Keracolor Decca 30 chassis - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

gec2110 · 20th Jun 2015, 12:52 pm

I cant believe what the test card looks like on your set.
That is smashing colour picture must have taken a while to get it like that .
The convergence pots in these sometimes burn up

bobbyball · 20th Jun 2015, 2:03 pm

You have done very well with your set so far. It's not to say of course you can't go further
especially as your set is a rare model and now in very good condition. Because it's your own set you naturally want it to be perfect!

The Decca hybrid chassis used in your set was never the easiest set to converge, not least helped by the convergence panel only having the "functions" of the controls and not a pictorial representation, though of course you do have the full manual.

The best I can suggest, and it probably is stating the obvious, is to (and again as you say) "evict" any suspect components, and especially the dreadful trimmers used to set the colour gains and balances amongst other things. Also if you haven't already, treat it to a new set of valves.

I have a box of various scan coils somewhere if you are looking for a replacement convergence unit, or anything else in fact to do with the coils...

slidertogrid · 21st Jun 2015, 2:39 pm

Many thanks for the offer, I will see how I get on. Some improvement to the frame linearity will be my next job. The linearity drifts as the set warms up, the top expands slightly and the bottom compresses. Adjustment is made difficult as the height pot is very scratchy and has so far not responded to switch cleaner.
I am hoping renewing a few capacitors and maybe the pots on the frame panel will sort things out. Most of the valves are replacements and seem Ok but I do have one or two spares if needed.
The last job which I will put off for as long as possible will be to strip the set out clean the inside of the cabinet and repair one of the top CRT mountings which has pulled through the plastic, repair the stand and the cracks in the rim. plus sort out the tuner and front panel mountings.
Someone has secured the top of the front panel with a self tapping screw through the front above the top tuner button. I want to make a tidier job than that, either doing away with the screw completely and filling the hole or possibly replacing it with a domed white nylon plug which would look neater.
To be honest the Keracolour was a bit of a spur of the moment purchase but I am pleased I did buy it now. I really enjoy working on a Decca 30 chassis again after all these years! It reminds me of when going to work was fun! and profitable.....

Rich.

20th Jun 2015, 12:52 pm	#21
gec2110 Retired Dormant Member Join Date: Feb 2008 Location: Croydon, London, UK. Posts: 408	Re: Keracolor Decca 30 chassis I cant believe what the test card looks like on your set. That is smashing colour picture must have taken a while to get it like that . The convergence pots in these sometimes burn up

20th Jun 2015, 2:03 pm	#22
bobbyball Octode Join Date: Jul 2011 Location: Stockport, Greater Manchester Posts: 1,215	Re: Keracolor Decca 30 chassis You have done very well with your set so far. It's not to say of course you can't go further especially as your set is a rare model and now in very good condition. Because it's your own set you naturally want it to be perfect! The Decca hybrid chassis used in your set was never the easiest set to converge, not least helped by the convergence panel only having the "functions" of the controls and not a pictorial representation, though of course you do have the full manual. The best I can suggest, and it probably is stating the obvious, is to (and again as you say) "evict" any suspect components, and especially the dreadful trimmers used to set the colour gains and balances amongst other things. Also if you haven't already, treat it to a new set of valves. I have a box of various scan coils somewhere if you are looking for a replacement convergence unit, or anything else in fact to do with the coils... __________________ Robert

21st Jun 2015, 2:39 pm	#23
slidertogrid Octode Join Date: Apr 2005 Location: Peterborough, Cambridgeshire, UK. Posts: 1,898	Re: Keracolor Decca 30 chassis Many thanks for the offer, I will see how I get on. Some improvement to the frame linearity will be my next job. The linearity drifts as the set warms up, the top expands slightly and the bottom compresses. Adjustment is made difficult as the height pot is very scratchy and has so far not responded to switch cleaner. I am hoping renewing a few capacitors and maybe the pots on the frame panel will sort things out. Most of the valves are replacements and seem Ok but I do have one or two spares if needed. The last job which I will put off for as long as possible will be to strip the set out clean the inside of the cabinet and repair one of the top CRT mountings which has pulled through the plastic, repair the stand and the cracks in the rim. plus sort out the tuner and front panel mountings. Someone has secured the top of the front panel with a self tapping screw through the front above the top tuner button. I want to make a tidier job than that, either doing away with the screw completely and filling the hole or possibly replacing it with a domed white nylon plug which would look neater. To be honest the Keracolour was a bit of a spur of the moment purchase but I am pleased I did buy it now. I really enjoy working on a Decca 30 chassis again after all these years! It reminds me of when going to work was fun! and profitable..... Rich. __________________ The rotation of the earth really makes my day...