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Meemil
Joined: 25 Mar 2016
Posts: 96
Location: Finland
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| Posted: Wed Dec 06, 2017 1:35 pm Post subject: |
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Alright, I'm very positive the fault is in OP-AMP on the blue focus channel. As the document Gjaky linked says, amps can easily get shorted by an HV arc. I did actually have a little HV leak a while ago resulting LVPS to pulse, so maybe that zapped the chip.
This is a little off-topic question but gotta end the upcoming vicious cycle 
I just cleaned the anode leads and noticed they're older type (without pvc shielding). I really wanna add some pvc tubing on them but first I've gotta desolder the connector tip. Does anyone know how this is done?
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Wed Dec 06, 2017 2:14 pm Post subject: |
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best to order 3 hv cables from curt if he has them still
_________________
1 answer always poses multiple questions.
marquee 9500ultra HD10L moome hdmi1.3 v3+ some mods.
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Wed Dec 06, 2017 2:15 pm Post subject: |
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oh yeah and replace them with tle2074... all 3
congrats on finding the culprit
_________________
1 answer always poses multiple questions.
marquee 9500ultra HD10L moome hdmi1.3 v3+ some mods.
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Meemil
Joined: 25 Mar 2016
Posts: 96
Location: Finland
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| Posted: Thu Dec 07, 2017 6:16 pm Post subject: |
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Thanks Dvh, I'm still speculating tbh but I don't really see what else it could be Also I need to get some real new anode leads but I first gotta come up with something as a temporary emergency solution. So really if anyone knows how to desolder the anode lead I'd love to know!
On another note, seems like tle2074 is not available in dip package anymore. I could get OPA4134, which performs quite the same, cheaply in dip so I think I'm going with that instead.
Thanks!
Eemil
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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Meemil
Joined: 25 Mar 2016
Posts: 96
Location: Finland
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| Posted: Fri Dec 08, 2017 1:26 am Post subject: |
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I was aware of the HV lead removal from the tube bell, but I was mainly thinking 'bout removing the small tip on the other end (connected to splitter) as I have the PJ set up and don't wanna take the tubes out.
Tim does mention something here (post #6)
http://www.avsforum.com/forum/16-crt-projectors/65042-electrohome-marquee-8500-screen-going-blank.html
but I think I've just done goofed and understood it the wrong way!
It's cool that Farnell does have them in stock indeed, but it will become more expensive for me than with the OPA4134. And as far as I know, both should be suitable substitutes, remember Draganm writing about this somewhere.
Thanks so much for the links though, your help's been great!
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Meemil
Joined: 25 Mar 2016
Posts: 96
Location: Finland
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| Posted: Sat Dec 30, 2017 11:33 am Post subject: |
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Little update: changed the op amps and blue is still f---ed  I think it's time to throw hands in the air and get a new board.
As a side question, could faults in other boards such as vertical affect the dynamic focus on one channel?
Thanks
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Sat Dec 30, 2017 3:39 pm Post subject: |
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Have you already checked resistors R302, R392, R315, R395 if they are open?
It would be possible to reroute for example the Green focus signal to the blue channel, that would help in deciding wether the output amplifier is deffective or there is no control signal at all.
_________________
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
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Meemil
Joined: 25 Mar 2016
Posts: 96
Location: Finland
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| Posted: Sun Dec 31, 2017 1:23 pm Post subject: |
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| gjaky wrote: | Have you already checked resistors R302, R392, R315, R395 if they are open?
It would be possible to reroute for example the Green focus signal to the blue channel, that would help in deciding wether the output amplifier is deffective or there is no control signal at all. |
I just tested the resistors you mentioned, and they all measured good. Would the rerouting be a big task? I'd be willing to give it a shot!
Thanks for the advice!
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Sun Dec 31, 2017 6:58 pm Post subject: |
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While I admire your persistence, you realize that you could buy a working tested board from me for $10 plus about $50 shipping, right?
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Meemil
Joined: 25 Mar 2016
Posts: 96
Location: Finland
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| Posted: Mon Jan 01, 2018 12:46 pm Post subject: |
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| Curt Palme wrote: | | While I admire your persistence, you realize that you could buy a working tested board from me for $10 plus about $50 shipping, right? |
I most likely will end up doing that, it's just a shame as this board is now updated with new caps and op-amps so the work ended up being redundant.
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Mon Jan 01, 2018 2:29 pm Post subject: |
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| Meemil wrote: | | gjaky wrote: | Have you already checked resistors R302, R392, R315, R395 if they are open?
It would be possible to reroute for example the Green focus signal to the blue channel, that would help in deciding wether the output amplifier is deffective or there is no control signal at all. |
I just tested the resistors you mentioned, and they all measured good. Would the rerouting be a big task? I'd be willing to give it a shot!
Thanks for the advice! |
Not at all.
One leg of C315 goes to the multirow connector PA11's Pin13, that is the input of the Blue horizontal focus, The same for the green channel is C215 PA11's Pin14. By lifting that pin and tying to the green's signal channel can help to rule out whether the FCM itself is the problem, or the input signal is missing.
_________________
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
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Meemil
Joined: 25 Mar 2016
Posts: 96
Location: Finland
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| Posted: Mon Jan 01, 2018 7:57 pm Post subject: |
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| gjaky wrote: | | Meemil wrote: | | gjaky wrote: | Have you already checked resistors R302, R392, R315, R395 if they are open?
It would be possible to reroute for example the Green focus signal to the blue channel, that would help in deciding wether the output amplifier is deffective or there is no control signal at all. |
I just tested the resistors you mentioned, and they all measured good. Would the rerouting be a big task? I'd be willing to give it a shot!
Thanks for the advice! |
Not at all.
One leg of C315 goes to the multirow connector PA11's Pin13, that is the input of the Blue horizontal focus, The same for the green channel is C215 PA11's Pin14. By lifting that pin and tying to the green's signal channel can help to rule out whether the FCM itself is the problem, or the input signal is missing. |
Alright new results are here! Thanks Gjaky for the instructions. I connected the pin 13 (blue) to pin 14's trace and disconnected actual pin 14. So basically blue's signal goes now both to green and blue channels, right? Anycase, now green's dynamic focus stopped working too! Does this mean the problem is somewhere else in the machine?
Thanks again!
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Mon Jan 01, 2018 9:47 pm Post subject: |
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The focus control signals are originated on the CLM.
To make everything sure please do a cross-check, ie. tie the green focus signal to both green and blue at FCM to se blue working that way.
_________________
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
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Meemil
Joined: 25 Mar 2016
Posts: 96
Location: Finland
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| Posted: Mon Jan 01, 2018 10:47 pm Post subject: |
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| gjaky wrote: | The focus control signals are originated on the CLM.
To make everything sure please do a cross-check, ie. tie the green focus signal to both green and blue at FCM to se blue working that way. |
Oh well, did that and blue hasn't changed at all, though green works now. Ramping up the dynamic focus on green wont do anything to blue. In my previous post I most likely got confused and tried to watch the green grid with its own controls even though the signal was routed thru blue  I'll redo the previous test tomorrow and report the results. So far I'm pretty convinced that fcm has crapped the bed.
Thanks!
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Meemil
Joined: 25 Mar 2016
Posts: 96
Location: Finland
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| Posted: Tue Jan 02, 2018 1:14 pm Post subject: |
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So I've rechecked everything and it's now clear that FCM is causing issues. Thanks Gjaky for your efforts in helping to diagnose the board, if there's any more possible dead components I should check, I'd really appreciate that sort of info! Otherwise, I think I'm just gonna get a replacement from Curt.
Cheers!
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