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-   -   Dynatron TV30CK (https://www.vintage-radio.net/forum/showthread.php?t=11476)

Kat Manton 26th Sep 2006 7:17 pm

Dynatron TV30CK
 
2 Attachment(s)
Hi,

Since some progress has been made with this set I thought I'd start a thread about it, then keep posting updates.

The cabinet has been washed with a damp cloth and my favourite all-purpose cleaner, Vanish bar. I ended up with a cabinet which looked somewhat lighter and a bucket of brown water. I then finished up with a beeswax polish, in spite of some damage to the lacquer (the usual water damage on top) it now looks quite respectable.

Unplugging the speaker, then removal of two screws at the top and four bolts underneath enabled the frame supporting the chassis, CRT, implosion shield and front control panel to be withdrawn. The subject of the damaged Metrosil EHT regulation VDR then discovered has been covered elsewhere.

Removal of the chassis from the frame is fairly straightforward, with the exception of the control knobs, which took a little careful study. First, the fine tuning and brightness knob grubscrews need loosening - these are accessible behind the front panel. Next, cover screws are removed from the volume and channel selector knobs. Finally, the fine tuning and brightness knobs are rotated to align a cut-out in them with the grubscrews which secure the volume and channel selector grubscrews, allowing these to be loosened and the pairs of knobs to be removed.

The chassis is secured to the frame by two screws at the front of the chassis which merely need loosening, three nuts, bolts and rectangular plates secure the rear edge. Then connections to tube base, scan coils and EHT unplug and the chassis can be removed.

Next, after removing the valves and inserting them in a sheet of polystyrene in their approximate original locations I cleaned the chassis. It was thick with dust and a waxed paper capacitor on the rear of the mains voltage selection panel had dribbled all over the timebase chassis.

Underneath there are no signs that "The Phantom" has been there before me, everything looks nicely original and unmolested. The line output transformer perspex support is in good condition; the windings for this check out with an ohm-meter. The main dual-section smoothing/reservoir capacitor is bulging ominously, I'll fit replacements inside this before I apply power. There are a few Hunts and waxed paper capacitors I'll probably replace before trying the set, too.

Advice received suggests disconnecting the screen grid and anode of the line output valve then bringing the set up with the line timebase disabled. This set also has VHF radio reception facilities; when selected the heaters for line and frame timebase and the video amplifiers are disconnected and replaced with an additional dropper. So, I think I'll try it first as a VHF radio as it means I can determine that the tuner, IF and sound stages work before working on timebases and video circuitry.

Attached are 'before' and 'after' pictures from my chassis-cleaning session, this involved isopropyl alcohol, Vanish bar, scouring cream, metal polish, toothpaste, toilet paper, dishcloths, an old toothbrush, a paintbrush and a large number of cotton buds... (I don't have a dishwasher...)

Regards, Kat

Heatercathodeshort 26th Sep 2006 8:42 pm

Re: Dynatron TV30CK
 
Hello Kat,
That is a very good job. The chassis is based on the EKco T330 with FM radio known as the T331.
The control panel has been rearranged from the side to the front. These sets give a really good picture and are very reliable.

After all these years the wax caps will all be leaky both mechanically and electrically!
The line output transformer CASE breaks down but yours certainly appears to be in very good condition.
The TV/FM switch can fail in spectacular fashion but by what you say, again yours sounds fine.

When you get it working you may find the contrast a bit low. The vision detector diode under a small screening can on the final vision I.F. transformer may have a heavy leak both ways.
Also the linearity coil on the back of the EHT 'box' [back panel] can slip down its former and short to chassis causing the U191 to spark and glow red....
It is quite O.K. to leave the metrosil out of circui - it has no noticeable effect on this model.

You can snip that goopy mains filter cap out of circuit to test the set. I would suggest you replace one component at a time, switching on after each replacement to avoid man made mistakes that can take some sorting out.
I have been there...Hope this might 'jump start' a few snags.

Regards
John


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