help,Marquee Convergnce board problems

A reall smart aleck would just tell you to converge blue and green to match red and call it a day!


Give Curt a call and get a replacement convergence board and yoke from him.

That's the simplest way to go, and the easiest.


I'd check my setup if I were you, too. Raster centering, etc... because the

less work you give the convergence circuit to do, the cooler it will run and the

longer it'll last. When you go to the convergence screen and hit 0,0,0 on

the remote, that'll reset convergence to default. At that point, the centers

of the rasters should still be perfectly converged, and the height and width

of all three rasters should be matched, too.


I'm sure you know this already, but it never hurts to repeat it for the benefit

of any newbies who may be reading. The better the mechanical alignments,

the easier the electrical alignments become, and the less work they have to do, resulting in a longer service life.


CJ

Hah. This is really funny. I went to do a full setup on an 8110 that I just got

a commitment to sell. I have spent several hours on it today and I'm not done yet.


I start by almost taking the machine apart, doing the thorough inspection thing.


I discovered that the convergence board is not where it should be on the rear

heatsink, the horizontal deflection processor board has been snapped off of

the conv/HDP board assembly, and, most significantly, one of the heat sink

clips is nowhere to be found!


I salvaged one off of my "spare" projector and tagged it so as to remember

not to run it without a clip installed on the heat sink.


I get the projector together (the one I'm prepping for delivery) and....


Would you care to guess what's not working?


Yep...the RED convergence!



Crisis time. I don't have an EXTRA convergence board, so it's going to get

the convergence board off my experiment-in-progress machine.


I have already secured a replacement convergence board off of ebay. If you

need one for yourself, there's another one there with a buy it now price of 95 bucks. I suggest you snag it in a hurry!


Odd, that I should end up with the same problem as you on the same day,

and there are two such boards available immediately on ebay.


CJ

I just found another oddity.


I transferred over the convergence board from one machine to another, as I

mentioned before, and it works, but it wasn't long before I noticed that on

this machine, an 8110 with version 4.0 software, I can't move the red or blue

convergence grids all at once like I can with my 8000 with version 2.0.


On that machine, I can move the entire grid at once from the central

convergence zone. On this 8110, I don't have that ability. I can move the

blue and red grids VERTICALLY there, but NOT horizontally.


In every other zone I have full freedom of movement.


Is this a version issue or a board issue? I'd really like to have the version

or board that gives FULL control in the center zone as even the centers can

drift slighly with time and I'd rather use the remote than have to realign the

tube toe-in to get convergence dead on.



CJ

Quote:
Yep, that's more likely your problem. And it's more likely that your yoke wire had been pinched all the while, with a final break in the cable later happening. Convergence boards will very rarely fail on their own, and if that happens, the failure would not cause one of the power transistors to fail, the self failure is more likely stabilty (drifting).


Repair is not as easy as it seems. The actual circuits are very similar to complimentary push pull audio circuits. And these circuits must have correct bias and off-set levels before the circuit will ever operate correctly. When one of the finals (mounted on heatsink) fails it'll usually take out the bias circuit. Therefore the best way to repair them would involve a variable +/- power supply and sine wave generator. Very difficult board to repair correctly, you'll need to see a good sine wave driving a 2 ohm test load (the coils are .6 ohms)... replace the board!


--------


CJ, check your connections. Make sure you have your red and blue yoke connectors on the right plug on the HDM.

I checked that very, very carefully. The first convergence board is definitely

out to lunch on the red channel. No movement.

The second one seems to work fine but I get no movement in red and blue

when in the center zone. All other zones move normally.


Software, maybe?



As long as I'm at it, I might as well ask about the focus magnets.


This 8110 has six pole magnets. I've found four pole magnets (well,

actually they do seem to be six pole magnets but they don't have

the rotating adjuster on them) and I was wondering if there's any

reason not to install six pole magnets in place of the four pole magnets,

and if there's any real benefit to doing so anyway.




CJ

Quote:
If your reference to center (left to right) is the same as the static (global) convergence, it's not controlled by the convergence board, it's controlled thru the HDM.


The convergence function/control is not effected by software version.

So if I can't move the entire red and blue grids from the central zone, it's an HDM issue?


Another piece of the puzzle: I can move the grids VERTICALLY from the center

zone, now that I think about it, but not horizontally.


Does this point to an HDM problem?


I guess my next step is to see if the whole image shifts if I use the phase

control, just for test.


I do remember specifically that the green grid can be moved in any direction.


CJ

I guess I need to break out the service manual and start poking and prodding.


That particular HDM went a bit flaky and was having a case of the horizontal

shakes when it was in my 8000. I retired it for a spare board, but I just

resoldered a bunch of connections on it that were questionable. Now the

shake is gone, but I've noticed this issue only since resoldering. Maybe I

bridged something?


I guess I need to take a good look at it.


CJ

cj,


have a close look at the connectors on the hdm.

maybe you mismatched red & blue.

exactly the same happend to me and it took several hours to find out.

i was absolutly sure that the hdm was right connected.


if you go into the guided setup menu, all 3 rasters will lit up during raster alignment. this was how i found it out.

the optics were taken off and in the angle of my eye i saw the blue moving while i tried adjusting red.


maybe this helps,


gernot

Double, triple, and quadruple checked. Plugs swapped just for drill though

I physically traced them from blue to the socket labelled BLUE and red to red.


Nope, this convergence board has issues in both red and blue.


That's OK, I have a spare or two and the machine is running perfectly with

a spare installed.


CJ