Decca CP0711

[attenborough]

Can any one help. I am after a CP0711 service manual.
The TV has a 17" colour tube, and was made in 1980-1981. Any help with restoring the TV would be appreciated.

There is sound, some pics, but the EHT sounds like it is a 405 line TV, and the pic is just lines. With no signal there is snow (see pics). I know this is an IC set, but got her as the lady that I got her from bought it new in 04/04/1981. This is my DOB, and I want to enjoy her in my collection with my Sobell 405 line TV.

[Tazman1966]

Morning! From the pic, it looks like the line frequency is miles off. Sort that first and it looks like you may be in business.

[FERNSEH]

Decca 70 series chassis. This set was designed before the takeover of the company by Tatung in 1981. Very advanced circuit design for 1979, the year the 70 and 90 series was announced.

DFWB.

[Roberto41240972]

That looks like too much Horizontal hold

[attenborough]

Thank you all for the input. I downloaded the data sheet for the TDA 2571.

Looking at the info on the chip, there should be 12+ on pin 12 for horizontal this was 6.35v, and 12+ on pin 16 vertical this was 11.69v.

So the voltage was down on pin 16. I traced this back to a resistor which was 47 ohm. One side was 12.89v the other side was 6.35V. so removed and I found that to be very high, 470 ohm. A new one fitted and bang. I got the picture back, but it was all over the place with lines on the screen.

I took the electrolytic, caps out one by on and tested them. most were out. all of the ones that failed were made by Pye. Do these normally fail?

Once I replaced it there was a nice picture. The only thing to note is the contrast is low.

This is getting better the longer the set is on.

Also, does the TDA 2571 get hot? I am so concerned that I have put a heat shield on it to help cool it down.

[Nickthedentist]

Yep, a 70-series chassis. Brings back memories because I bought exactly the same set from a jumble sale in about 1990, for 10p as no-one else wanted it. Never seen one before or since.

The initial fault on mine was no tuning because the feed R to the 33v regulator was o/c.

The second fault was... the same as yours! ISTR electrolytic caps (and dry joints) were responsible so changed the ones round the chip, but I have to say I don't recall the TDA2571 running hot at all. Maybe others could comment? I would certainly change all the electrolytics in the area, they're not many (half a dozen at most).

Performance was good, though the set was very bulky compared with slightly more modern sets with the same tube size. It did look rather cute though, as it was like a lilliputian version of a 26" set. It was a rough contemporary of the Philips KT3 and Thorn TX9, and I think all 3 were compared in an article in Television magazine in about 1979. It went into my brother's bedroom, and I can remember it being on for long periods while he watched the darts and the Tour de France, while supposedly doing A-level revision.

Contrast on mine was lowish too, though perfectly acceptable with the contrast control at max. No flaring though. Toshiba tube?

Yours looks in VGC. Mine had lost a lot of its screenprinting around the controls. I do love those DeccaColour badges with the rich, painted coloured bars in the centre.

Nick.

[attenborough]

The condition is very good but I think this was due to 20 years of sig (cigarette?) smoke and fat from somewhere keeping all like new.

Warm soapy water and all of this came off but the water was black.
The lady had it in the corner from new, it was moved only once to have a new resistor fitted to the psu in 1985.

I have the repeats (receipts?)for the repair, and the first one from when she bought it for £250.

I also have the user manual and a do's and don'ts sheet.

the condition is very good. but i think this was due to 20 years of sig smoke and fat from some where keeping all like new. warm soapy water and all of this came off. but the water was black. the lady had it in the corner from new. it was moved only once. To have a new resistor fitted to the psu in 1985. I have the repeats for the repair, and the first one from when she bought it £250 wow . also have the user manual and a do's and don'ts sheet.

[AidanLunn]

I had a bid on this set, as did a fair few, because of its' design, even though its' a portable from about 1980, it *looks* like something 10 years older so it generated a fair amount of interest amongst those who hanker after early colour sets.

You are one lucky git

[attenborough]

i love this set. i just have to find any silly reason to go into my workshop and turn it on. i know what you mean about the the looking older aidanlunn. it does not look so out of place next to sobell t278 that i have. when the 10 khz whistle bust my ears. it is nice to have some thing else to watch

[Nickthedentist]

What sets it apart to me is that its case is chipboard and wood-effect vinyl, whereas everyone else was using moulded plastic cases for sets of this size by then.

Nick.

[Tazman1966]

I for one think it's a smashing looking little set. Well done!

[attenborough]

help!!!!!!! as she was on tonight. All of a sudden the frame collapsed. i have no idea what is going on with her. can some tell me where i can get the service data from so i can find this fault. or point me in the right direction on where to find the fault.

[AidanLunn]

It's a Decca 70 series chassis, so you'll need the service information for that model.

As for the fault, I'd place any capacitors, especially electrolytics, as first suspect. I'm not very familiar with TV sets beyond valves so I don't have any experience of this chassis, though.

If it's dry joints, then have you tried slapping it and gently lifting it a centimetre or so up and dropping it down? As you'll know, if that's the problem, then an inspection for dry joints and a visit with a soldering iron is in order.

[Nickthedentist]

Original paper manual for £3 + post here if you need it: https://www.vintage-radio.net/forum/...366#post740366

[FERNSEH]

I've still got some bits for the 70 and 90 series.

DFWB.

[attenborough]

sorry for not getting back. i had to work away this week. thank you all for your help. nickthedentist i have used the link and asked how to get the manual. Aidanlunn this is now what i have done. i did this for my sobel and it made her much more happer, as all were hunts. fernseh i will keep you in mind. when i get to the bottom of her. after thinking about it, the TDA 2571 was getting hot and i put a rad on it. and the one next to it with the rad was also very hot. when she is on there are no sound from the scan coils. you know the nice buzz they make. so this is leading me to the TDA 2571 and the one next to it have gone pop

[Nicklyons2]

I'm definitely 'losing it' - it looked like an 80 series to me - how memory plays tricks; better get out the manual and 'revise' I think.

[Nickthedentist]

Bizarrely, the 70-series is a much more modern set than the 80-series! No giant dropper resistor here, rather, a modern SMPS.

Nick.

[attenborough]

yes there is no big dropper on the tv. there is a early switch mode psu using the tda 2581 if i am reading the pdf files on the chip right. sorry if i got it wrong, i will hope fully be getting the service manual soon.

[Nickthedentist]

Originally Posted by Nicklyons2

I'm definitely 'losing it' - it looked like an 80 series to me - how memory plays tricks; better get out the manual and 'revise' I think.

You can't always tell from the outside.

There was a Deccacolour set being given away here a few months ago that I was certain used the 80-series chassis... until the OP pointed out it had valves!