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-   -   Tv62 (https://www.vintage-radio.net/forum/showthread.php?t=52156)

oldticktock 25th Mar 2010 12:12 pm

Tv62
 
3 Attachment(s)
Well, what has OldTickTock gone and done!

He only bought a TV62, in a moment of madness he decided that his ever growing library of 30's 40 and 50's flicks would somehow seem more enjoyable on a vintage screen.

Found this nice example, its in excellent condition and whats more no rust, its all protected by lots of thick fluff. Getting ahead of myself also ordered an Aurora.

Now if you remember OldTickTock was a tad scared of the old AC/DC DAC90a's (completed 3 since then) well you can imagine how he's feeling about this beasty.

So to the matter in hand, I would dearly love to have a go at this but I do not know where to start and even if I should. Advice and guidance is very much sought and if I get too stuck perhaps someone in the area to help oldticktock.

I want to start by cleaning the muck out and removing the valves, perhaps replacing the waxies, but am I likely to get a belt, normally on radios I discharge the electo caps via my LCR, I've heard of the CRT's charging themselves, devilish fiends.

I have Trader Sheet 1236/T97 will this be enough?


Chris

ppppenguin 25th Mar 2010 12:35 pm

Re: Tv62
 
Well done! Read Steve P's TV servicing pages. http://www.oldtellys.co.uk/otindex.html The TV62 looks like a pretty conventional design but I admit I haven't worked on mine yet. Usual live chassis safety rules, same as for the DAC90. Make sure the set is stored in a nice warm dry place for a while before firing it up. This is kind to the LOPT. It's your choice whether to change the waxies before or after first power. I would change C79 and C88 to prevent possible damage to the sound and frame transformers. In any case a lamp limiter or variac is always nice to give it a gentle start. Becuase it has a valve HT rectifier the HT will come up fairly gently anyway.

The Bush service info is available from Jon's website (he's Duke Nukem in the forum). Scroll to the bottom of the page.
http://www.thevalvepage.com/tvmanu/bush/bush.htm

oldticktock 25th Mar 2010 12:49 pm

Re: Tv62
 
Thanks Jeffrey for the advice re C79 & C88.

Steve P's site looks like some excellent reading there.

HamishBoxer 25th Mar 2010 1:08 pm

Re: Tv62
 
Change the wax caps that matter ie coupling and any screen decoupling etc.AGC can wait till you get EHT up.Depending where its come from easy remove loptx and put on a radiator get it nice and dry.Then as Jeffrey says variac or bulb to be gentle.

David

Duke_Nukem 25th Mar 2010 3:14 pm

Re: Tv62
 
Under the fluff you'll find surface rust on the RF chassis - but not to worry I think it'll be minor.

Once you've got the front controls off, undo a few bolts and pull out a few connectors and the chassis are out giving excellent access, except for the boost cap which is hidden under the tag strip on the power chassis and a pain in the wotsit to access. Its probably the least accessible component in the whole design and really is a must to replace.

The LOPT is a plug in design, undo one (or is it two) screws and the LOPT comes out, no desoldering required, so you can bung the LOPT somewhere warm and dry whilst attending to the power chassis.

TTFN,
Jon

ekcopyephilips 25th Mar 2010 5:45 pm

Re: Tv62
 
Is the RF Chassis in this idenical to the TV53 ?

Steve_P 25th Mar 2010 6:01 pm

Re: Tv62
 
...and TV56, If memory serves me right.

The single standard Bush sets don't have the same problem as the Dual Standard ones, you'll be glad to know.

Nice sets.

Cheers,

Steve P.

Heatercathodeshort 25th Mar 2010 7:29 pm

Re: Tv62
 
I would not disturb the set too much as you may put more faults on it that will be very difficult to trace. Replace the two caps mentioned and wake it up slowly. Get the power supply and line output stages working and the CRT will display all the fault symptoms. It's not too difficult from this point. Cleaning and disturbance at this stage will introduce faults such as broken wires , displaced components, ion trap and a risk of valves put in wrong sockets. We have all done it! When it comes to replacing the waxies, do them one at a time once you have got something on the screen. The faults will 'unfold' as you do it and the effect is very satisfying! Take the usual AC/DC precautions and don't be scared of it. It's only a DAC90A with a picture tube! Take digital pictures before you start. An interruption when replacing a component can lead to an incorrect connection. Good luck with it! [PS Don't forget to snip the mains filter capacitor before you apply power..] Regards, John.

oldticktock 25th Mar 2010 7:37 pm

Re: Tv62
 
Hi John

Thanks for the sound advice, I will do as you suggest.

Once C79 & C88 are replaced, I will fire up via the Lamp Limter which is also fed by the variac. Variac.......LL.......TV62

Is it best to wind it up say 20volts every 20 mins and watch for issues. I guess its the same for radios, switch off if bulb glows bright.

what should i be watching for with regards to potential issues, other than smoke and unlit heaters.

