Repairing the Grundig/Thomson Digibox

GDS200, GDS300, GDS310, GDS2000, GDS3000, DSI4210, DSI4212

Grundig is no longer in business in the UK. However, Michael can carry out most repairs to these GDS models (see below) or you may be able to carry out the repair yourself. Thomson took over the Grundig manufacturing facility at Pontyclun and produced a very similar design Digibox.

Later Grundig models with S-Video socket at rear are prone to CPU overheating and may need a CPU cooling kit.

On some early Grundigs the input scart (VCR) had two colours swapped on the RGB connection. The output scart (TV) is fine. It is possible to rewire the VCR scart cable to compensate, or use composite instead of RGB, which would reduce the quality. (Sorry, I'm not sure which colours. It could be Blue and Red or Blue and Green. Red is pin 15, Green is pin 11 and Blue is pin 7.

Many problems with the Grundig and Thomson Digiboxes are caused by the demise of the power supply. The symptoms usually include loss of some programmes and occasionally "lines on the picture", sound faults or other strange things. Of course software upgrades, faulty LNB, faulty coaxial cable and misaligned dish can cause similar problems so it's best to borrow a good Power Supply Unit and try it before jumping to conclusions. (They are all interchangeable - except for the GDS3000 type - for the purpose of testing). But the PSU is very failure prone so it's probably going to die eventually. A failing power supply can even prevent any of the SkyLink remote extenders from working! (E.g. TV-Link, Digilink, SLXlink etc.)

WARNING

A Grundig that tries to download the software all the time is a common symptom that occurs when someone tries to download new software with either a power supply or tuner fault. The only cure now is to replace all four flash memory chips. This will get the box back to where it was originally, with either a dud tuner or dud PSU, which will then need to be repaired.

So it is MOST IMPORTANT that you do not try to download new software unless you are certain that the power supply and tuner are in working order and you have a good signal quality indication in the menu! (Tuner failure is extremely rare. Power Supply Unit failure is extremely common).

How can you be certain if the PSU is faulty? Four methods:-

2. Borrow another Grundig/Thomson and swap its PSU over into yours. If it now works, that proves that your PSU is not OK.

3. Use an oscilloscope to monitor the individual output voltages. If you can see high frequency ripply of more than 100 millivolts, the capacitors need to be replaced.

4. Measure each electrolytic capacitor with an ESR meter (not a capacitance meter - this will not usually show a faulty capacitor).

In our experience MOST Grundig/Thomson Sky Digibox PSUs start to fail after 12 months. Our RELIABILITY kit ought to be fitted before this happens. This is effectively a grundig power supply repair kit but please note that it will only fix a grundig power supply that is NOT completely dead (i.e. the fuse has not melted and no transistors have blown).

There are 8 versions of the power supply unit as shown in the photographs below. You can order a Repair and reliability upgrade kit and solder in the parts yourself or you can remove the Power Supply Unit (5 screws), pack it carefully in a cardboard box, and post it to to us for repair. Keep the screws in a safe place.

DSO-0385 REV.C

Order RELKIT 33a

REV.03 (GDS200 +300)

Order RELKIT 33c

You can order the optional large capacitor 220uF/400v with this kit.

DSO-0375 REV.A

Order RELKIT 33b

DSO-0385 REV.F

Order RELKIT 33b

These kits are listed in the Catalogue

Later Grundig PSU by SAMSUNG may be found in models from GDS200/1 onwards. Check the photos carefully! This one does not have a DSO- or REV. number near the mains input socket. The other four do.

<----- Order RELKIT 33d

These kits are listed in the Catalogue

Kit 33d always includes the large 68uF/400v capacitor as it is known to fail.

<--- REV 2.0

This is the PSSH370603A REV 2.0 PSU in the GDS3000 and Thomson DSI4101 (and possibly GDS2000 - anyone know?)

This appears to have some better quality capacitors and may not fail as early as others.

<----- Order RELKIT 33e (now includes C101)

This kit is listed in the Catalogue

WARNING

These power supplies are NOT interchangeable with other models as one of the black wires carries the 22v LNB supply.

The common fault with the PSSH370603A power supply is failure of IC101 which is a TO220 style 1M0365R. It causes "tripping" of the power supply. This part is NOT included in the Relkit but we can supply it separately.

The next most common fault with the GDS3000 is "No satellite signal" right from the start when installed. This is caused by the fact that the tuner is very sensitive. A cable run of at least 10 metres should be used. If less, then you'll need to fit our 10dB LNB attenuator.

This is the PSSH370604A PSU used in a few Thomson DSI4101

<----- Order RELKIT 33e (now includes C101)

(These notes might also apply to the Thomson Digibox - I simply don't know).

