Testing

WARNING:
If, at startup time, the normal display doesn't show up (either blank screen or strange patterns), REMOVE RAPIDLY THE BATTERIES!!
Reopen to check for soldering bridges and for bad soldered pins or wires...
I have had many times this problem... It didn't burned my HP, but I can not say it will not destroy yours!

To test new memory inside the HP48G, press ON, then ON-D to enter test mode, and after the vertical line(s) apear press the "k" key (arrow up). After this the display should say "RAM1 OK 128K" and something like "RAM2 90000". The first "OK" just stays on my display a very short time. Press "k" again to test it another time if you missed the message... Leave test with ON-C.
To test the new internal 128K (the previous test was an external port-mem test only), press ON, ON-D, and then EEX. Now wait for a message stating "IRAM OK 128K". Leave the test with ON-C. Don't be afraid if you see a "fail 100" or "fail 180" mesasage at the end ! This message was already present before you upgraded your calculator, and as far as i can see the "fail 180" means that both port-1 and port-2 memory are missing, and in the same way "fail 100" indicates the missing port-2 memory (you only installed port-1). So if everything is Ok, you should see the "fail 100" message after doing the upgrade.

To get rid of the "Invalid card data" message, type PINIT, or just start using the port.
I wish everybody good luck on doing the upgrade !
HP-256K HP-original
There's now 256K of ram! "You know what? I'm happy..."
On the left: Jean-Marc (the pictures are his HP)
On the right: Myself