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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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25th Sep 2006, 7:54 pm | #1 |
Dekatron
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Yet another TV22..... YAWN!
Yep, Ive got one too.
Ok, line oscillator - Check Spark off PL38 anode - Check Spark from EY51 anode - Check - bit feeble, but right frequency and colour Spark from CRT anode - our survey says........ So, no EHT (no suprises there then) LOPT does not look too clever..... Over to tellyland experts...... Cheers Sean
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25th Sep 2006, 9:10 pm | #2 |
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Re: Yet another TV22..... YAWN!
does the EY51 glow? If not, try changing it first, as there appears to be some EHT - you may be lucky!
Jim. |
26th Sep 2006, 12:01 am | #3 |
Heptode
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Re: Yet another TV22..... YAWN!
Check also the boost supply, as an overload here will upset things a bit!
Have you changed the caps in the boost circuit, and frame? Leaving the latter could kill the osc transformer. Danny |
26th Sep 2006, 7:51 am | #4 |
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Re: Yet another TV22..... YAWN!
Sean
Don't forget the PZ30 boost diode. which shares its envelope with the HT rectifier. LOPT failure does happen now, but usually because the iron core has corroded. Danny's suggestions are the first thing to try.
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26th Sep 2006, 8:04 am | #5 |
Octode
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Re: Yet another TV22..... YAWN!
Sean,
If I remember right I saw quite a lot of rust in that set, I would seriously check the Lopt windings and as Mike said the PZ30. also check the chassis connection to the the caps on the line oscillator board as this was the reason I couldnt get a frame and full HT. I have plenty of spare valves and even a rough looking spare lopt (untested mind) that you can try if needed. Are you trying this with the lower chassis HT line still connected? Try it with the red wire diconnected from the chassis interconenct plug. Andi
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26th Sep 2006, 10:45 am | #6 |
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Re: Yet another TV22..... YAWN!
Ok, Some progress - Changed a few caps, and bunged a new EY51 and PZ 30 in - now have some EHT, but very low - EY51 not lighting, so I guess a new one works well with very low heater volts......
HT rail is also low, so it looks like waxy armageddon time my guess is that once HT rail is up to scratch the line drive will improve, and the tube may see some volts! Proves the LOPT is still OK despite looking like something out of a horror film! Before I start to fabricate two new wooden sides for the chassis, does anyone have some that have not been eaten? Cheers Sean
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26th Sep 2006, 11:34 am | #7 |
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Re: Yet another TV22..... YAWN!
Hi Sean,
Just thought I'd let you know that the loptx in my TV12 (which I believe is about the same as a TV22) looks a bit of a mess (especially the old bitumen or whatever coating), but it works perfectly well, and has done so for a while now (famous last words as it goes up in smoke !!). So if I were you I wouldn't worry about the looks of the thing. From your description it all sounds quite promising. I would definitely change ALL the waxies in your set before going much further. I found that all the ones in my set were quite leaky, and that can't help things. All the Best, Alan. Last edited by Mike Phelan; 24th Oct 2007 at 2:57 pm. Reason: Missing caps |
26th Sep 2006, 1:32 pm | #8 |
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Re: Yet another TV22..... YAWN!
Ok, Have had a raster of sorts - is suffering frame collapse, but that looks like more caps needing to be changed.....
I reckon the set might have been better stored in a lake - certainly would have needed less work! Anyway, paid employment is calling, so need to leave off for now :-( Time to order a bucketload of 0.1uf caps! Cheers Sean
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26th Sep 2006, 5:13 pm | #9 |
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Re: Yet another TV22..... YAWN!
Hi Sean,
Frame collapse is most likely to an open circuited frame oscillator transfomer (mounted on the tag board at the side of the set). The transformer (T4 on the trader sheet) should measure 540 and 480 ohms. The line transformer is the same as on the TV12AM, but not the TV12. Cheers Andy |
26th Sep 2006, 5:37 pm | #10 |
Octode
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Re: Yet another TV22..... YAWN!
I have a spare T4 but check the caps on the tag strip thet t4 is on as they will also cause frame collapse if they are shorted.
Andi
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27th Sep 2006, 11:12 am | #11 |
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Re: Yet another TV22..... YAWN!
Aha!!!!
