[i]TDA3566[/i] ADVICE REQUIRED

[olly_k]

I have a Grundig CTV with (I hope) a dodgy TDA 3566P but I have been told the 'p' version is no longer available, with the only choice being a TDA3566 (not P). My supplier is unable to tell me whether this IC is compatible with the now obsolete version?
Anyone help me further?

 

[Nigel Goodwin]

I have a Grundig CTV with (I hope) a dodgy TDA 3566P but I have been told the 'p' version is no longer available, with the only choice being a TDA3566 (not P). My supplier is unable to tell me whether this IC is compatible with the now obsolete version?
Anyone help me further?

What is the fault with the TV?, and what chassis (CUCxxxx) is it?.

CPC at Preston are the UK distributor of Grundig spares, although Grundig themselves actually ceased trading last year.

 

[olly_k]

Hi Nigel, the telly is a 4410, and the fault started as a slightly green picture, but is now rather muddy and indescribable, although the picture is sharp. I initially thought it may have been the tube itself, maybe an internal short - cathode to heater maybe? but seeing as I don't know how to check for this (tried a megger at 500 volts without any results) I let the cathodes float which resulted in a nice blank screen.
I then checked the drive voltages to the base board which resulted in the green drive which appears to be stuck high.
I figured the only things next were either the RGB ic or the capacitors used to store auto black-level? these seem fine so I am hoping it is the ic itself. Although the possiblity of a knackered tube is still bugging me!
Anyway, I will check CPC out thanks never even occured to me LOL!
PS Hadn't heard that Grundig went under, I don't think they were the worst tellies out there by any means!

 

[Nigel Goodwin]

Hi Nigel, the telly is a 4410, and the fault started as a slightly green picture, but is now rather muddy and indescribable, although the picture is sharp. I initially thought it may have been the tube itself, maybe an internal short - cathode to heater maybe? but seeing as I don't know how to check for this (tried a megger at 500 volts without any results) I let the cathodes float which resulted in a nice blank screen.
I then checked the drive voltages to the base board which resulted in the green drive which appears to be stuck high.
I figured the only things next were either the RGB ic or the capacitors used to store auto black-level? these seem fine so I am hoping it is the ic itself. Although the possiblity of a knackered tube is still bugging me!

Try swapping two of the cathodes over, unsolder the actual pins of the CRT socket (obviously green and one of the others) and link them across to each other. If the CRT is still green it's the CRT, if it's the other colour it's the drive.

Anyway, I will check CPC out thanks never even occured to me LOL!

Grundig UK stopped supplying spares years ago, they sold the spares business to CPC.

PS Hadn't heard that Grundig went under, I don't think they were the worst tellies out there by any means!

The name still lives on, Dixon's bought the rights to it for the UK - actually a good few years before Grundig folded - they are using the name to replace their Matsui brand name, which everyone has now realised is total crap!.

 

[olly_k]

Try swapping two of the cathodes over, unsolder the actual pins of the CRT socket (obviously green and one of the others) and link them across to each other. If the CRT is still green it's the CRT, if it's the other colour it's the drive.

I remeber trying this, but by this time the green had turned to a rather muddy colour which mean't it was too hard to tell.
I shall maybe try again later and double check :roll:
PS. I assume letting the cathodes float isn't a very good test for internal leakage then? I have also heard that some CRT's can be damaged this way. can you elaberate on this please Nigel?
Thanks for your help I shall be back shortly!

 

[Nigel Goodwin]

Try swapping two of the cathodes over, unsolder the actual pins of the CRT socket (obviously green and one of the others) and link them across to each other. If the CRT is still green it's the CRT, if it's the other colour it's the drive.

I remeber trying this, but by this time the green had turned to a rather muddy colour which mean't it was too hard to tell.
I shall maybe try again later and double check :roll:
PS. I assume letting the cathodes float isn't a very good test for internal leakage then? I have also heard that some CRT's can be damaged this way. can you elaberate on this please Nigel?

I don't see how letting the cathode float could do any harm, but I wasn't suggesting doing that - I was suggesting swapping two of them over. So red becomes green, and green becomes red (or green and blue if you wanted). It proves if it's the CRT at fault or not.

 

[olly_k]

Sorry Nigel, I actually mean't that I had swapped the cathodes over but I can't remember what the result was, except for the fact that the colour of the screen had changed to 'muddy'. I can't remember the exact details it is one of those things that is taking forever at the mo due to lack of time etc...
I also held my meter to the floating caths (relation to chassis) and my other half reported that screen colours were quite normal. (tested one-by-one) I don't think she actually knows what 'normal' is lol but she did report that the green was quite green!
I shall try it again and come back with a clearer answer

 

[hotwaterwizard]

Here is the Datasheet if you need it.