Proview PL926Wbi, no power

[retiredcaps]

Re: Proview PL926Wbi, no power

I used the link you provided above and purchased the cheap regulators from eBay.

Aww, darn, for 2x the price, you could have gotten 10x the regulators. Auction is over.

50 regulators for $3 + free shipping.

http://www.ebay.ca/itm/120947003251

The K020 is the same code I received.

For fun, over at digikey.com,

http://www.digikey.com/product-detai...OSCT-ND/660708

50 x 0.36520 = $18.26 + $8 shipping to Canada = $26.26.

[SBlackfoot]

Re: Proview PL926Wbi, no power

Aww, darn, for 2x the price, you could have gotten 10x the regulators. Auction is over.

lol I thought even five was overkill...

[SBlackfoot]

Re: Proview PL926Wbi, no power

18 days later and my cheapo regularots have arrived. On my birthday no less! lol When I get a chance I'll break out the heat gun and try to get the old one off. It probably won't be until next week though. I have a basement to tear apart. *sigh*

[SBlackfoot]

Re: Proview PL926Wbi, no power

See you guys are amazing... I used some insulating wool to protect the surrounding board and replaced that voltage regulator. I managed to set off the smoke detector (new heat gun was smokey) and melt part of the connector to the inverter board, but when all is said and done she fired right up. It has been running for about ten minutes now without a complaint.

I really appreciate all of the help. If I ever get the chance I'd love to buy you guys a beer. lol

[retiredcaps]

Re: Proview PL926Wbi, no power

I managed to set off the smoke detector (new heat gun was smokey)

1) At least you know the smoke detector is working. It could save your life one day as many people neglect to test it or change it out after a few years.

2) If the new heat gun lets out smoke, maybe return it?

[SBlackfoot]

Re: Proview PL926Wbi, no power

By "new" heat gun, I mean a gift from last Christmas that I used for the first time. lol I'm sure it's fine. I'm sure they all smoke a little the first time they're fired up. The next attempt will be outside though. lol

[maybenever]

Re: Proview PL926Wbi, no power

I've got this same monitor apart. My PSB is a little different. I've replaced all the caps on the power board with FM panasonics. Old caps were all bloated and monitor would not power on. With caps replaced, power led lights up, monitor seems to be working, but no back light. I can see the display with a flashlight. The power out volatge is good on 14v pin (14.5v), but 5v voltage is only 4.98v. Therefore my voltage at the regulator is only 4.66v input with only 3.27v output. Is this close enough to the right voltage? I could not find the inverter transformer in LCDparts list, it's part # is 730 703 1900TLW JH. The ohm checks as 747ohm and .6ohm, I don't know if this right or not.

[jetadm123]

Re: Proview PL926Wbi, no power

I've got this same monitor apart. My PSB is a little different. I've replaced all the caps on the power board with FM panasonics. Old caps were all bloated and monitor would not power on. With caps replaced, power led lights up, monitor seems to be working, but no back light. I can see the display with a flashlight. The power out volatge is good on 14v pin (14.5v), but 5v voltage is only 4.98v. Therefore my voltage at the regulator is only 4.66v input with only 3.27v output. Is this close enough to the right voltage? I could not find the inverter transformer in LCDparts list, it's part # is 730 703 1900TLW JH. The ohm checks as 747ohm and .6ohm, I don't know if this right or not.

The regulator output should be around 3.3V. Not sure how accurate your meter is. I would start by checking to see if there's a fuse for the inverter section (F203 on some of the boards). Also check mosfets Q5 and Q6 (bottom of board) for shorts as outlined by retirecaps " 2 seconds to black" guide in post #3.

[maybenever]

Re: Proview PL926Wbi, no power

I've checked all fuses, they are good. My meter has always been pretty accurate. I'll try to check the mosfets.

[selldoor]

Re: Proview PL926Wbi, no power

= The ohm checks as 747ohm and .6ohm,

Hopefully you have measured in the wrong place

Try again - power off- meter on ohms 2000 measure S1 to S2 and S3 to S4

[maybenever]

Re: Proview PL926Wbi, no power

Hopefully you have measured in the wrong place

Try again - power off- meter on ohms 2000 measure S1 to S2 and S3 to S4

I must have measured in the wrong place. S1 to S2 =730 ohms S3 to S4 = 730 ohms.
Measured mosfets Q5 & Q6, part # K3615 7F. With meter set on 20k, pin 1 to 2 = starts at zero and just keeps climbing, pin 1 to 3 = 5.64, pin 2 to 3 = 2.66. Both parts test the same.

[jetadm123]

Re: Proview PL926Wbi, no power

Suggest you reconnect the main board back to the power supply and measure the voltage at the BL ON pin (at the 8-pin connector). You should see around 3V. Measure the BL ON voltage when you're pressing the on/off button on the front panel of the monitor.

[maybenever]

Re: Proview PL926Wbi, no power

Suggest you reconnect the main board back to the power supply and measure the voltage at the BL ON pin (at the 8-pin connector). You should see around 3V. Measure the BL ON voltage when you're pressing the on/off button on the front panel of the monitor.

Voltage at BL ON pin is zero or .01v, press the on/off button, zero for a few seconds, then clinbs to 4.54v, then falls back to .01v.

[jetadm123]

Re: Proview PL926Wbi, no power

The BL ON turns on the backlights when voltage is applied to this pin. Do see any activity from the backlights as the BL ON voltage climbs to 4.54V? Perhaps a photo of your mainboard would be helpful.

[maybenever]

Re: Proview PL926Wbi, no power

The BL ON turns on the backlights when voltage is applied to this pin. Do see any activity from the backlights as the BL ON voltage climbs to 4.54V? Perhaps a photo of your mainboard would be helpful.

I didn't have the backlights connected. I thought I had a photo of the main board, guess I didn't take one. I've replaced the 2 large caps on it, 220uf I think, the board is in my shop. That'll be a tomorrow thing.
The voltage is right for the BL On test?

[jetadm123]

Re: Proview PL926Wbi, no power

Depending on the manufacturer, BL_ON can vary from 3-5V. I don't know the specific value for your monitor.

[maybenever]

Re: Proview PL926Wbi, no power

So, it starts at zero, climbs to around 5v, then falls back to zero. Am I getting this right?

[jetadm123]

Re: Proview PL926Wbi, no power

The "climbing" part has me puzzled. It should be a solid number. I also believe it should not go back to zero.

[maybenever]

Re: Proview PL926Wbi, no power

That's what I'm thinking, but I don't know very much. I so thank you for taking the time for a learner like myself. I'll get that other picture tomorrow.

[maybenever]

Re: Proview PL926Wbi, no power

Perhaps a photo of your mainboard would be helpful.

Here are pictures of main board. I didn't see how crappy my solder job was on those two caps until now. I'll clean that up. What to check next?