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picked up two HP48s units today; would someone please post
the self test procedure? tnx in advance, barry, carson city, nevada


"major" self-test is started with the

sequence, i.e., with the calculator switched to ON:

press and hold [ON] key

press and hold [E] key

release [ON] key

release [E] key

This starts a cyclic self-test that would ends/starts-over wiht a beep and a

message at the top-left corner. To stop the cyclic self-test use the
sequence, i.e.:

press and hold [ON] key

press and hold [C] key

release [ON] key

release [C] key

this restarts the calculator and does not clear memory contents EXCEPT for stack, suspended programs and, consequently, local variables.

There is an interactive-mode test with the [ON][D] sequence, that starts, beeps and stops with three vertical lines. Press [E] key and a

message appears in the top-left corner. Press all keys in each line from left-to-right, top-line to botton-line, [ON] key in the sequence, and after the last one is pressed, the message changes to
. If you miss or repeat a key, an ERROR message appears and you can start it over with the [ON][D] and [E] keys again.

Hope this helps.


Luiz C. Vieira - Brazil

both "passed the tests"!!
these came out of a high school, and they marked the units
on the backside w/ the name of school in what appears to be
felt marker - an attempt at cleaning w/ windex did nothing,
what might i use to remove the markings which wouldn't hurt
the cases?
tnx in advance,
carson city, nv

Hi, Barry;

I'm glad "they made it".

About the back inscriptions, I am not sure about what to use. I have not much knowledge on chemicals, but there is a contributor in here that deals with this subject, I'm not sure about which of them. Plastic used it the HP48 series is somewhat flexible, it's the same used in Pioneers (HP42S, HP10B, HP17BII, etc.) and I do not know how would it react to ink solvents.

I'm sorry I cannot help in this matter.

But I am sure you'll be answered soon.

Best regards.

Luiz C. Vieira - Brazil

Denatured alcohol does a reasonable job on permanent marker. Keep it away from the keyboard bezel and especially away from the older pioneers with the window in front of the lcd. It will leave stains you can't get out.

I have found the older brown Pioneer cases to start to show white specs if you rub too hard. Multiple applications without a lot of scrubbing pressure is better.


thanks for the advice.

Should Barry be aware of what sort of marker (or ink) was used before trying any sort (even soft) chemicals? I think if he knows what ink was that it would easy the removing job.

What do you think? Hey, Barry, is it easy to identify what sort of ink is that?

Best regards

Luiz C. vieira - Brazil

If it's "Sharpie" marker, it should come off with the DA, paint pens are a different story. They tend to go gooey and smear, quite a mess. I haven't found anything for that, as it gets down in the "pores" of the textured finish.

hard for me to tell, it LOOKS like sharpie or some other
felt type marker; will report back tomorrow, THANKS to all
who responded!
carson city, nv

it LOOKS like sharpie or some other felt type marker

I have taken sharpie writing off of LEXAN with 70% isopropyl achohol no problem. Now with an HP case I have never tried.


The best ink solven I have found is called OOPS! Latex Paint Remover. It does not seem to affect the case or labels. Best to keep it off the keyboard and display though. Another solvent about as good is white gas/Coleman camping fuel/cigarette lighter fluid. Same cautions as above in regards to the keyboard. It does not hurt the LED/LCD window, and in fact I use it to wet red jewlers rouge to polish scratches out of the display windows.

I have found alcohols can leave white marks on the case and will definitely stain the LCD window.