CurtPalme.com Home Theater Forum

CIR Engineering · Posted: Fri Sep 26, 2008 12:23 am Post subject: Now the G90 is dead!

Been having this shaking problem http://www.avsforum.com/avs-vb/showthread.php?t=1059436.

I was watching the G90 today and suddenly seem to have lost high voltage. Picture was fine then became blurry, then dimmed out, all in less than 10 seconds. Now I have no raster, no OSD's, and no crackling sound when I start the projector. Also NO ERROR codes. Projector starts and runs fine except no image Wink

I'll start working backwards tonight or tomorrow, but if anyone has any wisdom on loss of high voltage with no error codes I'd be happy to listen.

Also, I just finished John's fan mod to the front fan right before this happened. Seems a little odd, but hey stranger things have happened.

craigr

**Curt Palme** · Posted: Fri Sep 26, 2008 1:00 am Post subject:

PA board maybe, the one in the front under the green lens?

I do have a test chassis here, plus two more G90s coming in. Let me know if you can't get it going.

**kal** · Posted: Fri Sep 26, 2008 2:08 am Post subject:

Get it fixed Craig! You need to keep testing Moome's IFB-FULLHD HDMI card! Wink

Kal

P.S. FWIW, I don't trust those SilenX fans. They don't move anywhere near as much air as they say they do. I mod'ed my Barco Cine 8 with 3 of them and my measured temps went through the roof so I put the stock ones back.

CIR Engineering · Posted: Fri Sep 26, 2008 2:18 am Post subject:

CIR Engineering · Posted: Fri Sep 26, 2008 2:22 am Post subject:

CIR Engineering · Posted: Fri Sep 26, 2008 2:24 am Post subject:

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

I did a test on my marquee with fans where I taped a placed a piece of paper over the focus and HDM exhaust holes with only one end taped down and measured the deflection of the paper, then i put in the new fans and measuer how much they moved the paper up, if it was less i tried a different fan. I ended up with a thermaltake fan but added resistors to slow it down till it deflected the paper the same as the stock fans, kinda how Tim did the belly fans .

I hope you figure it out Craig.

Athanasios

kschmit2 · Posted: Fri Sep 26, 2008 7:27 am Post subject:

Athanasios:

PC fans are meant to operate 8 hours/day over a course of 3 years.

Not one of them is spec'd for 24/7 operation, and definitely not for 50k-70k hours like the fans used in commercial grade CRT front projectors.

I would never trust PC fans for that very reason.

richardc · Joined: 13 Feb 2008 Posts: 32 Location: Australia

craigr
I did the fan mod on my newly aquired G90 and I also have gone back to the standard fans, it is quiet with the mod but it just does not push enough air.
I live in Oz and the temperature here can go to 40 degrees and down to 0 degrees C.
Also when we see Mike Parkers mod 1080P @ 72Hz this will really warm things up.
Just my thoughts
Richard

km987654 · Posted: Fri Sep 26, 2008 10:27 am Post subject:

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

I used these for my belly fans but used a resistor to slow them down as they were too fast a bit loud.but they are rated for 30,000 hours, mine should go longer since i slowed them down.

http://www.thermaltake.com/product/dcfan/combo/a2329/a2329.asp

And I used these for the LVPS: No hours rating but i have had these for two years so fat and i leave my PJ pluged in 24/7 and those fans never shut off.

http://www.enermaxusa.com/catalog/product_info.php?cPath=28_30&products_id=101

Athanasios

Chuchuf · Joined: 11 Mar 2006 Posts: 548

I to went back to the stock fans and built a hush box.
Craig, what boards do you need??

Terry

CIR Engineering · Posted: Fri Sep 26, 2008 2:38 pm Post subject:

**kal** · Posted: Fri Sep 26, 2008 2:50 pm Post subject:

CIR Engineering · Posted: Fri Sep 26, 2008 5:25 pm Post subject:

All right, I have an update and could use some help form you guys...

I have been trouble shooting the PA board.

Q602 is toast, D608 is toast, and all six fuseable links are blown (R614, 615, 616, 617, 618, 619). Q601 is a JFET and is "Sony" part number 2SK2349-CB. I have found them online, but at over $175 each Shocked

Page 10-111 of the service manual has the diagram for the transistor and page 8-28 lists the part number. I am not good with JFET transistors (or substitutions in general) so if someone can help me maybe come up with a substitute for the Q602 I would really appreciate a cheaper alternative. PLEASE I HOPE because that's the most freaking expensive transistor I have ever seen.

D608 is part number RD20ESB2. I am having trouble finding info on this diode as well but I think it might be a 2.0 volt, 0.4 watt, zener; can someone confirm this for me. If that's all it is, I'll definitely just get the diode from Digi-Key along with other parts.

craigr

JohnHWman · Posted: Fri Sep 26, 2008 7:34 pm Post subject:

Craig,

I'm sorry for your troubles on PA board Sad

Did you pay attention to the wiring of the PA boards incoming leads/connectors when you re-assembled all the things ? I'm specially thinking about big black HV connectors on the far left/right locations on the PA board. They are named CN89/CN90. Those two female connectors are 875Vpp HV power and must be well secured inside their male on-PA-board parts (you must hear a dual 'click' when they are properly inserted).

For Q602 : This is not a J-FET but rather a Power N-MOSFET for HV DC/DC switching PSU. It is not a Sony part but a Sanyo part. See: http://www.eu.sc-sanyo.com/ProductInfo/Transistor/MOSFETs/Datasheet/2SK2349.pdf
There should be equivalent part available on the market. Most important parameters are VDSS, VGSS, IDP, PD, VGS(off) and RDS (on) and the pinout should be standard for this package (2131-TO-3JML).

Beware that because Q600/Q601 and Q602 are acting in parallel with same phase, the three parts must share the same transcient specifications (so, same part numbers...)

Ending, if one part has burned, check its relevant PRE-DRIVE stage (Q507/Q508) health !

Hope this helps

John

P.S. FYI, I have three G90 (one is mine) in France that were modded with the SilenX fans that are running for years now without any issue Wink

CIR Engineering · Posted: Fri Sep 26, 2008 8:24 pm Post subject:

CIR Engineering · Posted: Fri Sep 26, 2008 8:46 pm Post subject:

Also John... I think at this point you MUST be the guru of component level repair on the G90's and I am very thankful to have your assistance.

Let's just hope I didn't miss anything while looking over the PA.

craigr

CIR Engineering · Posted: Fri Sep 26, 2008 9:55 pm Post subject:

dochlywd · Posted: Fri Sep 26, 2008 9:55 pm Post subject:

Criag,

If it gets to a point and your G90 is not ceiling mounted, you could always bring that thing down to the "LOU" and trouble shoot by board swapping! Wink

Doc