CurtPalme.com Home Theater Forum

[Nashou66]

Here are some pics of my HVPS replacement of resistors and caps. Have not tested yet since i finished the night before my trip to europe( Greece) where i am writing this from.

All resistors replaced Ohmite brand and .47 uf caps:








With 1 uf caps added resistors under replaced too!:


Vishay caps were kinda big but i sqeezed them in there!




View of all caps and Ceramic resistors in place:





Athanasios

[PaulB]

Does this look right?

Convergence Board
24 x RES 1.2 OHM .50W 5% MF FUSIBLE (Marked in RED)
R471 & R469, R470 & R468, R671 & R669, R670 & R668

R171 & R169, R168 & R170, R271 & R269, R268 & R270, R371 & R369, R368 & R370, R571 & R569, R568 & R570


12 x 2 (24 total) RES 1 OHM .50W 5% MF FUSIBLE (Marked in BLUE )

R118, R117, R218, R217, R318, R317, R418, R417, R518, R517, R618 and R617



[/i]

[PaulB]

Vertical Board
3 x 2 plus 5 (11 total) RES 1 OHM .50W 5% MF FUSIBLE (Marked in BLUE )


2 each at R721, R821, and R921. 1 each at R720, R820, R920, R5 & R6

[PaulB]

Blimey Athanasios, that is one SERIOUSLY modded HVPS

I've not seen that version of the mod before - did you design it yourself? What made you select these parts over the standard mod?

Fingers crossed that it works!
Paul

[Nashou66]

[Nashou66]

Here is where i read on the resistor changes foir the neck and HVPS.

http://archive.avsforum.com/avs-vb/showthread.php?s=c9d33be1287f937dc6c027271a09e752&threadid=416624&perpage=20&pagenumber=1

http://archive.avsforum.com/avs-vb/showthread.php?s=&threadid=401345

Have fun reading!

And the caps values i got form this thread somewhere, i thin the OP listed it somewhere. I just used different parts.

Athansios

[CZ Eddie]

[Nashou66]

Eddie i hope the mods i did to my HVPS work as well as you say yours have, did you look at my pics? what do you think of the caps? that is hat i'm worried about.

Athanasios

[Nashou66]

CZ said,

[CZ Eddie]

The green caps look like what I used in my HVPS. The Vishay's look pretty cool. If they are the correct value then I'm sure they will work fine for you!

[PaulB]

Ok, I've found the resistors that Mike refers to for the mods to the VDM. Part# FRN1/4 - 1 ohm 5% tolerance, - is this http://www.micro-ohm.com/wwfuse/frn.html the same as DIGIKEY Part # PPC.68BCT-ND RES .68 OHM .50W 5% MF FUSIBLE http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=PPC.68BCT-ND (marked in blue above )?

Also, still need clarification that DIGIKEY Part # PPC1.5BCT-ND RES 1.5 OHM .50W 5% MF FUSIBLE http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=PPC1.5BCT-ND is correct for the Convergence board (marked in red above)!?

I'd have thought a few folks would have carried out these mods by now but maybe not?

Thanks guys,
Paul

[Nashou66]

Has anyone had this happen after the HVPS mod shown on this thread. When trying to show individual tube lit up the one next to it will also show a very low level image. this is only when going into the individual tube colors. I have not seen any negative affect on the image at all. here is a thread storted on Avs by TEOnaki:
http://www.avsforum.com/avs-vb/showthread.php?t=976282

Most power supplies before the mod have the carbon comp resistors off of the original value by 50 -150 ohms at least from my own observations, having said that i am wondering if the new resistors that are very close to specs are actually closer than the originals and when the output voltage was set at the factory they were set for the higher valued resistors. And now that the new resistors are almost dead on it has affected the output voltage to G2. Anyone have any ideas?

Athanasios

Edit: Teo on AVs just changed the 560k ohm ceramics to 700k ohm ceramics the actual value he measured of the old removed carbon comps. This solved the anomoly. But i still wonder if there is a way to use those pot to trim the value for the new original spec'd 560k resistors.

[Nashou66]

Posted this also on Teo's AVS thread and on The oh boy smoking HVPS thread here but this is relavent to this thread as well.

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 from an 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

[Joust]

It might be time for a Marquee Improvements thread.

