akai lct3201ad won't power on

[shawnunder7]

Hello all,

I have an akai lct3201ad tv with a few issues. I had it working a while back, as I replaced a few caps on the mainboard and power board. It randomly stopped working and had no lights, so I decided to get a brand new power board which didn't remedy the issue. After that, I decided to get a new mainboard, which I installed this morning and it was working just fine. I had HDMI input working for a bout half an hour, and accidentally pressed the source button, and it went from HDMI, to DTV, and then to the next selection, which was a black screen. I tried powering it off, but it wouldn't turn off either. Pulled power left it alone for a few minutes, plugged back in, stanby light came on, power on, green light came on could hear dvd drive power on, but no picture on screen. There's no backlight, no boot animation nothing. It also doesn't power off at all either. What should I look at next to get this thing going

[shawnunder7]

Re: akai lct3201ad won't power on

UPDATE: I tested the Voltage, and everything seems to check out, except the 25V, it's around 30-31 when powered on. The 5V standby reads 0 but the 5V Power is at 5. Should I be concerned that the 25v line is giving around 30v?

[tom66]

Re: akai lct3201ad won't power on

Could be a concern.
Are you using a digital meter?
Are the batteries in your meter fresh?

[aaronwt6]

Re: akai lct3201ad won't power on

Shawn,

I saw your post here so I figured I'd reply to it instead of on Ebay. I checked both power supplies that I have here (one of which came out of the TV that you bought the mainboard from me for) and the 25V line on both is 25.2V. Looking at the wiring that supplies both the mainboard as well as the inverters. I'd be concerned about overvoltage possibly damaging some regulators. There is some tolerance on what those can handle but 30+ volts seems pretty high to me.

[shawnunder7]

Re: akai lct3201ad won't power on

Could be a concern.
Are you using a digital meter?
Are the batteries in your meter fresh?

Yes meter is digital and the batteries are brand new.

[shawnunder7]

Re: akai lct3201ad won't power on

Shawn,

I saw your post here so I figured I'd reply to it instead of on Ebay. I checked both power supplies that I have here (one of which came out of the TV that you bought the mainboard from me for) and the 25V line on both is 25.2V. Looking at the wiring that supplies both the mainboard as well as the inverters. I'd be concerned about overvoltage possibly damaging some regulators. There is some tolerance on what those can handle but 30+ volts seems pretty high to me.

Hmmm, on the power board it reads 25 but on the main board it reads higher. Since I'm positive the old power board is also fine, I'll plug that one back in and give it a check to see if it's gives the same reading or not. I definitely don't want to get another main board and risk it being damaged again until I get the 25v reading the right voltage.

[budm]

Re: akai lct3201ad won't power on

Can we see the pictures of this board and where the voltage is being measured?

[shawnunder7]

Re: akai lct3201ad won't power on

Can we see the pictures of this board and where the voltage is being measured?

Sure,will do when I get home!

[budm]

Re: akai lct3201ad won't power on

It looks like there are more than one version of this model:
http://www.shopjimmy.com/catalogsear...akai+lct3201ad

[shawnunder7]

Re: akai lct3201ad won't power on

here are some pictures of the mainboard and where i tested the voltage






If you need any closeups of anything, I will gladly post them!

[budm]

Re: akai lct3201ad won't power on

Power supply board (the whole board) pictures?

[shawnunder7]

Re: akai lct3201ad won't power on



Here you go

[budm]

Re: akai lct3201ad won't power on

Sorry, one more picture of the backside of the TV so I can see how all the boards are connected together.

[shawnunder7]

Re: akai lct3201ad won't power on

[shawnunder7]

Re: akai lct3201ad won't power on

So, I put the old PSU back in, and things seems to be more around normal. the 24V reads between 24v on the psu itself and actually reads around 20-23 on the mainboard when powered on. Every other one checks out with corresponding voltage, so i'm also guessing the PSU was wayyy to high for the mainboard as just now it was hovering around 39-40 volts, which was even higher than before.

[budm]

Re: akai lct3201ad won't power on

I think we are having measurement problem here. Are you sure that the battery is good? I cannot see the power supply can put out 40V.

[shawnunder7]

Re: akai lct3201ad won't power on

I think we are having measurement problem here. Are you sure that the battery is good? I cannot see the power supply can put out 40V.

Yeah, battery is brand new, got it on Friday. I checked multiple times just to make sure and it puts out around 39-40 volts while the original only gives the mainboard around 23

[budm]

Re: akai lct3201ad won't power on

BTW, dod some one work on the main board? It looks like cap CE22 was removed?

[shawnunder7]

Re: akai lct3201ad won't power on

BTW, dod some one work on the main board? It looks like cap CE22 was removed?

Not sure, I got it off of eBay after figuring out mine was the original issue. I'm sending it back for it to be looked at to see what's going on here.

[aaronwt6]

Re: akai lct3201ad won't power on

BTW, dod some one work on the main board? It looks like cap CE22 was removed?

budm,

I recapped the main board. However, there is no cap in that position from the factory. It must be for a different board version. The other 4 nearby were swollen. Board still functioned but I changed them as a precaution before I tested it.