Last month, I wrote about a completely foreign Sony colour TV set that had found its way to the Antipodes from Europe. As a result, it was difficult to obtain a service manual for it or any service information at all.

This month, I have another in the same vein but this TV is a Panasonic TX-29AD5050FB, purchased locally and owned by Melissa, a near neighbour. The set is a 100Hz Super Digital Scan model employing a Euro 3H chassis (circa 1997). And until it arrived in my workshop, I had never heard of such a model or chassis. However, it all eventually made sense when I saw a label saying "Made in UK".

The set was dead and with the back off, I soon found out where the problem lay - after all, Panasonic TVs do have their similarities. The problem was no vertical deflection due to IC451 (Philips TDA8350Q/N5) being faulty. In addition, the "micro button" fuse F352 (1.25A) was open circuit.

I replaced the IC and fuse and the picture was restored. However, it now had geometrical distortions in its scan. There was pincushion distortion and lack of height, plus retrace lines and top foldover.

I didn't have the remote control (EUR51923 - I believe), nor the instruction booklet - not that that would give you any information on how to get into the service mode. However, from a service manual for a similar model, I found that you can get into the service mode by setting the Bass to maximum and the Treble to minimum, then simultaneously pressing the Reveal Status and Volume down buttons on the remote control and the TV set respectively.

Items Covered This Month Panasonic TX-29AD5050FB TV set (Euro 3H chassis). UEC DSD700 and UEC IRD642 satellite receivers. Sony KV-ES34M31 TV set.

This brought up the "Self Check" menu which informed me that everything was OK and that the Option Hex Codes were 09, 73, E6, IF, BB, BF and 03. However, none of this helped in diagnosing the fault. Nor could I make any adjustments without the correct remote control and service manual.

Next, I spent a lot of time checking the voltages around the 13-pin deflection IC (IC451). There were two power supply rails, 50V and 16V, feeding this IC across diode pump D453. The 16V went to pin 4 and actually measured 18V, while the 50V rail went via R568 and measured 20.3V at pin 8. I found all the other voltages to be roughly as I would have expected but nearly all the waveforms around the IC exhibited a small amount of distortion.

Lacking any real clues at this stage, I initially decided to replace all the electrolytic capacitors (C452, C453, C455 and C560) around this stage and even swapped IC401 (TDA9151B). Unfortunately, this made no difference and I really couldn't proceed any further without a circuit diagram.

Fortunately, Panasonic Australia were able to lend me a circuit diagram of the Euro-3HW but for a model TX-W36D3DP. This was a great help, despite the fact that there were distinct differences between this diagram and the set I was working on. Also, there were no voltages or waveforms marked on the circuit for me to compare with those from the set.

I was about to give up when I decided to surf the net and do a search using Google. The trick here is to ask the right question, so I began by typing in "Panasonic Euro 3 faults" and was immediately rewarded with a repair tip. This mentioned a modification kit (TZS8EK003) that should be fitted when replacing the field chip.

Armed with this information, I went back to Panasonic Australia who immediately put in an order to Panasonic UK. Nothing happened for a very long time and when the client finally went ballistic, it turned out that the man dealing with it in the UK had died (truly) before he had completed the order. Well, if that's not a good reason, then I don't know what is and so the order was re-submitted. At the same time, I also tried to obtain a kit direct from the UK through advertisements in "Television" magazine (one of their advertisers, Grandata, had a kit called "PANKIT 2" which looked as though it might fit the bill).

Well, we sat back and waited and waited. Nothing happened, so after about a month, I started to chase the orders up. The first order had got lost in the system and the second (to Grandata) had got lost in the post! I re-ordered again but the frustration was getting to me. All I needed to know was what the modifications were and then I could source the bits locally.

I tried Grandata to see if they had any information but they are strictly a wholesale supplier. And as might be expected with a foreign set, Panasonic Australia didn't have any information either, so I tried to get the information from Panasonic UK. However, this initially proved tricky as there's no email address on their website.

Eventually, I came across a page that lets you contact them. This involves typing in a message plus your address but as soon as "Australia" is entered in the country field, it automatically flicks you from the UK website to www.panasonic.com.au.

