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CTV Dynatron CTV29 TV

 
hitachitv
(@hitachitv)
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Posts: 24

Hi All,

I've purchased another television! A Dynatron CTV29 Narvik! I'm not sure of what year it was made! I'd also be curious to know how much they sold for particularly with the 26" screen!

One issue I had is when powering on unfortunately, produced some smoke and the picture was very faint (hardly visible).

I presume its a capacitor? But not sure? I'd certainly like to learn how to fix it (I have experience repairing radios).

 

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Topic starter Posted : 22/09/2021 1:18 pm
crustytv
(@crustytv)
Vrat Founder Admin
Posts: 11044

Hi,

There were two versions of the CTV29 produced. One was 1974 and used the PYE 733 chassis, the other was a CTV29/5 produced in 1975 and used the PYE 744 chassis.

As for the smoke, presume nothing, test everything!

Use your eyes, ears, and meter. As with radios, thoroughly inspecting the device before powering on will reveal a lot, and save unnecessary damage. Finally, not all faults are capacitor related, that smoke could be a multitude of things, not least of which could be an overheating resistor. As with radios, TVs are not returned to health just by recapping them. 👍 

https://www.radios-tv.co.uk/dynatron/

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Posted : 22/09/2021 1:59 pm
Cathovisor
(@cathovisor)
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Posted by: @crustytv

As with radios, TVs are not returned to health just by recapping them. 👍 

I would love to know where this fallacy came from, because it annoys me no end. 

Suppose a waxed paper cap acting as a screen grid decoupler goes short in a set, making the screen feed resistor open circuit. Or, the coupling capacitor to the output valve control grid goes so leaky the output valve draws excess current, causing the output transformer to go open circuit? 

Blithely replacing all the caps won't fix that radio...

The key thing is - assume nothing. 

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Posted : 22/09/2021 2:26 pm
Nuvistor
(@nuvistor)
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Posts: 4199

From memory the 733 was a slightly modified version of the 731 chassis that incorporated tone, tint controls and one or two other “extras” just for Dynatron. The 731 was a 110 degree standard heater CRT A66-140X whereas the 741 used the quick heat A66-410X. Again the 744 would have slight mods just for Dynatron. I am not sure if Dynatron made 22 inch TV, if so replace A66 with A56.

Unfortunately the 110 degree CRT sets from these chassis’s where not as reliable as the 90 degree 725 chassis. The extra power required for the scanning perhaps a little too much for the design.

 

Hope all that is correct, it’s over 40 years since I saw one.

 

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Posted : 22/09/2021 4:27 pm
hitachitv liked
crustytv
(@crustytv)
Vrat Founder Admin
Posts: 11044

Maybe these might help identify what boards you have in your CTV29. Here are the Pye 731 chassis boards, do they match what you have?

  • Photo 1; Power Supply 212 27164
  • Photo 2; Line Timebase Panel 212 27167
  • Photo 3; Field Timebase Panel 212 27163
  • Photo 4; I.F. Panel 212 17161
  • Photo 5; Chroma Panel 212 27166
  • Photo 6; Convergence Panel 212 27165
20210922 220009
20210922 220026
20210922 220047
20210922 220105
20210922 220121
20210922 220157
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Posted : 22/09/2021 10:16 pm
crustytv
(@crustytv)
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Posts: 11044

Oh, I forgot to also mention that if you’ve not found the superb article by Mike Phelan from "Television 1979", then you should give it a read. It covers the PYE range of chassis', including the '731'. Packed full of useful circuit snippets, function descriptions and stock faults.

https://www.radios-tv.co.uk/pye-714-to-741/

p.s.

I have the full manufacturer's service manual, with mods. Though It's not yet scanned, and it would take ages. However, I'm happy to provide ad-hoc scans of parts of the cct you are working on, as and when required.

You can however buy the data from Paul Stennings site (see at the foot of every page of this site, links section) for just £1.99 which is an absolute bargain.

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Posted : 23/09/2021 9:57 am
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Till Eulenspiegel
(@till)
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The attachment shows the burn-out near the focus control.

Dynatron CTV29

Till Eulenspiegel.

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Posted : 25/09/2021 8:52 am
Till Eulenspiegel
(@till)
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It goes without saying the focus control needed replacing, that done it was found that the EHT tripler unit was faulty. Fortunately, I had with me a replacement for the original AEG part.   The replacement tripler was from HRS Ltd.  Remember them?  I guess the company is defunct now.

Dynatron CTV29 Focus Control 1
Dynatron CTV29 Tripler 1

The set now displays a blank raster, the 200volt supply to the video output transistors has failed.  The fusible safety resistor in the 200volt line has gone open circuit and only 140volts can be measured at one end of the resistor, the same voltage that supplies the line output stage.  I hope to complete the repair to the set on Thursday.

Till Eulenspiegel.

 

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Posted : 29/09/2021 10:49 am
crustytv
(@crustytv)
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Posts: 11044

This is all very confusing..... HitachiTV started this thread about his recent CTV29 acquisition and a failure condition. The last three posts are from Till (David) talking about a CTV29 focus control failure.

