HP w2338h goes black

[Daze]

I got HP w2338h that is doing the 2 sec to black issue.

What I have done:

• check the caps on the power supply with a inline ESR tester

I will update the post with pics when I get home.

[Daze]

Re: HP w2338h goes black

Pics

[jsog]

Re: HP w2338h goes black

Check the resistance of the inverter transformers.

Check the resistance between points in red and purple. Then check the other transformer, in green and blue. All four measurements should be very close in value.

[PlainBill]

Re: HP w2338h goes black

Check the resistance of the inverter transformers.

Check the resistance between points in red and purple. Then check the other transformer, in green and blue. All four measurements should be very close in value.

I doubt if that is going to work. The point in purple and the point in blue are the junctions of the two caps across the secondaries. Give yourself a Silver star.

Measure the resistance between the points in red. Measure the resistance between the points in green. Compare the two readings, they should match to within 3%.

PlainBill

[jsog]

Re: HP w2338h goes black

Doh--they're in series. I could've just said the two sets of points marked "7" and "8".

[PlainBill]

Re: HP w2338h goes black

Doh--they're in series. I could've just said the two sets of points marked "7" and "8".

Yeah, but by marking the pins with circles you can be sure the right ones have been used for the measurement. Murphy was an optimist.

PlainBill

[Daze]

Re: HP w2338h goes black

Both points measure 0.459

[alexanna]

Re: HP w2338h goes black

It is time to substitute some known good CCFLs,one at a time to see if you can locate a bad CCFL.
If you are lucky the repair may be as simple as repairing the solder connections to the CCFL bulbs.