Full raster! I think there might be a dodgy connection in the line output area - this will be sorted when the chassis is done properly - at the moment it is a mess of odd capacitors..... The frame collapse was due to our good friend, the 220k resistor - 780K and rising..... Now time to start doing things properly.... Cheers Sean
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29th Sep 2006, 7:33 pm | #12 |
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Re: Yet another TV22..... YAWN!
More done.......
The set is now in lots of bits for a serious clean - Enter the dishwasher! I have fabricated new wooden "feet" and lower chassis supports - Sad case of woodworm 1, TV22 nil..... Once the preliminary clean cycle has finished I might well post a few piccys! Looking for a spare focus lever if anyone has one laying about..... The LOPT has been running quite warm, as it has dripped half of it's pitch on to the choke that mounts below - I will probably look into refurbishing the LOPT - Has anyone tried to remove the central core of lams to de rust them, or should I pretend I never saw a problem? - I will probably melt a small quantity of pitch to re pot the transformer once repairs are effected. Cheers Sean
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29th Sep 2006, 8:25 pm | #13 |
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Re: Yet another TV22..... YAWN!
Hi Sean, congrats to your TV22!
Leave the LOPT as is, 6KV is quite low and there will be no arcing and moisture can come out. Do nothing on the lams, rust does not cause problems. The lams are insulated from each other with thin paper, if you clean them you may remove this. If you want, put black "Hammerite" paint on the central core. Kind regards, Darius Last edited by Mike Phelan; 24th Oct 2007 at 2:58 pm. |
29th Sep 2006, 8:32 pm | #14 |
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Re: Yet another TV22..... YAWN!
Hi Darius,
Ok, will just remake solder joints, and do basic tests and refurb work - nothing more than that. I was not too worried about EHT arcing - as you say 6Kv is not much - I will see how it all looks when I reassemble the chassis - I am amazed how much dirt gets into the smallest places! The LOPT is living in a warm cupboard for the next week or two - the set has been stored quite badly, so anything to drive out damp has to help. There is a spare fuse holder on the chassis - I might fuse the Ht supply - just for safety of the on chassis components. Cheers Sean
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29th Sep 2006, 8:32 pm | #15 |
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Re: Yet another TV22..... YAWN!
Hello Sean,
Sounds looks like you are making some progress with your TV22. Just to give you some encouragement I have posted a picture of mine. Regards John. |
23rd Jan 2007, 3:58 pm | #16 |
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Re: Yet another TV22..... YAWN!
Bilmey - Has it been that long since I did anything withthis set?
Well, It survived the dishwasher - I have refitted the removed wound components, and have recapped the whole set. So, the good news - I have a picture - needs a lot more work - it will not sync correctly, and the linearity is flipping awful....... But it is a huge improvement on how I got it! Cheers Sean
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23rd Jan 2007, 10:25 pm | #17 |
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Re: Yet another TV22..... YAWN!
Ok Problem time.....
I get a strange repetitive pattern of lines scanning horizontally across the tube - at approx 45 degree angle..... Any ideas? Otherwise it seems reasonable - tube is a bit tired, speaker rattles for England, and volume control is out to lunch...... Over to those that know far more than me! Cheers Sean
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23rd Jan 2007, 10:50 pm | #18 | |
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Re: Yet another TV22..... YAWN!
Quote:
How about some pictures of the restoration so far? Rich.
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23rd Jan 2007, 10:55 pm | #19 |
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Re: Yet another TV22..... YAWN!
Erm, can do - the lines are moving across the screen from left to right - Vertically (oops)
Will try to get some piccys over the next day or two....... Certainly not flyback lines though.....
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26th Jan 2007, 5:55 pm | #20 |
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Re: Yet another TV22..... YAWN!
Right, have sussed the problem with the strange patterning - Is a DVD player issue.....
However, disaster has struck! It looks like the LOPT has died - It has always been a bit strange getting the EY51 to light correctly - it was running fine, then pow - no raster, no EHT, and very feeble line whistle.... When I shut every thing off, the LOPT felt extremely hot..... So, begging time - Anyone got a spare LOPT for a TV22? Failing that, gould I fit a spare Ferguson 941 transformer in its place? Im off to sulk for a while..... Cheers Sean
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