of it, etc? Knowing that might help to understand it.

Related - does it properly report battery strength and is it printed even with brand new batteries?

[mendesp]

To make it clearer, here is a copy of the printout. You will have noticed that the message is rather INT BAD.

[mendesp]

Sorry about the attachment, the picture was too large.

[mendesp]

The message is printed with brand new batteries, with batteries and 12V dc adapter and with adapter and no batteries.

[Didier Lachieze]

(06-21-2022 04:12 PM)mendesp Wrote:  The message is printed with brand new batteries, with batteries and 12V dc adapter and with adapter and no batteries.

I don't think it is too important if you print successfully from your calculators. The only reference I've found on the internet is in this article from a Japanese site about the HP 82240B:

Quote:If you turn on the power while pressing the paper feed button, the self-diagnosis function will be activated. In the self-diagnosis function, the remaining battery level is printed from 0 to 5 at the end. I've seen INT BAD printed after F, but I'm not sure what's wrong (it was fixed after turning the power off and on several times).

Note that on the 82240B there is a factory code letter printed at the end of the character set, here it's F, which is not present on the 82240A.

[mendesp]

Merci Didier pour cette référence !

I'm going to try turning the printer on and off a few times and hope the problem resolves itself. For what it's worth, I noticed that after the +- symbol, other printers show the letter D, E or F. This may be related to the firmware version.

In the end, I'll just forget that there's a problem that seems minor with my printer.

Thanks to all !

[TomC]

It's curious/fascinating that this issue has never occurred (to our knowledge) in the decades since this component has been in service.

I would suspect that when the printer performs it self test, it performs a checksum. For whatever reason, your printer fails this and prints the 'error message'.

It's great though that the printer still functions properly.

I wonder if anyone can trace down who wrote the code for the (I believe it's an 8050?)processor that operates this printer.

Regards,
TomC
====================================================
I'm going to try turning the printer on and off a few times and hope the problem resolves itself. For what it's worth, I noticed that after the +- symbol, other printers show the letter D, E or F. This may be related to the firmware version.

In the end, I'll just forget that there's a problem that seems minor with my printer.

Thanks to all !
[/quote]

[cesarb94]

Mine does that too, but randomly. Sometimes it appears, sometimes it doesn't. However I did not notice any problems when printing from my 50g.

[TomC]

This is very interesting in that the failure is intermittent.

While I'm not too knowledgeable on the 82240, I believe the processor relies on an interrupt from the IR receiver circuitry.

Perhaps this intermittent case is due to an 'edge' situation where the timing of the interrupt is late. If this is due to a timing condition, it could be due to an aging capacitor in the printer.

And in the first-mentioned case the capacitor has detiorated to the point such that the timing error is greater - causing the failure all of the time.

I wonder if anybody has (or can do)/done a study of the timing within the 82240; and further the timing within a failed unit.

Just some thoughts/several cents,
TomC
======================================

(06-24-2022 01:44 AM)cesarb94 Wrote:  Mine does that too, but randomly. Sometimes it appears, sometimes it doesn't. However I did not notice any problems when printing from my 50g.

[mendesp]

Thanks TomC for your thoughts. When I get some free time, I'm going to take my printer apart and see if I can replace the capacitors. I hope they will be easy to find. Once done, I will post the results.

[teenix]

A factory ID letter is supposed to be printed at the end of the list after the +/- symbol. This letter is supposed to be "for factory use only" and is not appearing.

I'm wondering if the ROM has a "bad" byte in it and is causing some confusion in the processor.

cheers

Tony