Toshiba 22EL83G fixed for 5 mins :)

[magneh]

Hello!
Got this set with no power.
Opened it and found that 1 diode was shorted and other 2 were also doubtfull.
Well, removed all 3 and replaced them.
Set turned on red led, I pressed power and it blinked several times but turned on. Not bad.
I connected the set to the antenna and started the auto tune.
Maybe 3-4 minutes passed, and when I looked back to the TV she was Off. No red pilot led, nothing.Dead as in the beginning.
Opened it again and 1 of the new diodes was burned. Removed all three and it was just the brown one that is shorted.
I lifted L702 and mesured it. 0.05 ohm . is it OK?
In the schematic L702 is labeld "1u". What does it mean?

Here are some pics and schematic .

Hope to hear from you guys.

[budm]

Re: Toshiba 22EL83G fixed for 5 mins

That L702 (1u = 1 micro Henry) is just very low DC resistance inductor, part of the power supply PI filter (Capacitor-Inductor-capacitor).
What type of the diodes did you use as the replacement? It can be that the load connected to the 12V output is drawing too much current.
12V is used for audio, and audio power amplifiers.
24V is used for backlights inverter.

[magneh]

Re: Toshiba 22EL83G fixed for 5 mins

That L702 (1u = 1 micro Henry) is just very low DC resistance inductor, part of the power supply PI filter (Capacitor-Inductor-capacitor).
What type of the diodes did you use as the replacement? It can be that the load connected to the 12V output is drawing too much current.
12V is used for audio, and audio power amplifiers.
24V is used for backlights inverter.

Hello!

The original one were 2 SB5100 and 1 SB5B0.
At the store they gave me 3 BY253 as equivalent.
So L702 is ok. Should I check some resistors? All caps appear to be OK.
The 5 mins the set worked there were no sound or image issues...

[tom66]

Re: Toshiba 22EL83G fixed for 5 mins

BY253 is not an acceptable replacement for SB5100, this will be why it failed.
Use UF5402 or SR3100.

Replace all 3 diodes with same type from same reel.
Use thermal adhesive or settable thermal paste to thermally bond diodes (modification to improve reliability)
https://www.badcaps.net/forum/attach...1&d=1414018048

This power supply is junk and built to fail...

[budm]

Re: Toshiba 22EL83G fixed for 5 mins

Yep, the BY253 is just generic Silicon rectifier, not for this circuit application in switching power supply rectifiers.
https://cdn.badcaps-static.com/pdfs/...634af85168.pdf

[magneh]

Re: Toshiba 22EL83G fixed for 5 mins

BY253 is not an acceptable replacement for SB5100, this will be why it failed.
Use UF5402 or SR3100.

Replace all 3 diodes with same type from same reel.
Use thermal adhesive or settable thermal paste to thermally bond diodes (modification to improve reliability)
https://www.badcaps.net/forum/attach...1&d=1414018048

This power supply is junk and built to fail...

Well gonna swap them ... went to a store I never went before, and I trusted the guy blindly ... never again.

I'll post result with new ones.
Thanks for the inputs.
Cheers!