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Old 4th Oct 2020, 1:54 am   #201
Maarten
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Default Re: Which was the worst TV set / chassis you had to repair

Wasn't Elbe taken over by Sharp and transformed in their own design center / factory eventually? Since the mid to late 1980's, most Sharp sets I saw were clearly designed in Europe and often mentioned "Made in Spain".

I think other well known brands such as Scholtes and Fagor also had TV factories at some point in time and there would have been many more smallish manufacturers just as was the case in Italy, but I can be mistaken.
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Old 4th Oct 2020, 5:11 pm   #202
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Default Re: Which was the worst TV set / chassis you had to repair

Just remembered the Grundig portable that was unlike any other Grundig, which was understandable as it wasn't made by them, but I can't remember who was responsible. Maybe the G1000 chassis? Black plastic, and I think there was also a 20" version.
The nice fault was the speaker and audio feed resistor, or maybe the main smoother and subsequent PSU blow-up - both easy repairs. However anything else resulted in a nightmare of interconnected ICs.
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Old 4th Oct 2020, 10:44 pm   #203
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That must have been the G1000 chassis, made by Grundig's former Creutzwald, France factory that was spun off by a Mr. Gooding and used its own (or a design houses) design. They also made sets for Continental Edison. I think they had one other chassis after the G1000 that wasn't used in Grundig branded sets and they closed shop some time after Grundig stopped buying their sets (that may have been the moment that Grundig turned to Beko for the first time, or Grundig went back to their own design for low end sets to make better use of their own factory).
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Old 5th Oct 2020, 12:34 pm   #204
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Default Re: Which was the worst TV set / chassis you had to repair

That was it - Gooding. There was a more conventional chassis that followed this one which didn't resemble a Beko. I'd imagine it was an in-house design, though I can't remember the chassis number, but I think it sounded like a 'real' Grundig.
The G1000 was an odd design with a central control IC unlike anything we were used to. The main processor supplied the line drive digitally and a common fault was the line speed being too high but perfectly locked. However if it went too high things would happen lower down the chain and damage would result. A baffling service manual didn't help either with everything interconected, but not via I2 bus and data lines that might have helped. All this for a low-end set that didn't merit much bench time.
I remember the rep offering us some of these TVs. We didn't buy, and some months later he was complaing about all the returns he was getting.
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Old 5th Oct 2020, 5:56 pm   #205
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Default Re: Which was the worst TV set / chassis you had to repair

Hi!

Several Members have mentioned Tyne, whose cabinets looked like bits of old pallette wood nailed together –I can go one better!

How about the BerryVision 510?!

As well as the obligatory pallette–wood cabinet, this home–grown nightmare had a PSU that was a clone of the 3500, (but the h.t. was a good deal higher than the 65V the 3k5 used!), a convergence PCB with the same big huge wirewound in the line–scan circuit for the convergence sawtooth voltage, a TBA800 field o/p circuit in a daft arrangement in tandem with a BD131 power transistor on the output, a 4–chip Mullard decoder, an i.f. panel filched from the Bradford, the audio was a motley collection of transistors on the i.f. board, and the whole was built on grotty srbp boards fixed to pieces of L–shaped ali welded together, screwed to blocks at the top & bottom of the cabinet, and an ETT6016 based touch tuned unit, missing all the cosmetic finishing panels by the time I got it!

No circuits of course, I managed to draw the TBA800 frame o/p and part of the chopper PSU, and of course, there was no silkscreen anywhere on the boards, so I'd no idea what the correct h.t. supply setting was!

Chris Williams

PS!

I liked the Telpro Bradford redesign – the audio was a doddle on those as it was on top of a swing–up power supply box, a lot nicer to get at than having to pull the Bradford works back along the runners and hope they didn't jump out of the chassis, and then you had to lie under the thing like a garage mechanic to get at the PCL82 audio valve base!
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Old 5th Oct 2020, 6:02 pm   #206
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Default Re: Which was the worst TV set / chassis you had to repair

Sounds like the Italian job I wrote about earlier but even a bit worse.
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Old 5th Oct 2020, 6:56 pm   #207
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Hi!

From what I was able to decipher of the BerryVision 510:–

a) ETT6016 Touch Tuner Module – filched from the GEC S/S Colour chassis;
b) I.F. and Audio:– Decca Bradford with an oddment of transistors in one corner for audio;
c); Luminance, Decoder & RGB:– Four Chip Pye s/s decoder, Bradford RGB output;
d) Field Osc:– Bush A823 S.C.S. plus a TBA800 and BD131 for field output;
e) Line Oscillator, TBA920, Line Driver and Output, Bush A823 with a GEC LOPTY; and (I think!) the neon–based A823 overvoltage trip circuit;
f) Convergence, Thorn 3k5;
g) Power Supply, Non–isolated 3k5 minus mains–transformer, operating at much higher h.t. than the 65V of the 3k5;
h) CRT base, focus and e.h.t., thick–film focus unit, GEC tripler and a very "home–made" CRT base panel!

Chris Williams
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Old 5th Oct 2020, 11:29 pm   #208
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Default Re: Which was the worst TV set / chassis you had to repair

Chris W.... A lot of what you describe in design were from the same design house..It was based at Eldon House, just off Manningham lane in Bradford.....Thats why the set was called the Decca Bradford. Eldon Technology, were ex Thorn employees, or mostly.. They eventually relocated to a nice technology park in Bingley...I will not comment further on my connection with Eldon,...
Designers were left with a "Hobsons Choice".... select an IC to do a particular job and then use the IC manufacturers basic design, adding or subtracting tweeks as they went.
I was not clever enough to design circuits, but I was pretty good at prototype building and was involved in 3 new designs.
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Old 6th Oct 2020, 7:58 am   #209
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Default Re: Which was the worst TV set / chassis you had to repair

Quote:
Originally Posted by Wendymott View Post
Chris W.... A lot of what you describe in design were from the same design house..It was based at Eldon House, just off Manningham lane in Bradford.....Thats why the set was called the Decca Bradford. Eldon Technology, were ex Thorn employees, or mostly.

