CurtPalme.com Home Theater Forum

jarseneau · Joined: 06 Nov 2007 Posts: 323 Location: WI

Upon turning on the G90 today it seems to have no HV or perhaps other power. The fans come on but no HV crackle and no error code although it does say 88 momentarily which is normal IIRC. Any ideas?

**Curt Palme** · Posted: Sat Jul 31, 2010 1:01 am Post subject:

I'd reseat the boards under the green lens. That's the HV control board.

Sony with the 12XX and g70 had poor error sensing for no HV, (ie the set would keep working even though there was a fault), but had insane amounts of errors if the HV went over. Makes sense I guess...

If it's not working still, send me the LVPS and the HV boards under the green lens.

jarseneau · Joined: 06 Nov 2007 Posts: 323 Location: WI

Last night I was trying to think if there was anything that might have caused the failure. My son (who was the one using the G90 when it failed) said he heard an odd motor sound which slowed down and then stopped just before it went dark. That led me to suspect the SilenX fan mod near the PA/PD boards that I installed a few months ago. It wasn't so much the mod that did it but the cabinet piece that goes in front of it snaps in place and you can change the clearance to the fan by pressing on it. Once things are working again, I'll put both the SilenX fan and the OEM back in with a resistor to slow it down.

So I checked the transistors on the PA board's large heat sink (2SK2349) and none of them read the same with a DMM even out of the circuit. After doing a Google for '2SK2349', I found our good friend CraigR has also seen this and did a great write-up. Sure enough, I found the same fusible resistors open and diodes blown along with the MOSFETs.

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

Sounds like you found the source of your problem at least Very Happy

that G90 will be back up in no time Thumbs Up

jarseneau · Joined: 06 Nov 2007 Posts: 323 Location: WI

It's ALIVE Mr. Green

The G90 is up and purring!

Actually it is purring audibly because I put the stock fan back in so now it has that re-assuring turbine sound. I'll have to consider my future cooling options but for now I'll play it safe since the stock fan will shut the projector down if it stops rotating. I'm pretty sure the SilenX fan must have jammed against the front case and lead to the meltdown of the PA board.

$250 in parts later she is back in business. Pretty much exactly the same parts as described in Craig Rounds post.
most parts found at www.bdent.com
(3) #2SK2349's
(6) #GZB20.0B zeners
(6) #1-202-933-61 fusible resistors (ordered from www.electronix.com),

I ordered Q503-508 but decided not to put them in since they tested good and felt the risk from desoldering/replacing them was greater than just leaving them as is.

Many thanks to Curt and Craig pointing me to the PA board.

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

Glad to hear the beast is up and running again! Mr. Green

jarseneau · Joined: 06 Nov 2007 Posts: 323 Location: WI

It was an exciting relief to see the warmup screen actually come on. I feel good I was able to get the parts this quickly and get them put in. Out of the parts I listed, 2 of the original zener diodes tested good but I changed them anyway to be safe. The fusible resistors were obviously open. Nothing showed any physical sign of being blown but the DMM was very useful via the diode test.

In hindsite, I would have had Curt fix the board but I'd already ordered the expensive ($72 ea x3 for the 2SK2349's) parts on Sunday before I realized Curt would have done the job for $250. By then the parts were on their way and no way to cancel the order. Getting it turned around quickly was my first priority when the problem surfaced.

It seems like I was lucky to get the expensive power transistors at all. On checking the B&D Ent. website, they now list the 2SK2349 as out of stock and require a min. 5 order (ouch!). Maybe they require a larger order when they run out to justify re-stocking themselves.