14th Jun 2006, 9:27 am | #61 | |
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Re: TV22 Restoration
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Rich.
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14th Jun 2006, 10:00 am | #62 |
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Re: TV22 Restoration
Lol, well as this is my first TV I am just going on what the diagram and what others call it so A1 it is.
Well I still have that odd fault and need the meter on to get a full frame pic now. I have just finished recapping the IF panel and changing some very black resistors that were very very low in value. Mainly the trio of 470r resistors in the middle of the chassis. Andi
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Last edited by Mike Phelan; 14th Dec 2007 at 9:30 am. Reason: Unnecessary capitals |
14th Jun 2006, 12:41 pm | #63 |
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Re: TV22 Restoration
Hi Andi, temporarily connect a 2M2 from the tube in place of the meter (or whatever the equivalent meter resistance is).
This sounds almost like the case of old radios that would burst into life for a min or so when the grid was probed with a meter as the grid leak had gone O/C and the grid was charging up with no leakage path. Ed |
14th Jun 2006, 2:52 pm | #64 |
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Re: TV22 Restoration
Thanks Ed,
Will try that tonight. I have also now finished the recapping of the IF stage so tonight I might even get me a test card on it... Wish me luck Andi
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14th Jun 2006, 6:12 pm | #65 |
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Re: TV22 Restoration
Hi Ed and everyone else...
Well I finished recapping my IF stage and connected the ht back up to it and voila I didn't need the meter across the A1 anymore and the HT came up to 200v on the A1. Now the problem is I only have my Aurora as a signal and I get nothing out of the TV but a blank raster.... How on earth do I fault find an IF stage with no test equipment like that? Andi
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14th Jun 2006, 6:17 pm | #66 |
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Re: TV22 Restoration
Am I right in thinking that I could put a line level audio signal onto one of the pins of the chassis connector to feed the grid of the audio amp?
Is there anyway I could feed a video signal in from My aurora after the IF and tuner stages just to make sure it will display a picture? What if I fed a composite video signal into pin 6 of the inter chassis connector? and an audio feed into pin 3? Andi
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14th Jun 2006, 6:39 pm | #67 |
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Re: TV22 Restoration
OK, after looking at the circuit I know I can't just feed signals on to any of these pins, as there is a very substantial voltage on them, and not what it should be, I don't think...
Going to do some metering...
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14th Jun 2006, 7:30 pm | #68 | |
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Re: TV22 Restoration
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http://uk.farnell.com/jsp/endecaSear...=4284033&N=401 Anyway, sound like progress is being made, well done and all the best
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14th Jun 2006, 8:47 pm | #69 |
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Re: TV22 Restoration
I am very unsure about using my scope on valve stuff. I don't want to fry anything... Also the trader sheet is very limited, no information about what to expect scope-wise and I have no clue what I am actually looking for...
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14th Jun 2006, 9:45 pm | #70 |
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Re: TV22 Restoration
Hi Andi, this is where running an AC/DC tele through an isolating transformer becomes useful as there is no "common mode" voltage on the chassis that can zap the test equipment when it's ground is commoned to the test equipment ground.
There are "dirty" techniques you can use but not worth trying if you are unsure of what you are doing. The signal lead is not so much of a problem. A suitable value capacitor for the frequency of the signal being applied, and of a suitable working voltage will block the DC and get some sort of signal through. Getting the levels right and a good picture is a different matter! HTH Ed |
14th Jun 2006, 10:28 pm | #71 |
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Re: TV22 Restoration
Andi.
Before assuming there is a front-end fault, are you sure your standards converter is producing a signal on the right channel for your TV ? I'm just thinking about London and Birmingham versions.....just a thought. Rich.
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14th Jun 2006, 10:44 pm | #72 |
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Re: TV22 Restoration
Hi Rich,
The Aurora is a 13 channel converter so I set it to channel 3 The TV22 supports channels 1 to 5 so I guessed 3 should appear somewhere between zero and full adjustment. I need to get an isolating transformer... I have noticed that my main HT rail is 15v high... Andi
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14th Jun 2006, 10:55 pm | #73 |
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Re: TV22 Restoration
Ah!! Didn't know the Aurora was switchable !
Don't worry about the HT being 15 volts high. Mains variations can cause this. Rich.
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15th Jun 2006, 9:25 pm | #74 |
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Re: TV22 Restoration
OK Here we go, a few pics of what's been done so far...
Thanks for all the interest so far These are the 1st 4 pictures I would like to share, The first is how I found it. It was on ebay in Stratford which isn't far and I managed to negotiate a deal if I went round there and then, the asking price was £75 but I got him down to £60 because the tube was in 2 halves (see 5th picture)..... The sawdust is all that is left of the left wooden support bar from the kind woodworm, the right one although not looking bad was just as bad... Pics 3 and 4, this is how the case looks now, I havent finished the polishing yet and also havent tried Nick's lolly stick idea (apologies if it was someone else but I am terrible without looking back) as I thought it was much more important to get it working, than making it pretty. Thanks Andi
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15th Jun 2006, 9:32 pm | #75 |
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Re: TV22 Restoration
Another 5
There are probably somewhere like 100 pics so far, of the various strip and rebuild. I always take plenty when wanting to remove a complete tag board like the one on this that holds the power resistors and frame decoupling caps, and also the frame oscillator transformer. Hope they are ok. Like I said I am planning a website to do with the whole TV22 experience; just like the day in the life we used to read in Television. Was is Les Lawry Johns? Andi PS I know the .75uf cap isn't soldered very neatly but this is a 'get it working' job and will tidy up things like that once it's finished...
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15th Jun 2006, 9:36 pm | #76 | |
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Re: TV22 Restoration
Quote:
Les was always worth reading, a wonderful sense of humour and a d d good engineer. I consider myself lucky to have known him. Regards,
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15th Jun 2006, 9:43 pm | #77 |
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Re: TV22 Restoration
I used to read 'Television' just because of that column when I was in school as we (4 electronics club nutters who used to go round the skips of Multibroadcast, etc for boards) petitioned the library to add it to their periodicals.
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19th Jun 2006, 8:31 pm | #78 |
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Re: TV22 Restoration
Hi guys.
OK This is a long shot but if my friend and I are correct in our assumptions we think we know now why I don't have a picture on the TV when I attach the antenna. This IF stage when I got it had a band III converter fitted which I have removed. The thing is... What modifications had to be done to the IF panel to fit the band III converter to start with? I need to reverse whatever mods were made. Regards Andi
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Last edited by Mike Phelan; 14th Dec 2007 at 9:41 am. Reason: S&P |
19th Jun 2006, 9:15 pm | #79 |
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Re: TV22 Restoration
Hi guys, me again, I bet most of you are sick of this by now hahaha
OK I have found a missing contrast wire that I have replaced but are there any other mods made to the IF panel to allow the band III converter to work? Thanks Andi
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19th Jun 2006, 9:18 pm | #80 | |
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Re: TV22 Restoration
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