Looking at the physical construction of Decca Bradford CTV chassis and the contemporary single standard hybrid mono chassis (MS2001, etc), they are very clearly a product of some/all of the former Radio Rentals Bradford design staff (even the circuit diagrams use the same stencils!).

Presumably, some/all of the former Radio Rentals TV design staff were made redundant after RR was taken over by Thorn in 1968. I wonder what became of Decca's TV design staff, after their Battersea dual and single standard CTV chassis?

Did Decca "buy in" their CTV designs after the Battersea, or did they directly employ some former RR Bradford people? Presumably, after Decca's takeover by Racal and the sale of the radio & TV division to Tatung of Taiwan, plus the relocation of the factory from Bridgnorth to Telford, their CTV designs were still produced by the same team...?

Googling Eldon Design, it appears to have been set up in 1988 - much later than the Decca Bradford's time. Maybe this coincides with Tatung UK's withdrawal from TV manufacture in the UK...?

"But West Yorkshire engineering’s greatest growth potential is based on the rising number of electronics companies clustered around Bradford. Some, such as Filtronic, were set up by former Leeds University academics, while others, most notably Pace Micro Technology, a leading technology developer for global payTV industry, and Eldon Technology, an electronics design house now owned by Echostar of the US, can trace their origins back to engineers who worked at the new product research centre of the former Radio Rentals TV factory in Bradford."

"Eldon Technology was established in 1988 by 11 senior managers and design engineers from the former Ferguson New Product Research Centre in Bradford. Since its formation, Eldon has grown to over 70 employees providing extensive and widely diverse support services for many major manufacturers of consumer and non-consumer electronics-based products and components. These services include product design, feasibility studies and prototype development."

All very interesting!
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Old 6th Oct 2020, 4:15 pm   #210
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Default Re: Which was the worst TV set / chassis you had to repair

I only ever saw one Berryvision in a disposal house. I was almost tempted till I saw there was no back and someone had tried to change the TBA800 with a pick and shovel.
At least we know where Tyne TVs came from - I even have the manual. But the Berry Vision? No idea.
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Old 7th Oct 2020, 9:01 am   #211
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Morning Glyn!

The one I got didn't have the back either - it was also missing the finishing bits from the front of the touch-tuner module, the overlay from the convergence panel (I never got any luminance thro' the decoder/RGB panel on mine - I eventually tried rebuilding it from bits off a rescued G8 four-chip Signal Panel and that experiment failed dismally as well as I'd no circuits, oscilloscopes or decent meters in those days, and the crosshatch gen. was a butchered Technalogics CP6RF kit I tried to build and made a mess of it!) - I wonder if I ended up with the only one you saw?!

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Old 7th Oct 2020, 10:36 am   #212
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Default Re: Which was the worst TV set / chassis you had to repair

When I finally persuaded my parents to get a colour TV a friend and myself went to a warehouse to get a cheap and simple set for them. I ended up with what I now know as a Berryvision. Its fault was the tuner stabilizer IC the supply to the tuner wandered with the brilliance so the tuning wandered. A replacement IC solved it and the set ran quite well for many years. I used to have to tweak the A1's occasionally so the back was left off for easy access. This caused some consternation as the cat was known to walk, tail up, behind the set while it was on luckily the tail never touched the tube base.
My father never wanted a colour set since he was red/green colour-blind.
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Old 7th Oct 2020, 11:08 am   #213
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Default Re: Which was the worst TV set / chassis you had to repair

I did service a couple of Charly (DMP) decks. There was once an excellent article in TELEVISION magazine covering them. On both occasions, I did the job properly and fitted the full Philips repair kit and followed the article. I had no problems at all servicing them.
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Old 7th Oct 2020, 6:04 pm   #214
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Default Re: Which was the worst TV set / chassis you had to repair

Regarding those fast thyristors for TV line output/SMPS stages...

The SCRs were specifically made for that duty... Philips/Mullard and AEG if I remember. Now a guy called Tim Kriegel designed a 40kHz sinewave inverter around them and a bridge inverter invented by Neville Mapham at GE. Tim's design went in HP70000A modular mainframes for nearly 20 years without any problems, but Tim and Joe had put a lot of care into that design. I got the job of redesigning it when life-bought stocks of the SCRs were running out. I did it with IGBTs.

What this illustrates is that the SCRs could be used in 200W circuitry (1.2kW circulating power) without reliability issues, so it's likely that the TV circuits were the root cause of the reputation. The Mapham inverter was bad to get your head around but the TV circuits were much more complex.

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Old 8th Oct 2020, 10:02 am   #215
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Default Re: Which was the worst TV set / chassis you had to repair

Having quite a few Grundigs on my patch I got to know the thyristor stage quite well, and it wasn't all that bad. In fact most troubles were due to the tripler on that chassis. I remember as a teenager fixing one for a friend's father when a small 0.015uF capacitor below the devices had failed - I was thrilled!
The special capacitors and commutating transformers had to be of excellent quality, and Grundig ones were, though some other makes didn't quite make the grade. Grundig used a similar circuit for years after other firms had decided it wasn't for them.
Having said that, I wasn't so fond of the Rediffusion Mk3 as that seemed to me to have an overly complex power supply with yest another thyristor which could give the impression of a line output fault. However, they were a good TV and I know most Reddy engineers liked them.
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