Subject: Re: breathing life into old chips

From: Jules Richardson<[email-masked]>
Date: Sun Apr 6 08:12:00 2003

> hi,
>
>> (the chip in question is a ST9293J9B1/AEL for the record, 
> What is this TV model & brand?

It's a Ferguson T7073SJD, using an ICC9 chassis. One website containing a
faults database listed the failure of that chip giving the exact symptoms that
I see (no sound when the set warms up and the remote operation goes
unresponsive). 

I've pulled the main board and will re-solder all the joints in that area just
to check; there's only one electrolytic as part of the circuitry surrounding
that chip but I'll replace it with a known-good just in case. Tony's point
about the crystal was interesting - I didn't think those things ever failed.
I'll see if I've got a spare to try anyway.

The set's awful inside - very cheaply made with little thought to cable runs,
connectors, and how the various boards plug together. Guess they must have had
different teams working on different sections and management for the overall
project wasn't exactly what it should have been... (typical of more modern
equipment unfortunately!)

cheers

Jules
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---

From: [email-masked] (Tony Duell)
Date: Sun Apr 6 13:06:18 2003

> It's a Ferguson T7073SJD, using an ICC9 chassis. One website containing a

FWIW, Thomson-built ICCn chassis are _notorious_ for dry joints!

> I see (no sound when the set warms up and the remote operation goes

Those databases are not that useful IMHO. What that entry means is that 
somebody had a set with those symptoms, and that replacing the 
microcontroller cured it. It doesn't mean there was any logical reason 
why the microcontroller was the problem (maybe soldering in the new one 
cured a dry joint). It doesn't even mean that this is the most common 
cause of the fault. 

> that chip but I'll replace it with a known-good just in case. Tony's point

You need the schematic (it should be available -- maybe even in the local 
library -- look for the TV Servicing books). You want to check the reset 
line, which may well be routed across the PCB from somewhere else.

> The set's awful inside - very cheaply made with little thought to cable runs,

Well, all I can say is that in my experience Thomson sets are some of the 
better made ones out there. They're not good, but you should try some of 
the others!

-tony