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Equipment Repairs => LCD TV forum => Topic started by: davenjax on February 20, 2012,14:13:32

Title: megmeet mlt198l
Post by: davenjax on February 20, 2012,14:13:32

hi guys has anybody worked on this psu before ?? tv is completley dead this is a charitable job im doing as is most these days so any pointers would be appreciated or does anybody have a functioning psu for sale ?? cheers .dave

Title: Re: megmeet mlt198l
Post by: fix2003 on February 21, 2012,03:22:09

circuit if needed

Title: Re: megmeet mlt198l
Post by: tv tony on February 21, 2012,06:50:31

This manual looks lethal in the wrong hands, but if if its all you have ok. check r39/40, these are start ups, please note they are unmarked, they are 334k, it usually cures it, get your 5v up first, note you are working on the primary side of the psu, then if no good power up the ic with ext 5v, WARNING NON ISOLATED

Title: Re: megmeet mlt198l
Post by: Eddy on March 04, 2012,23:37:37

Hi guys, I wanted to report on my success.
I found an ILO LCT42HA36 with a bad power supply, I found this thread through Google and thanks for the schematic!
This TV has the Megameet MLT198L PS and it had no +5v standby voltage, T1 has 170vdc on its primary, but nothing on the secondary, very similar to the above issue, my resistors R39 R40 and R41 are OK, noticed a cooked area surrounding Z5 which is in the same circuit as IC2 which the resistors lead to. I dont have an Oscope, and Z5 buzzes out OK, but I thought id change it anyways, this fixed it. Must not have been able to keep up with the clock and pulse T1 enough to produce anything on its secondary.
Now all seems OK, thanks again!

Title: Re: megmeet mlt198l
Post by: Aa8ron on May 02, 2012,12:26:23

Would you be willing to share the value of the Z5 diode you replaced?  I removed the one from the board I'm working on, and I can't get anything off of it to identify the value.  Thanks in advance for any help you can provide.