1970 Decca CS2611

Bradford 10 Chassis

Medium size Console – Kind donation from Gary of S.E London, otherwise it would have been off to the tip, so many thanks Gary!

Model: Decca CS2611

Year:1970

System: 625 Line – Hybrid

Original List Price : £000.00 ( to be ascertained)

Valves:
V1 PCL82 Audio Amplifier
V2a PCF80 V2a Frame Oscillator (t) V2b PCF80 Sync Separator (p)
V3 PL508 Frame Output
V4a PCF802 Reactance Valve (t) V4b Line Oscillator (p)
V5 PY500 Efficiency Diode
V6 PL509 Line Output

Transistors: 34

Integrated Circuit: 1 for the sound i.f. amplifier

CRT: 26″ Mullard A66 120X

General Info:

A single-standard hybrid chassis using 34 transistors and 6 valves, 1 I.C. used for the sound amplifier. The set has the much liked Bradford chassis.

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A bit of preparatory work to do before this gets introduced to power. In the past lets say someone was a little architectural with their component replacement. I won’t go into all the bodegery but needless to say you would be appalled at the amount and just how bad some of them were. Also its been twiddled with.

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Large blue electrolytic has broken free and a valve is missing

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someone thought resistor sculpting was a good choice here

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I spy some rather odd looking and large pre-sets on the decoder.

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Replacement decoder found that has the correct pre-sets

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Repaired and cleaned the PSU board, looking much better

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Powered on, degauss thump heard, followed by a nasty electrical fizzing/crackling sound coming from the area around the main transformer and smoothing block. Nothing visibly obvious made its presence to me, I didn’t like the sound of it so powered down fairly swiftly. Looking further into it by removing the frame output transformer reveals the smoothing C601/C602 2x400uF 350Vcan.

It seems to have a bit of electrolyte puking out of the top, well a lot really so I think that might have exploded before long. New one to be fitted then. I had a suitable spare albeit a tad large can, still it was a 400+400+100uF so would be ideal. I had to put a sheet of insulation card to make sure the Frame TX tags did not short out to the can.

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Powered on and hey presto this time the set cam up heaters lit and sound followed by a raster.

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I then connected a signal source.  As you can see the line frequency was way off.

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Managed to adjust L401 to bring that back to 15,625

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A bit of quick grey-scaling

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Colour was very slight and not a lot could be gained from the colour control knob. What I did get was odd, bubbles ( The Puppet ) in a pink top!!!!!

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Finding the bodger had twiddled the Ident coil and reference osc pre-set. A quick and dirty set up of these gets better colour lock.

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I have many faults to fix before I can go forward with a full installation set-up.

  • The Telefunken tuner needs removing to clean, its gooey and hard to tune.
  • The convergence clover has two busted controls so I cannot full static converge
  • The mains switch has been dangerously bodged leaving the chassis live when plugged in but switched off at the set, Guess how I found out about that!!!
  • There are many resistor bodges as mentioned that are frankly awful and lazy fixes by the past bodger, these all need to be addressed.
  • The colour control does not see to work colour is just on.
  • The sound is distorted at low levels, this is a known stock fault the fixes will be applied.

Amongst all this I was greeted with a frame collapse, this turned out to be V3 PL508 frame output valve sticking its boots in the air. A new one fitted restored the frame scan.

Update

Replaced the duff on/off volume control, this had been strapped and left the chassis live when the TV was switched off but plugged in. New pot sourced and fitted now the chassis is safe. I’ve also performed another grey-scale and a few other set-ups. The set is still running on almost all of its original components, as usual, fix-on-fail will be the order of the day.

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One thought on “1970 Decca CS2611

  1. The Decca Bradford had more stock faults than most. Tinny sound, that big cap down by the width control I seem to remember dried out, cut the line oscillator and fried the PL501 was it? And as for the smoothing cans, it was hard trying to keep their innards in! I think I began replacing them as a matter of course when refurbishing these….

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