Sanyo FW43D25F no power

[jason424]

Trying to help a coworker fix this tv.
Does not power on, no standby light (which I'm not positive if it even has one). Testing the power coming in to the power board I do get 120v and hear a slight hum/buzz when plugging it in.
I couldn't find a legend for the connector that goes to the video board. But when testing the pins I get (from top to bottom in pic):
1: 0
2: 0
3: 0
4: 0
5: 0
6: 0
7: 0
8: 18
9: 18
10: 0
11: 0
12: 0

Unplugging the video board from power board garners no change.
NOTE: I did take pics of the boards while I had the cables unplugged already.
I did also test the F602 fuse (not isolated from the board) and it ohms out good. No leaking or bulging capacitors.
Not sure what else to check before buying a new power board.

[R_J]

Re: Sanyo FW43D25F no power

You only checked half the pins, there are 23 pins on that connector, The fault might be a shorted cap on the main board. see this thread: https://www.badcaps.net/forum/showth...light=FW43D25F
I suspect the power supply is ok if you have 18 volts, which is likely the P-ON+21V point

[jason424]

Re: Sanyo FW43D25F no power

Ugh, you’re correct. I will check the other side tomorrow. And to check the capacitor it needs to be isolated from the board correct?
Thank you for pointing out what I missed.

[budm]

Re: Sanyo FW43D25F no power

Check resistance between Gnd and P-ON21V jumper, Gnd and AMP+13V jumper, then check the Voltage between Gnd and P-ON21V jumper, Gnd and AMP+13V jumper. The 3.3V for running the main board is generated on the main board.
This TV is made by the same people that make Emerson/Magnavox.

[jason424]

Re: Sanyo FW43D25F no power

Resistance between Gnd and P-ON21V jumper: 0 and slowly increases
Resistance between Gnd and AMP+13V jumper: 0 and slowly increases
Voltage between Gnd and P-ON21V jumper: 31.7v
Voltage between Gnd and AMP+13V jumper: 16.5v

EDIT: and I did check that C3209 and it ohm'd closed.

[budm]

Re: Sanyo FW43D25F no power

Are you sure that your meter batteries are good due to the fact that those Voltages are reading much higher than normal?

[jason424]

Re: Sanyo FW43D25F no power

I did try another battery, although the orig was good. And got the same results. I'm trying to track down another meter...have a freebie from Harbor Freight somewhere around here.

[jason424]

Re: Sanyo FW43D25F no power

With another meter I got:
Voltage between Gnd and P-ON21V jumper: 31.4v
Voltage between Gnd and AMP+13V jumper: 16.2v

Also testing of all 23 pins (with cable from power to main disconnected):
1: 0
2: 0
3: 0
4: 0
5: 0
6: 0
7: 0
8: 0
9: 0
10: 0
11: 0
12: 0
13: 0
14: 17.7
15: 17.7
16: 17.7
17: 17.7
18: 0
19: 27.4
21: 27.4
22: 27.4
23: 27.4

[budm]

Re: Sanyo FW43D25F no power

https://www.shopjimmy.com/sanyo-a5gv...rial-only.htm#
1) Your result does not make sense, you trace the board out you will see that jumper P-ON21V and AMP+13V are connected directly the connector so I cannot see how you can the Voltages on the Jumpers not the same as the connector.
2) What Voltages do you get on the jumpers (P-ON21V, AMP+13V) if you have all the boards connected?
3) D653, 655A are for AMP+13V
4) D650, 651, 652, 659 are for P-ON21V.

[jason424]

Re: Sanyo FW43D25F no power

When the boards are all plugged in (power to main cable previously unattached) I get 31.5 at P-ON21V and 16.2 at AMP+13V.
I get this same measurement whether I'm checking the main board pins at the connector, or the connector on the power board.
I'm not familiar with tracing a board, I'm extremely novice (as you could probably tell).
I just re-read the posts and perhaps I'm not testing the "jumper"? I'm testing the pins right at each connector where the cable from main to power board connects.

[jason424]

Re: Sanyo FW43D25F no power

budm, is the testing I reported following your instruction or am I doing something wrong?
If not testing incorrectly, does the odd voltages point to a faulty power board?

Thank you,
Jason