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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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26th Jul 2020, 9:24 am | #1 |
Tetrode
Join Date: Mar 2020
Location: Newton Abbot, Devon, UK.
Posts: 73
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Bush TV22A Restoration
Hello All,
My second valve tube project after the Pilot U650 Radio (still looking for a replacement speaker and need to get the magic eye reacting properly) is this old TV. It belongs to a friend of mine who inherited it from his father who owned TV shops back in the day and it is very dear to him. It has not been used for over 40 years and may or may not have been working when stored. The crazy thing is he has entrusted it to me to see if I can get it working at all. Restoration is not the right title as that would be a whole other level best left to the experts. My aim is to provide a safe reliable set that will show a picture when used. Not sure if this has one or more channels - will learn about that on the journey. I have started by reading lots of threads - nearly all on the TV22 models and looking at video's on the net again all TV22's. This didn't put me off and helped to identify how to remove the case and back panel. Goodness me how filthy everything is!! There are also lots of drips of wax on the receiver unit from above - the caps all have evidence of this. One capacitor is not attached at one end at all and the Cap on top of PL81 valve has come away. This set has a Band III thing on the back which differs from the TV22's I think? Thanks to previous contributors for embedding schematics / service manuals etc which i will print off several copies. I have devised a cunning plan to do after that and cleaning everything first: 1 Replace cracked / brittle wiring 2 Replace Wax / Electrolytic Caps about 50 in total 3 Test all valves - 18 of these plus picture tube 4 Clean & test all pots 5 Check Transformers work While doing this - find out what a standards converter is and find out if / why I need one - the info on here should help with that. Then figure out how to convert potentially live chassis to safe 3 pin mains cord. I have some test equipment and some experience mostly related to solid state Hifi but have loads of patience and capacity to learn all be it slowly as my intelligence level if lacking as I have had no training at all in any of this stuff just self inspired tinkering. I do know enough about the safety aspects and have an isolated power supply / variac / dim bulb BUT will need lots and lots of help along the way please. |
26th Jul 2020, 11:30 am | #2 | |
Dekatron
Join Date: Dec 2004
Location: East Yorkshire, UK.
Posts: 3,959
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Re: Bush TV22A Restoration
Quote:
John.
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My favourite text message "I'll be there in five minutes, if not read again" Last edited by 60 oldjohn; 26th Jul 2020 at 11:38 am. |
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26th Jul 2020, 12:11 pm | #3 | |
Tetrode
Join Date: Mar 2020
Location: Newton Abbot, Devon, UK.
Posts: 73
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Re: Bush TV22A Restoration
Quote:
I will indeed await any advice. Lots of photo's already taken. A couple attached for interest. Thanks, Ben |
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26th Jul 2020, 1:15 pm | #4 |
Tetrode
Join Date: Mar 2020
Location: Newton Abbot, Devon, UK.
Posts: 73
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Re: Bush TV22A Restoration
A before and after photo of the receiver unit post cleaning which took about 4 hours!
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26th Jul 2020, 3:36 pm | #5 |
Octode
Join Date: Apr 2005
Location: Peterborough, Cambridgeshire, UK.
Posts: 1,897
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Re: Bush TV22A Restoration
You have made a superb job of that! it looks almost new.
A TV22 was my first full restoration of a TV set. There are a couple of Wax capacitors behind one of the tag boards which I nearly missed. I wouldn't worry too much about testing the tube or valves . I would Replace the wax capacitors and check / reform the main smoother then see what faults you have and repair them as you go. I find testing tubes can be misleading as often one that reads low gives a perfectly acceptable picture and improves with a run. Good luck with your restoration I will follow with interest! Rich |
26th Jul 2020, 5:40 pm | #6 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,809
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Re: Bush TV22A Restoration
My procedure would be (and will be because I have a TV22a awaiting restoration):
A general clean up of the chassis Visual check for poor condition wiring, 'got at' areas etc. Change all wax caps on sight Check and reform or replace large electrolytics Change all smaller electrolytics Remove and test all valves, cleaning their pins first Clean all valve bases Clean all switches and pots That lot for starters. I've never understood the process of wanting to locate and sort out all of these very likely problem areas on a piecemeal basis, but each to their own.
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26th Jul 2020, 6:26 pm | #7 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,173
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Re: Bush TV22A Restoration
Hi Ben, if you can get hold of an old 405/625 video it would act as a "backdoor" to running the set initially before going to the expense of standards converters
Ed |
26th Jul 2020, 8:22 pm | #8 |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,676
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Re: Bush TV22A Restoration
I think I know what you mean by that Ed, but I expect Ben could use a bit more explanation.
