bloke wrote in message
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On Apr 22, 8:24 am, "N_Cook" wrote:
bloke wrote in message

...

Hi there, noticed some discussion about this beastie on the group and
wondered if anyone had come across all of the relays clicking and
nothing else. It has been on the shelf for years and just when I need
to use it, it does this.

There is a grotty service manual floating about, but a good quality
scan of the digital schematics would be really helpful.

Anyway, any help would be gratefully accepted.

What a coincidence, this morning I was just about to put my one back
together to get back to exploring IR remote control hacking/cracking.

Persist with that low res schematic , it is useful.
But perhaps to save you going down a false route like me, I did not
realise
the large UVC3120 was the main ADC not the ZNA449 which is probably just
for
overlaying ch 1/ch2 levels of Y control.
In the process I managed to make matters worse and get that cyclic relay
business.
I removed the main processor chip VLC56C22 cleaned its pins and reinserted
and that problem disappeared. I suspect the original problem of no input
displayed , just the legends and levels was also due to surface corrossion
as that has gone , along the way
Mine is now working and I took a few scope pics of critical waveforms but
they won't be on the www for a week or more as I'm overloaded with work
If you work on the unit, brace with polyester or paxoling the lower board
to middle board in one plane and the front panel third in line beyond
that.
But most important a 3mm threaded stud or similar to brace the lower board
to the vertical back pannel with the weight of the transformer

Do you know of a user manual without a hefty fee, as I will need to
explore
the delay/trigger options and recall or pc/RS423 options.

I think I might have the manual somewhere, I can pop it up online when
I find it, do you have a dump of the eprom as I'm beginning to suspect
the data on mine is looking corrupt. (after all it is over 20 years
old, it's done quite well). Refitting the main processor didn't stop
the relays on mine clicking, sad to say. The battery had corroded but
the board cleaned up nicely and isn't conductive, as far as I can see,
it's infinate ohms everywhere, so that's a bit of luck. Anyway,
backung up the eprom's firmware might be a good idea anyway as they
don't last forever and tti.co.uk dont have a backup, I asked them, and
they said nope.

++++

Maybe replace the uP socket , my one had some definite green corrossion on a
couple of the socket pins, but as I say lightly abraiding the pins
immediately solved the continuous relay clicking performance.
I've taken the opportunity to remove the nicad and wire through a vent hole
to a couple of cells mounted on the rear (requires a wire link for the 2x
positive pins)
Reading / dumping eproms is not something I've ever done , under the ethic
that if it aint broke, don't poke .
How does partially corrupt eprom data show itself?