29th Aug 2020, 5:39 pm | #141 |
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Re: Which was the worst TV set / chassis you had to repair
Curry's original service organization I believe was called BELCHER? John.
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29th Aug 2020, 6:25 pm | #142 |
Dekatron
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Re: Which was the worst TV set / chassis you had to repair
I never really ad much to do with consumer-level TV servicing, but do remember one of the last 405-line GEC tellies where the dropper-resistor was so close to the cardboard back that after a few years the back was cooked black along one side and generally crumbled to nothing in this area if you tried to remove it.
Computer-monitors were more my 'thing' - there was a range [7002, 7003, 7009] made by "Newbury Data" that were popular in the academic world from the late-70s to the mid-80s: Steel cabinets, bottom part painted brown, top part cream - they used Brimar 'modules' for the line/frame scan and brimar CRTs, along with a simple transformer-and-rectifier DC supply. http://www.computinghistory.org.uk/u...duct-93789.jpg Problem was, there were myriaid variants of these so you couldn't have a 'standard' set of boards/modules to swap when you went out on a call. I loathed those things with a vengeance, and more than once attached a small magnet to the CRT neck so I could show 'convincingly' that there was a major, unfixable tube-fault so they'd accept my diagnosis of 'beyond repair'. |
29th Aug 2020, 6:43 pm | #143 |
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Re: Which was the worst TV set / chassis you had to repair
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29th Aug 2020, 9:28 pm | #144 |
Heptode
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Re: Which was the worst TV set / chassis you had to repair
My procedure was to take the expensive silicone, if not fried, and use it for spares in kv1820s that was a good chassis. When I encountered the 1810 they usually had worn out tubes and the value of such a set was less that the parts to fix the cost. As far as I remember they weren't service feindly either.
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29th Aug 2020, 9:50 pm | #145 | |
Heptode
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Re: Which was the worst TV set / chassis you had to repair
Quote:
UK sets didn't have much market share. In the late 70's a lot of "Rank" sets were sold. They were OK, but crude. There were some Thorn sets. 9xxx and TX sets. They also were OK, but others were better in my opinion. I only saw one PYE set. That was a 110 derge delta set. It didn't inpress me. |
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29th Aug 2020, 10:57 pm | #146 | |
Octode
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Location: Peterborough, Cambridgeshire, UK.
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Re: Which was the worst TV set / chassis you had to repair
Quote:
Probably the reason they exported Rank sets in the late 70s was because they had ruined their reputation here . The T20 was abysmal when new . My friend worked for a Bush dealer and when they unboxed the sets new a large proportion were faulty or packed up within a few hours / days. The T22 was slightly better and the T26 was much better apart from premature tube failure but by then the damage to reputation was done! Rank sets were so bad that they fitted a Toshiba chassis to the T24 which was the 20" model . The Thorn TX sets were very good . Reliable and long lived . Most TX10s and TX9s ran until the tube wore out. |
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29th Aug 2020, 11:59 pm | #147 | |
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Re: Which was the worst TV set / chassis you had to repair
Quote:
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30th Aug 2020, 9:22 pm | #148 | |
Nonode
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Re: Which was the worst TV set / chassis you had to repair
Quote:
That was by far the best Rank chassis ever produced thanks to Toshiba. They seemed to just keep working with very few problems. The Z718 chassis wasn't bad with its technically advanced Toshiba RIS tube. Things went downhill thereafter with the introduction of the T20 chassis. Poor reliability and plasticy pictures though the T20 was easy to service. What I liked about the T20 was its stand alone SMPS. It made servicing a little easier than say a design which is tied to the line frequency as in the Philips K30 for example. The T20 could have been much more reliable if better quality components had been used. I always remember the discolouration of the scan coil connector, one of those white Pressac 0.2" pitch multiway connectors that suffered overheating due to carrying full line scan current. The ITT CVC30 and CVC32 series suffered a similar problem. Philips with their G11 chassis used the same connectors but doubled up and trippled up on the connections which carried significant current thus improving safety and reliability. Regards, Symon |
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30th Aug 2020, 9:35 pm | #149 |
Nonode
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Re: Which was the worst TV set / chassis you had to repair
Yes, on the T20/T22 the head engineer where I worked at the time insisted we ditched the connector for the line scan plug altogether by hardwiring the line scan coils direct to the board, he did not trust that connector on these sets, he said they were a fire hazard and an accident waiting to happen.
Strange how one recalls these words of wisdom from many years ago.
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30th Aug 2020, 9:48 pm | #150 |
Nonode
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Re: Which was the worst TV set / chassis you had to repair
Talking of Rank sets, does anyone remember the Z179 chassis that drove a 26" 110 degree delta gun crt? Being a 110 degree delta set they were probably more of an export set like the Thorn 4000 and Pye 731 series.
I never came across any Z179s myself. I guess they were a stopgap between the A823B and the larger screen versions of the Z718. Regards, Symon |
31st Aug 2020, 10:38 am | #151 |
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Re: Which was the worst TV set / chassis you had to repair
Ben wrote: "On the whole those sets were a quantum leap in terms of reliability and picture quality compared to the aforementioned rubbish churned out by Pye and Rank in the UK."
