Restorer's dream part 2 the chassis.

[DangerMan]

Hi Col,

black band or red band, they both mean the same thing, the band is the cathode end. No need to reverse it.

Pete

PS You beat me to it.. I see you have while I was posting!

[Amraduk]

Hello Colin,

Originally Posted by Retired

Oh dear; I've just noticed whilst checking the pictures the bands on the diodes are a different colour one red one black; I put the bands together totally missing the colour difference. Whoops!!

Don't worry! The colour of the bands is irrelevant, only their position matters.

Regards,

Dave.

PS. I see I've been beaten to it!

[Retired]

Hi,

Thanks Pete and Dave; yes once I get cracking there is no holding me back. Fortunately I've moved forwards a great deal and only gone backwards occasionally but each time I do go backwards I learn quickly.

I already have problems with colours and here is a new one to me; when I can finally find a component and recognize a red band I find a black band means exactly the same; with diodes anyway? What a great hobby this is as it keeps me on my toes and the goal posts are liable to move when least expected to trip me up.

Roll on tomorrow and let me at it.

Kind regards, Col.

[ms660]

Hello Col, from the earlier picture the symptoms look like a limiter fault or AGC going over the top, although if it was AGC I would expect to see the picture possibly pulling or sync. problems.
I do not know what AGC system the set uses or the type of limiter or where it is in circuit as I do not have a circuit diagram. Has the picure been negative since first light?

Good luck.

Lawrence

[Heatercathodeshort]

Hello again Colin,
As the weekend is coming up I thought it might be of value to post the most likely components causing your odd display. The controls should not be in any was sensitive to adjust when the receiver is operating correctly. The vertical and horizontal holds should be rock steady with no drift. Many of these receivers were never adjusted over a 10-15 year life once set up by the installing dealer.
I know you have replaced a number of capacitors but just to retrace our steps it is very important that the capacitor marked on the timebase circuit is replaced. It is the sync coupling capacitor .1uf connected to the control grid of the sync separator valve. This needs to be 100% Perfect as any leak will cause 'cogging' and other odd effects. Just check that it has in fact been replaced.
The capacitors marked on the vision circuit are all part of the AGC and vision interference limiter circuit. Again you may have replaced them but recheck against the circuit. The .04uf are small brown affairs sleeved with an off white paper cover. .047uf will be fine in this position. The .1uf's and the .25 will probably be waxies.
Another component that can give very strange effects in the Ekco when it changes value is the video anode load resistor. It is 12k 2 watt on my circuit [green circle] and it is not uncommon to discover it has doubled in value. If it is only say a maximum of 2k out I would leave it alone for the time being. You may find slight circuit variations as I am working from the Newnes Books. Original Ekco service cards are a bit difficult to find due to the fact that if you were an appointed Ekco dealer [a very valued and important part of your business in the 50's] you could lose your dealership if you loaned your service data out to non accredited dealers...Hence you don't find original data around. You know have all the circuits highlighted including the sound stages. Good luck with the final mile. Regards, John.

[murphyv310]

Try turning the contrast down, with the good signal from the Aurora it is easy for the set to "take off" with high contrast levels.

[Retired]

Hi,

Thanks Lawrence; yes the picture has been negative since first light.

I tried turning the contrast down Trevor only to lose the picture completely but I did notice it appeared to swing positive before failing which was promising; thanks for the suggestion.

This morning I played around with the chassis so much it decided not to display the test card at all; I had even tried the signal attenuator but without luck so removed it.

At dinner time a parcel arrived and I would like to thank Gus for his generosity in supplying a pair of new 16uF 450V electrolytics. Once the chassis is running OK then I'll spend time and install these making a decent job of it. Thanks Gus.

After dinner I went into the workshop and told the chassis if it carried on in this manner it would have the choice of a big hammer or a six mile car ride to the council tip.

I've just come out of the workshop and the latest component I've changed is a 12V 50uF electrolytic; I reasoned that all the caps listed by John had now been replaced and as this electrolytic was sitting on the chassis deck quietly I decided to attack and stuff it with a new 50uF 35V item.

I've had enough for today but before knocking off I've just taken the following picture which at last I think is now correct; I aligned it roughly and can fine tune tomorrow; I'll also check the Anode Load resistor on John's list.

Hopefully it will also be soon talking to me; it makes me jump when I nudge the volume control so at least the speaker is alive with a loud voice.

I've been kindly given a Barker 88 "Woody" radio and am also meeting a forum member in a couple of weeks who is bringing me a Bush "woody" radio and both these are restoration projects; the projects are stacking up and I'm in for an interesting winter.

Today turned out well after all; I like to make a bit of progress at each session.

Kind regards, Col.

[Sideband]

Now that is looking much better. What you might call a 'positive' result! What did you do to finally get correct video? Not just the 50uF surely?


SB

[ms660]

Near the mark now Col.

Looking good.

Lawrence

[Patrick Dixon]

That does look good now.

[PJL]

Post 256 is positive too! Looking good now.

[coil1234]

Hello Col,
excellent results, you should be very pleased with yourself. Although not a TV person myself; the proof of the inverted video is in the "letter box" above the test card center circle which should be a black rectangle within a white rectangle, you can constast this (pun intended) with your post #267 (28th Sept.) Apologies if someone has pointed this out previously.
I've been following these posts, especially the cabinet restoration, avidly since their start and I'm greatly encouraged that these skills are still esteemed and encouraged, albeit within our small community.

Regards Mike A

[Hunts smoothing bomb]

Originally Posted by PJL

Post 256 is positive too! Looking good now.

Thats what I said in post #279

Yes Col you are very nearly at the finishing line now, this is looking good indeed!!


