| Author |
Message |
draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
|
| Posted: Tue Sep 28, 2010 3:48 pm Post subject: |
|
|
| Francesco wrote: | | If I understand correctly, one of the guys in that thread has made an extension cable (the red one in the picture) to check the value without opening the projector. Can I do the same? |
extension cable? no, you don't need any cables to check it
|
|
| Back to top |
|
 |
Sparky015
Joined: 12 May 2009
Posts: 1185
Location: Cleveland / Akron, OH
|
|
| Back to top |
|
|
Francesco
Joined: 08 Jul 2010
Posts: 64
Location: Italy
|
| Posted: Tue Sep 28, 2010 5:37 pm Post subject: |
|
|
Got it, no extension cable.
I contacted the previous owner and he confirmed me that he changed the power supply and the RGB board. I don't know which board is the RGB one, but the power supply is a few months old. I'll check the voltage anyway, to be sure.
|
|
| Back to top |
|
|
Sparky015
Joined: 12 May 2009
Posts: 1185
Location: Cleveland / Akron, OH
|
| Posted: Tue Sep 28, 2010 9:51 pm Post subject: |
|
|
Don 't take it for granted. He/she may have replaced it with an equally vintage LVPS, in which case the issue still remains. Follow that tech bulletin I sent a link to and you will be good. If you have a meter, doesn't take more than 10 minutes or so to check. Well worth it to make sure your new B and R tubes are in a good home.
_________________
~Paul
|
|
| Back to top |
|
|
Francesco
Joined: 08 Jul 2010
Posts: 64
Location: Italy
|
| Posted: Fri Oct 01, 2010 8:55 am Post subject: |
|
|
Just to confirm that the previous owner did change the power supply with a new one, but it's the HVPS and not the LVPS.
Tomorrow I'll be able to check the voltage.
|
|
| Back to top |
|
|
Francesco
Joined: 08 Jul 2010
Posts: 64
Location: Italy
|
| Posted: Fri Oct 01, 2010 6:42 pm Post subject: |
|
|
|
One last thing before checking the voltage: can I power up the projector with just two tubes or I have to reinstall the tube I've removed?
|
|
| Back to top |
|
|
dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
|
| Posted: Fri Oct 01, 2010 6:52 pm Post subject: |
|
|
nothing will happen but the pj will not start.
an error led will lit on the clm.
_________________
1 answer always poses multiple questions.
marquee 9500ultra HD10L moome hdmi1.3 v3+ some mods.
|
|
| Back to top |
|
|
Francesco
Joined: 08 Jul 2010
Posts: 64
Location: Italy
|
| Posted: Fri Oct 01, 2010 7:00 pm Post subject: |
|
|
Ok, thank you!
So there'll be no voltage to check... I have to reinstall the blue tube.
|
|
| Back to top |
|
|
Francesco
Joined: 08 Jul 2010
Posts: 64
Location: Italy
|
| Posted: Sat Oct 02, 2010 8:59 am Post subject: |
|
|
I've checked (without the blue tube) and it's 6.45V.
Is it too high?
|
|
| Back to top |
|
|
JustGreg
Joined: 07 Mar 2006
Posts: 3098
Location: Kenosha, WI
|
| Posted: Sat Oct 02, 2010 9:36 am Post subject: |
|
|
| Francesco wrote: | I've checked (without the blue tube) and it's 6.45V.
Is it too high? |
Well I say yes. E-Home's manual (IIRC) says you're OK.  Everyone here will tell you to take the time to do the P14 circuit mod to get the voltage to 6.35. It doesn't take long to do and is very inexpensive. I deviated from the standard procedure a bit and mounted the resistor on the printed circuit side of the board. Soooo much easier and not in danger of shorting on anything...especially if you put sleeves on the resistor leads. The thing about the voltage for the heaters is=Too low and you don't get good light output. Too high and you artificially age the filaments and then end up with low light output even though the face of the tube looks brand new. (I have a couple blue tubes in the basement like that!..and no I didn't wreck them  )
In my opinion you should seriously think about doing your learning on the old(er) tubes. Just don't turn the power off with the P14 connector disconnected! Conversely, you should take your voltage reading with the projector powered on and all the tubes connected. Then pull the P14 plug, check your voltage, adjust the potentiometer to get 6.35v, and then reconnect the P14 connector. I drilled a 1/4" hole through the plastic side panel so I could get at the potentiometer to adjust it. My projector was already ceiling mounted when I had to work on the spare LVPS so no way to remove the panels. If your pj is still table mounted then of course it will be a piece of cake to get at it.
As usual I'm rambling.  If this is your first CRT projector I'd keep it table mounted at the correct throw distance from the screen and learn on it that way before hanging it.
FYI-Watch out for them there fat red wires going to the tubes...they have a tendency to take all the fun out of poking around under the hood. 
_________________
Greg
"Is it ignorance or apathy? Hey, I don't know and I don't care!" --Jimmy Buffett
|
|
| Back to top |
|
|
Francesco
Joined: 08 Jul 2010
Posts: 64
Location: Italy
|
| Posted: Sat Oct 02, 2010 10:15 am Post subject: |
|
|
Greg, thank you for your reply.
Errr... what does it happen if I take the power down with the P14 disconnected?
