Repairing an HP3421A (Signature Analysis)

Rik Bos hp-fix at
Thu Jun 4 15:11:37 CDT 2009

In the HP Journal issue of May 1977 there is an
article about signature analysis.
Otherwise the service manual of the HP 5004 or 5006 should
help you further. 
The signature check is related to the CRC check.


> -----Oorspronkelijk bericht-----
> Van: cctalk-bounces at 
> [mailto:cctalk-bounces at] Namens vp
> Verzonden: donderdag 4 juni 2009 21:16
> Aan: cctalk at
> Onderwerp: Repairing an HP3421A (Signature Analysis)
> I am trying to repair an HP3421A data acquisition and control 
> unit that fails its power on tests.
> In the service manual it refers to a number of "Signature Analysis"
> tests that essentially mean that the unit runs some 
> diagnostic routine and you go and collect "signatures" from 
> various test points.
> Unfortunately I do not have a device to compute these signatures.
> Does anybody know how to calculate them using a logic 
> analyzer (I have a Bitscope and an HP 1630D), or something similar?
> Thanks
> **vp

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