Help needed with Granada TV

[GadgetM]

Hi,

I'm new to this forum, I'm not a tv repair guy, but I do have a few old models that I really like and what to keep going as long as possible. I have some electronic knowledge but it is limited (as is my test equipment).

I have a (1970's) Granadacolour TV, which has developed a frame collapse fault that I'm not quite experienced enough to repair without further assistance. I have kept the set going for years as any other faults it's developed over the years have been quite easy to diagnose and repair, but this one has beaten me. I changed the frame chip (TDA1170), it worked for 3 minutes, thought I'd cured it but then the new IC blew and left me with a single horizontal white line. Looks like something is causing the frame IC to blow, but can't find what.

The model is: C20TA5. All wood cabinet.

Does anyone know anything about this set? (make, year etc), or does anyone know where to find a service manual for this model?

Thanks

[Red to black]

Hi,

I don't know which set you have, or how the output stage is configured (does it have booster output transistors etc.), so this is just general guidance.

It will more than likely require electrolytic capacitor replacement, most likely around the flyback booster pins 3 and 5, usually 100uF @ 25-35 volts, or possibly excess ripple on the supply lines pin 2, or on the output pin 4.

Check for any dry joints and any short circuit silicon, diodes etc. and open circuit resistors

If you don't have the service manual for your set, then download the datasheet for the TDA 1170 IC (google it) from one of the many sites that offer free downloads.

I have listed the faults in order of most likely first, I hope this helps.

Ps. Elec. Caps are polarised, ie. they have to be fitted the correct way round, and are marked either + or - at one leg.

Cheers,
Baz

Added datasheet for TDA1170

[Red to black]

Hi,

Sorry, forgot to mention,

It will more than likely require electrolytic capacitor replacement, most likely around the flyback booster pins 3 and 5, usually 100uF @ 25-35 volts

This one usually destroys the IC when faulty.

Cheers,
Baz

[Michael Maurice]

From what I remember there are two versions of this IC TDA1170 and TDA1170S, they are not interchangeable.

[Red to black]

Re: Two types TDA 1170 and TDA 1170S

I think you are correct Michael,
the pinouts seem to be the same, and the same faults apply, but like you say, I don't think they are interchangeable.

Cheers,
Baz

[GadgetM]

Many thanks "Red To Black" and Michael for the advice. I took out the dead TDA7710 and replaced with an 1170S (as it was all I could find) and it lasted just 3 minutes. Possibly the "S" version not compatible as you say. However I'll probably replace all the electrolytics on the board to be safe. There's not that many. Pics attached

[HamishBoxer]

This looks like a Gec,dont remember many frame faults though supply caps as stated want changing at this age as would frame supply diode.

David GM8JET

X Granada Tech 1979---1986

[Red to black]

It does look like a GEC/early Hitachi, with the double sided print, but to which model I don't know

Was this

I took out the dead TDA7710

just a Typo ?, because I cannot find a datasheet for this number.

It is important to replace like for like, ie. whatever is in the set originally, replace with the same value/type/voltage etc.

Cheers,
Baz

[Tazman1966]

That board looks like it could be a variant of the GEC C2110 series but I'm certain that they used a pair of power transistors and a conventional driver transistor. Can we have another couple of pictures of the back of the set and it's panels in situ?

[Studio263]

It's a GEC Starline 20" with a Hitachi PIL tube. The larger (22" and 26") versions of this set used a 20AX tube and had some different panels.

When you refit the frame IC (TDA1170) make sure that the heat sink is well attached to the centre pins, you normally need a pretty big iron to do this properly.

[Red to black]

Hi Studio,

Does this set have booster transistors fitted on the main panel for the field output stage (as per the application notes) or not ?, or are these transistors (if at all fitted ?) only on the larger screen variants ?

I can remember one of the GEC Starline models (the one with the flimsy tinted control flap), but these sets looked much more modern than the Granada set belonging to the OP.

Cheers,
Baz

[GadgetM]

Hello all, thanks for all the advice and help so far, it's fantastic!

Apologies for the typo earlier, the original frame IC is indeed a TDA1170 (without the S). Thanks "Studio263" for identifying the set, I've been wondering what make it is for years, and yes the tube is a Hitachi, with a nice crisp/sharp picture.

I'll take some pics of the inside/back later in the week.

That heat sink on the IC was a pain to remove! (twice). I bought the 1170S innocently believing that it was interchangeable .

Cheers,
Meurig

[Peter.N.]

I had a lot of Granada sets with this GEC chassis out on rent. I may still have a frame panel somewhere.

Peter

[Andy Doz]

Originally Posted by Studio263

It's a GEC Starline 20" with a Hitachi PIL tube. The larger (22" and 26") versions of this set used a 20AX tube and had some different panels.

When you refit the frame IC (TDA1170) make sure that the heat sink is well attached to the centre pins, you normally need a pretty big iron to do this properly.

.... and don't stick heatsink compound underneath it !

I thought an 1170S would go in where an 1170 came out , but it was so long ago now.....

[GadgetM]

I've attached pictures of inside the back of the set (minus the frame board)
Does anyone know where to get a TDA1170? I've searched the net, and all I can find is the 1170S.

PETER.N. Do you know the value of the diodes (D351 and D352), the print on them is unreadable?

Cheers,
Meurig

[Andy Doz]

Try giving PJ Hill a ring on 01684 296902.

No connection other than a satisfied customer.

[davegsm82]

I'll have a look tonight if I remember, I think I might have one buried in a bag of 'junk' New in a 'Ferguson' blue and white box.

Dave.

[Peter.N.]

I can't read what is on the diodes, apart from being a bit grubby my eyesight is not that good. You can have the panel if you would like to pay the postage. It was in my 'good panel' store so it should be OK but I haven't used one in quite a while.

Peter

[GadgetM]

Thanks Peter, that's very kind of you! Just let me know the postage and how to go about it. I'll be away this weekend so won't be able to respond until monday evening.

Many thanks again,
Meurig

[Peter.N.]

PM or email me your address when you get back.

Peter