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Ekco T368, what have I let myself in for!

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Lloyd
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I picked up this rather smart looking Ekco at the NVCF this year as I'd decided I wanted another Ekco in the collection after seeing such first class results from the little TMB272. I really wanted a T161 or similar looking set, but unfortunately the only 2 I saw were sold, so I settled on this. The cabinet is in lovely condition, all the covers were in place and also in good condition, and it all looked good inside from a quick back off inspection on the stall. The only noted problems were the speaker grille has been replaced with what looks like a sheet of cork, the LOPTY housing has turned to dust, and the dropper had melted in a spectacular fashion and been bridged with a polo mint.

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The other day I finally decided to open it up and see if I could get some life out of it before embarking on the task of rebuilding the LOPT housing. I hadn't got the correct mains connector, so I used the most dangerous things I could find; a mains lead cut from an old toaster, and some crocodile clip leads! (don't try this at home please!!) I also found the mains connector is damaged too, one of the pins is pointing down because the paxolin is cracked around it. I gave it some power from the variac, at about 120v valves were lighting dimly, and at 150v I got a loud hum from the speaker followed by the line whistle starting up. Great, at least the transformer is OK! I pulled out the smoother can and bodged in 2 old 68uf caps leftover from the Philips 385U, this got rid of the hum, and now there was no sound at all... Line whistle still OK, so I upped the voltage to 200V, the line whistle got louder, but still nothing on screen, and the heater in the EHT rectifier wasn't lighting. At this point I noticed the blackened remains of a resistor that must have nearly set the TV on fire! I poked it with a screwdriver and it fell apart like fag ash. Not good! the 2 caps either side of it were toasted too.

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I decided to carry on trying to get first light anyway. I replaced the EHT rectifier with a stick rectifier I had, and managed 6KV! still nothing on screen though, except when the lights were off and you turn the set off, I got a defocused dot very quickly. I then got the B&K out on it, I had to guess what tube base to use, as the number isn't listed on my set-up chart. The worst was confirmed by the meter reading, the tube is as flat as a pancake! I left it to cook for 10 mins, then gave it 3 shots of clean and balance, and got it just to the end of the yellow, then decided to leave it at that.

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The service data was downloaded from the library, and the burnt resistor identified as R72 in the frame circuit, and looking at the tube carefully, you can see the set had been run for some time on high brightness after the frame fault occurred as there is a line burnt into the screen! with the resistor removed, the damage to the PCB could be seen, and it was quite bad. It had burnt almost all the way through, and on testing with the megger, even on 50v it was conductive. I thought there's only 1 thing for it, cut out the burnt areas! But that was too destructive, so I settled for drilling between the tracks. 1 broke so was replaced with wire. The 2 caps either side of it (C87 and 88) were replaced whilst I was there, but I have no 270 ohm resistors of high enough wattage to replace R72, so I've ordered some 5W ones.

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The line hold control was quite stiff to rotate, and didn't rotate very far, so that was opened up to find out why. The dribble of wax down the outside of it gave away what had happened to it, but when opened I could really see why it didn't want to move, it was actually half filled with wax! with that melted away, the line hold control now moves a bit better.

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I also gave the tube a good clean whilst it was out (yeah, like that's gonna improve it!), I rather stupidly let the hoover loose near the label, and it ate it without any hesitation! Next job is to replace the 2 melted caps on the line timebase board, then re-fit the tube and see what happens!

Regards,
Lloyd.

 
Posted : 16/06/2014 8:13 pm
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Marc
 Marc
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Hi Lloyd,

That CRT might surprise you, I've had one or two CRT's that show as flat as a flat thing can be (to pinch Marion's line) and ended up with a pretty good watchable picture.

Looking forward to the next instalment. 

Marc.

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Posted : 16/06/2014 8:33 pm
freya
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The lopt frame can easily be made up from 2mm GRP board from model suppliers, see my repair thread from a while ago.

Great set with a great picture

 
Posted : 16/06/2014 8:50 pm
valvekits
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I don't know if others would agree but restoring these is a lot easier with the chassis out and separated from the CRT. Should you need any parts,I think I have a spare T368 chassis minus the CRT and frame output transformer which I nicked for my T345. The T368 seems to be a slightly improved version of the T345 with some of the line components mounted on a board whereas on the T345 they are just mounted on the chassis.
Should be a fun restoration and plenty of information on here.