Are we to take it from these posts that David is now repairing the OPs (original poster) TV? If yes, then fine, but HitachiTV should have at least let us all know. If not, and David is repairing his own CTV29, then those posts need splitting off into their own thread.

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Posted : 29/09/2021 12:21 pm
Till Eulenspiegel
(@till)
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Hi Chris,

              I'm repairing the Dynatron for HitachiTV doing the job on site because of the size and weight of the set. The chassis is the Pye Group 733.

Till Eulenspiegel.

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Posted : 29/09/2021 2:55 pm
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crustytv
(@crustytv)
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Thanks for letting us know David, it all makes sense now. 👍 Didn't know HitachiTV was in our neck of the woods.

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Posted : 29/09/2021 3:03 pm
Katie Bush
(@katie-bush)
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Posts: 4885

Ah good! That means I can stop scratching me head now!

Like Chris, I was getting a bit confused over whom was doing which for who, with what and for how long?! 🤯💥💫😅🤣😂

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Posted : 29/09/2021 7:46 pm
hitachitv
(@hitachitv)
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Posts: 24

Apologies for myself also not making that clearer as well!
I actually used to not be when I joined but made my way up due to work and university! 😀 

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Topic starter Posted : 30/09/2021 7:16 pm
hitachitv
(@hitachitv)
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Posts: 24

Hi All,

A little update Till, informed me there was a PYE Manual for the 731 - 735 Chassis available on the internet. I thought it might be worth picking up and I thought folks might want to see it!

IMG 20220402 203151 191
IMG 20220402 203157 591
IMG 20220402 203222 144
IMG 20220402 203226 492

 

 

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Topic starter Posted : 02/04/2022 8:42 pm
hitachitv
(@hitachitv)
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Posts: 24

Hi All,

David came from on Monday to have a look over at the Dynatron. We assembled back the timebase panel and then switched on... to find it had short circuited! After some confused searching we realised when inserting one of the sockets of the board we had gone a bit to rough on it has bent the ground tag, meaning no contact was made... after bending it back voila we had power!

Post-David visiting I noticed the set was not tuning properly i.e it wasn't picking up a signal. David and I had noticed that the tuning box was loose and David reccomended soldering so I had a go and signal was restored.

Finally, I noticed that the colour was slightly off, but also the vertical hold was also off, however, I cannot find for the life of me where the vertical hold knob is!

Any advice would be helpful!

 

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Topic starter Posted : 16/04/2022 6:49 pm
Jayceebee
(@jayceebee)
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Posts: 1689

According to the TV mag servicing article on this series of chassis in the library the vertical hold control is RV509 which is located on the line timebase board. Hope this helps.

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Posted : 16/04/2022 10:08 pm
crustytv
(@crustytv)
Vrat Founder Admin
Posts: 11044
Posted by: @jayceebee

Hope this helps.

I think that will only muddle matters more for the op. That TV mag covers all the PYE solid state colour receivers from 713 thru 741. 

RV509 does not exist on the 731, but does on the 737,  I assume you quoted from page 588. A little further, on page 591, you would have found the 731 (see below) and that confirms its RV510.

tv2
tv1

I also have the PYE 731 manufacturers manual, the same one the OP bought, which he has shown 3 posts back.

Posted by: @hitachitv

PYE Manual for the 731 - 735 Chassis available on the internet. I thought it might be worth picking up

This manual confirms the frame hold is indeed RV510. Regardless of any designation, both on the 737 & 731 are 100K, and exist on the timebase module. Not sure why the OP didn't just refer to the manual he bought.

20220416 230351
20220416 230401
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Posted : 16/04/2022 11:08 pm
Jayceebee
(@jayceebee)
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@crustytv Thanks for clarifying that. Not seen many of these but the 90 degree version, 725 chassis I think was seen much more by myself. IF faults and tuners being the most common issues.

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Posted : 17/04/2022 10:35 am
Till Eulenspiegel
(@till)
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Posts: 4534

It may not be the frame hold that needs adjustment. When the overload protection circuit is in action the supply voltages will be subject to fluctuation which causes a flutter effect on the picture.

At 165 volts the HT supply to the video output transistors is low, the correct figure should be 200volts.

The short circuit across the HT supply: the attachment shows the bent over pin in socket 511. Managed to remove the pin to straighten it out and then refit it again.  

Dynatron CTV29 SK511

Till Eulenspiegel.

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Posted : 17/04/2022 11:00 am
hitachitv
(@hitachitv)
Busy V-Ratter Registered
Posts: 24

Where is the best place to look first for the vault? 

I've enclosed the voltage supply diagram in the manual!

IMG 20220705 204245715

Also having issues with the colour on the set - where should I look in the manual to adjust the colours.

Here is the issue I'm facing:

IMG 20220705 203056284

Thanks 

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Topic starter Posted : 05/07/2022 8:44 pm