Anyone for some Marquee Maintenance? - Page 7 - AVS Forum
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post #181 of 614 Old 03-01-2003, 01:18 PM - Thread Starter
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Jay,
I'm not sure but I believe the weak soldering joints would be on most of the early version boards, not really noticed on the vertical though, but it's best to solder them as well (Preventative Maintenance). I think it may come from heat and high hour usage, because the transistors on the heatsink get really hot. I had the same problem on the 9500 that I have here. It took awhile to isolate where the drifting was coming from, but I did get to put my finger on it (literally). Another way to check for this is to let the projector warm up for about twenty minutes, bring up a converged grid and press on the convergence board from the center, if the convergence shifts, it's the connections. You can also do this with the horizontal deflection circuit, bring up the grid and then touch the area where the coils are with a plastic non conductive, non magnetic object.

You may not have noticed this on your Marquee, but you've probably heard this before: "after the projector has been on for awhile I have to touch up on the convergence" The Marquee if properly setup and operating properly should show very little drift from cold to warm up. I have a few customers who has complained about this drifting, so I rolled my sleeves up and went to work here in my shop, and I had the perfect Marquee for it, it had high hours and it was a little drift happy. It's now very tight, and I like showing it off, but it required a little work to achieve that stability.

The good thing that I really like about the convergence and vertical boards is the stabilty of the output devices, especially the power transistors on the convergence board. These transistors can get very hot, yet they only show variance if they are not properly mounted to the heatsink. And I always revitalize the rubber isolator when I replace a semiconductor, I don't trust dry contact, it works fine when the isolator is new, but after awhile the surface hardens and looses its effectiveness.

Mongo, thanks for the offer. I'm sure it's something we'll probably need. I'm waiting on the gamma project, and would like to hear how the power supply filament fix pans out. I think that with our cooperative work effort, we'll keep this wonderful work of electronics at the apex of video display.

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post #182 of 614 Old 03-02-2003, 05:24 PM
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Mike would it not be a good to use heat-sink compound instead of Vaseline??

I have Gamma circuit in eagle I just had no time last week to do any thing. I hope to do the layout tonight.. Then all that will be needed it to adjust the trace width so it is 75 ohm.
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post #183 of 614 Old 03-02-2003, 07:32 PM - Thread Starter
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Sly,
sure, heat-sink compound should be fine, as long as it can revitalize that isolator, that's the real goal. I did not mention heat-sink compound because some of it can be so thick and pasty. I also use the small tubes from Radio Shack, it goes on just like petroleum jelly, but make sure you clean the isolators surface first.

Oh, and don't forget to use this same procedure on the stigmator board (next to the convergence board), for those who have 8500's, 9500 and 9000's

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post #184 of 614 Old 03-03-2003, 06:31 AM
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Hi Mike

Thanks for the latest installment of Marquee maintenance. I am
having difficulty locating "fusable metal film resistors". Digikey has
some described as "metal oxide resistors" or as "metal film resistors".
They carry the YAGEO RSF series which offers a .47 ohm or a .51 ohm
at 1 watt resistor. The BC and Panasonic resistors are only offered in 1
ohm or higher at 1 watt. will the YAGEO be OK even though it is not
described as fusable? They all have a 5% tolerance.

Thanks

DH
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post #185 of 614 Old 03-03-2003, 11:51 AM - Thread Starter
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DH,
here you go:

http://www.micro-ohm.com/

You'll want Part# FRN1/4 - 1 ohm 5% tolerance.

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post #186 of 614 Old 03-03-2003, 12:34 PM
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Mike

Thanks for the info.

DH
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post #187 of 614 Old 03-03-2003, 02:01 PM
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OK I found a cool free program to do the math for the trace widths.

http://www.hp.woodshot.com/appcad/version302/setup.exe

it won't be long now...
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post #188 of 614 Old 03-06-2003, 12:22 AM
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I think I almost got it done.

I think I will add 2 10uF caps on the power coming in
it looks like is will cost about $1 each for the raw PCB's from AP.

take a look .
LL
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post #189 of 614 Old 03-06-2003, 03:10 AM - Thread Starter
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Kudos!

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post #190 of 614 Old 03-11-2003, 06:46 AM
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Mike

Hellloooo Mike

I think there is still one board to go. I am waiting with iron in hand O Great One. Please impart more wisdom to those, like me, who kneel at your feet.

