Vizio M502i-B1 Power Supply Issue

[nomoresonys]

Re: Vizio M502i-B1 Power Supply Issue

The 20-30 seconds to turn on makes me think a weak capacitor somewhere, probably on powerboard, the startup caps maybe.

[JunkmanJimbo]

Re: Vizio M502i-B1 Power Supply Issue

R_J posted earlier in the thread to replace C9805, C9308 and C9112 and also C9305 to hopefully fix the problem.

[nomoresonys]

Re: Vizio M502i-B1 Power Supply Issue

Indeed, if you had one of those 4 or 5 dollar esr meters from ebay you could take m off the board n check m.

[JunkmanJimbo]

Re: Vizio M502i-B1 Power Supply Issue

I actually do have a meter to check caps. I have an assortment of caps arriving tomorrow and I was going to check them then so I would have a replacement. I will update tomorrow or Monday with the outcome. Thanks to all you guys for your help.

[nomoresonys]

Re: Vizio M502i-B1 Power Supply Issue

Lol, ok, I assumed that you didn't have one, a good example to never assume, especially when troubleshooting.

[JunkmanJimbo]

Re: Vizio M502i-B1 Power Supply Issue

My capacitors came a day early. I replaced C9805, C9308 and C9122 and also C9305 that R_J mentioned but unfortunately that didn't fix the problem. Does anybody have any other suggestions?

[nomoresonys]

Re: Vizio M502i-B1 Power Supply Issue

So what are those voltages now, still getting the 1.1?

[JunkmanJimbo]

Re: Vizio M502i-B1 Power Supply Issue

No change. Everything is still the same as it was before I replaced the capacitors.

[CapLeaker]

Re: Vizio M502i-B1 Power Supply Issue

I figured that would be the case. BLon is created on the main board not on the PSU and the STBY voltage was good while the on / off pin is low. BLon goes from the main board to one connector of the psu, through jumpers, then one SMD resistor and then out the other connector to the LED driver board. The LED driver board can't load the BLon pin down, because of this SMD resistor on the back. It has to be a main board problem or a chaffed wire grounding out or something stupid.

[JunkmanJimbo]

Re: Vizio M502i-B1 Power Supply Issue

I've changed the mainboard 3 or 4 times and get the same result. I will check the wiring a little closer. So, you don't think there could be another problem on the power supply?

[nomoresonys]

Re: Vizio M502i-B1 Power Supply Issue

Get the resistor and do the test in CapLeaker's post #16, it's not a hard test and it will tell you if the powerboard is doing as it should.

[JunkmanJimbo]

Re: Vizio M502i-B1 Power Supply Issue

I would need more detailed instructions and abbreviation meanings to even consider doing that. Can you help me with that?

[budm]

Re: Vizio M502i-B1 Power Supply Issue

Did you check the DC Voltage between the two legs of the main filter cap to see if the PFC Boosted Voltage (380 ~ 400VDC) is present or not when PS-ON is present?

[JunkmanJimbo]

Re: Vizio M502i-B1 Power Supply Issue

BudM, I'm not sure how to do what you're saying. Can you give specific instructions on how to do that? Sorry but I'm not very good at board level testing.

[nomoresonys]

Re: Vizio M502i-B1 Power Supply Issue

Good testing tutorial there, might help: https://www.youtube.com/watch?v=ocqnqmBxiqY

[JunkmanJimbo]

Re: Vizio M502i-B1 Power Supply Issue

I will definitely take a look at that. Thank you nomoresonys.

[nomoresonys]

Re: Vizio M502i-B1 Power Supply Issue

As always be careful working on the DEADLY HOT/PRIMARY side of the powerboard, watch out what you touch with your hands, use the meter probes, keep hands back.

[budm]

Re: Vizio M502i-B1 Power Supply Issue

At least plug what ever you are working on into GFCI outlet.

[JunkmanJimbo]

Re: Vizio M502i-B1 Power Supply Issue

Well guys, I finally decided to replace the power supply and that fixed the TV. I still wish I could figure out what's wrong with the defective board so I could repair it and sell it to offset some of the cost of the replacement board. I've been looking for repair kit for this board but can't find one other than one on ebay and they won't sell to me for some reason. Does anybody know where I can get a repair kit for this board? Thanks for all the help and sorry for the long post.

[JunkmanJimbo]

Re: Vizio M502i-B1 Power Supply Issue

Still trying to repair this power supply. I ordered a kit off Ebay and installed those components but that didn't fix the problem. Another problem I noticed could be the whole problem. When I install the old power supply, if I unplug the power cord and hold in the power button on the TV for 30 seconds, and plug it back in, the TV won't do anything. No standby light, nothing. As if there is no power. Could that be a voltage regulator issue? If not does anyone have any ideas? The only way I can get power back is unplug the cable from the main board and plug it back in, then I have power again. This was mentioned in an earlier post. Thanks in advance for any help you can offer.