Programming HP67



#2

I have recently purchased an HP67 from Ebay.
It is acting real weird in programming mode.
For the first seven programme steps every line is the same - 001 31 25 24 - no matter what keys you press. After the seventh line all keys act correctly. It isn't a sticking key because it rights itself always after the seventh line.
It does it every time. It seems to me like the programming gets in a tangle for a while. I have tried shorting across the two battery terminals (without batteries in) Don't some HPs get static build up or something. Anyway it has not fixed it.
It does this so regularly and behaves normally that I think it must be something simple like set flags or something like that.
It seems to do this after loading a pre-programmed card as well.
Help!!! It is driving me nuts.


#3

Once had an HP-25 that did something like that.

You might have to either:

a) Live with it and only write programs in the last 217 steps.

b) Find a dead HP-67 and see if you can transfer the memory chips from the dead HP-67 (assuming the dead 67's memory chips are ok) to your HP-67.

or

c) Sell it and keep looking for one that works completely.

It doesn't sound like something that is fixable short of surgery.

sorry! --Gene

#4

On the HP67, each program step is one byte. So 7 steps = 7 bytes = 56 bits = 1 'register' (this is the size of a floating point number too).
It sounds like you have a dead register in one of the RAM chips (I would guess the instruction you're seeing is the one corresponding to a value of 255 (all 1s) or 0 (all 0s) in the memory)
In the HP67, the RAM is combined with the ROM in the 8 pin ICs on the logic board -- and they're all HP custom. You will have to find another HP67 to take parts from :-(


#5

OK.
The next problem is which chip is which?????


#6

The Museum CD-ROMs have a service manual for the HP97, if I'm not mistaken, it should have the same chips as the 67.


#7

As it turns out I have a second HP67 with a non working card reader.
So I have taken the whole removable board from off that one and placed it in the other.
Problem sort of solved.
I now have one fully functioning HP67 and one that works after a fashion.
I can still programme with it but I have to start my programmes on line eight. Like so -

001 - anything. It types 001 31 25 24
002 - anything. It types 002 31 25 24
003 - anything. It types 003 31 25 24
004 - anything. It types 004 31 25 24
005 - anything. It types 005 31 25 24
006 - anything. It types 006 31 25 24
007 - anything. It types 007 31 25 24
008 31 25 11 (label A)
008 44 (clx)
programme start.


#8

As it turns out I have a second HP67 with a non working card reader.

So I have taken the whole removable board from off that one and placed it in the other. Problem sort of solved.

I now have one fully functioning HP67 and one that works after a fashion.

I can still programme with it but I have to start my programmes on line eight. Like so -

001 - anything. It types 001 31 25 24.

002 - anything. It types 002 31 25 24.

003 - anything. It types 003 31 25 24.

004 - anything. It types 004 31 25 24.

005 - anything. It types 005 31 25 24.

006 - anything. It types 006 31 25 24.

007 - anything. It types 007 31 25 24.

008 31 25 11 (label A).

009 44 (clx) programme start.


#9

You fixed it the way HP would have fixed it back "in the day". The repair depot probably had plenty of all the boards and just threw away anything defective. Anybody know where the Corvallis garbage dump is?

#10

Hello, Tony;

if we can base ourselves in the HP41's "RAM arrangement", then we should look for a series of two to four IC's with the same prefix (like 1LAxxx), replace the lowest-numbered one and try the calculator reaction.

I think RAM number may be close to the one found in the HP34C; better yet, the same one found in an HP67. I do not have an HP67 in hands, but a few days ago a call for help about an HP34C and its RAM chip is idententified with the prefix 1LB. As the HP34C has a lower amount of RAM, chances are that we'll find at least two RAM IC's in the HP67/97.

I tried to look at the MoHPC internal photo of an HP67 and, even without reading the # ID, the three top-right DIP-8 IC's seem to share the same code (MOSTEK MK-something), I'd guess RAM, while the lone top-left has a different code, maybe ROM.

Just my (doubtfull) US$ 0.05

Luiz C. Vieira - Brazil


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