Toshiba 37" inverter board failure

[budm]

Re: Toshiba 37" inverter board failure

hmm nevermind i read the leads are supposed to have resistance most ppl get .4 to .8 i get 1.2ohm (thanks harbor freight) so im told just subtract the resistance reading from my measured readings i hope thats correct

That is correct, so what ever you read just subtract 1.2 Ohms from the reading.

[whatusername]

Re: Toshiba 37" inverter board failure

hey bud can u do me a favor? where exactly on the board am i supposed to put the probe? there is a big green trace next to cn65 with 2 little copper choles in it and then theres also the solder pads next to them but they are not the same. so can u pin point exact location i put the probe?

[budm]

Re: Toshiba 37" inverter board failure

OK, put one probe on any one of the Vias, then use another probe to find the <1 Ohm resistance on the component.

[whatusername]

Re: Toshiba 37" inverter board failure

ok good that has been what i was using i just had to verify... also like in the other thread am i looking for 3 pin and 8 pin or am i going to test everything?

[budm]

Re: Toshiba 37" inverter board failure

Try the 3-pin and 8-pin first, it should not be very far from the pad I marked.

[whatusername]

Re: Toshiba 37" inverter board failure

ok will post back the results

[whatusername]

Re: Toshiba 37" inverter board failure

on the first thing i probed the top 3 legger by c7570 i get 1.2 ohm and meter resistance is 1.0 now so that means that 3 legger is giving me .2 ohms

[whatusername]

Re: Toshiba 37" inverter board failure

this one

[budm]

Re: Toshiba 37" inverter board failure

Boy, I hope it is the right one, it looks way too small to handle the current.
Turn the TV on and test the DC voltage on all the pins.

[whatusername]

Re: Toshiba 37" inverter board failure

actually bud i have multiple giving me the same reading i already found 5 of them and im sure there will be more.. are u sure the vias is the correct testing point?

[budm]

Re: Toshiba 37" inverter board failure

Yes, they are on that big copper trace to handle the current, that is why I am surprised when I see the picture of that small device.

[whatusername]

Re: Toshiba 37" inverter board failure

ok here are the first 4 with tv on

the 2 three leggers where i circled are 3.3 single leg 0v dual legs on both
ic931 8 pin bottom side 9.8 18.3 9.1 0 top 3.4 7.8 1.9 .8
ic 108 8 pin bottom 1.8 3.3 3.3 .9 top .9 .9 .9 0

[whatusername]

Re: Toshiba 37" inverter board failure

ic901 8 pin top .7v 0v 0v 12.3v
bottom .5v 5v 3.1v 3.1v

[whatusername]

Re: Toshiba 37" inverter board failure

not what we are looking for? those are the closest to the cn65... do u want me to test more?

[budm]

Re: Toshiba 37" inverter board failure

IC901 looks promising, Can you get the P/N? Also pin is connected to those Vias?

[whatusername]

Re: Toshiba 37" inverter board failure

i can get part number but how do i find out if pin is connected to the vias? do i need to remove the board and follow the trace?

[whatusername]

Re: Toshiba 37" inverter board failure

Z1017aI

[whatusername]

Re: Toshiba 37" inverter board failure

http://pdf1.alldatasheet.net/datashe...AOZ1017AI.html

[whatusername]

Re: Toshiba 37" inverter board failure

ALSO IC921 Part# MP1591DN http://pdf1.alldatasheet.com/datashe.../MP1591DN.html

voltages are BS 8.9V, IN 12V, SW 5.3V, GND 0V, REF 4.9, EN 4.9, COMP 1.1, FB 1.2

PAD = GND CONNECTED TO PIN 4 ALSO WITH OHM METER AT 200 I GET 1.2 OHM ON PIN FOUR - 1.2 = O OHM

[whatusername]

Re: Toshiba 37" inverter board failure

update to post 53

ic901
Z1017aI 8 pin

FB .7v AGND 0v PGND 0v VIN 12.3v
LX.5v LX 5v EN 3.1v COMP 3.1v
both of this chip pins agnd and pgnd give me 1.3 to the vias in 200 ohm setting so reading is .1 ohm
Apparently the gnds are connected to the trace by CN65 on both chips