This is the PSU in the Thomson DSI4212

<----- Order RELKIT 33f

These kits are listed in the Catalogue

We also have kits for the Thomson SKY+ and HD Digiboxes. Exchange PSUs normally available.

Typical symptom: Channels with typically strong signals (Movies/Sports) are beginning to pixellate badly.

This is the PSU in the Thomson DSI1421

<----- Order RELKIT 33k

These kits are listed in the Catalogue

Can I buy the capacitors from Maplin, Tandy etc?

I don't think they stock the Low ESR UHR (Ultra High Reliability) parts that are required.

Can I buy a complete Exchange power supply?

Yes, we can supply a power supply that will suit all Grundig models From GDS200 to GDS300 but NOT the latest model (see picture for Relkit 33e above). We also stock Thomson power supply units.

To buy a power supply, order it from catalogue page 12. In some cases you can return your old power supply in our packaging for a partial refund (use Recorded Delivery) as soon as you are happy that the new power supply works.

If you have the later model Power Supply you can post it to Michael for repair or buy the kit.

May I point out that you are wasting your time asking me if certain symptoms could be caused by the power supply. Here is my standard reply: There are about 12 capacitors - any one or ALL of which might fail. Supposing that a random 3 out of 12 fail: this would give 220 possible combinations, which means 220 possible symptoms. Worse - they might only partially fail and that increases the number of possible symptoms even more. Power supply failure in GDS models is VERY common after 12 months in service - especially (but not necessarily) if you've kept the Digibox nice and warm. Best advice is to use a kit to upgrade the PSU. If it doesn't help then I'm sorry but at least you know it will now be reliable once you've found the real fault cause.

The best suggestion I have is to disconnect the mains supply at the wall for an hour. Let the Digibox cool down then reconnect mains power. If the symptoms are now worse than before then the power supply capacitors are the most likely culprits. The original capacitors are not very good so failure is quite likely to occur within 18 months unless the Digibox has been kept very cool. The ones I supply in my kits are a much higher grade; they will cure the symptoms AND hopefully last a lot longer than the originals (if you fit them the right way round).

Note: Quite often you can actually *see* that one or more capacitors has failed. They are all tubular in shape with a perfectly flat aluminium top. If that top is bulging or domed or if the rubber bung underneath is bulging, then the capacitor has failed. In such a case it's likely that ALL the electrolytic capacitors are in the process of failing and should be replaced, for safety and reliability sake, with the correct, uprated type in our kit.

Above You can see the aluminium tops of the bad capacitors are no longer flat.	Above You can see the rubber plug is protruding beneath the bad capacitor and it has leaked electrolyte onto the board. (Do not confuse this with the brown glue that some manufacturers use to secure the capacitors. If it extends up the side of the capacitor then it is more likely to be hardened glue. Electrolyte remains WET.)
Even if the capacitors look *PERFECT* they may still be faulty. Safest to replace them ALL with the good ones that we supply. If you use any other type, don't be surprised if they make it worse.
Why did Grundig use bad capacitors in the power supply? Actually, the equipment was made by Samsung and they did NOT use poor capacitors deliberately. Read this page: http://www.niccomp.com/taiwanlowesr.htm Why did Thomson use bad capacitors? They probably haven't read this page!

LATEST INFORMATION:

Grundig Digiboxes can suffer from software problems. If the Digibox is receiving a signal then try forcing a software download as described on the FAQ page. DON'T try this unless you are certain that the PSU is OK!

Later (fast) Grundig Digiboxes with S-Video socket at the rear are now suffering from the same CPU overheating problem that affects later Pace and Panasonic Digiboxes. The CPU cooler kit should fix this.

Note: Our standard CPU cooler heatsink is too large to fit in the GDS3000 CPU because there is no space around the CPU. You can still use the kit but it will mean cutting and shaping the aluminium heatsink to fit the CPU and mounting the fan separately to blow air across it.

WARNING! If you own a Grundig GDT1500 Freeview box, read THIS page before it's too late!

Here are some messages from people who had PSU faults:-

>Thanks Martin,
>
>The relkit solved the following problem:
>
>......."The GDS200/1 Digi Box is suffering audible
>interference on some but not all channels, 101 to 199 all suffer but SKY
>News (501) and others do not. The noise would appear to be a form of digital
>breakthrough but their is an identical audible noise omitted simultaneously
>from the power supply but again not on all channels......"
>
>I suspect C13 was the culprit as it was bulging top and bottom!
>
>Once again thanks for the swift service, It's rare to find someone who will
>"supply on trust" its just a real shame that you obviously have some clients
>who abuse it.
>
>I've signed up to your monthly newsletter.

