Toshiba 37" inverter board failure

[whatusername]

Re: Toshiba 37" inverter board failure

ok so does that mean i still have to remove those 2 teeny tiny smd caps that i can barely see?

[whatusername]

Re: Toshiba 37" inverter board failure

DE90 is part of buck converter, the IC will be damaged if it operates without that diode (the substrate of the IC will become the diode which will be bad for it.)

oh damn ok so what do u guys want me to do?

[tom66]

Re: Toshiba 37" inverter board failure

If the short is gone with that diode out ... did you check the diode was actually shorted?
If the diode is shorted that is the point when you find or order a replacement diode and replace it, then test the TV.
Don't try it without the diode.

[whatusername]

Re: Toshiba 37" inverter board failure

well i dont think its bad i get a reading of 175 in 1 direction and dmm says 1 on other direction

[tom66]

Re: Toshiba 37" inverter board failure

That sounds OK, so do you still have a short on the board?

[whatusername]

Re: Toshiba 37" inverter board failure

no short when de90 and de91 is removed reinstall de91 and short comes back de90 still removed

[whatusername]

Re: Toshiba 37" inverter board failure

guess i will remove the 2 caps now

[tom66]

Re: Toshiba 37" inverter board failure

So is DE91 shorted out of circuit?

[whatusername]

Re: Toshiba 37" inverter board failure

no in circuit i didnt test it out of circuit but will do now

[whatusername]

Re: Toshiba 37" inverter board failure

yes it is shorted out of circuit too


but that dont explain how come i still had a short when it was removed

[whatusername]

Re: Toshiba 37" inverter board failure

reinstalled de90 and installed it shorts both ways so theres still a short and de91 is still not installed when this happens so which cap should i remove first?

[whatusername]

Re: Toshiba 37" inverter board failure

removed ce92 still shorted going to remove ce901 now de90 still installed

[budm]

Re: Toshiba 37" inverter board failure

"no short when de90 and de91 is removed reinstall de91 and short comes back " and "but that dont explain how come i still had a short when it was removed" I am totally confused now.

[whatusername]

Re: Toshiba 37" inverter board failure

ok if i remove de 91 alone i still have a short if i also remove de90 then the board does not have a short anymore . de 91 is shorted both directions out of circuit de 90 is fine out of circuit.. de90 shorts in circuit with de91 both out and in circuit. if i leave de90 out and just put de91 back in i have a short again. i now have de90 back in de91 is out ce92 and ce901 are out and i still have a short

[whatusername]

Re: Toshiba 37" inverter board failure

so all thats left is the ic i know for sure de91 is bad but i still short with it and the 2 caps removed and de90 in so the ic has to be causing it because if i also take out de90 no more short but de90 tests good

[whatusername]

Re: Toshiba 37" inverter board failure

still confused?

[budm]

Re: Toshiba 37" inverter board failure

If the IC is shorted, then this will not make sense "if i also take out de90 no more short" If everything are removed except the IC and the shorts is gone then it can not be the IC that is shorted.
We know that DE91 is shorted and you had verify it as shorted in/out of the circuit. So what resistance do you get when DE90 is in, <1 Ohm?

[whatusername]

Re: Toshiba 37" inverter board failure

ok am going to remove de90 again and retest.. all that will be left in board is the ic

[whatusername]

Re: Toshiba 37" inverter board failure

ooops sorry had the meter in diode mode lol ok with de90 in and ic in and nothing else there is no short

[whatusername]

Re: Toshiba 37" inverter board failure

so i will replace ce92 ce901 and de91 just cuz they are already out problem is i dont know what to order