Hi all,
I am still fighting to revive my second HP3457a
As suggested here, I bought a used 44701a board and salvaged the A/D converter 1QF6-0066.
Unfortunately, this didn't help, since the A/D controller (A2 U501) seems to be faulty.
When I power it up, it shows :
ADDRESS-22 and immediately after, it shows
FAILEDit does not beep and the keyboard does not respond except the
RESET key.
If I press RESET, it beeps and restarts but does exactly the same thing.
The main controller board (03457-66511) works fine, I tested it on my other HP3457a.
I also suspected the communication between the main controller A11 U601 and the A/D controller, replaced optocouplers A2 U509 + A2 U510 +A2 Q501 + A2 U502, it did'nt help.
As far as I know, A2U501 is a masked ROM P8051.
Is this something that could be "cloned" ?
I mean, somehow read the program from a good one, buy a blank programmable one and somehow flash it ?
Thanks for your help
Kind regard