Ekco CT101 is alive (Actually a CT100(M))

[Mikey405]

Originally Posted by Heatercathodeshort

I've got a spare 'crawling board' that I use to get under the trucks if its any help.

Thanks John - I think I could use it. Keeping getting up quickly from a lying down position makes me dizzy and I keep getting caught up in the soldering-iron and scope leads.

[ctc15]

Hi Mike
l hope these help.
(PS take the legs off and put it on it's side)
Keith

[Mikey405]

Originally Posted by ctc15

Hi Mike
l hope these help.
(PS take the legs off and put it on it's side)
Keith

Thanks for the pictures Keith - They're excellent - They'll be very useful indeed.

Kind regards.

From Mike.

[yagosaga]

Hello Mike,

the next step might be the video channel.

Can you adjust contrast and brightness?

Do you have a signal generator? Connect it over a 100pF cap with the grid of the video output tube. Change the output frequency (100 KHz to 50 MHz). Do you have any effect on the screen while tuning the generator?

If so, got to the next step before (video demodulator), if there is an effect on the screen, got to the last I.F. stage and so on.

Check the A.G.C. (video signal and line reference impulse).

Kind regards,
Eckhard

[Hunts smoothing bomb]

Hi Mike, this is very good news mate, I'm glad the LOPTY is healthy and it clearly shows the timebases are functioning too, just need to track down where the signal gets lost now.

All the best mate.

Lee

[Mikey405]

Originally Posted by yagosaga

Can you adjust contrast and brightness?

If so, got to the next step before (video demodulator), if there is an effect on the screen, got to the last I.F. stage and so on.

Hi Eckhard.

I have fed direct video in to the set and managed to get an almost synchronised picture - There is a lot of noise going on in the phase discriminator part of the (flywheel) line oscillator so the line sync is a bit wobbly although (overall) it's about right. I even get some attempt at colour but the decoder is going to be the last thing to sort out I guess (and besides, the burst gate etc. may be a bit hit-and-miss if the line sync is all over the place). I'm going to get the scope on the line oscillator and see where the noise is coming from - My first guess is that it may be one (or both) of the discriminator diodes, but I'll have a bit of a poke around and see if I can find the source.

Thanks Eckhard.

Kind regards.

From Mike.

[Mikey405]

Originally Posted by Hunts smoothing bomb

Hi Mike, this is very good news mate, I'm glad the LOPTY is healthy and it clearly shows the timebases are functioning too, just need to track down where the signal gets lost now.

All the best mate.

Lee

Hi Lee.

I'm fairly confident about working out where it's getting lost, although I'm a bit scared if it's inside the VHF tuner - The VHF tuner gets used as an IF amp when the set is switched to UHF - I'm a bit fuzzy when it comes to the "logistics" of stuff like the tuner etc. Anyway, I suppose it's just as likely to be anywhere else as the tuner so I shouldn't be too worried.

Thanks Lee.

Kind regards.

From Mike.

[Line whistle]

Hi,
Well done on finding that set and your progress. You're a braver man than me. Good to see something of this historic importance being restored. I look forward to further posts.
Cheers Des.

[Framer Dave]

Hello Mike,

I can't provide any practical help with this set, but, having seen it (and the toaster!) recently, I'm following the thread with great interest.

I'm sure you'll have a breakthrough soon.

Kind regards,

Dave

[ctc15]

Hi Mike
You can input video direct via SK3 and term SK4 with 75R.The gain control is
No 1 in diagram the video/RF switch is No 13.
(see diagram) (PS is this TV a CT100M?)
Keith

[Mikey405]

Originally Posted by Framer Dave

Hello Mike,

I can't provide any practical help with this set, but, having seen it (and the toaster!) recently, I'm following the thread with great interest.

I'm sure you'll have a breakthrough soon.

Kind regards,

Dave

Originally Posted by CTC15

PS is this TV a CT100M?

Hi Dave and Keith.

Thanks for your enthusiasm and help. You could well be right about it being a CT100M Keith, and I did forget to terminate SK4 when I put the video in, but I'll remember next time.

I've ordered a load of high-value (10M and 12M) resistors from Farnell for the focus chain - The focus control is very peculiar, it's an inductor, the core of which is worked on a little rack-and-pinion affair (although it's actually only friction that works the mechanism rather than a real "rack" or a real "pinion").

Kind regards.

From Mike.

[Mikey405]

Well, I've done a bit of digging and the set is indeed a CT100(M) and not a CT101 - The difference is in the cabinet presentation. (And the fact that the "M" has a video input) Thank you for the info Keith.

[Lloyd 1985]

Hi
Great to see the set lit up at last!!! I'm sure I said before that I can't wait to see a picture on the screen! Is the ct100 earlier than the ct101?

regards,
Lloyd

[Mikey405]

Hi Lloyd.

The CT100 and CT101 are really the same set, but the cabinet style is different between the two. As far as I know they are both the same age.

I'm looking forward to seeing a picture too.

Thanks Lloyd.

Kind regards.

From Mike.

[TNC]

Mike,

So sorry I wasn't able to join you in Solihull...but the sight of the awakening of such an early Ekco colour set is truly awesome!!
For me, living so close to the Ekco works (Westcliff-on-Sea) makes it seem almost like family!!
Good luck with the ongoing work - I am sure the end result will be amazing!
atb
Trevor

[Mikey405]

Well, the CT100 (not a CT101 ) now has a picture of sorts... Actually there is a HUGE hum in the sync and video although the HTs are rock-solid. I replaced the 2 phase-discriminator diodes (actually 2 diodes in 1 package) in the line oscillator with a pair of 1N4149s which has stopped the line sync from wandering wildly all over the place, and I've ordered a new ECH84 sync separator valve. As for the focus problem, I was going to measure the value of the resistor which goes from the focus rectifier down to deck but it is a 125M weird-thing and I don't have anything that can measure values that high. Replacing the manky old DY87 with a nice new DY802 has improved the focus no end though, although the control is still almost at one end. There is still a bit of a twitch in the line sync (as well as the hum) and the picture is a bit too wide, and of course there is still the colour and a few convergence problems to be looked at, but they can be for another day.

Thanks everyone.

Kind regards.

From Mike.

[Mikey405]

Originally Posted by TNC

Mike,

So sorry I wasn't able to join you in Solihull...but the sight of the awakening of such an early Ekco colour set is truly awesome!!
For me, living so close to the Ekco works (Westcliff-on-Sea) makes it seem almost like family!!
Good luck with the ongoing work - I am sure the end result will be amazing!
atb
Trevor

Thanks Trevor. I'm hoping it'll be a cracking set once it's working.

[Steve_P]

When the ECH84 comes, if it does not cure the hum, look towards the PSU and make sure it's OK. Is there an LT supply that powers any part of it, powered from say the PCL805.

I'll print off the decoder sheets and see about the lack of colour.

Great job so far. Well done!!

Cheers,

Steve P.

[Mikey405]

Thanks Steve.

There appears to be no LT supplies from the power supply at all, unless you count the 6.3V heater supplies. There is a 360V and a 200V line but they are rock-solid and have only the tiniest detectable amount of hum, and certainly well within tolerance I would suggest.

As for the lack of colour, that will be the fun part - I love decoder faults - They are always fun to try and sort out.

I'm still feeding video in directly so I still have to get to the bottom of the no-signals fault too, but I think there is enough to keep me busy for the time being.

Thanks Steve and everyone.

Kind regards.

From Mike.

PS. On the ECH84, there is a large amount of hum on the control grid of the sync separator until you momentarily unplug the valve, then all the hum goes and just leaves the sync. input.
PPS. I know I shouldn't be willy-nilly unplugging series-fed valves... (This ECH184 is series fed).

[dominicbeesley]

Firstly let me say how unspeakably jealous I am and how much I am following this with interest! Looks like it will be a lovel set when its going properly

Secondly does anybody have a circuit online for this one?

Keep us posted!

Cheers

Dom