I've reworked my HVPS according to Mike's HVPS maintenance docs but after putting it back I cannot get the projector to show individual colors. When I switch to red the green tube turns on too (with less intensity) and that's the case when I switch to blue. When I switch to the green tube both blue and red are lit too (with less intensity).

The HVPS is a model X2532 (I3)

I've changed the following components:
2x 1 uF cap
2x .47 uF cap

6x 560 kOhm - the older ones have drifted to ~700 kOhm already (I think here could be something wrong)

Any ideas? :confused:

Thanx
TEOnaki

Hello

The 560ks are the G2 circuits, did you redo your G2 adjustments in the service menu?

I've tried it already but the G2 levels are not affecting the overall picture. The problem is still there even if I set every colors G2 below 50.

:(

Hello

Go to the internal stairstep pattern and service/G2 adjust, you should see the second darkest step light up or disappear when running G2 up and down for that color. The tip of the resistor next to the G2 feed, R76, on a given neckboard should read near 0 to 660 volts with G2 run from 0 to 80 in the service menu.

If you run out of options, I can test your HVPS sent here.

Both of my modded power supplies do the same thing. I have not seen it affect the image at all. I wonder if its a by product of the mod itself? I also changed out the other carbon comp resistors as well. do you Think this mod might increase the output of the G2? If the new resistors are more close to actual reading(mine were dead on 560k) than the carbon comps were when they were first put in (my old one read 720) . this could be why were seeing this, when i did the mod i noticed two trim pots on that board that are sealed. I bet these were set at the factory to the proper level voltage with the orignal value of the carbon comp, and now that we lowerd the resistance that voltage would go up. Is this line of thinking correct or am I way off on a tangent?

Athanasios

That gave me an idea - I've changed the 560k resistors to 700 kOhms.
Now everything is back to normal. :)

I hope it will work for the long term too.

Thanx
TEOnaki

Thats cool it worked but i wonder if those pots are for this type of issue after replacing worn or blown parts? Tim any Ideas? I'm Afraid to touch them to see if they will adjust the output after the resistor change.

Teo did you use 700k ohm ceramics just like the 560k ones?

EDIT: Just checked the actual reading on my old carbon comps they all averaged close to 680k ohms so maybe this mod should be to first check your old value and order a value close to it. I will order some 680k Ohm Ohmites and try it out to see what happens and if Tim responds with how to adjust the trim pot on HVPS to compensate for the lower ohm replacements i'll also try that.

Athanasios

I've changed out those resistors a many times and have never seen this problem....:confused:


Whatever you do DON'T touch any pots or adjustments on that HVPS. The two in question has nothing to do with the G2 circuit. Any adjustment of any of the pots on the HVPS could easily cause the HVPS to either not operate at all, or possible exceed the rated operating voltage. Once that happens, good luck in getting it back to where it needs to be..

I've changed out those resistors a many times and have never seen this problem....:confused:


Whatever you do DON'T touch any pots or adjustments on that HVPS. The two in question has nothing to do with the G2 circuit. Any adjustment of any of the pots on the HVPS could easily cause the HVPS to either not operate at all, or possible exceed the rated operating voltage. Once that happens, good luck in getting it back to where it needs to be..

Yeah i was waiting for that confimation! thanks Mike! I think i'm going to swap out the 560k for 680k and see if i get the same results as Teo. i'll post back once i get the parts and confirm it. Although i havnt noticed any advers affects to the pic i'm just worried it might prematurly damage the tubes or other circuts or maybe the neck board.

Athanasios

Checked my old ones, averaged 713 ohms. Ranged from 672 through to 737.
Paul

Paul have you done the mod yet? I know from curts site you said you were working on it soon. If you have , are you also noticing this anomaly?

Athanasios

Hi Athanasios,
Yes, I have modded the HVPS ( with 6 x Ohmites and 2 x piggy-backed resistors at R5 & R46) but after doing so I only checked the 9500 to make sure the HVPS was still working correctly and then took it apart to replace the LC Bellows. The 9500 is still in bits so I can't confirm if I have any problems with the tubes or not.

From memory, I'm pretty sure that when I reinstalled the HVPS, I did a quick G2 and had the tubes light up one at a time and didn't see anything odd in the other tubes but then again I was looking into each tube face in less than ideal conditions and may not have noticed if another tube was lighting up.

