Matthias:  If you have been reverse-engineering the PCB, it might be
     helpful to us if you could post the schematics that you have developed
     for the PCB and/or a description of what the circuit does.

     Rob Green


______________________________ Reply Separator _________________________________
Subject: [TN] Help - Unknown Chip to identify
Author:  Matthias Mansfeld <[log in to unmask]> at SMTPLink-Hadco
Date:    2/13/99 4:39 PM


Help needed!

I need to identify an unknown chip!

A customer of mine sold until now a lot of electronic units from a
company in the USA which disappeared from the market totally some
months ago. These units fail often after some days of operation
(about 50%) and my customer has to fulfil the warranty.

To fulfil this warranty, he asked me for reverse-engineering this
unit. Then we would be able to build replacement boards and perhaps
to figure out why about the half of the original units fails after
some days of operation.

The problem is, the whole units were filled with (I assume
Polyurethane) coating and after dissolving it, we found some analog
circuitry and a 16 pin IC with removed labels. Because there exist no
schematics or other documentation, I try to figure out which IC it
might be.  We opened the IC and took some photographs from the chip.
The first idea (according to the citcuitry around) was XR2206 from
EXAR, but EXAR said no. On the chip you can find to numeric
signs, "8025" and "L7501".

Does anybody know of a company or other institution which collects
chip codes and which could help me to identify the chip?
Any other ideas?

You can find the pictures on my website
http://www.mansfeld-elektronik.de/unknown.htm.
Please be aware there are 5 jpg files with together about 1MB size...

Many many thanks in advance
Regards
Matthias Mansfeld
-----------------------------------------------
Matthias Mansfeld Elektronik
* Leiterplattenlayout, Bestueckung
Am Langhoelzl 11, 85540 Haar; Tel.: 089/4620 093-7, Fax: -8
Internet: http://www.mansfeld-elektronik.de

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