A Beginner's Guide to Receiver Repair Based on the original "Screwdriver Expert's Guide to Satellite Receivers" this "virtual book" describes the basic components and a typical power supply with diagrams and explanations. Shows how to solder and describes what to check and measure. It won't make you an expert but, if you are capable of soldering in components supplied as a kit, it will take you one step further so you understand why you are doing it and even help you figure out other possible fault causes and cures. If you buy a repair kit, you probably need this book. I guarantee you'll be delighted with this amazing book full of information!

Grundig Digibox Problem - 'No Signal being received' only for some channels

Hi, I stumbled across your site via the Alta Vista search engine and was very glad that I did! - it offers some invaluable advice - congratulations on an excellent site

I'm wondering if you can point me in the right direction regarding the above problem that I have.

The Grundig Digibox is circa 18 months old and was installed by Sky 'installers' as part of their £40 installation free digibox/receiver deal. Up until recently it's been working fine, but 3 or so weeks ago I started getting problems with the Eurosport channel (419) - just when I wanted to watch the bloomin Motorbike racing - typical! Intermittently, I'd get the message that no signal was being received or that there was a technical fault with the channel. Thinking nothing of it, I left it and odd occasions it would work fine, but now it's playing up more often than not

I discovered on the occasions that it wasn't working that if I left it on channel 419, turned off the digibox, removed the card and then turned it on (still with the card removed) when prompted to insert the card it seemed to work fine, but if you moved off of 419 onto another channel and then back onto Eurosport it reported the no signal message.

I've spoken to the Sky Help Desk on a couple of occasions and they've checked a few things - signal strength, cables were tight - I'm sure you know the sort of thing and have gone through the turn it off/turn it back on procedure, but to no avail. I'm getting them to send me a new card (just to eliminate this as a possibility) but I don't honestly think this is the problem - unless you can suggest otherwise

I've reviewed you web pages and see there's a couple of things that I can check - I'll give the turning if off and then turning it back on with the select button depressed in order to force a download of software a whirl, and also taking it around to a mate's house to see if it works there - hadn't thought of that one myself.

I'm in Birmingham and as with the most of the UK the weather's been lousy over the past few weeks and I'm wondering if the rain/wind has caused the dish to move, cable to come adrift, etc. Could this be a possible cause for the problems I'm having?

Based on your extensive knowledge I wondered if you could offer any further advice or things to try? Certainly if I discover that it is the digibox I'll get back to you if I may with a view to seeing if you can fix it for me

Sorry for the lengthy mail, but I thought that I would provide you with as much as I know regarding the problem (as you suggested)

Any advice that you can provide would be greatly appreciated

Many thanks

Regards

C.H.

Repairing Sky Digital Receivers Not just a repair book! In fact not even a repair book! Common problems and cures listed - many of which you can fix yourself with only the remote control handset or a soldering iron. Plus lots of general repair information including how to recognise various components. Written in simple terms, this book also gives the home user valuable advice on how to prevent failure. Read it NOW and save money in the future. But, if the worst happens, read it anyway because it will still save you money.

I hope you can help,

I have a Grundig Digi box it's about 2 years old. I am having trouble with certain channels.

I think channels started to drop off gradually 139 Men and Motors may have been the last to go.

• 567 .TV
• 139 Men & Motors
• 516 The Money Chan
• 562 History +1
• 561 History
• 559 National Gio +1
• 560 Adventure 1
• 510 CNBC
• 501 Sky News
• 416 The Racing Chan
• 419 Euro Sport GB

Not a full list, but No sky movie channels fail

The above all come back with "NO Satellite Signal Is Being Received" message.

Other channels are perfect.

I have checked signal strength and quality both are OK.

I have taken my Digi Box to my Brothers house, he has the same box and attached it to his feed with the same results "No Satellite Signal" on above cnannels.

We also tried his card in my box and my card in his box, the fault stays with my digi box.

I have tried the force download, and the reinstall option under engineer menu to no avail.

I have also checked 22khz setting, and reset all resetable settings back to factory defaults.

Any suggestions would be appreciated.

Regards

L.A.

Dear Martin,

I have a GRUNDIG GDS200 digibox that I purchased 27/11/98 and seems to be unable to tune into a number of channels.

Around April I noticed that 8 channels would give a "NO SAT. SIGNAL RECEIVED" banner after about 10 seconds of blue screen.

Up to the present day I have lost 20+ channels, the main ones I have listed below.

I have borrowed a PACE receiver and found I can pick up all the channels using my dish and cables.

I would be grateful if you could offer any advice and/or supply the address for the repair option

Thanks in advance

D.H.