I still need to replace the two (incorrect) Metal Film resistors at R5 and R46 with the (correct) Ohmites, as well as replace 3 other resistors. However, I'm loathe to change anything else until I'm absolutely sure that all the mods that need to be done are being done using the correct replacements.

Teo's findings (and your own) indicate that possibly some of the mods may need changing so I'm sitting tight on any further mods at the moment as I seem to be permanently having to undo something that was only done a week or so ago.

I've given up on the convergence board and VDM, I have no idea what resistors need to go into them! I've read and re-read the many posts and still can't grasp whats needed. Its a lot of work to redo if the wrong resistors get installed!

Anyway, looking forward to your findings with regard the 700kohm Ohmites.
All the best,
Paul

I can't recall how many of those 560K resistors I've changed over the years. Not once have I had the problems that you guys have mentioned.

And why would a resistor clearly be marker 560K, and the measured value is near 700K and that would be the value to use for replacement?

When the day comes that I'm no longer able to get the 560k resistors to do what they have been doing, I'll still leave them in the SMPS, and from there try and figure out WHY the 560K value is not working.

I can't recall how many of those 560K resistors I've changed over the years. Not once have I had the problems that you guys have mentioned.

And why would a resistor clearly be marker 560K, and the measured value is near 700K and that would be the value to use for replacement?

When the day comes that I'm no longer able to get the 560k resistors to do what they have been doing, I'll still leave them in the SMPS, and from there try and figure out WHY the 560K value is not working.

I find it strange also Mike. Teo had luck changing back to what the worn out value was and lost the anomaly in the tubes. What do you think is causing this? Also do you think it could cause any damage to the tube being affected? I have watched many movies since the mod and have not had any issue with what i'm seeing on the screen the only thing i'm worried about is hurting some component along the way. In my mod i changed all the carbon comps and the .47uf and 1uf caps all with the same value my resitors were of the 2 watt variation . Also Forum member 1031 in finland has the same issue with his marquees.

well i'm not going to let this stop me from enjoying my projectors, pic looks great and the blanking issues i had are gone. Not sure if the mod got rid of them but i'm happy none the less.


Athanasios

I'm not less confused than You Mike. I've tested the PJ with the ~700k resistors for only ca. 30 minutes but the odd behavior has almost gone. When I look directly into the tubes at C50/B50 the green tube is still not off, but the intensity is so marginal that you cannot see it on the screen, not even in total darkness.
I will test it for longer periods this week.

Actually I haven't used 700k resistors - there is no such value. I've put some other values together in such a horroristic way that I don't want to explain it :)
The sum of the resistors is at ~1.41 MOhm close to the original carbon pairs.

It's a very strange Marquee with several oddities.
(I had some problems with the FCM too - "strange waves" as I've described in an other thread.)
It was used in a 3D VR-Cube setup with very asymmetrical usage ~2800h on/ 14500h standby. The tubes are absolutely clean and white (9/9/9) but the p14 was way off (6.64V) so they are relatively weak.
Maybe these slightly damaged tubes causing this phenomenon.


to be continued
TEOnaki

Another strange thing is going on too, i have a few different Vims here. one 2035-03p that was in it when i first noticed the anomaly. I am playing around with two older 2005-03p vims trying to see what different op amps will do. well i had one that someone already did the max4224 mod to and i was testing out a newer Intersil EL5166 in place of the max's. the anomaly got a lot brighter on the green when the red was only on and i was using the chip on the red channel !!! so i thought this was weird so i put in the stock 2005-03p and now the blue was the brightest when the red was on !!so i put the 2035-03P back in and it went back down in intensity. not sure what's going on but it is definitely strange. i agree with mike that we should leave the 560 ohms in and try ti figure out what it is that is causing the other tubes to light up a bit.

Athanasios

Just noticed something else while trying to hunt this down. I had on a 2:35 movie playing while i was turning the tubes on and off one by one and in combinations and on the green behind the image playing i could see the grid in the back ground, in the rest of the unused 16x9 area! that almost seems like it be the switching dmos chip on the vim. the SD5401. Do you think the mod from the power supply did some damage to the sd5401 allowing it to leak the internal video into the video chain?

