Samsung P2270HD/LS22EMDKU - 2s To Black

[AlbertRoss]

Sammy has a 2s to black condition, stays switched on, has image (flash light test) Capacitors are Sam Young of which I have not yet replaced. Have read about the 2s to black condition in the previous thread. Am I correct in thinking that even though the power supply board appears to be operating i.e stays switched on etc, it could still have some faulty capacitors?

[drpj23]

Re: Samsung P2270HD/LS22EMDKU - 2s To Black

Yes the power supply is working but the inverter portion is not.

2 sec to black can also be bad inverter transformer, diodes, transistors or caps.

Those caps though look relatively new but wouldn't be a bad thing to check them.

Did you look at this sticky?
https://www.badcaps.net/forum/showthread.php?t=10419

[retiredcaps]

Re: Samsung P2270HD/LS22EMDKU - 2s To Black

2 seconds to black can be

a) bad caps
b) bad ccfls
c) bad ccfl wiring (especially the return wiring)
d) bad secondary windings on the inverter transformer

More details starting with post #19 at

https://www.badcaps.net/forum/showthread.php?t=10419

Also, see budm's Inverter tester using old CFL

https://www.badcaps.net/forum/showthread.php?t=19987

PS. Your transformer should read around 1K according to

http://lcdparts.net/TransformerDetai...ProductID=3722

PPS. I love the fighter jets avatar.

[AlbertRoss]

Re: Samsung P2270HD/LS22EMDKU - 2s To Black

Re-checked component values once again. There are two identical value resistors close to T301 which are R301 and R302. The bands are brown/white/yellow which I read as being 190K. The actual reading on R301 = 0.377M ohms and R302 = 0.384M ohms.

If I'm checking T301 correctly, I have 000.2 ohms between primary windings, 0.761M ohms between one secondary winding and 1.073 ohms between the other secondary winding (as per photo)

[tom66]

Re: Samsung P2270HD/LS22EMDKU - 2s To Black

Do you perhaps mean 1.073k ohms between secondary readings? Very few multimeters measure down to milliohms. In which case, if one secondary measures 761k and one 1.073k, you have found the open secondary, it's the 761k one.

[AlbertRoss]

Re: Samsung P2270HD/LS22EMDKU - 2s To Black

Re-checked again and yes you are correct, should be 761K on one secondary and 1.073K on the other. Think my 'grey matter' is finally going!

Have to way up the costs of parts against buying a second hand board?

[tom66]

Re: Samsung P2270HD/LS22EMDKU - 2s To Black

Well, a transformer is pretty cheap IF you can acquire it, as they aren't always available.

[vinceroger69]

Re: Samsung P2270HD/LS22EMDKU - 2s To Black

http://www.chsinteractive.co.uk/elec...80-general.htm

[AlbertRoss]

Re: Samsung P2270HD/LS22EMDKU - 2s To Black

Thanks for the link!