coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

[hmendez86]

I got this coby tv tftv4025.....it powers on blue ligth and no image even with looking with a flash light.....power supply give 5v only...I jump stbv to 5v and no 24v and no 12v......check for short transistor and caps and they seem good..I removed power to take a look and nothing seem burn like I said test transistor and they are good am just in ?? About the ones that are behind the caps were it connects the 24v to the inverter. They read .145 something like that and .3
They are 3 transistors

[hmendez86]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

I'll post pics later on the day...

[ReeceyBurger123]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

What inverter does it use ?

[hmendez86]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

inverter

[hmendez86]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

I marked 2 blck lines on the stby voltage that's were I jump to self start power.....and it just give me 5v and 0 on 12v and 24v...

[budm]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

Is this the your board? Please loo at the numbers as printed on the barcode sticker.
Coby MLT668TL-G Power Supply for TFTV4025

http://www.shopjimmy.com/coby-mlt668...pply-unit.htm#

Do you have about 400vdc between the two legs of the main filter cap when you force on the power supply?
Do you get the 24V if the inverter board is not connected to the power supply board?

[hmendez86]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

I don't get 24v on the power supply=this is by the inverted be disconnected

[hmendez86]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

I don't get the 24v and 12v on power supply......I just got 5v stand by....it just give the voltage to turn on the power once I do that nothing goes up like the 24v or 12v

[hmendez86]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

MLT668TL-v

[budm]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

Next you need to find out if you do have the 400VDC between the two legs of the main filter cap or not because the 24V PS needs that boosted Voltage to run.

[hmendez86]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

It is a 450v 120uf the big cap that's were u point to it......I replace it with a 450v and 150uf and same thing

[budm]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

Next you need to find out if you do have the 400VDC between the two legs of the main filter cap or not because the 24V PS needs that boosted Voltage to run.

Again, We need the DCV readings between the two legs to find out if you have PFC Voltage boosted Voltage or not.

[hmendez86]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

One led -1.344 dcv second leg 8.45dcv... am I right how I tested or need to put probes to both legs at DC voltage...

[budm]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

We want to measure the DCV between the two legs of the cap, red probe on the positive leg, Black probe on the negative leg.

[hmendez86]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

Ok 347 dcv

[ReeceyBurger123]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

Is that with the Tv on ?

[CapLeaker]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

kinda low for boosted voltage. The TV has to be on... other than that he would only get rectified mains at 170VDC.

[hmendez86]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

I jump start the power with the stanby voltage

[hmendez86]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

Cap leaker)) so that's means ??? So 347dcv should be ??? And what is causing this problem.......rectifier, resistor, or cap

[budm]

Re: coby TFTV4025 POWER SUPPLY 24V NOT PRESENT

What is the P/N as printed on top of the IC1?