[PaulB]

Hi Athanasios,
Striking whilst the iron is hot, do you have a digikey part number for the TLE2074. I had a look but there are a number of different 14 pin ones listed and I'm not sure which one is the correct one http://tinyurl.com/2scksp .

Also, did you change the other two 470uf's capacitors at C10 and C5 on the focus board for 1000uf as well and did you use higher temperature ones or just the same 85 degrees (I seem to recall that 95degrees were recommended)?

I'll probably go ahead and change the capacitors but might hold back on the op amps for the moment.
Thanks
Paul

[Nashou66]

Hello Paul, I changed those two out with same uf value but higher wattage and higher temp. The op amps make the biggest improvement on that board as far as my viewing experiance tells me.I also plan to change the square 2,2 250 volt caps to 2,2 305 volt caps of better quality than the mkp's(philips?). Looking ofr wimas in that value also i plan on changing the 22uf small caps near the the 1000uf caps to a same value higher quality and temp and voltage cap.

On the TLE2074 you can get them directly from TI as a free sample just set up an account and say you use them for repair work. i have gotten a lot of parts from many companies this way, from Intersill,TI,Analog devises,Linear systems technolgy, ect .

Here is the page where you get all the info for the chip and you can get free sample here too. i looked at the TLE2074CN.

http://focus.ti.com/docs/prod/folders/print/tle2074.html

Athanasios


PS as more upgrades are done I will report them.

[garyfritz]

Nice work highlighting those resistors, PaulB!

So Athanasios, when you replaced all those resistors in the VNB and HVPS, did you see the kind of amazing improvements that Jaehong claimed? What would you say has been the best "bang for the buck" of all the changes you've done?

[Nashou66]

All have a little to contribute and I think they work together. I'm not an EE and have just got into CRT in november of 2006. First off i had an 8000 first and the first purchases i got were neck boards form an 8500(clc449 chips) and a VIM from a 8110(2035-02p). Those are definitely first on a list for some one who has an 8000, if you have a newer 8500 no worries. The HVPS mod just gave a little bit of noise improvment which may have contributed to deeper blacks i was seeing before any other mods. Next was the ceramic resistors to the VNB's the ones i modded had the cap change already to 160VDC caps, that reduced some of the streaking at 1080p to the right of dots and grid lines, however i think a better job at astig magnet adjustment may improve this even more. Next i did the Focus board since this was easy to do remove the caps and swap out the new ones, i still have more to change on this board. After that mod i noticed an improved stability of focus, that is, it didnt drift out of focus as before the cap upgrade. But the mod or change if you will that i think was the best at cleaning up any back ground noise was the op amp change on the focus board. The MC34084's are just noisy and i never really understood what that really meant with regards to video, but now, after putting in the TLE2074's, there is hardly any noise in a full white screen while looking into the tube face. Before i could plainly see it and the image wiggled ever so slighly but not noticible while watching a movie. now the image has stablalized a lot and the noise is minimal to the point i cant see it on the screen as before. So this latter mod i think made the best performance change but it was the last one i did. So have saying that i cant really tell if that mod alone made the major drop in background noise of if it was some combination of all.

The thing i was most suprised by? The chip mod to the FB, the strange high intensity ghost image on the other tubes while only one was on had dissipated to the way it was before the HVPS mod, very dim and it could be the after glow inherant to crt tubes after you shut them off. I have not done the focus mod to my ceiling mounted 8000 but will do the chip mod to it before the cap mod and let you know if the background noise lessens. I have two more of the TLE2074 and 5 of the TLE2084's the TLE2074 are a better chip but the 2084 are still better than the stock chip on the board so I might try to put the TLE2074's on the red and green focus and the TLE2084 on the blue till i get another TLE2074 in. TI only allows 5 free samples and i always need 6 damn it!

I hope this Info helps some of you out there. so for those who have done the HVPS mod and have that strange Anomaly to the tubes try to change out the chips on the focus boards and report back if you see the same results I have.

Athanasios

[Nashou66]

Update to previous post:::

After checking for the problem all on the day that 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 increase in the value of the resistors.

Athanasios

[Nashou66]

Another chip upgrade ! I swaped out the MC34802 op amps in the focus board to a lower noise TLE2072. A little more detail with regard to lower
Back ground noise. Watched Hitch switching between my two projectors and the one that has the new chip seem a bit sharper but this also has
the focus mods done also.

Athanasios

Still waiting for the higher value 680kohm resistors to see if i can eliminate the tube intesity problem's