9th Apr 2010, 11:09 pm | #181 |
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Re: Tv62
Ahhh, without wanting to be on the wrong side of John's wrath, the time may have come to change a few.
Firstly, replace that suspect resistor. If that still shows the same then switch off and measure resistance pin 1 to chassis (looking for leakage in C15 or C16) and pin 2 to chassis (check the grid resistor chain R20 and VR2). |
9th Apr 2010, 11:12 pm | #182 |
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Re: Tv62
Ok new 1M res in place of the gone high (4M) one now I have nearly full width, without the clipped in .01 cap the collapsed line crossed the entire screen with cap clipped in just one small edge is missing, now warmed up whole screen filled
Ooooo we are getting there This is only working as I say with the clipped in cap on PCL83 pin 4 - pin 9 Last edited by oldticktock; 9th Apr 2010 at 11:24 pm. |
9th Apr 2010, 11:18 pm | #183 |
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Re: Tv62
What about the height? Will this be working by midnight? I'll check in later to see.
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9th Apr 2010, 11:29 pm | #184 |
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Re: Tv62
Check pin 1 voltage again. If it's still low replace C15 and C16 for starters.
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9th Apr 2010, 11:33 pm | #185 |
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Re: Tv62
R20 should be 680k but is 2.7M aha another way high res.... Cheers PJL your deductions are spot on.
The cap next to it is oh so sticky C13 another resistor replacement coming up Once out I read 703K so it must be the parallel cap C13 causing the odd reading, as now the new one read odd too. Pin 1 voltage is 4.1v C13 is in serious need of replacement it's just weeping, I mean theres dead and dead this thing is abuses the right to be dead. Chris Last edited by oldticktock; 9th Apr 2010 at 11:55 pm. |
10th Apr 2010, 12:18 am | #186 |
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Re: Tv62
Ok It still works with C13 replaced I know that was not discussed but it was weeping all over the place.
As for C15 & C16 well that's venturing into the mare I anticipated coming, under the Tag board. So as we have entered the wee small hours I think this is the place to pause and regroup for tomorrows attack. Perhaps tomorrow will bring the final success, Graham (Station X) soz did not manage it. Thanks to all for the patience. See you tomorrow P.s just to recap (scuse the pun) R19 replaced This had the effect of giving full width to the on screen noise R20 replaced C13 replaced 0.1 clipped in on pin4 - pin9 this stops from collapse. That's where we are folks Chris |
10th Apr 2010, 12:44 am | #187 |
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Re: Tv62
Hi Chris
Well done great result so far. A very interesting thread. Keep up the good work. Frank |
10th Apr 2010, 6:15 am | #188 |
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Re: Tv62
First light on the CRT is always a magic moment. It's looking really good. You've got a good CRT and LOPT so there should be nothing really nasty in the woodwork (bakelite?) now.
There will be a lot of resistors way off value, especially the high value ones, over 100K, which go even higher. There comes a point where you think about measuring the lot and replacing as required. Many can be measured in situ, others will need one end lifted to get a true reading. This is also the time to change all the waxies in the timebase section. JW would say do one at a time and test between each. I tend to do a bulk job and take a lot of care. It's worth marking up the circuit with highlighter pen to show which parts you have changed. |
10th Apr 2010, 7:45 am | #189 |
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Re: Tv62
Well done Chris, you've been extremely patient and very methodical in your approach and this has led to a great result. Have enjoyed the post thus far, look forward to seeing you getting all the final tweaks sorted now. Hope I have the same success with me ol' fergie!
Greg
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10th Apr 2010, 9:03 am | #190 |
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Re: Tv62
You can now remove the temporary feed capacitor as it has proved it's point. Yes I did give you component numbers from the trader sheet so I will just go over that last bit gain using the original Bush manual dated 1956 technical publication 1075.