Plymouth, Devon

LOST CHANNELS

• Breeze Money Channel
• Artsworld Nat. Geographic +1hr
• Liberty TV Adventure One
• Wellbeing History
• Moviemax 5 History +1hr
• Eurosport GB .TV
• The Box Nick Replay
• Kiss Fox Kids
• Sky News Fox Kids +1hr
• CNBC Pin

---

Other faults

Grundig Digibox GDS200 fault

Not so much a question but some information that may be of interest to you and a help to others.

I am a proud owner of a Grundig GDS200 Digibox? All worked well for about 18 months, just long enough for the unit to be well out of warranty. At about the 12 month point Sky rang me to say that people had been having trouble with digiboxes and did I want to take out two years extended warranty. No point I thought because the MTBF of a piece of electronics like a digibox is well in excess of three years (after all TVs work much longer than that). So at about the 18 month period I came home to a distraught son who hadn't been able to watch teenage rubbish after he came home from school.

The symptoms were that the picture gradually faded into noise and the unit eventually shut itself off. This happened even when the menu was on screen. Also the digibox was affecting the phone line. It kept answering any calls and wouldn't let us make any (works wonders for the phone bill thought). The thought did occur to me that the box could answer the phone line and accept commands to self destruct! However, I put the thought out of my head and easily solved the phone line problem, I unplugged it from the telephone socket. I unplugged the unit to reset it and after a few minutes plugged it in again. It worked perfectly again until it warmed up and then the picture faded again.

I rigged up an old analogue dish with universal LNB and took the digibox off to the workshop to solve the problem. I was looking for a problem that occurred after it warmed up. I had time to get a perfect picture up before the problem started again. Now for the freezer spray. Damn, no freezer spray, so I had to use a frozen lump of dead meat out of the freezer (chicken breast I think, 'cause it had a pointy end) - don't tell the wife. After probing around for a few seconds I found that cooling the crystal oscillator brought the picture back perfectly.

I couldn't identify the manufacturer of the oscillator but the marking clearly identified it as a 27Mhz device. Surprise surprise, 27Mhz is a non-standard frequency so I had to get a work colleague to order me a couple of samples from somewhere (I can dig out the name of the company if you're interested). I figured that the crystal oscillator was "drifting" so causing the IF stage to lose lock on the incoming signal. The oscillator also must feed the processor board (because there isn't any other crystal on there), hence the strange effects on the modem line.

After the oscillator was replaced the unit worked perfectly. If the device was faulty I'm home and dry, if the tolerance of the PLL circuitry is so tight that natural ageing of the oscillator causes it to drift out of the capture window I'll need to replace it in another 18 months.

Incidentally, all members of my family that have digital and a good number of friends have all had boxes fail at around the 12-18 month old period. These are mainly Amstrad and Grundig. So it is either a poor design or my conspiracy theory to blow up units was correct after all. You're probably in a better position than me to know just how many boxes are failing!

Hi Martin,

I have a problem with my receiver which occurs several times each day and although it's not a terminal problem (so far) it is irritating. Possibly it's an indication of a weakness in the receiver...

Several times each day, the picture produced by the receiver loses all colour output and everything, (picture, EPG banners, menus etc) goes black and white. Usually within a minute or two colour returns. It's not a problem with the TV as terrestrial channels are fine. I rarely get problems with "macro-blocking" (pixelisation) or picture freeze. It's been like this since the receiver was new and is particularly bad when selecting "Music Choice" on channel 480.

I previously had an early Amstrad Digibox and had no such problems (although I did get a lot of "macro-blocking" (pixelisation) and picture freeze). When the Grundig was installed the engineer managed to re-align the dish to get a much higher signal strength, about 80% plus, with a signal quality of 50-60%.

I don't have a terrestrial aerial attached to the receiver; its all done via SCART connectors.

Could it simply be too strong a signal swamping the receiver or is it a sign of bigger problems to come? Your help would be much appreciated.

Many Thanks

Bob

Although it's connected via Scart. you don't mention whether the problem changes if you select PAL or RGB in the menu. I recomment you try connecting a different TV set to see what happens. Could be an incompatibility.

Martin

Hello again Martin,

Thank you for your reply, it was most useful and looks as if you got it right.

The Grundig GDS310/2 is connected to my TV (Sony KV-E 2942 U) with a SCART connector and it's set to PAL. I set the menu to RGB and the colour loss doesn't occur. So it does look like a compatibility issue.

Going over to RGB does introduce another problem though - it produces quite a big shift of screen picture to the left. The shift isn't restricted to the Grundig - it also happened with my old (now defunct) Amstrad receiver.

Is it possible to overcome the incompatibility without replacing the receiver or TV? (i.e. kits, leads etc)

MP: Probably not.