Visio VW37L-HDTV20A - no 12/24V on PS

[ahickman]

Working on a Visio VW37L-HDTV20A that responds to PWR button in that VISIO symbol goes from orange to white, but no picture/sound. Exposed boards and did the following:

1. Checked for obvious visible damage
2. Checked fuses on PS, T-con and main board
3. Verified 5V line = 5.13V steady
4. Verified large filter cap has 163 VDC
5. Disconnected PS and tied ON/OFF to 5V STBY using a 1K ohm resistor.
6. +12V and +24V do not turn up (0.0 VDC).

Suggestions on where to start? The power supply is model FSP201-3M01. Did a quick search on this forum and did not come up with any links.

[ahickman]

Re: Visio VW37L-HDTV20A - no 12/24V on PS

I pulled the two Fairchild FQPF9N50 Mosfets that feed the larger transformer and measured the resistance between G, D and S pins for both. The Drain to Source reading varied between the two (924 & 778 ohms, + on D and - on Source). All other combinations were OL on the 2K scale.

[ahickman]

Re: Visio VW37L-HDTV20A - no 12/24V on PS

Anyone happen to have a schematic for the PS?

[johnboy1313]

Re: Visio VW37L-HDTV20A - no 12/24V on PS

I just fixed a VO42L with the same problem today, had a bad cap on the PSU, 2 bad caps on each inverter, and a blown fuse on the main inverter. Check the fuses and the voltage regulators on the main board too.

[budm]

Re: Visio VW37L-HDTV20A - no 12/24V on PS

OK, since this power supply has PFC Voltage booster, when you force it on using the resistor, does the voltage on that large cap go up to around 380~400V?
Data sheet: http://www.fspgroupusa.com/fsp2013m01/p/684.html

[ahickman]

Re: Visio VW37L-HDTV20A - no 12/24V on PS

No, it does not.

[budm]

Re: Visio VW37L-HDTV20A - no 12/24V on PS

Then we will need the P/N of the PFC Controller IC and the SMPS IC, and the one with ??? to get the pinout so we can check and see if it has any voltages on them. This power supply is also used in the VX37.
See if the picture matches your board.
This is not going to be easy repair since I do not have the board in front of me to see.

[ahickman]

Re: Visio VW37L-HDTV20A - no 12/24V on PS

Looks like L6598D 904J651 for the SMPS and 103AIW EZ737 for the PFC. The picture of your supply is identical to mine.

[caphair]

Re: Visio VW37L-HDTV20A - no 12/24V on PS

OK, since this power supply has PFC Voltage booster, when you force it on using the resistor, does the voltage on that large cap go up to around 380~400V?
Data sheet: http://www.fspgroupusa.com/fsp2013m01/p/684.html

Never heard of PFC voltage booster with ic controller. What's the purpose of it? I know normal pfc is to prevent noise into the ac line from high switching frequency of smps

[ahickman]

Re: Visio VW37L-HDTV20A - no 12/24V on PS

With the 1K resistor between 5VDC and ON/OFF, I got the following VDC values on the pins:

103AIW EZ737 IC

PIN 1: 13.10 VDC
0.30
2.50
0.00
0.00
1.60
0.00
PIN 8: 14.4 VDC


L6598D 904J651 IC

PIN 1 - 16 = 0.00 VDC

[budm]

Re: Visio VW37L-HDTV20A - no 12/24V on PS

I will have to look up all those IC spec sheet first to see how they connected.

@caphair, please see PDF for the PFC booster function.

[tibimakai]

Re: Visio VW37L-HDTV20A - no 12/24V on PS

If I remember correctly I have struggled(with bud) with this same TV for a while and it ended up to be some bad capacitor in the secondary causing the missing 12/24V.

[ahickman]

Re: Visio VW37L-HDTV20A - no 12/24V on PS

Was it a SMD cap or an electrolytic cap on the topside?