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Old 24th Mar 2011, 6:13 pm   #1
Retired
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Join Date: Mar 2009
Location: Fenay Bridge, Huddersfield. UK.
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Default Restorer's dream part 2 the chassis.

Hi,

Having now successfully completed the cabinet restoration of my 1957 Ekco T311 I would once again like to beg the indulgence of Paul and the moderators and be allowed to restore the chassis once again doing the restoration in real time. The extensive cabinet restoration can be seen here;

https://www.vintage-radio.net/forum/...ad.php?t=62371

Although by no means an expert I have restored many radio chassis and can tell the difference between a cap and a resistor but I’m a total rookie when it comes to TV work as this is my first one. I’ve already received many kind offers of help and advice and no doubt I’ll be very grateful for every one of these by the time this chassis sees first light as there is much to do; I previously described the chassis as in very poor condition which was a bad choice of words when I should have described the chassis as extremely filthy and dirty in fact like the cabinet the chassis looks like a wreck.

Please be gentle with me because I’m again sticking my neck out in public by attempting this restoration in real time and I have a great deal to learn but hopefully I will successfully restore the chassis whilst giving a blow by blow account of work in progress in order to help others in my situation by adding as much detail as possible.

Jeffrey (ppppenguin) has already kindly given me sound advice about not powering up without at least firstly sorting out the LOPT; (line output transformer) also Jeffrey very kindly sent me pictures of a LOPT he restored and I am grateful for such information as it gives me a good indication of what to expect.. The chassis is still sitting on the spare bedroom carpet but shortly I will disturb its slumbers and carry it into the workshop where I can inspect it closely. Before putting it into storage I used a compressor airline to blow most of the debris and dirt from the chassis so already it is looking somewhat better than it did and at least I can now see all the components.

New to me is the wire ended rectifier valve U25 as all the valves I’m familiar with have bases and pins whereas this valve is merely “floating” on two wires the third being broken. Please bear with me whilst I get to grips with the various terms used in TV work such as “Raster” which I believe is the picture on the screen.

I’m informed TV restoration can be easier than radio work because the raster gives a visual indication of faults and depending on what the raster looks like many faults are easily identifiable; please correct me at any time should I make a mistake as I sincerely want to learn how to restore this chassis and how to work on a TV chassis in general.

What do I need to know about safety? I believe there is some 16,000V present at the end of the CRT (Cathode ray tube) and also at the LOPT; I’ve already been informed that on this chassis such voltage would be most unpleasant to come into contact with but is unlikely to be lethal unlike a chassis with mains derived voltages in these locations. Are there any caps to watch out for that might be un-discharged as I work on the chassis? Is it better to assemble the speaker and CRT into the cabinet before commencing work or is it safe (with care) to have both loose on the bench to save bench space and avoiding damage to the newly restored cabinet. I’m used to having a bench full of live components so this doesn’t unduly worry me.

I expect to do a complete re-cap given the age of the chassis and would appreciate any advice or information regarding problems in this area and also what kind of caps to use and where to purchase them from.

Jeffrey very generously supplied a new U25 valve with the set and my friend Harold has very kindly supplied me a number of other new valves whilst other members too have contacted me offering to help with valves. When I restore a radio chassis the first thing I do is to pull the valves one by one and test them on my AVO MK1 VCM; this not only ensures the valves are working but that they are in their correct sockets so I will make this my starting point assuming my VCM (valve tester) will test the valves; years ago I downloaded lots of valve data for my VCM so hopefully I can ease into this restoration rather than jump in and start making silly mistakes.

I have previously rewound a LOPT although at the time it was just another transformer to me and fortunately it was one of the normal windings that had gone open circuit not the wave wound one.

I have also bought a second hand Aurora but don’t yet know how to use it and as we are on cable TV I assume I’ll need an aerial for the workshop and if so what aerial is recommended and where from?

At work I was always the one to ask the stupid questions whilst others all around me wanted to ask the same question but were scared to speak up; if I may be permitted I will ask the stupid questions in the hope that this thread becomes not only interesting but also instructive as well in supplying answers to very basic questions.

Unlike the cabinet restoration where I was very much out on my own I am certain this chassis will be an easier project in spite of my ignorance of the subject as there are so many TV experts on this forum whom I know are just waiting to bump start me into action. All suggestions and advice will be gratefully received by me so please sit back and enjoy the journey whilst I ramble on as usual.

Over the next few days I’ll get myself organized but to start with in the meantime I’m now gathering information.

To kick off with here are pictures of the chassis when I first collected the set; what a delight this restoration is going to be for me and I hope it turns out to be such a pain as the cabinet did as I hate a push over.

Kind regards, Col.
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