Some early VHS machines (possibly Batamax too, I'm not sure), were reasonably system agnostic and will record and reproduce any 50 field/second you offered it after a fashion. We are probably talking about 1980s top loaders with mechanical control keys, but maybe some later models too. So if someone recorded some 405 line material from an Aurora or a PC graphics card capable of outputting 405, and sent you the tape, and if you had a suitable old machine you could play it back into your set. You would probably be injecting the baseband video directly into the grid of the video amp valve. In order to use the aerial socket you will need a VHF modulator that produces positive-going modulation. A better solution would be to obtain an old PC and a suitable graphics card, this is my preferred method and doesn't restrict you to using 625 line source material. Here's my set-up in action https://youtu.be/ahzdx4KgWBg
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-- Graham. G3ZVT Last edited by Graham G3ZVT; 26th Jul 2020 at 8:39 pm. |
26th Jul 2020, 11:15 pm | #9 | |
Octode
Join Date: Apr 2016
Location: Ventnor, Isle of Wight, & Great Dunmow, Essex, UK.
Posts: 1,377
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Re: Bush TV22A Restoration
Quote:
Welcome to the fantastic world of old telly's!! I guess the TV22 is a good set to start with as there is so much information about them. You've already made your first discovery- TV's get really filthy- much more so than an old radio from the same environment. The very high voltage (EHT) used on the tube (CRT) attracts all the dust and crud. Given the average house in the 1950's had a coal fire and a couple of people smoking, that crud is really black and sticky! When TV got going again after the war, it used the 405 line system. The picture is made up of 405 lines (basically, but it's rather more complicated than that). The sound is AM (same as an AM radio) and the single BBC channel was transmitted on VHF on band 1. Your TV22 uses this system. Then ITV came along, and doubled the available channels to two- yes, two whole channels. There was no more space in band 1, so they used band 3. Hence the band 3 converter on your set. The TV aerials were huge for band 1 and another slightly smaller one for band 3. Then in the '60's everything changed. BBC2 started on the 625 line system broadcasting on UHF at much higher frequency. Almost everything about the 625 system was incompatible with the 405 one. Different number of lines in the picture Different video modulation system (negative rather than positive) Sound is FM rather than AM Different transmission frequencies The two systems ran in parallel for nearly 20 years, and set makers went through a period of having to make sets that worked on both standards. Nightmare! The 'dual standard' sets from the '60's are my own personal favourites. The 625 system lasted until the 'digital switchover' that happened fairly recently. Converting signals from 625 to 405 is a huge challenge and used to require a massive amount of electronics. The BBC converter to do this was about the size of a double wardrobe!! Luckily over the last 20 years as electronics and computing technology has developed, it's got a bit easier. So to be able to get pictures on the TV22, you will need a 625 to 405 standards converter. This takes in a 625 signal, converts it to 405 and then outputs it on the correct frequency for you to receive on the TV. There are three main routes you can take to achieve this. The main converter during the last 10 years is the excellent 'Aurora'. These are made in America but I'm not sure they are being imported into the UK at the moment. The next is the 'Hedghog' converter which was developed as a home build job, but there is a forum member who can supply them pre- built. They also work really well. Both converters will set you back about £200. Thirdly, depending on your computer skills, is the PC route developed by Graham (Rambo from the above post). This is also a great way to go and can be achieved cheaper as well! I hope that might help as an overview as to why you need a standards converter!! All the best Nick Last edited by 1100 man; 26th Jul 2020 at 11:24 pm. Reason: mistakes corrected! |
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27th Jul 2020, 12:01 am | #10 | |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,676
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Re: Bush TV22A Restoration
Quote:
Another forum member Semir_DE has recently further developed Kat's original Linux project. Inspired by Ed Dinning's remark on post #7 and a wish to prove or disprove what I said in response, I plugged the PC card 405 line video into my VHS machine, made a recording, and played it back through my System A modulator. https://youtu.be/P8MHUcEM0ts It's something I've been meaning to try, but never got round to. I was quite surprised, as the machine is a "modern" Panasonic NV-HV61EB I don't think that frame instability would be such an issue if I hadn't made the recording at the very head of the tape.
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27th Jul 2020, 12:57 am | #11 |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,676
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Re: Bush TV22A Restoration
Hi Ben and welcome.
I just know that you are going to have a successful restoration of that TV22. Please keep us updated and include more of your awesome photography. You've had some good advice, no one so far has addressed the three core mains lead question you posed. The only way you could earth the chassis of this set is to ensure the set is always connected to the mains via your isolation transformer. With the transformer, I think it is still debatable whether you should actually earth the chassis via the mains lead. Yes, the chassis could opportunistically become earthed via earthed test equipment, but otherwise could just be floating like modern "Class II" appliance eg. hi-fi separates or set-top boxes. I should certainly like to canvas the opinions of other members. A 70 year old TV is never going to pass modern safety scrutiny whatever we do.
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27th Jul 2020, 11:53 am | #12 |
Tetrode
Join Date: Mar 2020
Location: Newton Abbot, Devon, UK.
