DER TD6213 Colour TV ("Green" Gone)

[Atiq]

This had given me a good service as a spare TV for the last 28 years. Still runs but the "green" is gone from the picture. It seems like that one of the colour transistors is gone. I know we are all going to be switched over to digital very soon but wondering if spares are still available for this model.
I could do with a service manual for this as well.
Any help?

[William YZF-R1]

Originally Posted by Atiq

This had given me a good service as a spare TV for the last 28 years. Still runs but the "green" is gone from the picture. It seems like that one of the colour transistors is gone. I know we are all going to be switched over to digital very soon but wondering if spares are still available for this model.
I could do with a service manual for this as well.
Any help?

Wow, I think I remember DER rentals from my youth. Did they let you keep the TV?

I would consider it a sign and trade it in it for a new TV.

[LicensedTaximan]

Blimey I remember them as well D=domestic E=electronic R=rentals, I believe that's what DER stands or should I say stood for. I think you need to go to an antiques road show for any spares....and even then.

[Atiq]

Thanks for your thoughts guys. I knew it would raise a few eyebrows when I posted. And yes DER let me keep it after a long rental period. Its like having a pet, difficult to part with. Any more comments from anyone else pl. I mean serious ones.

[mechanic]

There will still be spares available if only "equivalents".I think you will struggle for a service manual though. I also remember DER and many others-MULTIBROADCAST-RADIO RENTALS etc.Happy servicing days.I think most of the sets were fitted with Ferguson/Thorn chassis.Feel free to correct me though.

[NST]

Provided it's not a degaussing problem (can give the same symptom), you might be lucky, it might just be something simple like dry joints on the CRT plate. Inspecting the solder joints here would be a good place to start.

For a transistor fault, a lot of TV's used BF869 or BF871 (Philips) or similar transistors for each colour (RGB) gun, so you'd need to trace through to the Green amplifier. If the PCB has any lettering or colour coded wires, you can usually trace through to the correct area without any service data.
With service data you can cross reference any voltages (usually on test points dotted around on the PCB), which usually speeds things up a lot, but I don't recommend working on a live chassis for a beginner.

Also inspect any nearby resistors, potentiometers along the route (they can go 'open circuit'), and the cabling and connectors down to the chassis for any dry joints.
If it does turn out to be the output transistor, then replacing all three would be recommended.

[Atiq]

Dear Mechanic/ NST. Many thanks for your replies. I shall certainly have a look at the CRT plate first. I remember about three years ago, the picture kept going dim and ultimately disappeared. Re-soldered all the joints on the plate and it cured the problem.
However, this time around, it started about a couple of months ago that after switching on all three colours would be present. Then after a couple of hours viewing, the "Green" would disappear leaving the picture all red & blue. Give it a rest for about one to two hours and switching it back on, all three colours would be present for the next two to three hours. But since yesterday, the Green is completely phased out even at the start.
Does this information give rise to any more thoughts Guys?
Thanks once again for your input.

[NST]

I'd see if you can bring on the fault by gently tapping the CRT plate with something plastic (a ruler for instance). This is sometimes a good way to check for dry joints. Give the connectors a wiggle as well.

Of course do not touch any metal parts of the chassis whilst it is plugged in to a wall socket.

[Atiq]

Thanks for the instructions NST. Will try tomorrow.

[Atiq]

NST!
I had a chance to look at this set this afternoon. As suggested, tapped the CRT plate gently with a light plastic stick and after a flicker, the picture went back to normal. Tapped it again and green went missing. Took the plate off, removed all the carbon from the pins, resoldered the joints, put the plate back on and there it was, normal picture perhaps evevn sharper than before. It was well worth the effort.
Thanks once again for all your help and support.