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CTV Decca CS2632

Colour Television

Last Post by Jayceebee 1 month ago

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The_Teleman

(@the_teleman)

Posts: 282

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I had this rather gorgeous Decca CS2632 in for repair this week now I don’t normally take on repairs for other people but this set grabbed my attention due to the fact it was such a gorgeous cabinet and I had never seen one in this style before

the set is a basic Decca 30 Bradford chassis with the usual 5 button telefunken mechanical tuner

the complaint was bright red raster , now this set is far too big to put on the bench so I removed the chassis and fitted it in my 20” 2030 to make things east to work on

on first switch on the raster was indeed red and quickly diagnosed as TR17 BF258 being short circuit a replacement cured the fault immediately as expected now while I had the set in a working condition I decided to do some service work on the chassis to improve the reliability a bit

the usual replacement electrolytic capacitors had all been replaced by another engineer at some time recently so had some of the convergence controls so not a great deal to do apart from the boost capacitor and a couple of capacitors in the line oscillator

my attention was quickly drawn to the excessive width and the inoperative width control so the usual width resistors were replaced R254A & R254B both 820k ohm and also R450 5.6meg this brings back into operation the width control but still too wide then I noticed the set had a replacement loptx fitted at some time any the earth lead from the tripler was on the wrong point as a rule this is normally on the black ground pin of the lopt so I suppose it was fitted that way to compensate for the width control not working, fitting this back to it’s original place restored Norman adjustable width .
th next to be checked was the high wattage resistors around the line osc as I recall R443 & R444 can and often do go high in value now I’ve had R444 go high ent to cause the PL509 to go red plate while still giving a reasonable picture this was found to be high at 70k ohm rather than it’s normal 33k so was replaced

a good setting up was all that was required after the service work and it gave a lovely picture on my 20” crt

now to refit in its own cabinet

again setting up to its larger crt with some convergence adjustments gave excellent results

All back together ready to be collected

Posted : 17/12/2024 12:14 pm

Nuvistor

(@nuvistor)

Posts: 4708

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@the_teleman Some of the early CTV’s could give a really good account of themselves.
Great work.

Frank

Posted : 18/12/2024 9:25 am

Jayceebee

(@jayceebee)

Posts: 2131

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Very nice. The Bradford was a nice little side income for me, back in the day usually the 0.1uF across the mains, the boost capacitor and occasional LOPT.

John.

Posted : 18/12/2024 11:24 am