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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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14th Feb 2022, 3:32 pm | #21 |
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Re: My time at Rank Bush Murphy
Very interesting film. The second film showing the TR82 production also includes the construction of the TV125 series, complete with it's VHF push button tuner, the first fully dual standard mono chassis from 1964.
The Ford Thames Trader lorry leaving the factory almost has a Toy Town feel about it. John. |
14th Feb 2022, 3:43 pm | #22 |
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Re: My time at Rank Bush Murphy
I went to the RBM Ernesettle plant when I was at PCFE a couple of times when they were recruiting in 1973 and 1974.
Most of the Plant was from what I saw/remember was for the production of Colour TV sets at that time. I don't recall seeing any Radio's being made I suspect they had already started the move to overseas manufacture certainly by 1974. When I was there the whole atmosphere was considerably different to that of the 60's video. It was noisy and busy was my lasting recollection and a career there didn't appeal to me at that time. Cheers Mike T
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15th Feb 2022, 10:45 am | #23 |
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Re: My time at Rank Bush Murphy
Thanks for the information and interesting video clip. Its nice to know where my original Bush TR130 was built.
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17th Feb 2022, 10:04 pm | #24 | ||
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Re: My time at Rank Bush Murphy
Quote:
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18th Feb 2022, 3:28 pm | #25 |
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Re: My time at Rank Bush Murphy
G8VSJDave wrote
"It was headed by Bernard Rogers who (it was rumoured,) had played a part in the development of the PAL colour system." I don't think it was a rumour, I had the very good fortune to work at Michael Cox Electronics for about 8 yrs, along with several others on these various forums including the late lamented Brian Pethers. Mike, Howard Steele, Stuart Sansom, Norman Green and others worked at ABC (Then Thames) on trying out the various colour systems and Bernard Rogers name came up many times in the conversation. John |
18th Feb 2022, 4:25 pm | #26 |
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Re: My time at Rank Bush Murphy
A bit more info with personal recollections:
https://www.ourwelwyngardencity.org.uk/content/topics/the_wo...history-of-the-murphy-radio-company I remember in the 1970s they had a factory at Skegness and a nearby scrapyard (Sid Dennis) had a lot of their waste. I called occasionally and literally picked up various components off the floor. The Japanese IF transformers and osc coils with coloured cores being some, plus various slider pots. Don't know when the factory closed though. Rob
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18th Feb 2022, 5:32 pm | #27 |
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Re: My time at Rank Bush Murphy
All fascinating. How sad that we have outsourced such endeavours to the Far East.
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18th Feb 2022, 6:42 pm | #28 | |
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Re: My time at Rank Bush Murphy
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22nd Feb 2022, 6:21 pm | #29 |
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Re: My time at Rank Bush Murphy
Part Two.
The A774 – It was the summer of 1968 when, as part of my apprenticeship I was transferred to the Monochrome TV lab. There were five engineers and two project leaders working in the lab, one engineer was fresh from university, the rest being old school but very experienced in the field of television circuit design. The design aim specification for the A774 had been issued to the Lab some months earlier and by the time I joined the project the basic circuit blocks of the A774 had been decided upon and component values were being optimised. Early development and testing of the prototype A774 circuits was done by bread-boarding them and grafting them into A640 sets One of the engineers was tasked with making the first draft of the main printed circuit board using the Dot and Tape technique. This was done by laying out the pattern of copper tracks to scale on to an A0 maylar sheet using self-adhesive black tape to represent the copper tracks and ‘dots’ made from the same material for the component holes. The maylar sheet was then used as a ‘master’ from which the printed circuit boards would be made. This method was used at least up to the Z718 project. About 20 ‘A’ models of the A774 were then made from the new PCB and distributed to the engineers for testing and used for field and life testing. This stage of testing revealed a few problems of unwanted interaction between some circuit blocks that were corrected either by modification to the PCB layout or the addition of an extra decoupling capacitor. Flash-over testing resulted in a change to the CRT aquadag earthing position to prevent damage to the tuner RF amplifier – something no one could explain. A few months later a run of ‘B’ model chassis were made using a pre-production