In the end, I managed to fool the system by putting all my address into one field. I then emailed them my enquiry regarding the modification kit, explaining that I was an authorised Panasonic technician. This is how I met "George"; his response, for Panasonic UK, was:

"PROBLEM: RESOLUTION. We would explain that we do not recommend that customers effect their own repairs. Instead, we suggest that the product is submitted to an authorised Service Agent for attention"; and "please be advised that for safety reasons Panasonic UK will not be able to provide any technical guidance or assistance".

However, I wasn't about to be put off that easily. I shot back a reply, reiterating that Panasonic Australia was faced with trying to repair a Panasonic UK manufactured product and could do with a bit of help from the people that made it. Eventually, after staying up late, the best I got was an address to buy parts from (SEME Ltd) and a telephone number. But there was no email ordering here - it was going to be snail mail again and we had already been waiting now for over five months.

And so, not to be deterred, I continued emailing "George" from Panasonic UK until finally - as a special concession - he gave me a little useful(?) information: "The F in the suffix (TX-29AD50FB) denotes the model is French. I am unable to disclose technical information on this model because we do not have any as it is not a UK model".

I mean, what can you do? Life is too short. I felt like emailing him a photograph of the compliance plate on the back of the set with words "Made in UK" emblazoned upon it. But I knew I was dealing with a Mr Plod.

A search through "Television" magazine didn't reveal much on this set either. The magazine had published articles on servicing the Euro 1 and 2 Chassis and the Euro 4 chassis (but not the Euro 3), so these had no bearing on this problem.

In the meantime, Panasonic Australia had had some success, and came up with the TAA8350Q/N6 vertical deflection IC as an improvement on the "N5" chip. I duly fitted this new IC but it made no difference to the problem. Finally, things came to the crunch - either we fix the set immediately or Panasonic Australia was going to have to supply a brand new TV to Melissa (not, I hasten to add, the same model).

And then, there was a minor miracle of sorts. A colleague at the repair agency (I do regular contract work for them) had, unbeknownst to me, decided to check out the set for himself. And so it was that I was utterly amazed when I returned after an absence of several hours to find he had fixed the problem completely!

I mentioned earlier that there is a 50V feed via R658 to pin 8 of IC451. There was 20.3V on this pin but, as I found out later, it should have been much higher because R568 is only 33W. In fact, this ceramic fusible resistor was open circuit. Replacing it increased the voltage on pin 8 to approximately 45V and fixed up all the symptoms!

My colleague, although uncharacteristically modest on this occasion, is usually arrogant enough without being told he did well to find what I had overlooked - so I didn't! Perhaps I should have got him to deal with "George"!

However, all was not as it seemed, as I discovered only this very morning. In fact, the credit was due to another Panasonic technician from Queensland who had been asked to assist with yet another of these sets that had been in someone else's workshop for three months (talk about parallel lives - it could have been me!). Anyway, the set was moved to his workshop and it was he who discovered the cause - in just about 15 minutes flat!

Just as well I didn't waste any praise on my colleague!

The set went back to Melissa and ironically enough, only one day later, my PANKIT 2 finally arrived from the UK. This kit includes the updated TDA8350Q/N6 (IC451), while C453 is now changed to 10µF 160V (previously it was 100µF 63V). In addition, F351 is now a 10W resistor, there is a replacement for F532 (which isn't fitted in this set) and ironically a brand new 33W 0.5W resistor to replace R568!

Satellite receivers

I have been repairing satellite receivers for a while now and have recently encountered two interesting cases.

The first was two UEC DSD700s set up for Impajah and 7 Central in a block of units in the central business district (CBD). They were installed with a bank of several others, plus some other sophisticated "channelised" distribution amplifiers which were kept in a small service cupboard on the seventh floor.

The problem was caused by lack of ventilation and the heat generated in such a small enclosure which gave the symptom of digital patterning. To begin with, as soon as the problem started, it was realised that this cupboard was getting too hot and so cooling fans and ducts were installed but the damage had already been done.