Can I re-install the old blue without the plastic housing, like temporarily laying the tube on a plastic wrap or something similar?
|
|
| Back to top |
|
|
Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
|
| Posted: Sat Oct 02, 2010 11:26 am Post subject: |
|
|
You can power down the PJ with P14 disconnected no problem actually its a safety valve incase you ever have a run away G2 value when the tube goes really bright. You pull P14 while the set is running and you wont get spotburn if the spotkill circuit fails.
here is a repost from my marquee thread. 6.45 will kill the cathode on the tubes quick!
http://www.curtpalme.com/forum/viewtopic.php?p=106293#106293
The first installment I thought should be the Heater filament fix . this is to save the tubes
from over voltage to the heater elements in the tube causing premature failure.
remove the LVPS from the projector and open up the case being careful to remove all
connectors before completely opening. Locate the 6.35 voltage trim pot on the section
that houses the fans. a 470 ohm metal film resistor and a 20ohm trim pot is needed.
here is a close up pic.
remove the old pot that causes the drifting of the voltage as shown here
then I wrapped one end of the resistor around the existing resistor as shown, I did
this backward for the pics, I should have cut the trace first as in the next pic after this
one.
this pic you can see the trace cut and the resistor soldered to the other
resistor, i found it easier to keep the lead on the resistor then cutting it after its all done.
Then I fed the other lead through the whole that the cut trace goes to. Make sure all the
old solder is removed so the pin from the trim pot can also fit.
Now with the new trim pot in place.
Back side of board showing lead from resistor and trim pot leads.
Solder the pins from under and put power supply back together and test the output before
you connect P14. trim pot to get as close to 6.35 as you can.
While you have the cage for the power supply out you can cut the screen area to allow better
airflow and it could also help reduce and turbulent noise, i used a pair of metal snips then a file
to smooth it out. I also added dynamat to the inside stop any vibrations in the chasis.
A fan noise post will also be in this thread too.
Parts needed: I get mine from Newark:
http://www.newark.com/jsp/search/productdetail.jsp?SKU=62J1506
http://www.newark.com/jsp/search/productdetail.jsp?SKU=94C3568
Athanasios
_________________
Don't blame your underwear for your crooked ass~ unknown Greek philosopher
"Republicans believe every day is the Fourth of July, but the Democrats believe every day is April 15." --- President Reagan
One Smart Dog!!!
Marquee High Performance Bellows now shipping!!
Marquee Modifications and Performance Enhancement
Marquee C-element and Bellow removal
|
|
| Back to top |
|
|
Sparky015
Joined: 12 May 2009
Posts: 1185
Location: Cleveland / Akron, OH
|
| Posted: Sat Oct 02, 2010 12:23 pm Post subject: |
|
|
If the blue tube is removed, you may not be loading the curcuit all the way, making the 6.45V number meaningless. I would encourage you to put the blue in and try again before calling it bad and modding, or adjusting the filament voltage without having the proper load. All tubes should be in when doing the test. It's the only way your going to know.
_________________
~Paul
|
|
| Back to top |
|
|
Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
|
|
| Back to top |
|
|
Sparky015
Joined: 12 May 2009
Posts: 1185
Location: Cleveland / Akron, OH
|
| Posted: Sat Oct 02, 2010 1:38 pm Post subject: |
|
|
maybe I mis-interpreted the post. I thought he said he measured 6.45V with the blue tube not in the projector. If that is the case, you have basically a 1/3rd of the load missing, which I would think would affect the voltage. Maybe I'm just not fully comprehending yet this morning without my morning coffee
_________________
~Paul
|
|
| Back to top |
|
|
Sparky015
Joined: 12 May 2009
Posts: 1185
Location: Cleveland / Akron, OH
|
| Posted: Sat Oct 02, 2010 1:40 pm Post subject: |
|
|
OK, so I thought about it, and just realized I check filament voltage by basically disconnecting all three tubes and checking it, so ignore my last two posts. THat's what I get for thinking technically without first having my morning coffee
_________________
~Paul
|
|
| Back to top |
|
|
dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
|
| Posted: Sat Oct 02, 2010 2:00 pm Post subject: |
|
|
how did he fire up the pj with one tube out??
_________________
1 answer always poses multiple questions.
marquee 9500ultra HD10L moome hdmi1.3 v3+ some mods.
|
|
| Back to top |
|
|
Francesco
Joined: 08 Jul 2010
Posts: 64
Location: Italy
|
| Posted: Sat Oct 02, 2010 2:27 pm Post subject: |
|
|
well... I just connected the power cable and pushed the power button on the remote 
I had two error lights (h.fail and v.fail) and no light out from the tubes, but the fans fired up
|
|
| Back to top |
|
|
dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
|
| Posted: Sat Oct 02, 2010 2:47 pm Post subject: |
|
|
ah lol, i know it gives those error lights and doesnt fire up the pj but you still can measure the filament voltage, did not know that.
makes sense only hv isnt switched on.
_________________
1 answer always poses multiple questions.
marquee 9500ultra HD10L moome hdmi1.3 v3+ some mods.
|
|
| Back to top |
|
|
Francesco
Joined: 08 Jul 2010
Posts: 64
Location: Italy
|
| Posted: Mon Oct 04, 2010 9:02 am Post subject: |
|
|
Hi all, a little update: I've tried to reinstall the old blue tube to make some practice... but I think I have to make some *more* practice: I did something wrong because after 2-3 seconds from the powerup I heard a buzz and then a POP! from the neck board. I also saw a spark in the middle of the neck board, somewhere near the G2 plug on the tube. After that I had a h.fail error light. I think that I did not push the neck board enough so maybe the little pins on the tube did not properly go into place... I'm 100% sure that the G2 was in the right place, it was exactly like this
What can I have done? Maybe the G2 plug was not properly in place?
Do you think that I've seriously damaged something? I don't care about the tube, it's the old one, but I fear that I've damaged some of the boards...
|
|
| Back to top |
|
|
|
|