Athanasios

So Teonaki, any news with going to the old worn resistor values regarding pic quality and the intensity anomaly? I haven't ordered new resistors yet to try it out.


Athanasios

Hello, not sure if i should have started a new thread for this but it is related to what has been said here so far with regards to the weird happenings after the HVPS mod. I have been looking at doing component upgrades to all the boards on the marquee starting with the HVPS mod that has caused some here to have intensity problems with the other tubes lighting up brighter than normal while showing only one color. The nex board i was working on was the Focus board. I changed out most of the electrolyitic with higher voltage and the 6 470uf to 1000uf caps which helped with tightening up of some focus drift i had, i had to keep going into the focus for each color to readjust it every week or so. I still have to changeout the sealed square plastic encapsuled caps with better quality ones but now on to what is related to the tube brightness.
I have been going through all the chips on all boards looking for newer replacement chips for most of the op amps in the marquee. I was looking at the specs for the MC34074 and MC34084 op Amps and it seemed that there were better less noisy chips out there so I started my quest and found the Texas Instruments TLE2074 Excalibur http://focus.ti.com/lit/ds/symlink/tle2074.pdf that is a direct drop in for that amp . I wanted the OPA 4134 but they no longer make that in dip style and I did not want to use a chip carrier since they can add noise themselves. Well the first thing i noticed was a big drop in background noise when i was looking into the tubes with a full white field . I had a lot of snow before and even after the HVPS mod, but now it is almost all gone. So this is where i noticed a change in the Higher intensity tube glow from other tubes while showing only one, I wanted to see how each tube faired individually with this new chip and discovered that the tube anomaly is gone!! It is back to the normal barely visible intensity as from a non modded HVPS.

I'm not an EE but what would cause this, I am definitely going to change the chips now on my other marquee. For those of you who have this same problem try to change your focus board MC34084's out for the TLE2074's it definitely made a difference to background noise since the new amps are a third less noisy and have a higher slew rate along with double the bandwidth of the MC34084.

If anyone else tries this upgrade let me know your results. I did the upgrade to a 2034-02 board(not sure of exact number).

Athanasios

Update to previous post:::

After checking for the problem all that day i changed the chips and all day yesterday after watching a couple movies every thing was fine. Today i went to check it again and now the problem is back. So the new chips will not fix the problem although they still have reduced the noise level in the back ground. So now i will try the increas in the value of the resistors.

Athanasios

Hi Athanasios,

I had now two weekends in a row without my wife and the kids :)
(they're at granny)
so I could test my PJ thoroughly. I've set it up and watched several films for 10+ hours and nothing has changed. The problem has gone and there are no new ones.
I've read your post from 01-24-08 and I was glad that you've found a cure to this problem until I read your update. So I think I'll finalize my temporary solution and order some 680k Ohmites. They're not exactly the same value but I'll give them a try. I know its not the right direction but I haven't got the resources to figure this out.

Tough I'm an EE but unfortunately I'm not an expert in CRT-s (I'm on the dark digital side of the electronics) - so I don't know the cause yet, and I find it quiet interesting that I have to choose a part not according the schematics but the actual (drifted) value of the component to be replaced.

I'll be back when I have some news.

=:-)
TEOnaki

Thanks Teo, one thing i noticed last night was if i lower the contrast the other grid goes down considerable if its set at 50 or below. I think this was the case from my first assement when i changed out the op amps on the focus board, i had to turn down the contrast to look into the tube face and this may be why it wasnt as pronounced in intensity. But if i remember correctly before the focus op amp mod the higher intensity grid was still there even at a lower contrast so maybe that mod does reduce it somewhat.

I also orderd new resistors at 680ohms and will put those in as well.

Athanasios

Update:

I received the 680k ohm resistors that were close to the value of the old resistors removed from the HVPS before the mod. I installed them and the anomaly is gone , even after watching a movie, all is good. So I suggest to anyone doing the HVPS upgrade to keep your old resistors or measure them before throwing them away. This way if you have the same Problem Teo , 1031 and I have had you can swap out the 560k's for a closer value to the ones you removed. Mine were closer to 690k i just went a little under to see if it works...and it does.

Athanasios