Posts: 73
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Re: Bush TV22A Restoration
Thanks very much to Ed, Nick and Graham for the further explanations of the Tape Options in particular. My Initial thoughts are to wait until I get to a stage that I think the set will actually work before investing in the next stage. Alas, I don't have a video machine or any tapes and I am being encouraged to get a standards converter by the owner who may be somewhat over confident at the moment bless him!
So I have ordered the 2 tubes and 50 caps required and will keep cleaning things until they arrive. I hadn't really given much though to the 3 prong plug idea, just seemed a good idea but now looking at it I can see what you are saying. The power cord is semi polarized in that it has the 2 core wire attached to Live & Neutral at the 3 pin plug attached at the wall end but obviously the 2 pin plug can be connected either way to the set. When I get the circuit printed off will see whats what there and possibly either hard wire the 2 core cord to the set or mark which way round to connect the plug if this prevents a live chassis - it may make no difference - don't know yet. I notice some of the control pots have open backs and others are closed so expecting some fun getting access for cleaning but nothing I haven't dealt with before. Will watch out for any caps hidden behind the boards - a nasty trick there, and use my usual systematic approach of verifying connections using visual inspection and / or testing and cross referencing with the schematic to make sure the current state is as was initially intended. Looking at the set, I don't thing anyone has done anything at all in terms of replacing components except one Pinnacle tube so hopefully there will be no "findings" to deal with. There are some good videos showing how to clean and polish up the bakelite housing which looks like it will come up very well. Will add a few pictures next - getting close to finishing the cleaning so the recapping can start. Cheers, Ben |
27th Jul 2020, 12:01 pm | #13 |
Tetrode
Join Date: Mar 2020
Location: Newton Abbot, Devon, UK.
Posts: 73
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Re: Bush TV22A Restoration
I agree Steve, once caps are found to be failing then I like to just replace them all. I have never tried reforming any but the "Big One" may be worth a try. But I suspect it will get changed regardless even thought the new ones look ridiculously small. I may leave the old one in situ for the look and snip off all the contacts and wire the 2 new ones directly.
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27th Jul 2020, 12:13 pm | #14 |
Dekatron
Join Date: Sep 2005
Location: Seaford, East Sussex, UK.
Posts: 5,997
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Re: Bush TV22A Restoration
It is important to get to 'first light', the point at which the EHT is proven and ideally a raster is displayed, as quickly and economically as possible as LOPT , Frame Blocking Transformer, or a faulty CRT can stop you in your tracks.
Others can tell you where best to start but the PSU, line output stage and clipping out the pesky Hunts capacitors from the heater chain is a pointer. |
27th Jul 2020, 12:56 pm | #15 |
Tetrode
Join Date: Mar 2020
Location: Newton Abbot, Devon, UK.
Posts: 73
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Re: Bush TV22A Restoration
A couple of pics showing cleaning progress of the main deck attached
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28th Jul 2020, 8:05 am | #16 | |
Tetrode
Join Date: Mar 2020
Location: Newton Abbot, Devon, UK.
Posts: 73
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Re: Bush TV22A Restoration
Quote:
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28th Jul 2020, 9:30 am | #17 | |
Dekatron
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 9,145
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Re: Bush TV22A Restoration
Quote:
It's surprising how little you need to do to produce 'first light' and make an assessment. Many questions are asked and help given just to find 50 threads on the guy says that he had put a cap on the wrong tag! We all have our own procedures and I wish you good luck with it. John |
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28th Jul 2020, 10:18 am | #18 | ||
Pentode
Join Date: Jul 2020
Location: Staines, Surrey, UK.
Posts: 130
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Re: Bush TV22A Restoration
Quote:
I would like to give it a go. I have a spare i3 pc with I hope suitable graphics. I already have a VHF modulator - David Looser design from Television mag I built some years back. What was that software you used? Modeline Editor? Do you have a link? And what did you use to get from VGA into the modulator? Thanks Simon |
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28th Jul 2020, 1:21 pm | #19 |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,676
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Re: Bush TV22A Restoration
You're 90% there if you've built David Looser's excellent modulator.
Download Winmodelines from the author's site http://www.geocities.ws/podernixie/h...deline-en.html Cut a VGA cable in half and use this simple circuit to matrix the RGB and syncs into a composite waveform. What OS do you have on that i3 Simon? Does it have a spare PCIe slot? It's quite limited as to the graphics cards that work.
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28th Jul 2020, 2:33 pm | #20 |
Pentode
Join Date: Jul 2020
Location: Staines, Surrey, UK.
Posts: 130
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Re: Bush TV22A Restoration
Graham
Thanks for that info. The card is an Nvidia GT440. HDMI but also back to VGA. It has Win 10 at the moment but it is spare so I still have 7 or for that matter XP! I confess I do have the splendid Aurora but your video has inspired me. I'll let you know how I get on. Simon |