"Pincushion" problem on Philips TV
 

I got this Philips TV from a school before christmas, and it works great, except for one little thing: There is some kind of picushion adjustment fail on it. Look at the screenshot, on the right side on the picture. Sometimes it is also visible on the left side. It is most noticeable when i use a high quality signal source, like a Playstation or a DVD player. It also depends a lot on the colors and brightness/contrast levels in the picture. I can not find any pincushion adjustment inside the TV, only H size, V size, H position, V position and so on. I suspect that the TV may have been droppen on the floor or something, and maybe the electron gun is knocked out of position. Or could there be something else? I do not think the TV is much used. It has a great sound system: 20 watts output power, bass reflex speaker system, separate bass and treble controls and audio line out. Maybe it´s not vintage yet (it´s from 1984), but it soon will be. By the way, does anyone know the model number? The label is missing.

welcome larschr!

I've never seen a philips like that before! See what we miss here in the states! :D
As to the pincushion problem, I would look in the vertical section of the chassis. There is a pincushion transformer and related circuitry that corrects this problem. It could be something simple like bad solder joints, faulty caps, or a resstor that has changed value. Worst case senario may be the pincushion transformer. Best bet would be to locate the factory service manual and start troubleshooting (yeah, i know better said than done.)

good luck. I hope you can get it fixed.

I looked at the TV today. As i don´t know the model number, it is difficult to get the service manual, so i just tested the capacitors with my multimeter, and i found 7 that had a considerably changed value. The worst was a 22uF that tested 1uF. I found a capacitor with the right value in a broken power supply, so i soldered that into the TV, and now it works much better. Now the pincushion is almost right, and the picture also became clearer. I will replace the rest of them when i get some money, and i hope to get the picture perfect.

Thanks for the help.

you will likely find many dried out caps in that set.cant really make out the parts but the pcc trans may be on the right board.
and a dried out cap can check fine with a capacity tester but be high esr which is bad too.

Another question: Is there any reason to check the "dry" (ceramic) capacitors? I have only checked the electrolytic ones.

Cermaic caps are extrealmy reliable. 99% of the time they never fail. The lytic caps are the most problematic ones because they dry up and can easily become leaky or shorted.

You can test them as though you would test an electrolytic cap, but I believ this is time not well spent as they rarely ever fail.

K 40 chassis Philips
 

hello, the tv you show in your pictures is an old Philips with chassis K 40/system 4 : It's a very reliable chassis except for solder joints. If you need the schematics I can do a copy and ship it to you.
Marco
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I replaced all the bad caps yesterday, and now the set works perfectly. Thanks for all the help.

Glad to hear you got it working right again :thmbsp: