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CTV [Sticky] 1974 HMV 2726 Coloumaster; Thorn 4000

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crustytv
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Vertical now locked

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Posted : 29/07/2022 8:24 pm
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Jayceebee
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Convergence looks far better than either of my A823s after they were woken from their slumber meaning so far so good with the most unreliable TFs. Have you tried the remote?

John.

 
Posted : 29/07/2022 8:47 pm
crustytv
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Moved colour control to almost max (it was set at mid-point) and I have colour, slight move down, and colour loss. I've taken a short video so you can hear the odd sounds that are emanating.

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Posted : 29/07/2022 8:49 pm
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crustytv
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Video here

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Posted : 29/07/2022 8:51 pm
Jayceebee
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Sounds like digital noise from the remote board. Sounds like some filtering/decoupling issues. I wonder if that huge electrolytic was fitted on the remote board in an attempt to troubleshoot this fault?

John.

 
Posted : 29/07/2022 8:59 pm
crustytv
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I'm also wondering if there is something going on with the tuner, do I have the correct voltages etc It's very tetchy, and noisy, it reduces a little when I tune off. ELC1043?

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Posted : 29/07/2022 9:04 pm
Jayceebee
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Well, you well know my opinion of the Mullard ELC1043 vs the Thorn SC4. What happens if you press the reset button and does the noise change when operating the Vol + & - on the RCU?

John.

 
Posted : 29/07/2022 9:13 pm
crustytv
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Another demo, of the off tuning to on tuning and the motor boating when on signal.

see here

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Posted : 29/07/2022 9:16 pm
crustytv
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Posted by: @jayceebee

What happens if you press the reset button and does the noise change when operating the Vol + & - on the RCU?

Not using the remote, not even considered that yet, all manual at present.

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Posted : 29/07/2022 9:18 pm
crustytv
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I'm quitting while I'm, ahead for tonight as it's late, and I've been at it on and off all day. Back at it tomorrow, I need to locate the components that are causing the bent verticals, and delve into this tuning & odd sound problem. Oh, so tempted to put in the replica Vertical deflection module we made, but I'm not going top get ahead of myself. Get the TV mostly right first, then try it.

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Posted : 29/07/2022 9:28 pm
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Jayceebee
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Is there any test card audio present or is it unmodulated? I don't think that ELC is faulty, usually they go grainy or with a strong signal, smeary.

John.

 
Posted : 29/07/2022 9:28 pm
crustytv
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No tone input, purely vision only

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Posted : 29/07/2022 9:33 pm
Jayceebee
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Ok, the noise seems different now to the first video. Possibly due to one or more of those orange ROE plastic capacitors. Great work so far though.

John.

 
Posted : 29/07/2022 9:37 pm
crustytv
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Trouble is it's not consistent, when I switch off and back on. Sometimes it is like the first video, other times like the second, and sometimes no colour, and you have to retune.

To be fair it's just woken up, I've done the very bare minimum, fixing the W308 killer and the no raster, and there's no doubt many components on the edge of failing or are failing.

This is all that's been replaced thus far.

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Posted : 29/07/2022 9:41 pm
Lloyd
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Fantastic work Chris! I can imagine you are well chuffed with it 🙂

what’s causing the wonky picture at the top?

 Regards 

Lloyd 

 
Posted : 29/07/2022 9:41 pm
crustytv
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👍 Not sure yet Lloyd, I think It's to do with N/S pin cushion, maybe R402. As you can see from what I have, there's a whole load of problems to address, hopefully I can make further progress tomorrow.

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Posted : 29/07/2022 9:45 pm
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Jayceebee
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Posted by: @crustytv

👍 Not sure yet Lloyd, I think It's to do with N/S pin cushion

Correct, adjusting the N/S phase and amplitude pots will put that right.

John.

 
Posted : 29/07/2022 9:59 pm
colourmaster
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Excellent progress Chris, looking forward to seeing tomorrows episode.

Regards Gary 

 
Posted : 29/07/2022 11:22 pm
crustytv
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A few more tweaks. N-S Phase, N-S Pin Amp, smidge of line-shift, height adjust, and it's looking better.

I'm not happy with the tuning, it's very knife edge. Definition is really poor (grainy) and when the tuning draw is closed, there's a pop and the picture always reverts to B&W. Colour control has to be almost at the top to get colour. However, if I move it up the last couple of mills, (max) extent, the colour goes over saturated. With the volume set to zero the speaker motorboats, with the volume up, I hear all that hash like data. I'll try and do a short video to demo.

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Posted : 30/07/2022 11:36 am
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crustytv
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The funny data sound seems to coincide, in sync with picture fluctuations. The picture seems to have pulsing highlights too.

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Posted : 30/07/2022 11:58 am
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