53132a ROM checksum failure

[martinr33]

I picked up a unit with this failure. Easily fixed by reflashing the memory. Seems to be a problem for 20+ year old units.

The parts are AMD 29F010 in a PLCC package. They are reprogrammable, so you don't need spares.

The HP sockets don't seem to fit a standard extractor, so you need care and some jeweler's screwdrivers (risk of cracking the socket).

You will need a PLCC adapter for your programmer. Fixed socket versions are available on Amazon Prime, or on eBay from China for a bit less money. ZIF sockets are also available, but you don't really need them.

In my case, it was one bit in one memory at the very end of the address space.

It is worth reflashing all four devices. You can also upgrade to the latest code, but this update requires a recalibration.

Then you can do all the upgrades...

[wn1fju]

Exactly the same experience here.  Turned out to be a single bit at address 130022 in U8.  Should have been FF, but was EF.  These bytes were at the end of the ROM in a big block of FF's, and the error didn't seem to degrade the 53132A, so perhaps the counter wasn't reading those addresses.  It only threw the ROM error at startup, but otherwise worked fine.  New set of AM29F010 with the (version 3944) binaries from KO4BB's site fixed all.

[Cyclotron]

Thanks for the hints. I also found a bit flipped in the lower region of U8, which caused my ROM FAIL issue.
Now I have a nice 53132a ready for me to build and add an Ultra stable oscillator.

[wraper]

Exactly the same experience here.  Turned out to be a single bit at address 130022 in U8.  Should have been FF, but was EF.

Strange, I'd expect opposite, Flash losing the charge. Not unprogrammed bit reading as programmed. So it looks more like accidental programming due to some glitch rather than retention issue.