Dynatron CTV10 - various faults. - Page 3 - UK Vintage Radio Repair and Restoration Discussion Forum

Focus Diode · 18th Oct 2006, 9:31 pm

The Macrovision on some DVDs is annoying on my domestically used ITT/RGD CVC5 model, namely two sloping lines from the top which come and go at intervals. On normal VHS (following simple mods) and DVDs however the results are perfect.

I was never able to get perfect VCR playback on Pye Hybrids though, there was always some hooking at the top despite carrying out suggested modifications.

I plug the lot into a Maplin UHF modulator box, designed for equipment made without SCART connectors with excellent results.

Mike P and I have mentioned this before, but don't forget the PCL84 grid leak resistors which should be changed to 680K from the original 2M2. Will save a good deal of trouble later.

Cheers,
Brian

Tazman1966 · 18th Oct 2006, 10:17 pm

Hello Lee

My brain's just kicked into action again so I thought I'd offer some help. Did you say that the grey scale is okay but the colour is weird? Two things to check would be dry joints and cracked print near the PCL 84 valve holders. The panel on our Invicta was a work of art in soldering eventually! The other thing to mention are the two presets at the rear of the CDA panel. The one in the middle is for green and if advanced too far clockwise you'll find the greens too vivid and fleshtones will be a bit on the purple side. Equally if the one on the right is for blue and you'll find that if that's too far advanced the blues will be too bright and fleshtones sort of "Simpsons" like!

I hope that this helps. Sorry I can't be more specific about circuit reference number but I'm doing this from memory

Good Luck!

Tas

Mikey405 · 19th Oct 2006, 7:50 am

Hi Lee.

The advice from Taz, Brian and Mike is very good. The resistors that Taz is talking about are RV26 and RV27, although personally I think I would assume that they are set correctly unless proven otherwise. If you can mark where they were originally set then there is no harm in twiddling, but if the colours are that far out I think I would still suspect a fault. (Taz's cracked-print is pretty common - I've also seen boards with the coating rubbed off the copper tracks and then the whole lot swathed in solder.)

If the grey-scale controls don't make much difference though when you adjust them even with the colour turned right down, then I think I would still be chasing this problem first.

From Mike.

Mike Phelan · 19th Oct 2006, 9:08 am

You should have quite a swing on the A1 pots on the convergence panel -of not, there is a problem (probably resistors gone high).

The two pots on the CDA panel do not make very much difference, unless they are noisy or o/c.

There are a couple of Suflex caps in the burst phase detector that can cause some very strange colour effects.

18th Oct 2006, 9:31 pm	#41
Focus Diode Octode Join Date: Jan 2006 Location: Borough of Gateshead, UK. Posts: 1,420	Re: Dynatron CTV10 help required The Macrovision on some DVDs is annoying on my domestically used ITT/RGD CVC5 model, namely two sloping lines from the top which come and go at intervals. On normal VHS (following simple mods) and DVDs however the results are perfect. I was never able to get perfect VCR playback on Pye Hybrids though, there was always some hooking at the top despite carrying out suggested modifications. I plug the lot into a Maplin UHF modulator box, designed for equipment made without SCART connectors with excellent results. Mike P and I have mentioned this before, but don't forget the PCL84 grid leak resistors which should be changed to 680K from the original 2M2. Will save a good deal of trouble later. Cheers, Brian

18th Oct 2006, 10:17 pm	#42
Tazman1966 Nonode Join Date: May 2006 Location: St Albans, Herts, UK. Posts: 2,193	Re: Dynatron CTV10 help required Hello Lee My brain's just kicked into action again so I thought I'd offer some help. Did you say that the grey scale is okay but the colour is weird? Two things to check would be dry joints and cracked print near the PCL 84 valve holders. The panel on our Invicta was a work of art in soldering eventually! The other thing to mention are the two presets at the rear of the CDA panel. The one in the middle is for green and if advanced too far clockwise you'll find the greens too vivid and fleshtones will be a bit on the purple side. Equally if the one on the right is for blue and you'll find that if that's too far advanced the blues will be too bright and fleshtones sort of "Simpsons" like! I hope that this helps. Sorry I can't be more specific about circuit reference number but I'm doing this from memory Good Luck! Tas

19th Oct 2006, 7:50 am	#43
Mikey405 Octode Join Date: Jul 2006 Location: Solihull, West Midlands and Beaford, Devon Posts: 1,626	Re: Dynatron CTV10 help required Hi Lee. The advice from Taz, Brian and Mike is very good. The resistors that Taz is talking about are RV26 and RV27, although personally I think I would assume that they are set correctly unless proven otherwise. If you can mark where they were originally set then there is no harm in twiddling, but if the colours are that far out I think I would still suspect a fault. (Taz's cracked-print is pretty common - I've also seen boards with the coating rubbed off the copper tracks and then the whole lot swathed in solder.) If the grey-scale controls don't make much difference though when you adjust them even with the colour turned right down, then I think I would still be chasing this problem first. From Mike.

19th Oct 2006, 9:08 am	#44
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Re: Dynatron CTV10 help required You should have quite a swing on the A1 pots on the convergence panel -of not, there is a problem (probably resistors gone high). The two pots on the CDA panel do not make very much difference, unless they are noisy or o/c. There are a couple of Suflex caps in the burst phase detector that can cause some very strange colour effects. __________________ Mike.