line at the Plymouth factory. Several were sent to Chiswick for field trials by the engineering staff, pre-production testing and more development work, others were used for assembly training, Electromagnetic Compatibility (EMC) and BEAB consumer safety testing. I had spent a full year of my apprenticeship working on the A774 project and in that time I saw it develop from a rats nest of circuits to an almost finished television. Sadly, at this stage I was moved on to another department as part of my training, so I didn’t get to see A774 finally go into production. From comments here, I know many of you don’t like the A774 due to poor reliability. I know the Line Output Transformer gave a lot of trouble, but were there any other troublesome components? There were to my knowledge two additional minor projects that year. One was the single standard A640, which if I recall correctly, was known as the A793. The other was a modification to speed up the A640 AGC. Apparently a transmitter mast somewhere, was moving in the wind, causing contrast variations that resulted in complaints from Bush dealers. Does anyone have any information on this modification? I am sorry this is not as comprehensive an account as I would have liked, it was fifty odd years ago and my memory is not what it once was. The last part will be my memories of the A816 and Z718 Dave |
22nd Feb 2022, 9:52 pm | #30 |
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Re: My time at Rank Bush Murphy
Interesting to hear from the coal face!
Besides the infamous LOPT, the main quibble with the A774 was the picture quality was inferior to the A640. This was more to do with the excellence of that chassis as the A774 was a better performer than the Thorn 1500 IMHO. The construction of the single-board chassis led to many earthing problems. The A793 was arguably the best performer of the Bush hybrids. Your a816 instalment will be interesting. A high-spec large screen solid state mono seemed like an answer looking for a problem when everyone was buying colour. |
23rd Feb 2022, 10:49 am | #31 |
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Re: My time at Rank Bush Murphy
After the excellent A640 AND A793 expectations for the A774 were probably very high but unfortunately it was a huge disappointment for many. Poor picture quality, odd flickering and sync faults that could not be cured by resoldering the chassis earth lugs, strange flashovers across the on off switch when you switched the set off and many other strange faults. Then of course was there hunger for LOPT's and some required replacement CRT's every few years.
But some A774's did work well and we hardly saw them but some were a nightmare. Interesting what you said about the AGC modification on the A640. They did suffer a bit from signal bounce in some areas but as they did not suffer from intercarrier buzz on 625 sound and had a good black level it generally was not an issue for us or our customers.
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23rd Feb 2022, 12:32 pm | #32 |
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Re: My time at Rank Bush Murphy
Simon's comments are true some sets were better than others . It did depend on the customer to a degree. Some houses had no central heating and were cold and damp this had a bearing on the heater loop on the LOPT which often burned out, It was so common that there was an aftermarket kit to remove the valve and holder along with the winding and replace it with a stick rectifier along with a new EHT lead and cap. Some customers were heavy smokers back then and nicotine and condensation didn't help as far as anode cap flashovers were concerned. Some sets had grey blacks and wishy washy brightness so it meant adjusting the contrast and brightness depending on the programme, the controls on the back being recessed didn't help with that.
Then of course some customers were more fussy than others. We as engineers then only saw the ones that failed I am sure there were many that chugged on for years. Again usage had a bearing some sets were used a lot more than others. There is no denying it wasn't as good as the A640 though, one A774 was featured it the consumer programme "That's life" as their "heap of the week" It had been so much trouble. I seem to remember they shot the screen with a rifle and then made it into a pot plant stand! Ironically smashing the tube which was probably the best part of the set! I what I find strange is that Rank thought it was worth producing new models when the take up for colour was so high and was going to get higher as time went by. I would have saved my money and stuck with the single standard A640 they could have fitted it into more modern cabinet designs. The customer wouldn't have been bothered what was inside! Maybe the A774 was a lot cheaper to make and took less assembly time? I was never a fan of the later solid state chassis either but to be fair I didn't see many and most were written off by then for LOPT failure or poor tubes , for some reason most of the solid state ones I saw were 24" a tube that didn't focus well in the corners after a few years. All of this said the A774 I found last year has a good LOPT and looks to have had few previous repairs. (It doesn't work though). The A774 certainly wasn't a set I picked when buying second-hand sets for refurb for resale.
