The Museum of HP Calculators

HP Forum Archive 13

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Message #1 Posted by Howard on 20 June 2003, 6:37 p.m.

I recently purchased a HP55 off Ebay. The advertisement said it works fine but it doesn't. Before I try to get my money back I'd like some advice in case I'm doing something wrong or else it is a simple problem to fix. I don't have the manual but MOHPC site says to Press GTO 00 then move switch to programme and then press the sequence of keys. I do this and the line (with 1 exception) reads "01. -15" for every entry. The exception is that if I press GTO 1, 2 or 3. What is going on??

Re: HP55
Message #2 Posted by Vieira, Luiz C. (Brazil) on 20 June 2003, 7:07 p.m.,
in response to message #1 by Howard


I have an HP55 and if I switch it to ON and set mode switch to PRGM and press nothing else I see [ 00. ]. What do you see in yours if you do the same?

The [ 01 -15 ] display indicates you pressed [GTO] [1] [5], or GTO 15.

For the records: which keys did you press? Can you list them?

Thenk you.

Luiz C. Vieira - Brazil

Re: HP55
Message #3 Posted by Howard on 20 June 2003, 7:17 p.m.,
in response to message #2 by Vieira, Luiz C. (Brazil)

Switch on 00 Press "g" -15 press any key except GTO 1, 2 or 3 gives the same result.

Re: HP55
Message #4 Posted by David Ramsey on 20 June 2003, 7:45 p.m.,
in response to message #1 by Howard

The HP-55 has 50 programming steps, numbered 00-49.

With the program switch set to "Run", pressing GTO xx where xx is a two digit number between 00 and 49 will set the program counter to that number.

If you press GTO 23, then move the switch to PRGM, the display will read:

23. -00

The "-" is the 55's shorthand way of representing "go to". Thus, when there's no program in the calculator, every step is "GTO 00", represented as "-00".

All GTO addresses must be two digits. If you try to enter an illegal line number, i.e. GTO 56, the GTO will be ignored and the two digits will be entered by themselves. In this case "5" and "6" would be entered as separate steps.

Try this:

1. Turn calc off, then on.

2. Move switch to PRGM.

3. Press these keys: ENTER, 2, /, 5, 2, 8, 0, X, R/S

4. Move the switch back to RUN. Press GTO 00.

5. Enter "23" and press "R/S". The display should flicker and show "60720".

I suspect your calc works fine. Have you used any of the older keystroke programmable HPs before?

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