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Re: HP 4957A Protocol Analyzer - Option 001 High Speed Data Capture?

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ndemarco:
Hello,

I picked up the cute little HP 4957A recently for a few reverse engineering projects, and to have a little bit of fun. One of the projects runs at 115,200 baud. Unfortunately, the 4957A max speed for for bit oriented protocols is 64 kbits/sec. There is an Option 001 for high speed data capture.

From my thorough look at the internals, I'm thinking this would be either a ROM change or a software application. Does anyone know more about the High Speed Data Capture option?

Nick

gslick:
I have an HP 4957A with Option 001. I have no idea what differs between an HP 4957A with and without Option 001.

What are the part numbers on the labels of the programmable devices on your HP 4957A?

There are some images of two different HP 4957A versions here:
https://www.curiousmarc.com/instruments/hp-4957a-protocol-analyzer

My HP 4957A is closer to the second one there, except:

* The part labeled 04957-19051 there is missing the label on mine. The label probably just fell off and got lost. Can't be sure without removing the part from mine to dump its contents to compare to the 04957-19051 dump there.
* The part labeled 04957-19049 there is labeled 04957-19052 on mine.
* The parts labeled 04957-19002 and 04957-19015 there are both labeled 04957-19062 on mine.
* The 8 way switch next to the part labeled 04957-19050 might have different settings. On mine switch 8 is to the right (away from the LEDs), switches 1 through 7 are all to the left.I didn't take a careful look to see if there might be any other differences.

gslick:
Just took a quick look at the HP 4957A Protocol Analyzer Operating and Reference Manual.

On Page 2-20 it says "High Speed Capture is a ROM based application that is available only in the HP 4957A with Option 001. You can capture data at speeds above 64 kbps."

So maybe it is only a firmware difference between an HP 4957A with and without Option 001.

ndemarco:
I have exactly the same ROM part IDs as Marc's A0002 version. For reference, my serial is 3235A03736, with main board serial 0791A05804.

Nice eyeballing. I missed the narrow switch bank part. My switches are configured the same (1-7 are against the arrow, so off; where 8 is with the arrow - on?).


-19001
-19002
-19015
-19044
-19049
-19050
-19051

So it appears this is the matrix:

No option / Option 001
-19001
-19002 / 19062
-19015 / 19062
-19044
-19049 / 19052
-19050
-19051 / ?

Can we get a ROM dump from you of the ?, the 2x 19062 - interested to see if they diff at all, and 19052?

gslick:
The 04957-xxxxx N27C010 part dump from my HP 4957A does not match Marc's 04957-19051 dump.

The two 04957-19062 M27C1001 parts in my HP 4957A read with identical binary dumps.

Attached below:
04957-19052_M27C1001.BIN
04957-19062_M27C1001.BIN
04957-xxxxx_N27C010.BIN

Mouser has a very small number of AT27C010 PLCC parts in stock at the moment, none at DigiKey. If you program some with these binary dumps and give it a try, let us know if it works for you with your 4957A.


The power supply in my HP 4957A has died since the last time I powered it on so I can't do any run time experimenting with it currently. At least one dead bootstrap power capacitor for the M51995P switching controller IC. Hope that is the only one I have to replace.

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