CurtPalme.com Home Theater Forum

[brokenbarco]

Hello everybody,

I'm new to this forum, as well as new to CRT projectors.
Today(!) i bought a Barco 700 and wanted to install it.

After setting it up for table/front mode i went to the 'guided setup'
tried to get a good image and getting the convergence right.

I went throug the menu a few times, to get the picture right.....
one time during the convergence setup (red over green) i got a 'twitching' image from the red CRT

Turned the projector off, and after 5 mins. on again.....evrything was ok again...

i went through the menu once more and went to see a movie.....then all 3 crt's started twitching.
and i smelled something hot....

Upon inspection i saw a burnt resistor (or mH coil) and a 5W resistor on the convergence board that got very hot (text was vanished)

Now, i DID change the connectors on this board (as well on the horizontal/vertical board) to switch to table/front mode.
As far as i know i did that correctly, as the intro screen states table/front mode.

Now for the question....see attached picture....




Could anyone please tell me what the value of this resistor (or coil) is?
And
Can i just replace them or...(which i fear) are they just symptoms of an underlying problem?


Is this problem known?? if so, i hope someone cares to tell something about it....

THanks already for any help....

Best greetings,

brokenbarco

[/img]http://www.uploadarchief.net/files/download/ssa43510.jpg[img]

[locoman]

Hey Brokenbarco,

I own a Barco 708, similar to Barco 700 and according to the service manual, the burnt component is an inductor 1.5uH. You can buy replacements on Ebay for very cheap. But, with experience, I would recommend getting a replacement board from Curt Palme. My convergence board also failed and it was cheaper to get a replacement. I purchased a Barco 701 convergence board on Ebay and repair my old 708 convergence board by swapping the replacing the faulty electronic components. I found one burnt transistor (IRF9630) and a few leaking capacitors.

Also, before you buy a replacement board, I suggest you should disconnect the power connector on the convergence board to test and see what else has failed on the PJ. The PJ should work fine, except the convergence controls wont work at all.

Hope this helps,

Hein.

[brokenbarco]

Thanks Hein,

So it seems there is the same circuitry around the 3 convergence connectors.

I'll try to get me an 1,5uH coil......unfortunately it is christmas now.
(it's not unfortunate that there is christmas, but it's timing is bad )
I'll also replace the 4r7 5 watt resistor, just to be sure.

Strange thing is.....this projector has been playing for 5 years or so, without one hickup....
I take it to my home, and it breaks!

aaarrrgggh, bad luck? or....can it be that by adjusting convergence close to the
'end of adjustment range' does this??
I don't understand why it went....


The projector works well, just this convergence problem.
If it still doesn't work after replacing the parts.....i'll consider sending the board.
(what a pity....i didn't even get to see 1 movie completely, before it broke )

best greetings,

Brokenbarco

[brokenbarco]

Hello Everyone....

Finally i got my inductors today.
I replaced the parts and fired the projector up again....

Well, the good news first..... the parts are not burning out again.....i tried the pj for 15 minutes.

The bad news.....the picture is still 'twitching' or vibrating up and down....
It does play movies though.

if i look into the lenses i can see the twitching also, the upper half of the fluorescent screen is looking normal, but the lower halve looks as if it is tracing lines...together with a vibrating motion...
it is the same in each of the 3 cannons

Now, the burnt parts were on the convergence board...but, is this a convergence problem?
i have no error lights on the front of the projector...what to do?

Any help is much appreciated.

Best greetings,

brokenbarco

[locoman]

Disconnect the power that leads to the convergence board, not sure which cable you should disconnect, this should narrow it down if the convergence output board has gone bad. I disconnected my convergence board completely, undoing all the plugs, and test to see if the projector would power back on and it did.
If memory serves me right, there is a power connector, labeled "convergence", on the SMPS you could try to disconnect.

Hope this helps,

Hein.

[brokenbarco]

Hello Hein,

Thank you so much for your answer.
I'm new to crt's and the sight of all these electronics make me quite unsure......

You said to disconnect the power from the convergence board....

To be honest, i'm not so sure anymore it is the convergence board.....
when i open up the projector, and tilt the electronics up, it seems the top-right board is the convergence board (with all the flat micropchips) because there is text written on it where the chips should be placed.
(convergence bottom right, left etc.)

This board wasn't the one which had the burnt parts.....


It was the lower right board (nr. 762202), which holds 3 of the 9 connectors for adjusting table/front to ceiling/rear etc.
(and a lot of fets/transistors mounted on the sides for cooling).
Is it safe to disconnect this board??

OR DID you mean the board with all the microchips.??
(i'm scared of breaking it even more...)

if you would like some pictures i will be happy to provide

best greetings,

henk

[locoman]

Hi Henk,

You should only disconnect the convergence output board, 762202, and it is safe to disconnect. The only problem is, I cannot remember which connector to disconnect. I will go through the service manual tonight and let you know which one it is.

Regards,

Hein.

[locoman]

Henk,

You only have to disconnect the cable connector J6 (power) on the convergence output board, that should narrow the problem down.

[brokenbarco]

Hello Hein,


Thanks for pointing the connector...... now i was sure i disconnected the right board!

I tried it today.....

with the convergence output board disconnected, i have no output from the projector...
(also no color visible in the lenses)

also, on the front the second green led (starting from the red leds) is pulsing slowly.


When i reconnect the board, all green leds stay on, i have image, but the flickering is there....


best greetings,

Henk

[locoman]

Hi Henk,

That is really weird, but keep in mind, I own a Barco 708 and that it is different to your 700. I'm gona install my g70 tonight and will be taking down the old barco 708. Once I have it down, I will go over the connections and see if I'm missing something.

[brokenbarco]

thanks for looking into it hein!
Hopefully we can make this thing work!


wine will be flowing

Best greetings,


Henk