28th Mar 2010, 9:13 am | #81 |
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Re: Tv62
John,
Thank you for the comprehensive 10 point step, with Jeffreys already valuable assistance and now this,it certainly hits the spot with regards to my first post, where to start. I spent most of last evening and some of the night reading various members TV restoration write ups and studying the Bush and Trader service sheets. The Bush TV62 service manual is by far the better one and I shall be working from that. I like the way the schematic shows the different stages and labels them for you and even gives the component values on the actual schematic, something the trader does not, it's ordered and OldTickTock likes order. When I have enough experience I guess dripping caps will not disturb me so much, as at the moment I keep getting the urge to snip and replace. Thanks to all members who have publicly and privately given their kind words of encouragement,it's much appreciated and If theres one thing I don't do, it's give up. Chris Last edited by oldticktock; 28th Mar 2010 at 9:28 am. |
29th Mar 2010, 10:52 am | #82 |
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Re: Tv62
John takes a pretty hard line on this and I'm certainly not going to argue with his huge knowledge and experience. Sometimes it's just not possible to power up a set "as is". The LOPT in my Ekco TC311 was in such a horrible state that powering it looked very dubious. Can't remember what I did in the end but I certainly did an extensive mechanical rebuild of the LOPT before any other serious work on the set. I also tend to do bulk cap replacement, against John's advice. Don't think I've made a serious mistake yet but it's very easy to be distracted if the phone rings. Marking up the circuit diagram with candidates and completions helps.
A bit of initial cleaning is a good thing. It's nice to be able to see most of the components emerge from the dust but don't be overzealous at first. There's plenty of time after you've had light on the screen. One thing I would recommend, and I suspect even John would be with me here, is to get heater chain continuity before plugging in. Valve waggling usually fixes this, a shot of cleaner in the worst valveholders if necessary. |
29th Mar 2010, 12:29 pm | #83 |
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Re: Tv62
Hi Jeffrey,
The clean I did was purely a hoover with fine nozzle and an artist brush, nothing more, so i'm confident i did not disturb it. The set according to the previous owner went to bed in 1980 and by the looks of it the fluff blanket kept things nice and insulated If the build date stamp on the LOPT is also the set's date then it was in service for 22 years before that, maybe the PL81 that had failed was why it went to bed. Just waiting for the PL81 to arrive and then I'm back in business following your advice of Friday/Saturday. Hope to see a test card on it like some of the other posts, In the meantime i'm sticking my head back inside another DAC90a..... I just love Bush's Chris |
29th Mar 2010, 12:59 pm | #84 |
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Re: Tv62
Half inch paintbrush is fine for most cleaning like this. Pulling out the LOPT for a clean and polish wasn't wise but you'll probably get away with it.
PL81s lead a hard life, look at the brown stains on any used specimen. It's a lot to expect of a small valve like this - I've always thought it miraculous that you could scan a fairly wide angle CRT and make EHT using a B9A valve. Yours was cracked and the vacuum gone which is mechanical damage. It could have been a latent weakness brought out by the repeated and harsh thermal cycling inherent in using a PL81. |
29th Mar 2010, 8:02 pm | #85 |
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Re: Tv62
Completely agree Jeffrey, that is why early in my notes I suggested it's wise to have a general visual look very early on and any obvious burn outs noted. Certainly we can risk a bulk cap replacement as we are aware of the pit falls but I was worried about a beginner with television to do a mass snip and solder. The tag boards on these sets are certainly confusing with link wires and wrapped connections.
You built a superb Ekco housing for your Ekco T311 the standards obtained excelled the mighty Ekco themselves. We really must steer Chris away from Bush for his next restoration before he becomes brainwashed and suggest he has a try at a real telly [Ekco T330..] Regards, John. |
29th Mar 2010, 8:21 pm | #86 |
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Re: Tv62
If I ever get the TV62 going and get TV restoration bug then what I really want for christmas is predictable, a TV22, just missed the TV12...... Glum
Chris |
31st Mar 2010, 2:12 pm | #87 |
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Re: Tv62
Back In business the PL81 turned up today, so down tools on the DAC's, back to the TV. The quest will continue tomorrow as I've got some croc clip fly leads so need to make up that cable to supply F1.
To recap my course of action Jeffrey suggested. Have TV62 mains lead plugged in with F1 pulled, A live fly lead from Variac to the top of F1 and neutral to chassis. Turn on mains and wind variac up slowly for F1 powering HT, then watch and be ready to turn off. Both Variac and Mains for TV are fed via same four gang with RCD and the souse consumer unit is RCD Do I need to worry about that dripping cap and the loud humm I had when just doing the heaters Chris Last edited by oldticktock; 31st Mar 2010 at 2:32 pm. |
31st Mar 2010, 2:16 pm | #88 |
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Re: Tv62
The hum would bother if HT was present as could be duff electro as for dripping cap.Well that must need replacing asap.
