Dynatron TV48V.

[slidertogrid]

This is the third set rescued from Essex with the KB deep scene and the Ekco which went to Mick, (MickMcMichael).
Inspired by Mick's restoration of the Ekco I decided to have a look at the Dynatron and see if it is repairable and/ or worth keeping.
I put it in the shed until Mick got his set done in case he needed any major parts, Tube, LOPT Etc.
So This is it's final reprieve...The original owner told the builders to dump it, they were going to strip it out with an angle grinder and a hammer to sell the cabinet, then it could have been needed for parts to repair Mick's set.
Having survived all of these plot's against it it must be time to show it some kindness.
I fitted the valves from the bag inside it, only one valve was missing, this being one of the tuner valves, I found a suitable replacement snipped the filter cap and powered the set up slowly... 110v 5 mins.. full mains
I could see heaters on some valves but not others, I suspected one of the heater decoupler caps to be short and looked at the diagram to see which one it was lightly to be.
I then saw the Tv/Radio switch in the heater circuit! Switching the turret from the light programme resulted in the rest of the valve heaters starting to come on
After a while I had a low line whistle and low sparks from the top cap of the line output valves.
Looking around the front I just caught a glimpse of a raster before it shrunk and vanished.
The line whistle started to sound a bit strained so fearing for the already fragile looking Lopt I switched off.
Time to take the chassis out!
What a Job!
Dismantle the control panel on the side, remove the tuner knobs, release the 'handbrake' on the top of the chassis, remove the wing nuts and washers and then struggle and wriggle the chassis until it comes free! (Well that's how I did it!).
The cabinet is now safely back in the shed and the chassis on the dining room table!
It looks a bit grotty, I have tested the boost cap and it reads short so I will lash in a replacement later and see what happens.
Pictures of the set so far....
Rich.

[MickMcmichael]

Hi Rich

Will you perform "surgery" on the LOPT or leave it to dangle? I've some spare perspex if you need it!

The chassis looks relatively clean like mine. I wonder if these two sets were originally owned by the same person from new or was one bought as spares for the other in the long distant past?

Good luck with it, keep us all posted.

[HamishBoxer]

LOPT certainly deserves attention.

David

[Heatercathodeshort]

This is an Ekco T344/370/371 chassis. Plenty of notes on the Forum. The T330 is very similar for fault lists. The LOPT case will require a rebuild. The windings will be fine. John.

[slidertogrid]

Thanks Mick! I may well take you up on that...Unless I bring the lopt round and benefit from your previous experience.... (hint hint).
I want to get the set working as far as possible before I remove the lopt though, I have lashed a boost cap in it this afternoon and despite the state of the lopt cover I have EHT and can get a raster on the screen for around 5 mins.
There is no vision, the raster is folded up at the bottom and after it has on for a while the width comes in the line whistle becomes faint and the line output valve starts to "clink" as I guess it starts to overheat.
The tube looks fairly good though!
I am going to have to get on with this one, it was mentioned in dispatches this evening that the house is beginning to look like a junk shop (again)!
I think I will change the waxies around the line osc and output and try again.
If I can get the line stage running reliably I can then concentrate on getting some signals.
This is going to be more of an essentials only repair than a restoration but looking at the state of it there might not be much difference between the two!
I hope it doesn't try my patience like yours did! I still have the option of turning it into a rabbit hutch if it won't play ball
Thanks for the tip on the Ekco versions John I will do a search and see what I can find.

Rich.

[slidertogrid]

