Memorex MLT3221 - No Power

[shorteddiode]

Re: Memorex MLT3221 - No Power

It tested good but I guess changing it is worth a try, I don't have the 5sbv or any voltage on CON3 I guess it just shut down while they were watching it. After seeing all the bulging caps I can understand why. But changing all the caps didn't seem to make a difference. Changing D10 today, I'll let you know what happens

[shorteddiode]

Re: Memorex MLT3221 - No Power

I finally gave up and replaced the power board. Fixed the TV
Thanks for the help

[fred0927]

Re: Memorex MLT3221 - No Power

Thank you guys, i've been reading the forum for a little while because i have a momorex tv with the same power supply like Dgtech and the same problem so i decided to replace diode
d10 and that was it. Tv working perfect now. Thanks again.

[CR Designs]

Re: Memorex MLT3221 - No Power

It was my mistake, you were right about the part number. I checked out those components and found that they were good. I changed the cap just to be sure - same result.

I did find a shorted diode at D10. This diode is marked as HER304. I have circled it on the attatched photo. It is attatched to a heatsink and is standing upright. As also seen in the 2nd photo. This is the classic case of "I thought I checked that before". Taking notes would have made all the difference.

Now I have to find a solution for a match if I cant find the exact component.

Her's a picture of the D10 diode

[dnafix]

Re: Memorex MLT3221 - No Power

I've worked on a few of these and changed the 450v caps but also found that soldering joints on the micro down in the corner by the led on the power supply can keep the inverter from turning on. The soldering joints did not look bad but they were.

[battlecat]

Re: Memorex MLT3221 - No Power

Hi saw this posts ended ages ago ... Any idea why the tubes would be overdriven ?
My TV is tedelex with the exact board and rev numbers and got it up and running reading all the post and help..but it's white out at the moment. And for some arb reason I have audio on the headphone jack but none on the speakers.volume , channels , menu etc all works.. But seem I have no control... In saying that what voltage should be at the AGN pin , I have my 5v,20v , stdby5v,and 12v... Any ideas would be appreciated. Can't seem to load pics from my iphone..

[meszy18]

Re: Memorex MLT3221 - No Power

Hi. I would like to keep the long story short. I got a BUSH TV with a problem: no power.

PSU number: 200-P00-HM150H
Rev.no.: 1.8 2006.11.25

I took it apart to see,what can be the problem. C17 & C18 were blown. I replaced them,then i got power,but no screen. I never checked it with flashlight,but i guess,there could be something,cause the inverter didn't want to work only. The LED on the PSU was flashing every second too. Then I found out, F2 is blown. Replaced it,powered on,but the fuse was blown straight away. I was keep looking for broken parts,then i found out, Q16 & Q17 were gone too. I measured 0.0000 on every ways. Replaced them with F2 and now,Voila,the TV working great. So,just the main things...

Parts to be replaced: C17 & C18: 10uF/450V
Q16 & Q17: FQFP9N50CF
F2: 250V/3.15A

I hope,i could help for a few people,but don't forget,it's my story only. Good luck everyone.

[Black Rock City]

Re: Memorex MLT3221 - No Power

I have a IPOS 150 rev 3.3.

My R55 resistor is pink ceramic and has gold silver violet yellow bands which digikey identifies as 470 megaohm. The schematic for the board clearly labels R55 as 0.47ohm. To complicate matters my R55 measures 2.1ohm out of circuit. I think I need to replace this resistor but with what value?

[budm]

Re: Memorex MLT3221 - No Power

I have a IPOS 150 rev 3.3.

My R55 resistor is pink ceramic and has gold silver violet yellow bands which digikey identifies as 470 megaohm. The schematic for the board clearly labels R55 as 0.47ohm. To complicate matters my R55 measures 2.1ohm out of circuit. I think I need to replace this resistor but with what value?

You forget to add the resistance of your meter probes to the value of that 0.47 Ohms resistor to get the TOTAL resistance value. The resistor is fine, when they are bad they go open circuit.