I take it the back of the CRT and the actual CRT is where the lethal EHT is to be found

Luckily I have a box full of TV valves and after sorting I have all replacements except EY51 and ECC83

Yes filter cap must remember that, forgot on a philips 151u and it popped, set still carried on working unlike my nerves for the next couple of mins.

Chris

audiomagpie 25th Mar 2010 7:38 pm

Re: Tv62
 
Quote:

Originally Posted by Heatercathodeshort (Post 316455)
It's only a DAC90A with a picture tube!

Must be quote of the year! This gives great confidence to those of us entering the world of vintage TV repair!

Greg

ppppenguin 25th Mar 2010 7:49 pm

Re: Tv62
 
Quote:

Originally Posted by oldticktock (Post 316457)
Once C79 & C88 are replaced, I will fire up via the Lamp Limter which is also fed by the variac. Variac.......LL.......TV62

Is it best to wind it up say 20volts every 20 mins and watch for issues. I guess its the same for radios, switch of if bulb glows bright.

First stage is to get the heaters going. Best to check the resistance across the mains before you apply power - you can pull out a valve to prove you have continuity.

If you're using an LL then the variac is hardly needed. You'll need a 150W bulb or a pair of 100W in parallel. You can put a meter on the HT to see it coming up if you like. The problem is you won't get much HT until the PY82s warm up and that will need virtually full mains. Sound should come first, along with a bit of buzz from the frame scan. Then line whistle if you can still hear 10kHz.

John is right abot DAC90 with a tube. The real dangers are mains and HT. And of course the implosion hazard from the CRT. The EHT is fairly harmless if you touch it though you won't enjoy the experience.

oldticktock 25th Mar 2010 7:54 pm

Re: Tv62
 
That's a pain, I built the LL on a finite platform no room for a second lamp, and I don't have a 150W bulb. I will have to look for one.

ppppenguin 25th Mar 2010 8:28 pm

Re: Tv62
 
Try it with 100W but I don't think you'll get much to happen. A 100W bulb takes about 400mA from the mains, about the same as a telly. Remember that 300mA goes down the heater chain alone. I know the bulb has a lower resistance when cold but you're still not going to get much joy. Perhaps foget about the bulb and just use the variac. Wind it up to 160V or so and you'll start to see a glow from the heaters. At 180V to 200V you should start to get something happening. Watch out for smoke and switch off if there's a problem.

oldticktock 25th Mar 2010 8:39 pm

Re: Tv62
 
Think I might resist the temptation to make a start and wait, just ordered some 150W bulbs. Just picked up a spare LOPT as well.

MALC SCOTT 25th Mar 2010 8:49 pm

Re: Tv62
 
Hi, i have a variac with volts/amp meters on it you are welcome to borrow.

oldticktock 25th Mar 2010 9:10 pm

Re: Tv62
 
Hi Malc,

Thank you for the kind offer, I have a variac with a Volt meter.

Guess I'm just being over cautious wanting to run the TV62 via Lamp Limiter via the Variac. I know jeffrey said it was unecessary but I've been doing it with the radios, it's just that extra comfort factor.

Chris

Steve_P 25th Mar 2010 9:14 pm

Re: Tv62
 
Well, yes you are. If it's got a valve rectifier, it won't start to generate HT until you hit about 180v at least.

Start at 150v at least and keep your hand on the On-Off switch.

Cheers,

Steve P.

ppppenguin 25th Mar 2010 9:16 pm

Re: Tv62
 
TBH, even a 150W lamp may not get the telly up to working. Just bung it on the variac.

There is a theoretically better way if you can be bothered. Separate the HT and heater circuits by pulling F1. Then get the heaters running nicely, eventually at full volts. Then conect the variac output to the rectiifer end of F1 to bring up the HT gently.

Heatercathodeshort 25th Mar 2010 9:25 pm

Re: Tv62
 
I doubt if any of the valves will be faulty. The lopt is another reliable component together with the mains droppers. It may well work to some extent when mains is first applied. I like the sound of that dry dust. That is a very good sign. Don't forget to snip the cap across the mains switch. If its still in place it might 'pop' or blow the fuse. It will do no harm to the receiver if it fails with 'entertainment'.. J.

Ed_Dinning 25th Mar 2010 9:56 pm

Re: Tv62
 
Hi OTT, not sure if you got your answer ref the EHT, it is the connector on the side of the tube. This is the bit that bites and can store a charge for a long time.
The safe way to handle this is to get an insulated screwdriver and connect it to a croc clip through a length of insulated wire and a 10K resistor.
After the set is off, clip wire to chassis and contact the EHT connector with the insulated screwdriver. You may get a small spark. With the screwdriver still in contact remove the connector.
Repeat the process with the tube before replacing the connector as the capacitance of the tube can have a memory effect.
Volts on the tube base are only DAC90 levels.

Contact me if you wish to borrow any valves for checking the set with.

Ed


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