A bit more progress with the Dynatron, I changed some very sweaty looking waxies in the line stage which got the drive and output right in so much as the raster would now stay on with no straining noises.
I then had a poke around the I.f stage to see if I could get some signals.
The set is plagued with intermittent valve holders. I assumed the builder had removed the valves when he said he had made a start on stripping the set out.
I now think that the valves have been out of the set for some time which has caused the contacts in the holders to tarnish.
After a lot of cleaning of holders and valve pins I fitted a speaker transformer from a scrap record player amp and lashed up a test speaker.
I now have good sound and a picture of sorts, the line lock is jumping around and false locking, the frame is a little better.
The tube looks very good though so I will press on, if it had been flat I think I would be plonking it back in the shed!
The next challange will be the cabinet, the sad thing about it is that most of the damage looks recent, including the carving on the side!
Then I need to find a nice big speaker to fit it, I think my mate may have a scrap Hacker record player with something suitable, I could end up with a Hi-Fi Dynatron!
I am thinking the next step will be a recap of the remainder of the waxies,
Then a desision must be made as to what to do with the lopt, leave it as it seems to work or replace the cover and risk damage to the windings, the thought of those solder cups on fine wires is a bit daunting!
If the lopt had been in the state of the one in Mick's set I would have a go as I would have nothing to lose but mine works and does just about support the valve...
Rich.

[ppppenguin]

If the LOPT is anything like my T311 most of the wires are fairly thick. Only the EHT overwind is thin. I posted my T311 LOPT rebuild photos and notes a long time ago.

[slidertogrid]

Thanks Jeffrey! I had a look earlier at your repair of your lopt, if I could get mine as good I would be very happy!
I have made a bit more progress this evening and can now get a stable watchable picture.
The capacitors on the IF strip are still original as are two small Hunts that I have missed in the line stage.
The radio won't work yet and to be honest I doubt the TV side would if if wasn't for the signal level coming from the Domino?
It has suprised me that such a rough looking set has sprung into life without a lot more attention, I have had none of the resistor trouble that Mick had and all of the valves with the exception of two (one which was missing) are the ones that were with the set.
The tube is exceptional and really shows how good 405 line pictures can be, it makes my poor old TV22 look a bit poor!
I am tempted now to give the set a good run to see what faults show up before doing a full recap and then I suppose I will have to tackle the lopt
This telly collecting is getting addictive !

Rich.

[Heatercathodeshort]

Hello Rich,
A very nice approach to tackling this receiver. The tube certainly looks very good and I suspect it may only have been used to 'view the news'. The first picture shows the effect of a badly leaking sync coupling capacitor. Looks great so far. Regards, John.

[slidertogrid]

Thanks John,
I have taken a essentials only approach to this set, (mainly because I was keen to get it off the dining room table before it caused a domestic) but to be honest have enjoyed doing it bit by bit and seeing it come back to life. My first Tv restoration was a Tv 22 and I did a full recap before running it and it almost worked on switch on, spoiling all the fun!
So far the set still needs the lopt cover repairing and the last few waxies in the IF and video stage doing I think I read somewhere that there is one in the tuner, so that should be fun...
I decided to put the set back in it's box for the time being and run it to see what faults may occur.
The cabinet was very dirty and scratched so I set out to smarten it up a bit before bringing it back into the house.
It has responded well to a good clean and a few coats of Danish oil, the green painted mask for the tube cleaned up like new, maybe protected from the sunlight by the doors?
The doors were sticking and one would not open fully this was due to a build up of crud and an old fag end in the track!
The speaker cloth came up well and the brass trim cleaned easily with chrome polish.
The set produces good bright pictures, it knocks spots off my tv22, but there are a few issues to sort out, the first is strange but not really a fault with the set, if I play a dvd of old programmes that were (I assume) 405 lines originally I get a strange liney effect on the picture and the vertical lines have a slightly stepped look to them, this effect can be seen on the trombone in the first picture.
The aspect ratio is wrong from some dvd's and sky which gives the picture a slightly stretched look, but video tapes and the testcard are pretty much ok.
I am feeding the converter from the rf2 output from the sky box via a dvd/video player and adjusting the ratio on the box makes no difference to the picture. I will try it from the scart socket and see if that makes any difference.
The radio won't work but I suppose it may be more fussy about the old caps in the I.f than the tv side which is getting a lot more signal from the converter.
There are also flyback lines visible on scene changes and dark scenes. They can just be seen in the second picture, I don't know if this is down to remaining capacitors or not as Mick's set despite a full recap and a lot more work than this set has exactly the same lines.
On the whole though I am pleased with it so far, so much so that I have put my prized Dansette "Hi FI" (I know ) upstairs and installed it in the lounge...

Rich.