HP-65 goes on hold after reading a card

[albertofenini]

Hi Tony, Hi Everyone

don't worry, we will ask Santa to bring us a new reworking station, our is quite dated ..
The hybrid pins reparation works very well, is the hybrid itself that doesn't work ...
To your knowledge, is the process of storing and executing a program involving the ROMS ?
I feel that the storage space for programs is in the hybrid, and the card reader handling as well, so I would say ROMs have little to do with that ...
We have a set from a old unit and we will give it a try replacing the actual ones

It would be nice to know what exactly each ROM ids responsible for, is that complicated ?

By the way, the unit that keeps on all the C segments (Disp0 and RCD low in amplitude...) would benefit from a ROM change ?
HP-65 1605A02841 - weird display and card reader issues

(11-29-2020 10:06 PM)teenix Wrote:  

(11-29-2020 05:03 PM)albertofenini Wrote:  Hi Tony, hi everyone

It has hurt a little since pin 4 and pin 11 broke ...
Anyway, we fixed with two ultra thin cables
Inspection one removed the hybrid didn’t reveal anything
Once the hybrid has been put in place again the behavior was exactly as before

When loading or executing a program it goes in a hold status

Tony How much is worth to replace the ROMs set ?

Hi Alberto,

Sorry, I thought you would just re-solder each pin one at a time while the hybrid was still in place.

I don't know about the ROMs as I have never replaced any.

cheers

Tony

[teenix]

(11-30-2020 10:23 AM)albertofenini Wrote:  Hi Tony, Hi Everyone

don't worry, we will ask Santa to bring us a new reworking station, our is quite dated ..
The hybrid pins reparation works very well, is the hybrid itself that doesn't work ...
To your knowledge, is the process of storing and executing a program involving the ROMS ?
I feel that the storage space for programs is in the hybrid, and the card reader handling as well, so I would say ROMs have little to do with that ...
We have a set from a old unit and we will give it a try replacing the actual ones

It would be nice to know what exactly each ROM ids responsible for, is that complicated ?

By the way, the unit that keeps on all the C segments (Disp0 and RCD low in amplitude...) would benefit from a ROM change ?
HP-65 1605A02841 - weird display and card reader issues

Lucky you :-)

The commands that access the program storage are in each of the 3 ROMs.

I assume ROM 0-3, ROM 4-7, ROM 8-B are in ascending chip numbering

1818-0073 - 1 command
1818-0074 - 11 commands
1818-0075 - 8 commands

All the logic is in the hybrid

Yes a ROM change might fix the display, even though it seems more likely elsewhere.

cheers

Tony

[albertofenini]

What do you mean with 1 command or 11 commands or 8 commands ?
Do they contain specific instructions that are loaded at the power up ?
Thanks !
Take care !

(11-30-2020 11:17 AM)teenix Wrote:  

(11-30-2020 10:23 AM)albertofenini Wrote:  Hi Tony, Hi Everyone

don't worry, we will ask Santa to bring us a new reworking station, our is quite dated ..
The hybrid pins reparation works very well, is the hybrid itself that doesn't work ...
To your knowledge, is the process of storing and executing a program involving the ROMS ?
I feel that the storage space for programs is in the hybrid, and the card reader handling as well, so I would say ROMs have little to do with that ...
We have a set from a old unit and we will give it a try replacing the actual ones

It would be nice to know what exactly each ROM ids responsible for, is that complicated ?

By the way, the unit that keeps on all the C segments (Disp0 and RCD low in amplitude...) would benefit from a ROM change ?
HP-65 1605A02841 - weird display and card reader issues

Lucky you :-)

The commands that access the program storage are in each of the 3 ROMs.

I assume ROM 0-3, ROM 4-7, ROM 8-B are in ascending chip numbering

1818-0073 - 1 command
1818-0074 - 11 commands
1818-0075 - 8 commands

All the logic is in the hybrid

Yes a ROM change might fix the display, even though it seems more likely elsewhere.

cheers

Tony

[teenix]

(11-30-2020 11:20 AM)albertofenini Wrote:  What do you mean with 1 command or 11 commands or 8 commands ?
Do they contain specific instructions that are loaded at the power up ?
Thanks !
Take care !

Whereas the HP-67 does code handling of the program which is stored in memory, the HP-65 does it through instructions that interface to the program buffer which is a separate chip not related to other memory storage.

These are the program buffer access commands and what hexadecimal ROM address they appear in.

pointer advance - Advance the program pointer by one
1EA 47B 49B 49D 930 9F4

mark and search - subroutine handling
444 488 4FC

search for label - Looks for a label like LBL A
4A8 4AC 4AF 4C2 9A7 A09

memory insert - insert a program step at the current pointer position
4E2 A1F

memory initialize - clear the program memory
936 A3C

memory full -> a - determines if program buffer is full
B6B

Memory Delete - delete a program step
091 460 462 4B4

In your case, maybe the [Memory Full -> A] instruction is not working properly. There is only one of these codes in ROM 3 (probably 1818-0075) Through a bunch of other instructions, this is what eventually lights the G segment when the buffer is full.

It may not be the instruction however, as the program buffer and or its logic might be faulty. Hard to tell.

cheers

Tony

[albertofenini]

Hi Tony, Hi Everyone
we swapped the ROMs, all of them but nada ...
We put the spare ROMs in the unit with the C segments always on but it still behaves like that
At this point we took the ROMS taken out from that unit and we put them in the unit the goes on hold, but it still does it ...
I would say both types of problem do not depend from ROMs ...
Would can we try if anything ?
take care !!!

(11-30-2020 12:01 PM)teenix Wrote:  

(11-30-2020 11:20 AM)albertofenini Wrote:  What do you mean with 1 command or 11 commands or 8 commands ?
Do they contain specific instructions that are loaded at the power up ?
Thanks !
Take care !

Whereas the HP-67 does code handling of the program which is stored in memory, the HP-65 does it through instructions that interface to the program buffer which is a separate chip not related to other memory storage.

These are the program buffer access commands and what hexadecimal ROM address they appear in.

pointer advance - Advance the program pointer by one
1EA 47B 49B 49D 930 9F4

mark and search - subroutine handling
444 488 4FC

search for label - Looks for a label like LBL A
4A8 4AC 4AF 4C2 9A7 A09

memory insert - insert a program step at the current pointer position
4E2 A1F

memory initialize - clear the program memory
936 A3C

memory full -> a - determines if program buffer is full
B6B

Memory Delete - delete a program step
091 460 462 4B4

In your case, maybe the [Memory Full -> A] instruction is not working properly. There is only one of these codes in ROM 3 (probably 1818-0075) Through a bunch of other instructions, this is what eventually lights the G segment when the buffer is full.

It may not be the instruction however, as the program buffer and or its logic might be faulty. Hard to tell.

cheers

Tony

[teenix]

(12-01-2020 11:01 PM)albertofenini Wrote:  Hi Tony, Hi Everyone
we swapped the ROMs, all of them but nada ...
We put the spare ROMs in the unit with the C segments always on but it still behaves like that
At this point we took the ROMS taken out from that unit and we put them in the unit the goes on hold, but it still does it ...
I would say both types of problem do not depend from ROMs ...
Would can we try if anything ?
take care !!!

As the problem moved when you switched CPUs to a known working 65, I would say the logical culprit is the hybrid. The only other circuitry is the power supply.

cheers

Tony