Removing the covers back in the workshop revealed two boards, one for the switchmode power supply and the other for the receiver circuitry. And the latter was covered with about 50 of sub-miniature surface-mounted electrolytics - the type that give so much trouble in video cameras and the like.

Now that the unit was no longer in its hot environment, the patterning effect wasn't so bad. However, a quick blow wave with the hairdryer really brought the symptoms on strongly. With the aid of some freezer, it didn't take long to pinpoint the culprit as C113 (10µF 16V) next to one of the large microprocessor chips.

The other models that came in were also made by UEC but this time they were IRD642s and both were dead.

I checked what I thought was all the diodes by measuring the continuity on the solder side of the board. I also checked the electrolytics for leakage with my ESR meter before changing the IC zener (TL431C, IC3) and then IC1 (TOP225-1). None of these had any effect and the switchmode power supplies continued to "tick" (or pulsate), even when they were unplugged from the receiver.

Lacking any information on these units, I just had to get some help from somewhere. After a lot of searching on the Internet, I discovered that Nationwide Antennas were the agents for UEC and after speaking to their service manager, I was told it was extremely likely to be the extra diode fitted between the positive output of the bridge rectifier positive and the cathode of D8 via a 10W resistor.

He was of course spot on - it was short circuit. The reason I had missed it was because it was mounted on the component side as an extra "add-on" afterwards, so I wasn't able to measure it from the solder side of the board.

The diode was a P1.5KE220, which is a special 220V 6.8A quick response device. Perhaps if it was rated at 240V it wouldn't fail quite so often!

Incidentally, the service manager also pointed out that the digital interference patterning was usually caused by dry joints on the large microprocessor ICs.

New cabinet

An electrician called me out to replace the cabinet for his Sony TV.

What had happened was that a good friend (at that time) was helping him to move his 1999 $4000 Sony KV-ES34M31 (AG3 chassis) to another corner of his lounge room. However, his (now ex) mate let go of his end of this 84kg 80cm TV set which landed heavily on its front bottom righthand corner, badly damaging the cabinet.

Fortunately, the picture tube was not damaged (thank goodness, at $1900 for a new one!). Even the vulnerable shadow mask which normally shifts, resulting in incurable purity errors, was undamaged and the picture was still excellent. Even so, I checked the self-diagnostic system first to make sure everything was OK.

I decided that it was better to replace the cabinet in his home rather than carry the set to and from the workshop. The only problem was that the spare parts list did not show the front cabinet assembly, or "freznet" as Sony calls it, in the service manual, even though there is a picture of the assembled unit in the exploded diagram.

Eventually, I discovered that you are expected to "knit" your own cabinet from individual sub-panel assemblies, as shown on page 179 of the service manual. The reason is not immediately obvious until you do the bean counting. The average price of each panel is $260 (ouch!), thus making it over $1300 for five panels. And that doesn't include brackets, corner blocks and trim which often are not even shown in the parts list (even the back costs $325).

Anyway, the damage seemed to be confined to the base plate, the bottom and righthand frame sub-assemblies and the back. We decided that the base plate and back weren't worth replacing, considering the amount of visible damage and the replacement cost, and settled on replacing the two remaining parts.

First, we removed the back and loudspeakers and I then unclipped and unplugged the chassis. We then removed the picture tube, making sure it was fully discharged(!). After that, it was simple to dismantle the rest of the cabinet until we reached the offending parts.

The bottom frame sub-assembly was a solid piece of aluminium which was badly buckled, while the right frame was bent at the edges. These two alone would cost $566.06, so my client said he would try taking them to a panel beater first before deciding whether I should order the new parts (none are ex-stock).

This turned out to be an excellent decision as a really beaut job was done by an expert and you could hardly tell that it had been damaged.

Reassembling the telly was more stressful than disassembling it but eventually we worked out what went with what. It was difficult to work out where some of the earth leads went, and there was an additional unmarked plastic assembly that fitted under the top control panel that wasn't mentioned in the service manual.

Finally, we switched the set on and everything looked just great. And my client had saved a fortune by going to the panel beater!