Cheers

[Retired]

Hi,

Thanks SB. I had noticed a small black hunts cap hiding away right in the bottom right hand corner of the chassis and when I snipped it out after making a sketch of it's tags it fell to pieces; I tried to reassemble in order to obtain its size and thought it to be a .01uF so installed a new one; this made the test card much worse so I then installed a new .001uF and the test card displayed again but still wasn't quite right. I then changed an electrolytic attached to the interference limiter this being a 12uF 100v item; I installed a 10uF 450V and now as I tried to adjust the controls I could get the positive test card to display briefly before becoming extremely bright then fading away completely leaving a blank screen. I found that I could get the card to display but I had to keep backing the contrast off until it failed again so I thought something is causing some kind of drift.

I then remembered that there was a 50uF low voltage electrolytic that I hadn't changed and this was on the chassis deck not far from the limiter so I became suspicious. I snipped the leads after noting the connections and removed it. As I cut it open with the junior hacksaw it released a powerful "capacitor smell" and was wetting the saw blade; I was surprised to find a very slim cap in a much larger diameter can and the bottom of the can was wet with a muddy type of liquid.

I cleaned the can and installed a new 50uF 35V item and connected up. now suddenly the positive picture was displayed so at last I had found the cause of the strange test card behaviour.

Thanks Lawrence and Patrick; yes I'm now on a roll once again.

Well spotted PJL and Lee; I've just checked and sure enough the test card is displaying positive in post #256. I missed this completely as I've stared at this test card until I needed taking away in the white van; it just proves how easy it is to lose the plot after spending a couple of weeks concentrating extremely hard on a fast moving project. Normally I can't remember what I did yesterday so restoring this wreck into a working chassis is nothing short of a miracle for me.

Whilst at work I had to attend many seminars and training courses mostly one day events. On one training course there must have been over twenty of us and we were each given an A4 page to read and asked to memorize it. After being allowed plenty of time the pages were taken from us and questions asked about the content.

The theme of the story was someone dashing into a store demanding money. It was amazing how each person had read the same story but gave different answers when asked the same question. We all thought this was regarding a robbery when it fact it was part of a story about a security person dashing in to the store to collect the days takings and there was nothing sinister at all; the person was running late. I say the person because one of the questions was whether the the security person was male or female.

The point of the above is that apart from when Mike kindly popped over I've been working entirely from the written word; working on a chassis that I didn't have a component layout for; trying to understand unfamiliar terms which are taken for granted by the more experienced;working with EHT for the first time and although I'm not timid I didn't want to come into contact with it; thinking an AO90 diode to be a valve the list goes on so how come in a couple of weeks the test card was displaying and now the chassis is much more stable?

I believe I've had the backing and help of some of the best TV engineers in the world who have not only explained with great clarity in text but also kindly taken the time and trouble to add highlights and detail onto the printed circuits as I've worked through each stage. Yes I admit I still found it highly frustrating at times trying to apply all the information onto the actual chassis and the chassis was certainly pushing the wrong buttons at times but with patience and asking questions this in my opinion has been a rapid restoration from wreck to working TV by a novice. Taking the story above which was about something very simple in every day life I think you all deserve a pat on the back for putting complex information across in such a manner that I made very few mistakes.

You might have also noticed I ramble on forever but its much better than watching the telly these days.

Kind regards, Col.

[Amraduk]

Hello Colin,

Originally Posted by Retired

You might have also noticed I ramble on forever but its much better than watching the telly these days.

So, what on Earth are you restoring a TV for!!??

Regards,

Dave.

[ppppenguin]

Originally Posted by Amraduk

So, what on Earth are you restoring a TV for!!??

Some of us who are interested in vintage TVs actually rarely watch anything on the box. Seems perfectly within normal range for this forum

[Omegaman]

The test card is far more entertaining than the drivel they serve up on the TV these days!

[Retired]

Hi,

Thanks Dave; I'm restoring this vintage TV so that I can hopefully watch intelligent programs like copies of The Flower Pot Men and Andy Pandy.

Thanks Jeffrey and Howard I totally agree. I've just returned from a pleasant three mile walk having just paid £145.50 for a TV license; OUCH!!

Kind regards, Col.

[dominicbeesley]

Well get a move on Col and you can pay £50 next year instead - if you just watch the Ekco!

Dom

[Retired]

Hi,

Thanks for that Dom; even £50 is a rip off and to be honest I think they should pay me to watch the rubbish put out as entertainment these days.

Today is momentous;WOW;WOW and WOW; its working on both visual and now audio. I switched on just to make sure it hadn't died on me again and displayed the test card then I removed the Aurora connection and hooked up my 30' long ceiling aerial; turning from channel one to VHF I heard voices as the switch went over which was heartening. I turned the fine tuner and suddenly a program came in loud and clear; a bit more adjustment brought in classical music and I was very surprised just how good it sounded to say the set must have not been used for many years. Two stations came in clear and another two could be heard.

I knew I had replaced all the waxy caps but expected to replace the odd smaller cap and perhaps a resistor but it sounds fine.

After a friendly nudge by Andrew I started work in earnest on this chassis only a few weeks ago on the 7th September and here it is now fully working. To say I'm over the moon doesn't describe my delight.

I'm now undecided just how far to go with working on this chassis before putting it back into the cabinet and declaring it a total success. To have reached this stage in such short time takes my breath away and just listening to it playing happily with classic music brought a lump to my throat as surely I couldn't have done this.

You have taken me by the hand and guided me through this chassis restoration so the final word is yours; how far would you take this before considering it finished?

Thank you so much everyone for the information; advice; components and for following this remarkable story. What a truly superb hobby.

Kind regards, Col.