| Author |
Message |
listenlounge
Joined: 29 Apr 2007
Posts: 48
Location: NSW, Australia
|
| Posted: Sun Jun 29, 2008 11:56 am Post subject: Blue tube illuminated when Marquee is in STANDBY??? |
|
|
OK - here's a weird one, pulled out the trusty 8500 today to set it up in its final home ( my NEW HT - such a long time coming ) and pulled the HD144's off to get the rasters centred on the tube face. Put it into standby mode, and PRESTO!
The blue CRT still has illumination. Pretty much the whole tube face - like a white field test pattern, but EVER so feint. If the lenses were on and the theatre was dark, you wouldn't even notice it on the screen. You can only see it with the lenses off.
More...
It flashes!
Oh dear..... Can anyone shed light?
Cheers
Ben
|
|
| Back to top |
|
 |
David_Web
Joined: 02 May 2007
Posts: 418
Location: Sweden
|
| Posted: Sun Jun 29, 2008 12:24 pm Post subject: |
|
|
Marquee does keep the filaments at around 4.4V when in standby. So they might emit enough electrons to make a faint light.
However should that not be prevented by the spotkill circuit? IIRC there are charged caps on the VNB to make sure the beam is muted until HV is bled down. Maybe they are bad or the HV is not bled down properly.
Maybe you should measure P14 when in standby as well as it might be too much, IIRC it is for keeping the internal parts of the tube warm but not electron emitting hot.
Or maybe arcing (or more like static electricity) sparks generate enough electrons to make a faint light. Bad grounding?
I'm just guessing here.
_________________
SNR of people are ridiculously low.
|
|
| Back to top |
|
|
Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
|
| Posted: Sun Jun 29, 2008 12:29 pm Post subject: |
|
|
There is also a charged cap on the vim that keeps things like spot kill on while the pj shuts down or turns on, changes inputs ect. its .1f cap on the vim. But I doubt its that, I would do as David says and chech the heater voltage in stand by and on, you may need to to the LVPS heater fix. If you do just click my signature for instructions.
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 |
|
|
Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
|
| Posted: Sun Jun 29, 2008 1:26 pm Post subject: |
|
|
| David_Web wrote: | | Marquee does keep the filaments at around 4.4V when in standby. |
You better check your filament voltage when the set is on. EVERY Marquee that I've had in has 3.89 volts going to the filament in standby. It's so accurate that I set the filament pot to 3.89 volts after I've put in the modded pot, and rarely have to tweak that voltage when I turn the set on, it's already at 6.3 volts.. 
So make sure your filament is at 6.3 volts. I think it's sitting around 7 volts if your standby is at 4.4.
|
|
| Back to top |
|
|
|
|
