Memorex MLT3221 - No Power

[Dgtech]

Re: Memorex MLT3221 - No Power

Both of you should replace the power board. There's not going to be an easy fix to this problem.

[graywebdesign]

Re: Memorex MLT3221 - No Power

matmarkgo

when you described the voltages on IC2, I assumed you ment the low voltage controller( because you only showed 6 pins). In the picture that you posted, you actually have IC1 circled.

pin 1 of IC2 does go directly to HOT ground, so that is not a problem.

i am having a little diffuculty visualizing what is happening when you turn your set on. when you say the red light on the front of the set goes off. do you STILL have ALL of the correct voltages on CON3? (STB,5vstb,5v,12,24v) And you never see it change to blue? Does the backlight try to come on, even briefly?

[graywebdesign]

Re: Memorex MLT3221 - No Power

kobkobk

Is the DC voltage across the big cap 160v or 400v? I also tried to feed 12v to pin 13 of the SG3525AN and got a dim screen. It turned out that I only had 160v across the big cap. Finally, when I got it to it's proper 400v (when set is on) the screen came up to full brightness.

[kobkobk]

Re: Memorex MLT3221 - No Power

thanks all friends i am working when you slipping. i am on the other said of the world
i put back the p/s and connected to tv
at stby got 5vdc and red light at front
try to power on:got back light for 2sec and off. no back light,5v,12v,22v are on the red led at p/s is on,at the front blue light on
for my understanding the ic D78F9222CX test the high voltage and if fault he cut off the vcc to ic SG3525AN then the high voltage cut offi also try to connect directly to ic SG3525AN at pin 13 12v [vcc] the back light on but weak
i can't fund the reason for this cut off
need your help or suggestion
thanks

[kobkobk]

Re: Memorex MLT3221 - No Power

hi
it is the seem power supply used on 32'' Telefunken tv there is no problem for the pic but...

thanks

[mattmarkgo]

Re: Memorex MLT3221 - No Power

[QUOTE=mattmarkgo;196624]thank you Dgtech!!!!!

[mattmarkgo]

Re: Memorex MLT3221 - No Power

I'm looking around for IC2 but I cannot find it on your picture. Please specify. Also, I recently got a similar set working after I found the transformer above the main cap to be bad. It was arching intermittently. Whenever the set would fail, the LED on the bottom left hand side would come on. I had to replace the whole board cause there were no replacement transformers to be found for this board. Good luck.

thank you Dgtech for you effort to answer my question...........

[Dgtech]

Re: Memorex MLT3221 - No Power

Post a picture of your board as well.

[kobkobk]

Re: Memorex MLT3221 - No Power

more test:
operation the p/s out of the tv,connect 220AC
at con. 3, between pin stb to 5vsb solder 1k resistor-got 5v,12v,22v at output
at con.4-5V with 1k resistor connect to pin BK-ON
results;got high voltage for 1or2sec,the red led blinking,12v supply for 2 sec to ic8 pin 13,15.at con 3 no change 5v,12v,22v are on
be continue

[kobkobk]

Re: Memorex MLT3221 - No Power

dear sir
i also got this problem at this power supply
i have checked all the outputs at con3 the tv power on for 2sec and shot off.
at ic8 pin 14i connect 12v constant the back light was on at half power
any suggestion?
thanks
kob

[Dgtech]

Re: Memorex MLT3221 - No Power

I'm looking around for IC2 but I cannot find it on your picture. Please specify. Also, I recently got a similar set working after I found the transformer above the main cap to be bad. It was arching intermittently. Whenever the set would fail, the LED on the bottom left hand side would come on. I had to replace the whole board cause there were no replacement transformers to be found for this board. Good luck.

[mattmarkgo]

Re: Memorex MLT3221 - No Power

resistance to hot ground to pin 1 of IC2 is shorted....need help.......please!!!!!

[mattmarkgo]

Re: Memorex MLT3221 - No Power

result of ic2#52722
pin1- 0V
pin2- 7V
pin3- 9V
pin4- 0V
pin5- 14V
pin6- 4V

[mattmarkgo]

Re: Memorex MLT3221 - No Power

they have pin1-3v, pin2-5v, pin3-5v, pin4-11.5, pin5-o, pin6-0,pin7-0v,pin8-0v, pin9-23volts in con3,


connector4
pin1 - 3volts
pin2 - 0 volts
pin3 - 0volt
pin4 - 0volt
pin5 - 5volts
pin6 - gnd...

[Dgtech]

Re: Memorex MLT3221 - No Power

what are the voltages that you see all the way across the output connector - in order?

[mattmarkgo]

Re: Memorex MLT3221 - No Power

any suggestions please!!!!!!!

[mattmarkgo]

Re: Memorex MLT3221 - No Power

24 volts ok,when i plug i see a red light i a seconds black screen......

[mattmarkgo]

Re: Memorex MLT3221 - No Power

thanks in advance.....

[mattmarkgo]

Re: Memorex MLT3221 - No Power

i already cheack 5volts,12 volts ok....

[Dgtech]

Re: Memorex MLT3221 - No Power

Did you check the things that were mentioned in the first few pages of this thread? If you've done this already and you still need more advice, post pictures of your power board and we'll go from there.