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23rd Feb 2022, 12:53 pm | #33 |
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Re: My time at Rank Bush Murphy
Oddly there was a choice of chassis in the TV181, TV183, TV186, TV191 and TV193. They had the suffix D (A640, dual standard) S (A796, single) and SS (A774, single standard). They looked the same from the front, but obviously the backs were different. Maybe the SS versions were to trial the new A774? Don't think I ever saw one.
Yes - heap of the week was a TV191S, I think. However I think they made it into a puppet theatre complete with curtains and puppets of the presenters. Quality Sunday night ntertainment, huh? |
23rd Feb 2022, 1:05 pm | #34 | |
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Re: My time at Rank Bush Murphy
Quote:
Rich
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23rd Feb 2022, 1:12 pm | #35 |
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Re: My time at Rank Bush Murphy
A problem I saw in the 70’s was poor mono CRT’s from new, poor corner focus, grainy phosphor, I think they were imports, not a patch on the production from Mullard and Mazda. I don’t know if RBM used them but others did.
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23rd Feb 2022, 1:17 pm | #36 |
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Re: My time at Rank Bush Murphy
Yes they were "Unitra" a lot were sold as replacements. I don't know if they were fitted to production sets. I suppose they were cheaper than regun tubes and the re-gunners were concentrating on Colour by then. We had them where I worked in the late 70's early 80's so they must have been cheap!
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23rd Feb 2022, 2:05 pm | #37 |
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Re: My time at Rank Bush Murphy
Yes - Mullard used them - they had a purple label. The Thorn 1615 used them from new giving those TVs a poor reputation (that and catching fire). Not sure if Bush used them - certainly not in the A640 or the 774 as far as I know.
These CRTs turned up around the time of the colour boom so no-one was really interested in mono then. Unitra did actually make a whole TV that was imported around 1980. It was a big Eastern European wooden thing and I believe was one of the very last hybrid TVs. |
23rd Feb 2022, 4:18 pm | #38 |
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Re: My time at Rank Bush Murphy
I remember those purple label Mullard tubes. I didn't realise they were relabelled Russian ones though. Some years ago my mate Mick (Mick McMichael) had a new old stock Thorn 1500 - The plastic cabinet Marconi version a few years back that had one fitted.
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23rd Feb 2022, 9:22 pm | #39 |
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Re: My time at Rank Bush Murphy
Comparing the two chassis, I think the A774 must have been cheaper to manufacture than the A793 (the UHF/625 only version of the A64) - single board, no real chassis as such, fewer connectors.
The A774 had several modifications incorporated during its production run and they did make a noticeable difference, but I would agree that the pictures weren't up to the A640/A793 chassis standard. The original A774 chassis DY802 LOPT was changed to a Z734/Z735 in order to meet BEAB product safety requirements. I have an RRI genuine spare LOPT with a voltage doubler attached (ITT type 11TEZ), instead of a DY802. The A816 solid state UHF/625 chassis produced much better pictures than the A774. |
24th Feb 2022, 10:44 am | #40 |
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Re: My time at Rank Bush Murphy
I only saw a few A816's, similar sort of circuity, PSU, as used in the Z718 colour chassis if memory serves me correctly.
As well as having lots of RBM black and white TV's out on rental we also had a lot of RBM colour sets out mostly using the RBM A823 chassis. Ok this chassis did have a few issues with picture quality, had their fair share of stock fault and were quite heavy on tubes but we never had a LOPT fail on the A823 and have never heard of anyone else having to replace one. We had to change lots of triplers and line output transistors which on the earlier versions was quite a tricky job as you had to carefully balance them or off they would pop. But overall our customers likes them with there warm soft picture and very good sound quality.
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Simon BVWS member Last edited by Hybrid tellies; 24th Feb 2022 at 10:58 am. |