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Christmas was fairly quiet for the trade in my neck of the woods and, thankfully, I did not suffer the usual idiots who phone and expect me to do a "free call out" on Christmas day to tune in their Video that they had "been meaning to get fixed for months". I'm pleased that nobody phoned because verbal abuse down the telephone wire often offends.
The weeks since then have been busy but uneventful with less analogue repairs than previously, as Sky Digital takes over, but higher sales of Sky Digibox remote control handsets, "TV Eyes", Scart leads and Scart switching boxes.
Digiboxes are starting to fail out of the guarantee period and I heard that one customer had been quoted 300 for a replacement Amstrad DRX100 because nobody repairs them (I you do, please let me know!) For this reason alone, I think I would prefer one of the other three brands.
You know how jobs can defeat you and you put them to one side meaning to look at them later. A few weeks go by and you have another go, replacing dozens of suspect parts without curing the intermittent fault. Then, suddenly, two years have gone by and you fall over it while looking for something else! Well, so it was with this SAT1700 which belongs to our local Farrier.
It had a silly habit of intermittently switching itself off (in a pulsing on and off fashion!) then resetting to Channel 1. It would do this about once every three days, usually while Jim was watching an important race. Understandably he was annoyed with it and I agreed to lend him another receiver while I took his away.
Having tripped over it in the workshop, again, I felt that I really OUGHT to get it repaired. On inspection I discovered that I had replaced every single component in the primary side of the power supply. I had even swapped the mains transformer with one from another receiver. I decided to eliminate the primary side from my mind completely. What could cause this fault on the secondary side? Back when Nokia Technical department still existed, they had suggested that I resolder all the wire links which are connected to zero volts. This I did but with no effect. I felt each of the seconday diodes and D12 was distinctly warmer than the rest. It supplies the 5 volt rail and carries much more current than the others. Maybe it was "leaky". I replaced it with a BYW98. That was three weeks ago and the fault has not occurred since then.
Now I'm in a quandary. Should I call Jim and ask him to pay for the repair or, bearing in mind we haven't spoken for almost two years, should I keep very quiet and simply sell the receiver? No, I didn't mean that. Honest!
This receiver had been - to use my favourite term - "pizzafied"! I fitted all the parts in Relkit 1 but pictures were still "streaky". I decided to measure all the electrolytics associated with the video path and my "Genie" ESR meter led me to C87, 98, 99, 100, 107, 108, 109, 196, 562 all 10uF around the "Nicky" chip, U9. Also C91 (100uF/35v next to the tuner), C97 (1uF) and C71 (10uF) both in front of the RF modulator.
The elderly owner was unimpressed when I suggested fitting a fan.
"It's lasted six years wi'out a fan an' if un lasts another six ah'll be dead b' then!"
I had a call last night from someone who wanted me to describe how to connect his D2Mac decoder to his new Sky Digibox. As it was nearly midnight, I guess he was desperate to watch one of those naughty Scandinavian movies! I told him that plugging his decoder into the Digibox would be as useful as plugging a banana into a light bulb socket. He seemed to take exception to this and, before I could explain the reasons for my glib statement, he slammed the phone down. I've had this all my life. People ask me for my expert advice but they are very unhappy unless I tell them what they really want to hear. Next day I called him back and apologised, saying that I'd been tired. I told him that what he really needed was a 2 metre long gold-plated Scart cable to connect his D2Mac decoder to his Digibox. He could probably buy one for only 29.95. He was obviously pleased by this suggestion and wanted to come and buy one right away! Some people are just born to be ripped off. I didn't like to disappoint him so I told him he could get from the adverts in "Wot, Satellite?" magazine. When it fails to produce the pictures he wants I shall offer to align his dish to 1 degree West of East and to supply a used analogue receiver that will work - for a very reasonable fee, of course! He can find his own card. I don't get involved with those.
The market is flooded with these cheap French Cable TV boxes, purporting to be D2Mac decoders. Indeed, with only minor modifications, they will work with many different analogue satellite receivers (but not all). My advice is always "try it before you buy it". If it doesn't work with your own receiver, don't take it out of the shop.
