3rd Jun 2006, 11:25 am | #21 |
Octode
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Re: Can somebody please repair My TV22
Hi Jim, I think the frame collapse is one line, the tube setup is all over the place and I havent even tried to focus it yet.
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3rd Jun 2006, 11:27 am | #22 |
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Re: Can somebody please repair My TV22
The frame panel on the right hand side had been completely cooked, so I took the one I had out of a scrap TV22, and metered every resistor and replaced all the caps on that.
The 2 main green resistors are spot -n and well within tolerance and not showing the slightest wear. The rest being 10% ones are all quite close although a couple are marginally high. But with the transformer disconnected I can't get a reading from one side of it, but the correct reading from the other. Andi
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3rd Jun 2006, 11:39 am | #23 |
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Re: Can somebody please repair My TV22
That doesn't look promising
Is there a spare transformer in the scrap set? Make sure that all the other components are OK before you fit it though, we don't want a repeat performance! Jim. |
3rd Jun 2006, 12:02 pm | #24 |
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Re: Can somebody please repair My TV22
Another update, sorry for this Paul...
I have now found a mustard C57 and I still only have a nice flat line, nothing like before... Nice and sharp (focussed it a bit too) Heres a pic of what I now have Andi Jim, the one in the scrap set reads the same with a good secondary but a shot primary...
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3rd Jun 2006, 12:25 pm | #25 |
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Re: Can somebody please repair My TV22
Hi Andi,
that's what I would expect for frame collapse I think you need to start looking for a new transformer, or re-winding the one you have. Don't run the set like that for long, or you will get a burnt screen - turn the brilliance right down while you're making further tests. In the meantime, you can sort out the RF strip Jim. |
3rd Jun 2006, 12:43 pm | #26 |
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Re: Can somebody please repair My TV22
Just started on the RF board, I dont have many of the low value caps, so need to get an order into Farnell soon...
MODERATORS : Please dont delete this thread as I am going to use it to write up a complete repair guide (hopefully) and if anyone else has any symptom/repair info from their sets please let me know and I will add them to the site too. Andi
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3rd Jun 2006, 12:53 pm | #27 | |
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Re: Can somebody please repair My TV22
Hi Andi
Quote:
Regards, Kat |
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3rd Jun 2006, 12:57 pm | #28 |
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Re: Can somebody please repair My TV22
Thanks Kat Seeing these old sets in action at the NVCF kinda gave me the bug and incentive to get one and get one running. So you in part are an inspiration to this...
Andi
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4th Jun 2006, 6:43 pm | #29 |
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Re: Can somebody please repair My TV22
Hi again,
A new update. After getting My AVO 8 back I have re-metered the frame transformer and it's metering ok with the Avo. Even though it wouldnt read at all with the DMM; very odd... So my next question as I don't quite understand voltages: where can I check for the sawtooth and what voltage is it likely to be at? I am guessing at the grid of V15b? Andi
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4th Jun 2006, 6:56 pm | #30 | |
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Re: Can somebody please repair My TV22
Quote:
I always use my £1-at-a-boot-sale 1950s ex-GPO meter for this, spot-on measurements in seconds. Nick. |
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4th Jun 2006, 7:32 pm | #31 |
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Re: Can somebody please repair My TV22
Should the metal rectifier read as a normal diode? I get about 1.2Meg one way and 1.7Meg the other...
About 115v on the green side and about 160v on the red Is there anything else that can cause frame colapse? Andi
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4th Jun 2006, 10:32 pm | #32 | |
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Re: Can somebody please repair My TV22
Quote:
Rich.
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4th Jun 2006, 11:19 pm | #33 |
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Re: Can somebody please repair My TV22
Internal appearance is not what I am doing at the moment, I just want it to work. I doubt I could ever make it look original inside as some of the caps I have used are as big as the waxies I have taken out and a few parallel caps too, in places to get the values.
Once it is working and stable I might then tidy the tagstrips back up, but right now its bottom of my list. I didn't know that about metal rectifiers, so that's very very interesting. Thanks Richard Andi
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5th Jun 2006, 11:49 pm | #34 |
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Re: Can somebody please repair My TV22
Hi,
Can someone please tell me where to scope for the sawtooth. I have changed every capacitor in the whole section and nearly every resistor and also T4. Apart form changing T5 and the scan coils I am at a loss... Thanks Andi
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6th Jun 2006, 3:14 pm | #35 | |
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Re: Can somebody please repair My TV22
Quote:
sure that the pentode is not overloaded during your experiments. Darius |
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6th Jun 2006, 3:20 pm | #36 |
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Re: Can somebody please repair My TV22
Hi Darius,
Thanks for that I want to see if the sawtooth is actually being generated and then see whats happening. I cant see anything that could be wrong... Andi
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7th Jun 2006, 4:18 pm | #37 |
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Re: Can somebody please repair My TV22
Hi Guys...
Latest update... All component numbers I quote are from Trader sheet 1003/T15 T4 has been changed as has C51, MR1, C52, R52, C53, R53, C55, V15, C56, C57, and the scan coils on the tube itself and I am still getting no frame drive... Any more clues? Andi
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7th Jun 2006, 9:57 pm | #38 |
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Re: Can somebody please repair My TV22
Hi Andi, any joy with the scope pictures yet?
BEWARE that you will need to run the set through an isolating transformer as it is an AC/AC type before you attach the scope (there are other tricks but if you don't know what they are it's best not to! You can also try injecting 6.3V 50 Hz from an old heater transformer into the op valve grid to see if that stage works (the art of coarse servicing!). HTH Ed |
7th Jun 2006, 10:40 pm | #39 |
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Re: Can somebody please repair My TV22
Hi Ed, right now I will try anything as my head hurts and I am lost and in well beyond my depth.
I am no TV repair person and even though I haven't blanket changed everything, I did the waxies, then looked at the circuit at what I thought could cause it and now have everything changed, bar T5 and I have one, but its a pain with all of the short tight wires to get a new one in. I will try the heater tranny option as I don't have an isolating one and I don't think my scope goes above 100v input anyways... :-( Andi
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8th Jun 2006, 12:24 pm | #40 |
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Re: Can somebody please repair My TV22
Hi Andi. The scope input voltage range is not the problem. It is the fact that the scope is earthed and you then connect the probe common to and ac/dc chassis. The probe common is connected to earth via the scope mains lead, hence possible large current thro scope (not good) from the chassis of the TV.
Ed |