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Old 1st Nov 2018, 8:44 pm   #21
Colourstar
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Default Re: Decca DM4/C

I've now re-capped the Decca, which didn't particularly bring about any spectacular improvements but I think those black Hunts caps are better out than in. The smoothing seems to have sorted itself out now, with the gentle undulation affecting the picture now gone.

I must say I'm hugely impressed with the stability of the picture. It's rock solid under all circumstances. It really is a pleasure to watch.

I will re-unite the chassis with its cabinet this weekend, although sadly it lets the side down somewhat with it's chipped veneer.

Steve
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Old 1st Nov 2018, 8:50 pm   #22
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Default Re: Decca DM4/C

That looks first class, Steve! I guess you have spent some time tweaking the line & frame linearity, size etc. to get it spot on.
How hot does the LOPT get on this one?

Good work!

Cheers
Nick
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Old 1st Nov 2018, 8:57 pm   #23
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Default Re: Decca DM4/C

You`ve done a great job with that decca steve.
That crt looks really healthy and the test card is excellent.
You got to make the cabinet look nice now.
I`m sorry to say I scrapped one of these perhaps 20 years ago but think I`ve still got the tambour doors.


Robin
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Old 1st Nov 2018, 10:33 pm   #24
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Default Re: Decca DM4/C

Hi Nick

Careful tweaking of the ion trap magnet made a huge difference to the brightness of the picture. As for the crt, Midland Tubes did a good rebuild back in the day! I've not checked the LOPT to see if it's getting hot, but there's plenty of width and no signs of distress.

Hi Robin

I wonder if your salvaged doors are any better than mine...!

Steve
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Old 2nd Nov 2018, 12:00 am   #25
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Default Re: Decca DM4/C

I`ll have a look over the weekend and yes they were in much better condition.


Robin
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Old 2nd Nov 2018, 10:34 am   #26
bill knox
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Default Re: Decca DM4/C

Before you try to reinsert the chassis, make sure that the clamp around the tube is tight, I have seen where, even when the TVs were going through the factory the tube slides forward then touches the safety glass and gets scratched in the centre.
It may also pay that while the chassis is out, to remove the 3 little screws from the thin piece of wood on the outside of the top of glass and remove the safety glass as over such a long period the glass maybe stuck in place, this will help if dust falls down inside and save you having to take the chassis out again, give the tube face and the glass a good clean and then reinsert the chassis, if the mask (that's the plastic/rubber/wood surround that is fixed to the cabinet, is dirty I am not sure what you could do to clean it
I know that when we did our final inspection on the set in the factory we were very careful not to touch it as fingerprints were difficult to remove, and clean the inside of the cabinet of all the dust, etc.

Bill

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Old 2nd Nov 2018, 2:41 pm   #27
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Default Re: Decca DM4/C

A lovely set both in design and construction. I obtained an ex-rental one from work in the early sixties when I lived 'at home'. After fettling the tuner, and a noisy volume pot and a boost(? I think, but can't quite remember) cap., it continued to work without futher major attention for, IIRC the next seven/eight years. First class picture in every respect. Replaced only when a similarly cheap colour set became available.
Hope yours gives similar sterling service after that substantial overhaul, Steve. Well done! Tony.
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Old 2nd Nov 2018, 8:35 pm   #28
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Default Re: Decca DM4/C

Hi Bill

Thanks for the tips. I will check on those points you mention. The crt faceplate and inside of the safety glass were both very sooty but have been given a wipe and a polish.

Hi Tony

Glad the set revived some happy memories. One slight irritation with the design is that the rather fiddly inner knob on the left is for volume, whereas the outer is on/off/brightness. On most sets these were the opposite way around. It seems more of a pain to set the brightness every time you switch on, rather than the volume. Still, all part of the period charm I guess!

Steve
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Old 4th Nov 2018, 9:27 am   #29
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Default Re: Decca DM4/C

Just to conclude this thread, the Decca is now back in it's shabby old case and working very well indeed. I'm not sure what to do with it next to be honest. If anyone fancies taking it on and restoring the cabinet then let me know!

Steve
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Old 4th Nov 2018, 12:17 pm   #30
Peter.N.
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Default Re: Decca DM4/C

Used to service quite a lot of those 'back in the day'. Looks like an excellent CRT and almost 3mhz bars!

Peter
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Old 4th Nov 2018, 12:33 pm   #31
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Default Re: Decca DM4/C

wish I could take it on but think my house mate would go nuts. I had one of them many years ago and it was a lovely set. I can't remember why I eventually stripped it out but my aunt used the cabinet for years as a cupboard not sure what happened to it in the end though
Steve
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Old 4th Nov 2018, 9:03 pm   #32
FERNSEH
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Default Re: Decca DM4/C

Only one grumble about the design of the Decca DM4/C. The frame sync consists of a simple resistor and capacitor integrator, there is no pulse clipper circuit to remove the presence of line syncs among the 20mS frame sync pulses.
However, with careful adjustment of the frame hold control good interlace is possible.

DFWB.
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Old 5th Nov 2018, 8:47 pm   #33
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Default Re: Decca DM4/C

Hi Steve ,
The weekend didn`t work out like I expected so no news of the tambour doors yet but I wont forget.
By the look of your pictures the doors are the worst part of the cabinet.

Robin
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Old 13th Nov 2018, 8:54 pm   #34
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Default Re: Decca DM4/C

Hi Steve , Well I finally sorted out these tambour doors for the decca.
Because I`ve had these for so long I cannot remember for sure if they did come off a decca tv so I`ll give you the measurements for you to compare against your set.
17 1/4" (438mm) from top to bottom plus a little to go in the runners and each door 12 1/2" (317mm) long.
They are in nice condition as you can see in the picture.

Robin
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