Jerry at the local TV repair shop is my friend. He has a CTU900 attached to his MSS300 and it has worked well for six months. Now, however, it was displaying a screen full of coloured, narrow, vertical lines except for a narrow strip down the right hand edge where some semblance of a picture appeared.
"It's the codes, again", he moaned.
I didn't think so. When the encryption codes change, the result is usually a scrambled picture composed of *horizontal*, coloured lines, not vertical ones. It looked as if the decoder was trying to reassemble the picture but with the wrong algorithm.
"Try unplugging it for a few seconds", I suggested.
"It's the codes", he repeated but reached behind the CTU900 and pulled out the power plug. On reconnection the TV showed a perfectly decoded picture.
"There!" I cried, smugly. "It's like a computer. It just needed to be reset".
At that moment the picture scrambled, briefly, then reappeared. It continued to do this repeatedly at intervals of a minute or less. It was random and was accompanied by occasional clicks. Sometimes the screen would go completely blank but the audio would remain.
"Bad connection on the Scart?" I suggested.
"Can't be. The plugs are pushed in tightly".
He looked at my expression and wiggled both Scart plugs behind the CTU900 and the MSS300. The picture now remained stable.
"I shot myself in the foot there, didn't I?"
"You would have paid me to take it away and fix it. In fact, I could have taken it and done nothing and it would have worked perfectly when we plugged it back in. I'm too good to you. Where's that cup of tea?"
This receiver arrived by carrier, with a note that said "Streaky decoded pictures". The card supplied with it was one of those naughty ones with two I.C.s soldered to it. One of the problems with these "cards" is that they are made from fibreglass laminate which is twice as thick as a plastic smart card. In addition, the edges are sharp and the contacts are soldered instead of gold plated. The sharp edges often damage the gold plated spring contacts inside the card reader slot so I filed them until the front edge of the card was nicely rounded. I couldn't do anything about the lack of gold plating. In theory, the solder coating will cause a bad connection, resulting in intermittent operation. In practice, this seldom seems to happen. The card now slid easily into the slot but I was careful to place my free hand on the metalwork of the receiver to equalise potentials because it's very easy to discharge body static through the card and destroy the card reader I.C. inside the receiver.
On test, the receiver gave pictures but they were obscured by short, black, horizontal lines. Tuning the channels did not improve the picture and the on-screen menus floated diagonally across the screen. The receiver had already had a "Relkit" fitted so most of the capacitors in and around the power supply were new and of the correct low ESR type. I measured the ESR of the electrolytics around the tuner and the measurements were within acceptable limits. However, my "Genie" showed that several electrolytics on the D2Mac decoder board were not so healthy. C72 (220 F) was causing the horizontal short black streaks and C39 (100 F) was causing menus to drift across the picture. I replaced nearly a dozen capacitors in total, before I was happy with the picture quality.
However, I was puzzled because the part numbers failed to tally with those on the circuit diagram. In fact the decoder layout was quite different from the picture in the service manual. Even the lads at Pace Technical could not explain the differences until I gave them a detailed description. It transpired that the D2Mac board belonged to an MSS260G but quite a lot of MRD950+/960+ receivers had been built with this board (182-0163203) instead of the older version (182-0163105) used in the MRD950/960.
This model is notorious for overheating because it has a Dolby Prologic board and an antenna positioner board inside. If people would install the unit in a sensible place (a nice open shelf in a cool room) there would be no problem but modern "Hi-Fi" cabinets and central heating make sure that they require constant attention.
This one was exhibiting the usual intermittent "motor error" and "no signal" messages so I fitted the capacitors in RELKIT 10. That fixed those faults but the contrast was now apparently switching itself from high to low and back again every few minutes. This affected the picture from the RF modulator but not the Scarts. I traced the cause to Q61 (BC846B) and fitted the other four surface mount transistors from TRANKIT 10 for good measure.
Finally, the pictures were very streaky and I traced this with my "Genie" to C502 (1000uF/16v next to the tuner).