Can someone tell me if I can perform a test for functionality and which buttons to push.




locate the [ON] key and [C], [D], [E] and key. With the calculator switched to ON:

1 - press [ON] and hold;

2 - press [E] and hold;

3 - release [ON];

4 - release [E];

The test is "circular"and starts over after reaching the end. You should see "OK 48 SX" as a result for test OK. The self-test may be interrupted anytime with:

1 - press [ON] and hold;

2 - press [C] and hold;

3 - release [ON];

4 - release [C];

To test the keyboard:

1 - press [ON] and hold;

2 - press [D] and hold;

3 - release [ON];

4 - release [D];

You'll see three vertical lines.

5 - press [E];

you'll see "KBD1" in the top of the display. Now press each key on each roll, begining with the leftmost on the top roll ([A]) continuing to right till the last one ([F]) and going donw to each roll, always left to right, top to bottom.

After the last key is pressed ([+]), the display shows "KBD1 OK". If one key is not pressed (bad contact) or repeats, "KBD1 nnnnn" is shown, where nnnnn is an internal code for the missing/repeated key.

In both cases, the kbd test may be interrupted with the sequence:

1 - press [ON] and hold;

2 - press [C] and hold;

3 - release [ON];

4 - release [C];

These sequences are also known as [ON]/[C], [ON]/[D] and [ON]/[E].

Hope this helps.

Luiz C. Vieira - Brazil


I'll add a few other useful tests that can be done once you're in the
[ON]&[D] interactive self-test mode:

[H] is a wired UART loop back test. *Gently* short the transmit and
receive pins (the two center pins) together, or better yet, attach a
cable and short the the transmit to the receive signal at the other end.
If it passes, then "U_LB OK" will be displayed.

[O] is an IR loopback test. For this one, have the IR/port cover in
place, or point it at something white (within a couple inches), so that
you'll get some reflected IR. this one should display "IRLB OK" if it

[K] tests port RAM devices. The ports can be either free or merged. If
it passes, then the results are displayed as "RAM1 OK" or "RAM2 OK" in
the upper left, and "32K" or "128K" in the upper right. The RAM1 results
are displayed very briefly. For a 48GX with a multi-port card in slot 2, I
surmise that only port 2 is tested. If a card is missing, or is a ROM
card or write-protected RAM card, then the test for that port will fail.
Personally, if I don't see an "Invalid Card Data" when I turn the
calculator on, I assume that the cards are ok. In the case of an
"Invalid Card Data", storing anything in each of the ports should clear
it up, or in the case of the 48GX, the PINIT command is available to
initialize all ports with one command. So maybe this test isn't very
useful after all.

And of course, use [ON]&[C] to do a warmstart to get out of self-test





Hi, Steve;

thank you, too. A feedback means our help succeeded. BTW, did your SX succeed as well?

Also, if you want to go further, James' post describe usefull tests, too. If you are new to the HP48 team, it's a good idea to know if internal circuits and external ports/connections are fine, too. These are major positive points in an HP48: expandability and external comms; in easy, standard ways.

Best regards.

Luzi C. Vieira - Brazil

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