Telefunken TLCD-26J

[burntfingers]

On this old set, the six screen lights start flickering about four times a second, after 5 minutes on.
Already checked power supply for dry joints, swollen caps, used lectro freeze on caps - replaced a suspicious one - but problem persists.
Picture and sound normal.

[newtothis]

Re: Telefunken TLCD-26J

Bad lamps?

[burntfingers]

Re: Telefunken TLCD-26J

Thought about that, actually, but would one faulty one affect the other five?
I even thought about disconnecting one and see if the other five would go.
What do you think?

[budm]

Re: Telefunken TLCD-26J

There are 12 lamps, only take one bad lamp to cause the protection circuit to kick in.
Is the 24DC feeding the inverter board steady, this TV uses MAGMEET power supply which are known for bad caps.

[burntfingers]

Re: Telefunken TLCD-26J

OK, thanks.
Supplies are stable.
I also checked for sparking noise in the lamps or smelling [without stripping the assembly], but so far noticed nothing.
Using freeze didn't reveal anything wrong in the power board.
You might be right with one faulty lamp - sometime ago I had to replace a bad one that would trigger protection and shut off the lot.
Thanks again for the tip.

[budm]

Re: Telefunken TLCD-26J

You should also do the resistance checking of secondary winding of the inverter transformers, 12 of them.

[burntfingers]

Re: Telefunken TLCD-26J

You should also do the resistance checking of secondary winding of the inverter transformers, 12 of them.

OK, thanks; I will also do that this morning [Johannesburg time, here :-) ]

[burntfingers]

Re: Telefunken TLCD-26J

Well, after testing each of the six pairs of lamps - by replacing them with a good pair from another set - none revealed a fault.
I concluded it is the converters board.
Sadly, there are no spares for this set here anymore.

[Grunder]

Re: Telefunken TLCD-26J

Well, after testing each of the six pairs of lamps - by replacing them with a good pair from another set - none revealed a fault.
I concluded it is the converters board.
Sadly, there are no spares for this set here anymore.

Hi Burntfingers, just looked through my box of old inverter boards- no luck unfortunately. Living in Cape Town SA, thought I could courier one if I had one.

But did you do what Budm suggested- check the TRANSFORMERS. I have repaired a few inverter boards by replacing the transformers off other inverter boards. (obviously you have to match the ohmage on the secondary winding)

I've experienced transformers measuring okay, but failing to light lamps as well, and only responded when changing the transformer/s.