Well I wouldn't consider those two makes rubbish, I had loads on rental and didn't have many problems with them. OK, the Rank T20 had it's problems but the faults were predictable and very few were brought to the workshop for repair. The scan coil connector was a source of trouble as was the start up capacitor on the signals board. A fully wired scan coil lead and connector was available form the RRI service department. Anyone remember the Philips G110? Superb pictures and sound but the power supply circuit gave me many problems. Major rebuild job to return a blown up power supply to working order. Every component in the kit of parts supplied by Philips Service had to be fitted otherwise the PSU would fail again. After the repair the degauss posistor and power switch should be checked, and any doubts replace them. The G110 sets I sold and rented were badged as Dynatron. Supplied through Roberts Radio. Didn't have much time for continental sets, in the mid seventies I did buy in a few Telefunken models which were alright. In 1980 TFK introduced a new chassis, the 615 and that was an awful thing. A flimsy single PCB supported on the cabinet floor by means of plastic spacers. Another set best forgotten. DFWB. |
31st Aug 2020, 12:07 pm | #152 |
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Re: Which was the worst TV set / chassis you had to repair
I only saw a few early 70’s European made CTV’s, don’t remember makes but they were not that good on performance or reliability.
The Pye 691/693 sets I thought were decent, the 697 chassis had its problems but the 90 degree 725 series I liked, faults I had were straight forward. The 731 110 degree chassis was not as reliable but straightforward to repair just the same. The RBM sets were fine, had there problems but straightforward. The only T20 set I had problems with was the tripler didn’t last long, not surprised, it was in a chip shop on a high shelf near the gas cooking range. Had to be carful it didn’t slide out of my hands while getting it down from the shelf. Probably scrap after 3 or 4 years. Probably familiarity helped, just got used to knowing what went wrong with them. I occasionally had a Thorn CTV sets to fix, always a pain for me I saw so few but they were probably no different than others once used to them. From reading this thread some of the real horror stories seem to be in the 80’s onwards.
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31st Aug 2020, 12:07 pm | #153 |
Nonode
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Re: Which was the worst TV set / chassis you had to repair
Just recalling some of the other stock faults on the T20.
(1) There was a 910 Ohm resistor in the 12V regulator circuit that ran hot and went O/C. (2) The line output transistor's 1 Ohm 4W W/W base feed resistor going O/C. (3) Black line disturbance on the picture due to earthing problems again due to connectors on the signal panel (4) E/W modulator faults due to faulty diodes (5) SMPS failures (6) Resistors in the G2 (A1) control circuit going high or O/C (7) The LOPTx became troublesome on older sets I think there were other stock faults too but the above were pretty common in the sets that I encountered. I don't remember many tuner and I/F faults and the decoder was quite reliable. Regards, Symon |
31st Aug 2020, 12:55 pm | #154 |
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Re: Which was the worst TV set / chassis you had to repair
As for the T20, you go on a service call armed with everything you might need.
That 910 ohm resistor, some reckoned you could get away with a 1K resistor but I always believed someone did the maths so 910 should be the replacement. RRI supplied their dealers with service case with of all the bits one would ever need to fix the basic T20. Might still have that box somewhere. It was a big cumbersome thing so I rarely took it with me on service calls. Getting back to the Philips G110 power supply. From the performance point of view it was excellent. Connect the set to a variac and adjust the input voltage between 190 and the full mains voltage. The DC output remained dead steady. DFWB. |
31st Aug 2020, 1:19 pm | #155 |
Nonode
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Re: Which was the worst TV set / chassis you had to repair
I did quite a few G110 rebuilds, fitting both kits when the second one became available.
It was always with some trepidation powering up for the first time after all the hard work had been done. Rich (aka Sideband) wrote two very good articles in the TV mag which was very helpful, thankfully the two kits did just fix the majority of sets. I think we only ever had a handful that had further problems, a couple of failed lopts which could not have been foreseen and which might have been responsible for the PSU failure in the first place, this was really not a cheap repair! Oh yes, we also soak tested these for another 8 hours in standby too after the initial usual soak test in normal running after a rebuild.
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31st Aug 2020, 3:46 pm | #156 |
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Re: Which was the worst TV set / chassis you had to repair
Here's a few parts to repair a T20. You never know there might be someone out there wishing to have one repaired.
Going back further in time I remember so-called engineers slagging off just about every TV set in existence. Sure, there was a few horrible sets about but if one spent a little extra time even on those most sets could be made to work properly. Of course those guys didn't like certain sets, the reason was simple, they couldn't fix the sets, in fact they couldn't fix anything. Most customers were delighted when their TV set was finally repaired properly but I did encounter the odd customer who reacted quite differently, "how have you managed to repair my set when my man couldn't do anything with it". Anyone else experienced this kind of customer reaction happen to them? DFWB. |
31st Aug 2020, 4:01 pm | #157 |
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Re: Which was the worst TV set / chassis you had to repair
The boss of the shop I worked at took in very few repairs that he hadn’t sold, his decision. Occasionally I had one on the bench and if it had been near one local repair shop it had usually been bodged beyond economic repair. Favourite short out the o/c dropper sections, most valves and CRT low emission with the correct dropper values fitted. No idea why they did that, even fitting resistors on the failed dropper would have got the set working until a correct type was available and the valves etc would have been fine.
Luckily I didn’t see many horrors.
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31st Aug 2020, 4:10 pm | #158 |
Nonode
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Re: Which was the worst TV set / chassis you had to repair
Oh we saw it all! heaters jacked up you name it!
Later on I did a lot of trade repairs, more in bulk so fifty sets was about a normal weeks work, no normal faults here at all, and I tended to get a lot of Thomson, Sony and Sharp mostly, with a lot of top end Philips (MG and EM series) thrown in for good measure, I also did quite a lot of Panasonic, Sanyo and Vestal as part of that mix! These all tended to all have oddball faults, but I needed to earn a crust.
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31st Aug 2020, 9:36 pm | #159 | |
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Re: Which was the worst TV set / chassis you had to repair
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'My son works for the Electricity Board and he said it was beyond repair'. You can't win David, right or wrong! John. |
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31st Aug 2020, 10:06 pm | #160 | ||
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Re: Which was the worst TV set / chassis you had to repair
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