Products > Test Equipment
Some old school instruments showing how it's done (HP 3325A and Fluke 8506a)
SilverSolder:
Actually, it made sense to concatenate the two EPROMS before disassembling, because the code runs across both EPROMS and makes subroutine calls from one EPROM to the other...
Attached: disassembly of entire firmware across both EPROMS. This one actually seems to make some sense, but would still need an amazing amount of work to correct and make sense of...
joeqsmith:
I pulled my controller board last night and when I attempted to use my programmer, it was dead. Looking into it, the parallel port board is dead. A bit of probing and of course, the main IC has a low impedance pin. I am not sure about the programmer. It's rare I program parts like this anymore and suspect the it was damaged during a lightning strike we had a while back that damaged some of my test equipment.
I scrapped my old XP computer over the summer assuming I would never need it. That leaves the old dual Pentium 200MHz PC. lol.
Anyway, thanks for capturing the PROMs. It looks like my controller is revision J.
In the mean time, I am still very interested in what others are finding for times. Again, no need for GPIB and PC software. Just use the sync and a scope.
bdunham7:
8505A with scope on 'Scan Advance' BNC on back.
Power on, no changes except selecting AUTO range: 1.87Hz
Press AVG button: 232mHz
Press FILTER button, no change. Turned filter off again.
Press SAMPLE button, light flashes faster and 6.41Hz
Press "STORE 6 SAMPLE" or any number over 6 and the rate goes down, I didn't record them.
Press "STORE 5 SAMPLE" and I get 6.41Hz again.
Press "STORE 4 SAMPLE": 9.62Hz
Press "STORE 3 SAMPLE": 12.7Hz
Press "STORE 2 SAMPLE": 15.5Hz
Press "STORE 1 SAMPLE": 17.6Hz
Press "STORE 0 SAMPLE": 18.6Hz
All numbers are a bit approximate and weren't perfectly stable. I have a National Instruments GPIB-to-USB adapter but my lab labtop (labtop?) is being used elsewhere at the moment. I suspect that the scan advance doesn't happen at the same rate as the rate that you might get readings over GPIB, but someone will have to try that.
AFAIK, it is 27 samples at power on and 25 when you press SAMPLE one time.
joeqsmith:
Thank you very much for running that. 18.6Hz is in the ballpark of what I was seeing (21Hz). What version of firmware does your meter have?
I found the exact same printer port card and thought I should test the programmer first. Pulled out my old Dec 486 PC and sadly, the programmer also appears to have been damaged. It's a very old EETOOLs ALLMAX. I've hacked their software a few times to add support for odd devices. They used some PALs right on the printer port interface so I doubt there is anything I can do to repair it. Someone has one on ebay but they want $200+ for it. :-DD Time to look for a new programmer.
SilverSolder:
STORE 0 SAMPLE ---> ~20Hz on the scan advance output.
8506A rev. 6.0.7
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