How do I know for certain that an IPM is bad?

[Dang]

As above, I have an LG 50PC1D with a picture issue, well, no picture at all accept for a white fuzzy screen or a scrolling block on other AV channels, I'm quite sure from my research that it's the IPMs on the Y-sus but how do I test to be absolutely certain?

[Ltank]

Re: How do I know for certain that an IPM is bad?

They usually short out to ground. The silkscreen labels the pins

[tom66]

Re: How do I know for certain that an IPM is bad?

As above, I have an LG 50PC1D with a picture issue, well, no picture at all accept for a white fuzzy screen or a scrolling block on other AV channels, I'm quite sure from my research that it's the IPMs on the Y-sus but how do I test to be absolutely certain?

Sounds more like a Y-buffer fault.

SUS-IPM faults cause shorted Vs or blown fuse. Or in rare cases, a picture works but it flickers randomly, and a ticking is heard from the ER-IPM (this is probably the ER-IPM breaking down internally and a sign that it will pop soon, which may or may not damage the SUS-IPM at the same time.)

[Dang]

Re: How do I know for certain that an IPM is bad?

OK, so I've removed both the Y-sus and what I believe is the X-sus(opposing board), I've measured both IPMs on both boards and as far as I can tell they are fine, no shorts to ground, I'm not totally sure I've measured them properly so some help here would be appreciated. The buffer boards look fine from a visual point of view so yet again, how can I measure these to be absolutely certain? thanks again for the help, Andy.

[tw2005]

Re: How do I know for certain that an IPM is bad?

OK, so I've removed both the Y-sus and what I believe is the X-sus(opposing board), I've measured both IPMs on both boards and as far as I can tell they are fine, no shorts to ground, I'm not totally sure I've measured them properly so some help here would be appreciated. The buffer boards look fine from a visual point of view so yet again, how can I measure these to be absolutely certain? thanks again for the help, Andy.

I think the PC1 buffers have surface mounted FETs on the buffer boards, I'd check them and see if shorted

[Dang]

Re: How do I know for certain that an IPM is bad?

I think the PC1 buffers have surface mounted FETs on the buffer boards, I'd check them and see if shorted

Thanks, had a check and they measure normally. So I think the IPMs are OK, I'm not getting any shorts to ground except for the pin marked "NO", but if I use this to check all other pins then the numbers go back to normal readings, this is the same for both boards. All fuses are fine, no burnt components, PSU powers up just fine, so????? could the boards running along the bottom have some thing to do with it?

[tw2005]

Re: How do I know for certain that an IPM is bad?

I was thinking along the same lines as Tom. A pic would be handy. Could try isolating the lower buffer, run just the top one and then vice versa.

If you do, there's a cable that interconnects the upper and lower buffers together, disconnect that and the relevant cable from the ysus.

From memory these are a pain to work with, if it's the same setup as the 50PX5D

[Dang]

Re: How do I know for certain that an IPM is bad?

Thanks, the design will only allow me to run the top buffer alone as the signal cable is attached to that only, I'll give it a try now. I'll get some pictures too and yes, I think the design is the same.

[tw2005]

Re: How do I know for certain that an IPM is bad?

Yeah, I forget and not really a LG fan. I might be thinking of an old 42v6 or ?

That's all the ideas I have.

[Dang]

Re: How do I know for certain that an IPM is bad?

Yeah, I forget and not really a LG fan. I might be thinking of an old 42v6 or ?

That's all the ideas I have.

I must thank you again, one thing I thought was OK from the start, considering I had a full picture, were the buffer boards, I've disconnected the bottom buffer and I now have a good picture, albeit in the top half. So now my question is, how do I check the buffer board properly for a short? I've tested all the fets and quite a few of the other components and all seem fine to me(the fets test between 100 to 150 ohms), could it be a bad screen maybe or if this were true would it take out the buffers and Y-sus? thanks again, Andy.

[Alastair E]

Re: How do I know for certain that an IPM is bad?

The FETS should read O/C....

Only between S. G. may you have a lowish reading--but even then its usually about a K or so....

So--If you've got a vertical band that moves depending on picture content--The FETS are stuffed.

[Dang]

Re: How do I know for certain that an IPM is bad?

The FETS should read O/C....

Only between S. G. may you have a lowish reading--but even then its usually about a K or so....

So--If you've got a vertical band that moves depending on picture content--The FETS are stuffed.

Just found this which is exactly what's been hinted at and what you are saying, it's good info: http://blog.coppelltvrepair.com/2010...-lines-in.html, looks like some new fets are in order.