BUSH 22" TV kEEPS BLOWING INTERNAL FUSE

[garrymc123]

Hi Guys i got this tv from a friend to see if i could fix it for him he said he plugged it in and it went bang so i opened it up and noticed a resister with a chip on it so replaced it and also q1 which was shorted ( circled in red ) which is a FQPF8N60C transiter so replaced that and also two diodes (RL205 ) which was testing both ways so replaced them it its still blowing the fuse any ides guys any help much appreciated

[dick_barton]

Re: BUSH 22" TV kEEPS BLOWING INTERNAL FUSE

What is the part number on IC1 on the underside of the power supply?

[garrymc123]

Re: BUSH 22" TV kEEPS BLOWING INTERNAL FUSE

Cheers Dick_Barton its a js2269sp

[dick_barton]

Re: BUSH 22" TV kEEPS BLOWING INTERNAL FUSE

I can't find any information on it but maybe someone will be able to.

[R_J]

Re: BUSH 22" TV kEEPS BLOWING INTERNAL FUSE

Were all three legs shorted on Q1 fet, if they were its a VERY good chance the ic is bad. ic's don't like 160v on gate drive pin.
Seems to be same as OB2269

[garrymc123]

Re: BUSH 22" TV kEEPS BLOWING INTERNAL FUSE

I couldn't find any info either on that chip. I will check tonight when I get home and check for short on pins and let you guys know cheers

[Andrew F. Ali]

Re: BUSH 22" TV kEEPS BLOWING INTERNAL FUSE

Looks like JS2269 to me or is the J an O with part of the print missing?

[garrymc123]

Re: BUSH 22" TV kEEPS BLOWING INTERNAL FUSE

Hi Guys have tested the ic1 and no shorts found but I have found that I have continuity on cap 1 is it because its a 400v cap on the primary side the multimeter has continuity on this cap?

[budm]

Re: BUSH 22" TV kEEPS BLOWING INTERNAL FUSE

Hi Guys have tested the ic1 and no shorts found but I have found that I have continuity on cap 1 is it because its a 400v cap on the primary side the multimeter has continuity on this cap?

How did you go about testing for shorts on that IC?
What resistance do you see on the main filter cap?
The replacement MOSFET still tested OK?
When that MOSFET shorted out it will more likely take out the IC at the same time, and if IC output stuck high it will cause the new MOSFET to be stuck on and will blow the fuse and may also damage the new MOSFET.

[Andrew F. Ali]

Re: BUSH 22" TV kEEPS BLOWING INTERNAL FUSE

how did you go about testing for shorts on that ic?
What resistance do you see on the main filter cap?
The replacement mosfet still tested ok?
When that mosfet shorted out it will more likely take out the ic at the same time, and if ic output stuck high it will cause the new mosfet to be stuck on and will blow the fuse and may also damage the new mosfet.

+10

[garrymc123]

Re: BUSH 22" TV kEEPS BLOWING INTERNAL FUSE

Hi Guys Yes all three legs shorted on q1 I tested ic1 with continuity on each pin and had no bleep on the meter and I'm getting 000.9ohm resistance on the main cap I have just rechecked q1 and all three legs are shorted again and I'm getting continuity on all three pins from q1 to pin1 which is ground on ic1 ..Will I replace q1 and ic1 and take it from there is there anything else I should check and also what will I replace ic1 with if I can't find any info on it.. will OB2269 do the same job .. Thanks in Advance

[budm]

Re: BUSH 22" TV kEEPS BLOWING INTERNAL FUSE

Need to check for any damaged parts (resistors, diode) between the Gate of the MOSFET and the Gate drive pin of the IC.

[garrymc123]

Re: BUSH 22" TV kEEPS BLOWING INTERNAL FUSE

Hi Guys did a couple of checks on the power board I'm going to replace the main filter cap as it's out of range and also ic1 and q1 q1 was shorted on source and drain i can't find anything else wrong checked all the smd caps and none is shorted how would I check the smd resistors. Thanks in Advance