[Techtoolslist] Looking for Fluke 9010a U62 (82S123) PROM Image
Grant Goodes
grant.goodes at gmail.com
Wed Aug 9 10:30:08 EDT 2017
A list-member kindly provided me with the image-file for U62, and I
have provided that to John, along with a small PDF describing the logic
of the bank-select circuit, and that has now been uploaded to the FTP
site under the Fluke/9010 Series/9010 ROMs directory. I hope that this
will help out others who had this problem.
Turns out that, yes, the 82S123 in my friend's board had failed, and
the contents were reading incorrectly. Burned a new PROM, but that
didn't fix the non-booting issue, so there's something else wrong. At
this point, we are suspecting the Watchdog circuit, and will debug that
next.
grant..
On 2017-08-03 4:49 PM, Grant Goodes wrote:
Hi list-members,
A friend has a Fluke 9010a that won't boot. After finally tracking
down a z80 pod, we used my functioning 9010a to do some debugging
(using information in the Service Manual), and figured out that the ROM
at 0-3FFF was colliding with the ROM at 4000-7FFF: When you try to read
address 4000, you get the contents of address 0. Schematic spelunking
implicates the Memory Page Selector chip U62 which is a 82S123 PROM.
We could just replace the PROM, but I've not been able to find the
image-file for this one. Does anyone have an image-file for U62, or
even better a spare U62? A local guy in Ottawa can burn this PROM for
us, but then we'd need the image!
We will of course do some more debugging: In particular, we need to
trace the ROM chip-select signals back through to the z80 with the
9010a in Read-mode/loop, but ran out of time in our late-night
debugging session last night.
Thanks for any help: Would be great to get my friend setup with a
working 9010a!
grant..
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