Is this PSU poorly?

Dan Walton

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Hi all, I've been looking around to on here to see what the problem with my old HD box is, it doesn't always get a signal on one or both channels when you turn it on. I've seen that this is often caused by PSU's giving in, particularly the capacitors. So, before I order the kit from Satcure, these capacitors don't look healthy, do they!?

DSC00601.jpg


Excuse the poor quality phone pics, but I'm guessing the white gunk all over the PCB shouldn't be there?
 
The white gunk is a 'glue' to help secure the caps in position. The caps don't look like they're bulging to me,3 or 4 of the ones in my 3year old box were. If your box is showing the classic faulty psu symptoms,I'd change the caps,it can't do any harm.:)
 
Actually the two big ones in the right/middle do look a little raised. The shorter one above those slightly to the left opposite the white cable looks a bit suspect as well. That one might just be the flash.You should be able to feel it. They should be flat, almost concave but at least flat. If there is the slightest raised surface the cap is on its way out and will cause your problems. The PSUs are the same in Sky+ and HD boxes.

Run your finger across the top of them and as lotstoys says get a kit anyway and just change the faulty ones first and see what happens.

If you feel energetic change the rest as well but I changed just the 3 that were raised in mine and its been fine ever since. In fact better than its been before with a really big PQ improvement as well as not missing channels. Good luck
 
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I reckon your a bit brave,only changing the ones that are obviosly bulging:D I fitted the upgraded cap kit and can confirm the box runs much better, and have had no problems at all since.I fitted a 640g avvs WD drive externally at the same time and believe that this 'green' low power drive helps relieve the psu from stress,which has got to be a good thing.:)
 
I'm with Lotsatoys. If you are going to go to the trouble of removing the board, it makes sense to replace all the capacitors. The originals were rubbish even when new, the Thomson box tends to be far more stable once it has a decent power supply as well.

I too would recommend an upgraded hard disk while you are doing the PSU. The disk Lotsatoys suggested is a very good one but as it is over 508 Gb it will need to be pre-formatted before installation. If you want things easy, this one is very good and fully compatible with the HD box's firmware, while still giving you 2 1/4 times the personal recording space. Either way these drives should run cooler, quieter and draw les current than the oroginal dries fitted at the factory. If there are any programmes on the old disk you want to keep these can be transferred to the new disk with the excellent Copy+ programme.

A Thomson with an upgraded PSU and HDD makes for a very solid and stable box (new EPG bugs excepted of course).
 
Oh..I agree guys. Just saying I did a quick change of the obviously faulty ones to see if it was my problem. It was :clap:

To be fair the advice to change them all is the right approach. Difficult call if its not certain to be the PSU but it would only take 30 mins to change all the caps so go forit. I have the full kit delivered now.

I only fitted 1000uf caps instead of 1200 caps. They'll last but I want to do it properly anyway and will tackle all of them over the weekend. Its too easy to leave well alone and wait until/if it fails again.

I used to be an electrical/electronics engineer so I am obviously quite confident at doing this stuff....just lazy

I don't need more space as my current 160gb disk (Sky+) is never less than 55% available with the usual 80gb space. I don't have films etc to record..or HD of course. I did take the opportunity to back up my programs using Copy+ to my PC and I will be doing that more regulary..its so easy.
 
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They dont have to bulge. When my psu blew, there were no bulging caps - only a resistor, (R45, from memory, the one lower centre standing up next to that great heat sink thingy) had quite literally burnt out. This resistor fault is caused directly by bad caps according to satcure.
 
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Thats true but a bulging cap is generally an age/quality issue as the elctrolytic fluid drys out/eveaporates. The most commonest fault in these PSUs. Funny enough I had the same problem a few months ago with the contril PCB in my Potterton boiler, mind you thats 20 years old so fair enough. These things should last for years and years but they are not of the highest quality in these boxes. But of course they are built to a tight cost demanded by Sky and not quality.

Higher current draw will cause the resistor to fail and caps are as likely as anything as indeed Satcure state.

It really is a simple fix as the actual circuit board is of a decent quality and as long as "you" are careful with the soldering iron and use either a good solder braid or preferably a solder sucker..oh, and good quality silver solder it should present no real problems
 

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