A Dark Side Disciple
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post #191 of 614 Old 03-11-2003, 11:58 AM - Thread Starter
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Ok, we'll get back to this in a day or so. We have the focus and control boards, and then we'll go over what we have covered, and I'll throw in another nugget or two...

mike

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post #192 of 614 Old 03-11-2003, 12:58 PM
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I got some sample jacks from Connect-teck very nice guys.
so I will be sending out the PCB as soon as I check that the jacks look OK.
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post #193 of 614 Old 03-18-2003, 11:34 AM
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I got my Gama PCB back and have finished building the first one. I have not powered it up yet.. I need to find a split power-suply I can use and good pulse gen. to test/tune it..
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post #194 of 614 Old 03-18-2003, 05:54 PM
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Betcha Mike's got a bunch of split power supplies (+/-5V) ala MP-1.

Cary

PS. You can also get +/- 12V from a PCI slot. I use a riser card with a thru-hole PCI connector on it and solder wires to the back of it to get at +/- 12.
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post #195 of 614 Old 03-18-2003, 07:12 PM
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I found a supply + - 5V


There is some over shoot I trying to get rid of.
the mini RCA is crap and causing some ringing on its own..

I think one of the mods should be to remove them all and replace with something that is 75ohm impedance.

I have been busy so I have not spent much time on this
but I am in the tuning stage now..
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post #196 of 614 Old 03-19-2003, 12:33 AM - Thread Starter
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Quote:


Originally posted by sly
I found a supply + - 5V


There is some over shoot I trying to get rid of.
the mini RCA is crap and causing some ringing on its own..

I think one of the mods should be to remove them all and replace with something that is 75ohm impedance.



Sly,
the circuit (by itself) should not cause overshoot, nor should the mini RCA's. It sounds like the chip could be oscillating, and that's one of the problems when using high bandwidth Op amps, that's where the bypass caps come in, and that's also why they are to be placed as close as possible to the chip. Your board design looked good (I'm not sure here), so I would not suspect the board design, and therefore redesign the circuit itself to tame the "overshoot".

Why would you use a separate power supply when there's +/- 5 volts on the board?

I would think you should mount the circuit board as close to the main board as possible (I would mount it right on top of the RCA jack). Get your power from the board, but use 100uh inductors (one for each +/- power rail) for 'decoupling' from the main boards supply.

I wouldn't worry about the RCA's, your problem could be more related to grounding, decoupling or board location.

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post #197 of 614 Old 03-19-2003, 03:46 PM
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I am using a lab power supply because I have the board in the lab not in a PJ.
I have a pulse gen. feeding it and then the output goes to a scope. I had to make the 50 to 75 ohm network for the output of the pulse gen. And a 75 to 50 ohm network for the scope. This is how I am tuning it. So far its needs a 1 pF cap in the feedback loop the bypass look good but there is a tad bit of drop on the edge so I am going to add some small caps on the power I think the .1 is to big for the real high frequencies. I have only spent about 1 hrs on it so far I been busy doing other stuff.

It is getting there. When I think it looks good then it will go on the VIM and it is plugged on the connector there is no way to get it any closer then that..

I know the mini RCA cause some ringing because if i run it through the connectors going from the generator to the scope my nice square wave gets distorted with some over shoot. This just makes the tuning a bit harder thats all. I am feeding it with very fast edge's off a HP pulse gen. probably a lot faster then it will ever see in the PJ but it is good to tune too.
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post #198 of 614 Old 03-19-2003, 03:59 PM
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Quote:


Originally posted by sly
I had to make the 50 to 75 ohm network for the output of the pulse gen. And a 75 to 50 ohm network for the scope.

This is incorrect. The input to the scope is not 50 ohms, it is a high impedence on the order of 1-10 megohms. With a 10X probe it's higher still.

The output from the board should be terminated with a 75 ohm termination (assuming that the load presented by the next stage is 75 ohms). Ignore the load presented by the scope.

Marvin Match
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post #199 of 614 Old 03-19-2003, 04:34 PM
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Unless he's not using a scope probe but a coaxial input to the scope.

Cary
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post #200 of 614 Old 03-19-2003, 04:55 PM
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Quote:


Originally posted by jcmccorm
Unless he's not using a scope probe but a coaxial input to the scope.

Cary

Nope. The direct input to the scope is 1 megohm shunted by 20-35 picofarads. Thru a 10X probe it's more like 10 megohms and 2-4 picofarads.

A far cry from 50 ohms, probe or not.

If he's going directly into the scope, then he needs to use 75 ohm cable and a 75 ohm thru termination right at the scope.

Marvin
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post #201 of 614 Old 03-19-2003, 05:32 PM - Thread Starter
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Quote:


Originally posted by Marvin Match
Nope. The direct input to the scope is 1 megohm shunted by 20-35 picofarads. Thru a 10X probe it's more like 10 megohms and 2-4 picofarads.

A far cry from 50 ohms, probe or not.

If he's going directly into the scope, then he needs to use 75 ohm cable and a 75 ohm thru termination right at the scope.

Marvin

Yep, and the scope should not effect the circuit at all, even if the circuit is connected directly to the scope (1 meg) using a 75 ohm terminator.

