Problem with Thomson DSI 4212

O

oldnwrinkly

Member
My Satellite Setup
Just SKY (at the moment)

Win. XP
My Location
Wales UK
Hi,

I have a problem with my old Thomson DSI 4212. - this has recently been displaying picture break-up/pixilation and I need a little info and advice.
This is a box that was given to me about a year ago and has worked well up until now despite only ever showing 25% signal and approx 60-70% quality! The receiver is just six metres of, good quality, cable away from the LNB (in a bedroom) and I know the dish is aligned correctly - an Amstrad DRX 550 ( in the living room) at the end of a 40 metre cable run shows approx 80/80.

A quick look at the power supply does not reveal any obvious capacitor problems - no swollen cans - but I have yet to delve any deeper to test anything. Apart from the big reservoir/smoothing cap - 47uF @ 400V - are there any others that regularly give problems?
Other than a power supply problem, are there any components on the main board that are likely to cause the problem I have?

I have some experience with electronics repair but SKY boxes are new territory for me so any information or advise would be gratefully received.

Dave.
 
Not too sure of your cabling arrangements as you describe them. Your Thomson has 6M of cable running to where? On the same dish as the Amstrad?
 
Llew,

I have a quad LNB on a standard Sky dish - one of the four connections feeding the Thomson and another, the Amstrad.
I have tried swapping the Thomson to one of the two spare connections of the 'quad' but the problem persists.

I also have another, single, LNB on a bracket on the Sky dish aimed at 19E and feeding a TM 5400 - but that's another story ..... :)

Dave.
 
The Thomson STBs are notorious for power supply problems; it's quite feasible one of the supply voltages could be causing you the video problem. Don't know the box myself, but if voltages are marked on the board, it might be worthwhile checking them from the PS.
 
Problem fixed.
I noticed the pins the PSU multi-plug connects to on the main board looked a little scruffy so I applied a few drops of switch cleaner and 'worked' the plug in and out a few times before re-assembling the box. The signal level has now leapt up to a dizzying 40% (highest I've seen it) and quality is a stable 70% - good clean picture.

Dave.
 
Interesting solution!

One to remember for future reference, I think.

Thankyou.
 
Good news! A squirt of Servisol works wonders :)
 
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