CurtPalme.com Home Theater Forum

[tschaeikaei]

Hello CRT-pros, I am Julian, living in germany.
I recently bought a Barco Graphics 400 in good condition with a RCVDS 400 quad and the remote control.
The seller had no idea that its able to display higher resolutions than PAL, so it was a cheap ebay-buy.
After some disadvantages, i got it running with a DVD player via scart.
(I had to add an 100ohm resistor in the sync line, otherwise it switched itself off after some minutes , lighted up, switched off...) Sometimes it happend again after I placed the resistor, but not that often.

First question: Do i have to solder resistors in the colour channels too? Meaning to put one in red, one in green, one in blue?
I added the 100ohm (better75 ohm?) between the scart pin 19, wich is sync signal with fbas and the cable to the RCVDS box.

But thats not the main problem:
thinking of connecting the PJ to a HTPC, i build this little thing as a sync combiner:




played with powerstrip, (of that i think that is a really cruel tool, never got it really working)...,
testing some sync polarities (worked with oszilloskope) and never got it working.
At that point, i had not turned any potentiometer on the projector, just turned off autosync and blanking
using the jumper and switch on the vertical deflection & sync board.
Never got a picture.
then i decided not to use powerstrip, changed the frequency in windows to 1280x1024 at 60Hz and began playing with
the manual adjustment on the projector.
At that point, my dvd player did a good picture on the proj without deactivating anything, but i wanted more.
I downloaded the manuals and instructions in Curt Palmes maual section and began reading, read some hours and hours..


Now: Real big thanks to you, Curt. I had to throw the projector away, if you had not uploaded them. Really nice to give them to us.

I discovered that the SMPS has to be set to 17 V at Pin 7/8. It had slight undervoltage (believe it was 16,3V) and adjusted it to 17V. I measured 24V on HTHD, ok.

Everything running well. Then played with some pots on the boards, on the vertical sync board the horizontal and vertical frequency pot.
In the manuals, they are in pdf 04 (vertical sync board) on the first page, right.
When i turned the horizontal frequency pot all the way in, the picture switched off.
I did this a few times, it switched off, i switched the projecotrs main switch back on.
projector worked. the tubes lighted up, no real picture (depending on the picture signal from my PC, wich was not synchronised).
I read about a manual scan frequency adjustment in the owners manual (not service manual), where you have to shortcirciut 2 caps and manually adjust the frequency using horizontal and vertical frequency pots.
it did this, projecotr was still working at this point. HV was there, not a real picture, but light out of the tubes.
I turned the horizontal frequency pot on the same board an wow... i got a picture!
The red LED on the autolock board was still on, saying " not synchronised", but i had a picture on my screen.
Then, something strange happend. i turned the pots, plus some others, wich are NOT factory sealed, and puff, fuse 4 on the SMPS board blew up.
Turned the pots to the position i belive they were before and changed the fuse. The SMPS powered up, green LED on SMPS glow green but no high voltage sound.
The voltage 24V on the TP2 was 13,5V, 17V and 15V at Z100 were ok. I measured on pin 29 : 45V.
"Overvoltage HTHD, protection TH1, D26, IC 5" says the manual.
Now, i know where the protection circuit is, but where is the failure?

Another failure occures: the scan fail led on the electrical focus board is on.
It is not flashing, as I read in other posts in this and other forums, it just stays on everytime i switch on the projector.

Now, i think the main problem is the SMPS, that detects a failure. on itself or on another board.
If i knew, what hthd is... googled it and dint find any explanation. what does this word mean?


Sorry for this big text in bad english.
I have to say this: you are my last hope, CRT-pros, i tried in other (german) forums, but nobody had an idea.
If i forgot things to mention, please ask me.

Hoping you will help me and wishing you a nice day,
Julian

[tschaeikaei]

Hello,
I'm currently measuring voltages on the vertical deflection & sync bord, because: when i take this board out of the projector,
the red scan fail led on the focus board is out. If I put it half way in (I know I shouldn't do this, but I did..)
the horizontal-eht board runs, meaning there is high voltage and the tubes crinkle when i switch the proj off after that.

Don't know if crinkle is the right word, they do this "HV-discharge"-sound that they usually do, when you switch a working crt off.
The voltages that should come from the SMPS are ok,measured on the vert. defl. board-connectors without the board put into them:
Conn. A pin1 -17V, pin3 14V,
pin 7 7,3V (no voltage written in the manual), pin 10 28V (i measured 24,3V, is this still ok?) pin 26 17V.
pin 20 (350v peaks): 0V. there is nothing, but i think (because it should come from the hor. def. board)
the vertical board should give an "ok" to the horizontal board.


conn B: pin 13 (SCAN FAIL) 30V ---> wich was measured with the vert defl. board put in, without it, there is 0V.
pin 15 28V measured without the board.

Does this tell me, that the scan fail comes from the vertical deflection board or is it still because another voltage from the smps is not ok?

I'm going on with measuring, next step are smps input and outputs.

Please: write something, even "i don't know, .... will maybe help you" would be good.

Thank you,
Julian

[tschaeikaei]

Another question: HTHD (whatever it means) should be 24V, am I right?

[fuchs]

Hey, and welcome. I can't really help you on the electronics.
If you want to connect a HTPC, I would suggest starting with something like 800x600 resolution, then first figure out what H and V sync it wants, and (maybe) if it needs custom porch-settings (the empty spaces before and after the image, in the signal) and so.
I know that many Barcos do not accept just any sync-configuration, so figure that out first. +/+ , +/-, -/+, -/- .
Oh, and maybe those older Barcos want Sync-on-green or composite sync.

Many people are grateful for Curt+others, for putting up how-tos and information.
I really needed it to get started with the old NEC I have, too