David |
31st Mar 2010, 2:32 pm | #89 |
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Re: Tv62
Rather concerned about the hum with heaters only. There's nothing legitimately there to hum. Can you pin down where it's coming from? Are all the heaters alight (except EHT rec)? Not so worried about a drippy wax cap, unless it's connected to the heater chain. C67, C68 etc are probably ceramic but best to have a look.
The Bush service data is LOT better than the Trader sheet. |
31st Mar 2010, 2:37 pm | #90 |
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Re: Tv62
That's been bugging me too hence why I keep asking. I checked the array of heater decoupling caps visually and they as you say are little peanut shaped ceramics.
I will power up again and check, I guess I can check the bottom of the PY82's with my DMM. Agreed on the Bush service data I came to that conclusion when I read through both that and the trader. |
31st Mar 2010, 4:18 pm | #91 |
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Re: Tv62
Powered on without F1 in, hum present all heaters lit, py82's brightest
V19 PY82 Voltage readings pin1 20 pin2 6.4 pin3 14.5 pin4 145 pin5 162 pin6 49 pin7 37 pin8 35 Last edited by oldticktock; 31st Mar 2010 at 4:26 pm. |
31st Mar 2010, 4:53 pm | #92 |
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Re: Tv62
At this stage you have only energised pins 4 and 5 of the PY82s. They will have AC voltages on them. I assume you mean V9, not V19, using the Bush service info.
All other pins are irrelevant at this stage. When you apply power to the HT side then you'll get AC mains at pin 9 and rectified DC at pin 3. All other pins are irrelevant. To add confusion, the fuse numbering is different between the Trader and Bush circuits. To avoid confusion can we please now work exclusively with the Bush data. It's freely available from Jon's website for others to help too. |
31st Mar 2010, 8:26 pm | #93 |
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Re: Tv62
Ok got fed up being nervous and decided to subscribe to the HCS school. Powered the set up fully via the variac upto 240v.
The sets hums loud very loud. Then I heard this strange oscillation a high pitch squiggle. No lights on the EY86 nothing on screen all other valves lit. That hum puts the fear of god in me its a real deep Van Helsing hum, if you know what i mean. Chris P.S. I can tell you the adrenaline is running, If I still smoked I would be drawing away by now |
31st Mar 2010, 8:43 pm | #94 |
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Re: Tv62
Great that you took the bull by the horns but there's clearly something very wrong. I'm wondering if the main smoothers have had it but that's really just a wild guess. Any other signs of distress? Any valve anodes glowing red hot? Smoke? At the very least I think you need to get a meter on the HT rail and see if it's getting to a sensible voltage.
Let's hear John's comments before going further. |
31st Mar 2010, 8:49 pm | #95 |
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Re: Tv62
No Smoke
V9 one of the PY82's looks like it is a lot brighter at the base compared to the other. I did wonder if it was worth swapping the EY86 for a new one. What an earth was the oscillation I was hearing? I thought It can't be the 405 sound as I'm not generating EHT? any ideas? Chris |
31st Mar 2010, 8:56 pm | #96 |
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Re: Tv62
Been watching this with considerable interest. Well done on taking the bull by the horns, we'll make a TV Restorer out of you now! Next thing is your first bang...
Smoothing caps - change them both and try again. At a guess that's your problem. You won't get any light from the EY86 until this is sorted as the line oscillator won't work. If you want to build new caps into the cases then go ahead. Or just put new caps underneath and disconnect the original cans. No EHT will still give sound by the way. HT problems wont. May be worth trying two new PY82's. Then grab the bull by the horns again.... Cheers, Steve P.
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31st Mar 2010, 9:08 pm | #97 |
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Re: Tv62
Hi Steve I take it that's C33 (200uF) C34 & C35 (100uF)
That's me stuck all me spares electolytics are radio values. I will have to try and find them to purchase. Chris |
31st Mar 2010, 9:33 pm | #98 |
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Re: Tv62
Sounds like the main smoother is O/C and the strange sound is probably the line timebase trying to work with loads of ripple on it. You say you have some radio values.
Even these clipped across should considerably improve the hum situation and get it going to some extent. Maybe 32uf or something similar. Make up some croc clips and just clip a couple across the old smoothing block. See what effects it has, failing that I can probably find you a large NOS telly multi block that you can experiment with. PM if you would like it. Regards, John. |
31st Mar 2010, 9:38 pm | #99 |
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Re: Tv62
I'm still worried that we're missing something important with all this remote diagnosis. We've got a few skilled telly folk up in the NE, would one of them be willing to let OTT bring his TV62 for a visit? It's only 25 miles or so to David Boynes' place.
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31st Mar 2010, 9:42 pm | #100 |
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Re: Tv62
I agree Jeffrey, It's so frustrating as a few checks with a meter in the right place will confirm the problem. I remember when I first started and digested hours of 'Servicing Television Receivers' and articles in Practical Television. RIP F.J. Camm. I owe him a lot. John.
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