Philips 107S61 (CRT) power supply problem

[microcont]

Hello,

here I have an Philips CRT monitor and when turn in power ,relay in power supply starts clicking. Section around flyback transformer doesn't have voltage on tranzistors.What could be problem and how to find it?
Capacitors all look fine and on primary side is voltage fine.
thanks for help!

[stj]

Re: Philips 107S61 (CRT) power supply problem

get a service manual.
you need to isolate the B+ line from the line-output transformer or remove the line output transistor.

then you can power up the psu to test without having the 16-20Kv supply running.
B+ should be between 70 and 140v.

if the line output transistor or transformer shorts you will see the psu section pulsing with a ticking sound.

[microcont]

Re: Philips 107S61 (CRT) power supply problem

I removed the line output transistor but the problem is still there, i think that is not worth of time to repair!

[Agent24]

Re: Philips 107S61 (CRT) power supply problem

Does the relay click in a consistent pattern or randomly? If it's consistent, the PSU may be power cycling. Check for shorted parts in the PSU. If it's random, could be bad solder joints.

[bigjohn22]

Re: Philips 107S61 (CRT) power supply problem

Before anything give it a good clean.

[microcont]

Re: Philips 107S61 (CRT) power supply problem

Yes relay click in a consistent pattern

[Agent24]

Re: Philips 107S61 (CRT) power supply problem

Then I'd treat it as a power cycling problem, unless someone else can suggest otherwise.

Look for shorted rectifier diodes in the PSU secondary, Bad electrolytic capacitors in the PSU control section (and\or outputs), something wrong in the feedback circuit possibly.

And yeah, clean off the dust...