Eddie

 
Posted : 16/06/2014 10:31 pm
colourstar
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Hi Lloyd, I had one of these some years ago and it produced a very good picture indeed. A very neat set too with a nicely finished case. Thinking about it, mine was actually a 19" version (T377?) but in the same case so very well packed in!

The missing speaker grille is a brown plastic affair that is actually a generic part, not specific to that set. In fact I think you will find Hacker record players use the same grille (in grey) as a vent underneath the cabinet.

Good luck with the restoration!

Steve

 
Posted : 16/06/2014 10:55 pm
slidertogrid
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Hi Lloyd,
I have a Dynatron with the same chassis, it was one of the first TVs I restored. I did a writeup on Paul's forum a few years back, but have no idea if it is still there..

I wouldn't trust a B&K on a mono tube, I found tubes that read flat are usually not too bad and ones that read very low are fine on a picture. I read somewhere that someone else had the same experience with one. The chassis is a bit difficult to recap with the tube in situ but it can be pushed back into service position which makes access a bit better. Since recapping my set has been totally reliable, the lopt casing could do with a rebuild though...

Good luck with the restoration. Fine sets!

Rich.

 
Posted : 16/06/2014 11:58 pm
Lloyd
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These set's certainly get some good reviews! I've read a couple of threads on them, which helped me get the chassis out of the case. The tube is out, trying to find somewhere safe to put it proved a bit of a challenge, it's currently sat on top of a pile consisting of a Samsung slimfit TV, a Panasonic portable boom box thing, some junction boxes, and my box of new resistors..  nice and safe...!

I've changed C91 for a new 0.22uf 630v cap, and was going to change C85, but I hadn't got anything close in stock, so some new 0.15uf 630v caps are now on order. I took the opportunity to clean up the PCB, as it was all black and sticky. the 2 caps I pulled from it looked like waxies, but on closer inspection they turned out to be TCC 'plastiseal' capacitors, which I've never seen before! they clean up nicely, shame they are completely useless!

Tomorrow I'll look at rebuilding the LOPT housing, I got a couple of bits of what looks like paxolin to play with, I'll test it first with high voltage to make sure it's not conductive at all.

Good to know about the Hacker grilles matching the Ekco! I'll look out for one.

Regards,
Lloyd.

 
Posted : 17/06/2014 12:43 am
Terrykc
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Ah yes! Memories of decomposed housings, eaten away from continual arcing - the material seemed to turn conductive as it decomposed - with a U25 perched in mid-air above the remains of the carcass, reliant entirely on the stiffness of the heater winding connections for support ...!

There used to be third party suppliers of replacement shells. The simplest one - and one perhaps worth considering today - was simply a perspex sheet bent into an inverted U, but it did the job.

If you can find suitable eyelets for the connections, it might be the easiest solution.

When all else fails, read the instructions

 
Posted : 17/06/2014 11:24 am
Lloyd
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According to John Wakely those Ekco LOPTs seem to carry on working even though the casing is completely trashed.

I remember reading his comments on these being some of the most reliable transformers made, apart from the housings! When I tried testing the set, I just made sure none of the connections were touching and then carefully powered it up. It makes a 'telly' noise, and higher voltages come out of it, so I think it might be OK.

I'll make it out of the paxolin like stuff I got first, and if it does become conductive, I'll get some PCB type material or perspex and use the paxolin as a template!

It would be good if we knew of an ex-Ekco employee who knew just what was in this stuff!

The new caps and resistors haven't arrived yet, so I'll get on with cleaning up the chassis a bit more. It's quite dirty, looking at how nice clean and tidy the cabinet is, you really wouldn't expect to see so much muck inside it!

Lloyd.

 
Posted : 17/06/2014 7:31 pm
Lloyd
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I couldn't resist trying to get some sort of first light, I tacked in another 0.22uf in place of C85, as I'm still waiting for the new 0.15uf's to arrive, and 3 100 ohm resistors in series in place of R72, and the stick rectifier in place of the U26. Powered up and couldn't see anything, but on switch off I saw a good sized raster collapse, so powered it back up and connected the Aurora. As it warmed up I could hear the tone very quietly (not done the audio coupling cap yet..) and then a small raster appeared! I did only have the variac set at 170v.

I turned up the voltage to 200V, and adjusted the line hold, frame hold and height. I couldn't get a good lock on either frame or line, but the tube is nice and bright! looks like everyone was right about the B&K reading low.

Regards,
Lloyd

PS: excuse the bodgery visible in the photo's...

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Posted : 17/06/2014 11:09 pm
valvekits
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That's a really good result, the CME1705 sure does seem to outlive the CME1703.

Eddie

 
Posted : 18/06/2014 1:17 pm
colourstar
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Great work Lloyd. At least you know the LOPT is sound and the CRT is good, so now you should see steady improvements as you start to replace components.

I saw your set at the NVCF and it looked very appealing. Manufacturers of that period really did try their best to make sets compact, resulting it some very attractive models at the turn of the 60s.

Steve

 
Posted : 18/06/2014 8:53 pm
Lloyd
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I must say, I very nearly didn't buy this set! I walked past it several times looking at it wondering whether or not to buy it. Couldn't resist it in the end!

New resistors arrived today, so R72 is now replaced with the correct value, no real improvement in picture quality, but there's still a long way to go with this. I've removed the LOPT now for rehousing, and so far I've come up with this:

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Ok, I know paxolin isn't very good at keeping it's insulating properties at high voltage and with heat, but this should last a fair while, at least until I can work out how to print a load of new ones off on work's 3D printer 

I also need to add a bit of strength to the thing, as it will probably fall apart when I try to fit the LOPT into it. Superglue seems to hold this stuff together very well, so that's what I've used.

Anyway, I need some sleep now!!

Regards,
Lloyd.

 
Posted : 19/06/2014 1:10 am
Marc
 Marc
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Ok, I know paxolin isn't very good at keeping it's insulating properties at high voltage and with heat, but this should last a fair while, at least until I can work out how to print a load of new ones off on work's 3D printer
Lloyd.

Hi Lloyd,

Send one of those "printed" LOPT frames my way please, that's just what my T344 needs 

Marc.

Marc
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Posted : 19/06/2014 1:17 am
freya
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That looks fine, as soon as its added to the core of the lopt it will be much more rigid anyway. :aad

 
Posted : 19/06/2014 8:21 am
Lloyd
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That's if it fits properly!! I did put it together wrong to start with, and had to pull off one of the strips with the 3 connections on it, it didn't want to come off!

Marc, if I can work out how to use CAD and whatever it is that runs the 3D printer, I'll send you one! Might take me a few years though!

Regards,
Lloyd.

 
Posted : 19/06/2014 8:43 am
Lloyd
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Well, it fits!

I think I could have made the hole for the EHT rectifier a little further up, it hangs down a bit further than I'd like, and I'm not impressed about the whole end of the EHT rectifier holder being charged to full EHT when the set is on!

I found some nasty green corrosion on one of the leadouts from the primary, which caused it to snap when I was trying to reconnect the wires to the studs, I ended up having to extend it with a length of enamelled copper wire. I also had to extend one of the wires to the smaller studs, as I think it should have been on the side of the LOPT housing, rather than on the top, which is where I'd put it.

I've replaced a couple of caps, one of which was what I believe to be the sync coupling cap, C102, which has resulted in a good solid lock on both line and frame. The other cap was C86, between the primary of the blocking oscillator transformer and earth. I've also fitted the correct value for C85 0.15uf 630v, as the new ones arrived today.

There is a problem with the U26 EHT rectifier valve's heater, it either doesn't light at all, or glows dimly then flashes bright orange. This comes out in the picture as either no picture at all, or picture blooms when brightness increased. When it starts flashing bright orange the picture gets nice and bright and looks quite good! For now, the EHT rectifier stick has been fitted.

Regards,
Lloyd.

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Posted : 20/06/2014 12:34 am
danny
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Hi this set came from the Sutton windmill auction it was in a bundle lot I wanted a Phillips set that was in the lot . I already have one of these in my collection . It was a last min decision to do the nvcf . But glad I did as I sold almost everything I took. As for the lopt casings you could use your paxolin casing as a plug for a mould then cast new casings in resin. I wonder how many takers you would have if you went into production?. Danny

 
Posted : 20/06/2014 12:46 am
Marc
 Marc
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Hi Lloyd,

That LOPT frame looks very good to me and and judging by the test card it won't be long before that set is sorted !
Great stuff 

Marc.

Marc
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Posted : 20/06/2014 1:00 am
freya
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Do you think it could be the heater pins on the U26 socket causing the flashing from the rectifier ? seen blue flashes but never orange. tube is looking great for such a low B&K reading

 
Posted : 20/06/2014 10:55 am
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