The resisitors mentioned are R19 directly connected to pin 1 of the PCL83. The other end of this is decoupled by a 2uf capacitor marked C14. This point is then taken via R37 to the boost supply rail. I think you have worked this out and taken the required action. Yes to everyone. I think it is time to replace the wax capacitors as they all appear to be in a sorry state in that circuit. C11, C12, C13, with particular regard to C15 and C16. If in doubt, clip one end clear and as a temporary measure connect the replacement on the tag side of the board. Carry this out which ever way you feel comfortable with. The only reason I say replace one componenet at a time is that it prevents introduced faults and probably more importantly allows you to observe the effect of faulty components. Emample, 'cogged' picture due to leaky sync coupling capacitor, squashed top or bottom or both of picture due to poor frame linearity etc. You are almost at the point of getting a picture and it will be a very good one. To help clarify the circuit numbers I have scanned the manual I am using so you can tie it up with yours. Just one note about the Aurora. It might appear to be a Dinky toy when first encountered but its one of the few things in life when size is not important. It's a fantastic bit of kit that will allow you to see 405 line television exactly as it was transmitted. It is so realistic that when working on 405 receivers and playing test card 'C' CD's and music, I honestly forget sometimes that it's 2010 and not 1964. Now can we have a version please that can reverse my age back to 16 instead of 61.... Take it easy Chris and you will get there. Regards, John. PS Just been called out on HGV recovery so may not be back till later. Good luck! |
10th Apr 2010, 9:08 am | #191 |
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Re: Tv62
Morning John,
Thanks for the advice and I shall once more enter the fray. Fantastic fun and great to learn from all the masters of TV. I have to say all last night I was dreaming of TV62 circuits, caps resistors frame collapses, madness!!!! amazing how the mind just does not stop. I made a cable up this morning for the Aurora and found a 9v 300ma adapter from one of my DECT phones, this is the closest to the 9v 250ma specified in the Aurora manual. It would be nice to see a test card by the end of today, those tricky to get at caps might slow me up though. All the Best Chris Last edited by oldticktock; 10th Apr 2010 at 9:36 am. |
10th Apr 2010, 9:28 am | #192 |
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Re: Tv62
Just before I get cracking and recapping, thought I would just pop up some of the photos of yesterdays re-assembley before all the fun started.
I know It went against the grain to not clean before testing, but by taking a methodical approach taking, notes and extreme care i'm sort of glad the mucky work is done. I also fully accept this is not best practice and have visited the headmaster Chris |
10th Apr 2010, 9:41 am | #193 |
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Re: Tv62
Excellent work! Almost makes me want one as well.....!
Rich.
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10th Apr 2010, 11:13 am | #194 |
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Re: Tv62
I take it 0.022uF can be used instead of 0.02uF
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10th Apr 2010, 11:20 am | #195 |
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Re: Tv62
Yes.
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10th Apr 2010, 1:42 pm | #196 |
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Re: Tv62
Busy morning replacing cap's, the under tagboard ones were tricky.
One side was easy to see where the wire was attached, I noted their relative tag points down on my notes then snipped that side. Checking the schematic I ascertained where the other end should be attached, gently pushing the waxy cap back and forth under the tag board confirmed. Snipped the other end and again noted tag position on my notes. So for the benefit of John and others following this is what has been changed so far At the Outset C36 snipped one side (mains filter cap) Yesterday C31 0.5uf C38 0.5uf C33,C34 &C35 100+100+200uf Electrolytics R19 1M R20 680K Today C11 0.022uf C12 0.022uf C15 0.05uf C16 0.1uf C26 0.1uf (As It was next to C16 and I had to snip a wire to gain access, thought i would do it now instead of later) Ok just going to tidy the bench and make a cuppa then start the set up. Chris Last edited by oldticktock; 10th Apr 2010 at 2:08 pm. |
10th Apr 2010, 2:28 pm | #197 |
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Re: Tv62
Ok powered up after recap without the clipped in cap, and still frame collapse.
I suppose on the positive It does not look as though I introduced another fault with the recap. On the negative side did'nt fix anything. Chris |
10th Apr 2010, 2:31 pm | #198 |
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Re: Tv62
Check the voltages on the frame output valve and frame oscillator valve. Has anything come off?
Cheers, Steve P.
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10th Apr 2010, 2:46 pm | #199 |
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Re: Tv62
I don't want to add to any confusion Chris but the cap' trick might also show if the oscillator stages are capable of functioning if you stab it from the heater to V3a pin 2 or V2a pin 1
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10th Apr 2010, 2:47 pm | #200 |
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Re: Tv62
Try measuring the voltage on pin 1, 2 and 3 of the PCL83 again.
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