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Dave,

The board has only HP numbers and labels and the display unit is a stock
1345A.

The board appears to be divided with the program ROM on the left,
display driver in the center, and the global RAM on the right. Maybe
with lots of coffee I can read through the A8 "how it works" and try to
match it with the new board.

Chuck

On 1/19/2013 10:15 PM, Artekmedia wrote:

Chuck

I just looked and your right.....this has all the fingerprints of being
another "3rd Party" drop in like the power supplies starting in the 90's
...a close look at the board and other stuff related to the display
assembly might reveal the original / "real" manufacturer and trace it
that way?

Dave

On 1/19/2013 8:59 PM, ChuckA wrote:

I recently purchased another 3562A analyzer, this one is late

production

I believe 1990. I have repaired two other units, earlier production
(1984/85). Of course there is a major change between the units, the A8
RAM/Display board isn't used and a new board (A38) is used for the A8
and A3 ROM board.

Problem is there is no display, the display unit is good as I can put
it in the setup mode and everything checks out. I have the service
manual for the later unit and the meager troubleshooting fix for "No
Display" is replace the A38 board. Oh yes, one other thing, there's no
schematic for that board in the manual. In fact other then a passing
note about the replacement board, there is nothing about the A38 board
in the manual.

Does anyone have any experience with this failure mode that could
point me in the direction of what part(s) to try replacing first? Or
have any documentation on this board?

Thanks
Chuck

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