| Author |
Message |
draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
|
| Posted: Mon Jan 19, 2015 6:31 pm Post subject: Drifting mechanical focus- HD8 lenses |
|
|
anyone else notice this before? It just makes no sense, the focus keeps drifting on my 8500 and always think there's something wrong with the Focus circuitry and then finally realize it's the actual lens, the back knob closest to the tube. (Yes, I tighten it down snugly after setting but the focus still changes).
This is an all plastic lens, would a 20 degree change in room temperature really jack it up so badly?
Last edited by draganm on Mon Jan 19, 2015 6:38 pm; edited 1 time in total
|
|
| Back to top |
|
 |
macgyver655
Joined: 22 Aug 2007
Posts: 8508
|
| Posted: Mon Jan 19, 2015 6:38 pm Post subject: |
|
|
|
I remember someone else here with this issue and a discussion developed. I think it was Tim but cannot remember for sure.
|
|
| Back to top |
|
|
draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
|
| Posted: Mon Jan 19, 2015 6:45 pm Post subject: |
|
|
|
well hopefully Tim chimes in, A search only returns this thread.
|
|
| Back to top |
|
|
cosaw
Joined: 08 Mar 2006
Posts: 164
Location: Nottingham, England
|
| Posted: Mon Jan 19, 2015 7:09 pm Post subject: |
|
|
I've noticed mechanical changes (not due to rotation) with HD6-C lenses. Just pushing the lens caps on can be enough for me to think the convergence has drifted (usually left or right). I usually find if I gently press on the side of the front barrel of each lens, in the direction required, it's enough to bring the convergence back in line without touching the electronics. I think one of the lenses is more affected than the other two and there is a sloppyness between the front and back barrels regardless of them being rotationally tight with the knobs/wingnuts.
Last edited by cosaw on Mon Jan 19, 2015 7:12 pm; edited 1 time in total
|
|
| Back to top |
|
|
Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
|
| Posted: Mon Jan 19, 2015 7:12 pm Post subject: |
|
|
Yup
Twenty degrees would be enough temperature swing to mess the focus. Warm up your machine two hours in a warm room, focus it, and run a hair dryer on the red lens barrel for an hour and see how that looks.
|
|
| Back to top |
|
|
Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
|
|
| Back to top |
|
|
gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
|
| Posted: Mon Jan 19, 2015 9:50 pm Post subject: |
|
|
In my XG there was a fan that was oddly placed between the green and blue lens... I removed that fan (realigned actualy to cool the focus board instead), focus drifts on mine too (HD-18 lens) I should put back that fan to cool the lenses eh? 
_________________
projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB, VIM-DB
|
|
| Back to top |
|
|
tschaeikaei
Joined: 08 Apr 2013
Posts: 490
Location: Germany/Saarland
|
| Posted: Mon Jan 19, 2015 10:31 pm Post subject: |
|
|
Same at my PG 9 with HD6C-ML lenses. You just have to look evil at them and they move.
And I retightened every screw on the lenses. Just does not help.
Regards, Julian
_________________
Marquee 9500U edgeblend P43 | NEC 9PG
|
|
| Back to top |
|
|
hansilili
Joined: 09 Mar 2007
Posts: 302
Location: Köln, Germany
|
| Posted: Tue Jan 20, 2015 7:24 am Post subject: |
|
|
I have the impression, that convergence stability improved since putting the projector in a hush box with forced ventilation because of a quickly establishe equilibrium of temperature inside the box. At least, the hush box didn't make it worse.
However, mine are GT18 from metal and glass.
Cheers
hansilili
_________________
HansA, alles andere ist euer Bier!
|
|
| Back to top |
|
|
CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
|
| Posted: Tue Jan 20, 2015 10:39 am Post subject: |
|
|
| gjaky wrote: | | In my XG there was a fan that was oddly placed between the green and blue lens... I removed that fan (realigned actualy to cool the focus board instead), focus drifts on mine too (HD-18 lens) I should put back that fan to cool the lenses eh? |
Mine doesnt have that fan and i havent seen it drift in terms of focus, i cant say ive ever seen them get hot though.
_________________
Barco Cine 9, ,Sony VPL570ES 4K SXRD, 135" OZ Theatre Majestic 16:9 screen, Denon X6700in preamp mode, 2x 7ch Tonewinner amps, 2x Tonewinner 15" subs, 2x 10" subs, 7.2.6...
RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 7.1...
|
|
| Back to top |
|
|
|
|
