Re: HP 1000 A400 repair #HP1000

Roland Dietiker

Hi Glen
Thanks for this useful complementary information about the contents of the Firmware ROM.
I have also found the sources on bitsaver with PN 12100-1xxxxx Rev 4012 as Master Files..

I am missing in the ERD for A400 the Part containing the Part Location on the board and the list with the Replaceable Parts like in the A900 ERD 3-46 and following pages.
It seems not to be planed for this manual.
Did you know where this specific information could be found for A400?

Best regards

-----Urspr√ľngliche Nachricht-----
Von: [] Im Auftrag von Glen Slick
Gesendet: Montag, 30. November 2020 07:33
Betreff: Re: [VintHPcom] HP 1000 A400 repair #HP1000

On Sun, Nov 29, 2020 at 9:35 PM Roland Dietiker <roland.dietiker@...> wrote:

Hi Rainer

I propose to exchange the VCP EPROMs (U908 U1108, 2764 EEPROMs) and check if the error allready persists. This is the easiest way to exclude an error on VCP EPROMs.

If this not change the situation, let me know which FW revision the board contains: partnumber of the firmware ROMs 12100-800xx (212, U312, U1412, U1512, U208).
The Communicator/1000 for Software Update 6.0, 5961-6201, December
1992 manual lists these 4 sets of part numbers for the A400 microcode PROMs U1212 - U1512:

12100-80010 - 12100-80013
12100-80015 - 12100-80018
12100-80019 - 12100-80022
12100-80023 - 12100-80026

As far as I can tell there might actually only be one version of the microcode for the A400. The different part numbers might just mean different blank PROM parts, that is 4K x 8 vs 8K x 8, and different part vendors.

I have one A400 CPU with DM87S421 4K x 8 PROMs screen printed with the
12100-80010 - 12100-80013 part numbers. I dumped the contents of those PROMs and they are identical matches for the 12100-16005_Rev-4012.src - 12100-16008_Rev-4012.src ASCII-Hex file format source for those PROMs in the HP 1000 Software Archive. And those appear to match the A400 microcode source files 12100-18003_Rev-4012.src and 12100-18002_Rev-4012.src and the assembled listing files 12100-17005_Rev-4012.src and 12100-17006_Rev-4012.src.

I have two A400 CPUs with CY7C263 8K x 8 PROMs (actually OTP EPROMs) screen printed with the 12100-80023 - 12100-80026 part numbers. I dumped the contents of those PROMs and they are identical matches for the 4K x 8 set 12100-80010 - 12100-80013, but with the first 4K half set to zero in the 8K set. The A400 CPU schematic shows that the CS3 /
A12 pin of the microcode PROM sockets is tied to a +5V pullup so only the second 4K half of the 8K PROMs is accessed.

Join to automatically receive all group messages.