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post #202 of 614 Old 03-19-2003, 06:49 PM
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Most scops have a 50ohm term you just hit the button and the 50ohm lites up...

I had a bad SMA I have replaced it and I am getting very good results now. I added 2 .01uf to the bypass and the 1 pF on the feed back. They stole my scope to do work, how dare they.... so I moved down to my lab and used my old 1Ghz analog scope ( I trust it more anyways the digitals lie)
I took some snaps I will download latter.. but I think it is working as well as the op-amp will let it. If the 1pF is left off there is a bit of over shoot.
If there is some role-off elsewhere we might want that boost in the hi-end..
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post #203 of 614 Old 03-19-2003, 07:11 PM
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...and they have the 50ohm input because you need this when using a 50ohm coax as your probe.

My TEK2230 just has two 1M/20pf inputs but the digital at work lets you switch to 50ohm.

Cary
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post #204 of 614 Old 03-20-2003, 12:51 AM
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the normal thing if you cant see any thing try http://www.geocities.com/hvps2001/gamma/


so here is the circuit board



here it shows the gamma boost in vs out notice the ramp change.


here is the speed test

and here is my mess with my old analogue scope
the ramp Gen. and the Pulse Gen. power supply etc.

LL
LL
LL
LL
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post #205 of 614 Old 03-27-2003, 06:42 AM
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Quote:


Originally posted by mp20748
Guy's,
the MAX4224ESA (Dallas Semiconductor) chips arrived on Friday. I've already installed them on a neck board, tested and viewed. So far this chip seems to be a perfect substitute. Could not even notice any difference in the gray scale.

This chip seems to be a good replacement for the now obsolete CLC449.

That completes the neck board, now we'll pick back up on the VIM...

Where can one get this chip. I tries everywhere and they only do quantity of 100.

Is their somewhere I could purchase 12 or so?

Thanks!
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post #206 of 614 Old 03-27-2003, 06:50 AM
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jrichards,
Go directly to the Dallas semiconductor website. From there you can request samples and get your 12 for free! This is the only place that I know of where you can get them in small quantities (less than a hundred). Good luck!

Paul

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post #207 of 614 Old 03-27-2003, 04:32 PM
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Thanks!
They are sending me 10.

I have a Marquee switcher which has the 409 chip in it's output circuit. Do you think it would be worth while changing it out with the new part? Also is their any other mods fot this switcher which might help it's performance?
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post #208 of 614 Old 03-27-2003, 04:39 PM - Thread Starter
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Quote:


Originally posted by jrichards
Thanks!
They are sending me 10.

I have a Marquee switcher which has the 409 chip in it's output circuit. Do you think it would be worth while changing it out with the new part? Also is their any other mods fot this switcher which might help it's performance?

Yes, remove the CLC409's, and I'm sure there's other things that could improve on the switchers performance, but I can't say because it's been a while since I've seen one.

The MAX4224 would definately improve that switcher...

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post #209 of 614 Old 04-07-2003, 12:59 AM
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I been very Busy but I thought I would start a parts list for what has been covered so far.

I think I got everything.


Neck

6 22uF 160V 105 degree
3 MAX4224

VIM

6 MAX4224

Vert squeeze

3 56.2K ohm digikey # 56.2KXB

HVPS G2

r9,r10,r15,r16,r21,r22 560k 2watt
r5,r46 220 ohm 2watt
c1,c2 .47uF 630V
c6,c3 1uF 400V

Allied part #
BC COMPONENTS 2222-468-28105 Capacitors, Metallized Polyester, Radial, 1.0uF, 40
0 Volts 648-3080


BC COMPONENTS 2222-468-40474 Capacitors, Metallized Polyester, Radial, 0.47uF, 6
30 Volts 648-3116


OHMITE OY564K Resistor, Ceramic, Axial, 2 Watt, 10%, 560k 296-5456

BC COMPONENTS 5083NW220R0J12AFX
Resistor, Power, Film, Axial, 2 Watt, 5%, 220 Ohms (Pack of 100) 649-6128


LVPS heater fix

20ohm pot
digikey 3299X-200-ND 20 OHM 3/8 SQ CERM MT SL POT

475ohm 1206

Vertical

fusable metal film resistrors at 1/2 watt
R720, R721, R820, R821, R920 and R921 R5 R6
change to .5 ohm

Convergence
There are twelve of them on the convergence board
R118, R117, R218, R217, R318, R317, R418, R417, R518, R517, R618 and R617

and
There are also 48 1.2 ohm near the power transistors.


horizontal deflection module 220 mfd @ 160vdc cap (C50)
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post #210 of 614 Old 04-21-2003, 01:06 PM
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Is this thread dead? I was hoping to get the last of the information needed to finish my Marquee 8000.

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