AVS Forum banner
Status
Not open for further replies.
1 - 14 of 14 Posts

·
Registered
Joined
·
16 Posts
Discussion Starter · #1 ·
I have a BG800 which seems to be developing a problem with the red CRT.

The red seems to overpower the other CRT's. Her are the specifics. I have to turn down the red voltage on the G2 panel to almost it's absolute minimum to get a decent black level. Even then in scenes where there is a lot of black I see red hot spots. Also, in the lighter areas the red blooms all over the place. I don't know what component to suspect. I am leaning toward the [email protected] focus board going bad. But Then I think that the voltage supplied to the G2 board my be bad which would indicate the Quad was the problem. Or is there a feedback of voltage from the splitter to the G2 board? and if so could that be the problem. I don't think it's a vga board problem but I must admit that I haven't swapped vga boards to verify it. It seems that for some unknown reason the voltage to the CRT's g2 is increasinf which produces the ever increasing red level. Any thoughts for the community. I am almost sure that the problem resides in the an HV component, but almost drives me crazy. I need to know for sure. Is it possible that an adjustment to the astig mags on the CRT can cause or correct this problem?
 

·
Registered
Joined
·
445 Posts
paap95-


Your description sounds very similar to a problem that popped up a couple of weeks ago on a customer's BD800.....also the red tube. Turns out the RGB output board was bad. A fairly quick test is to simply swap the board with that of another color and see if the problem follows.


-Chris
 

·
Registered
Joined
·
667 Posts
ChrisH,


I have a Barco Data 800 that the red tube won't even fire using input number 5 from source(HTPC). It comes on fine using internal gridlock patterns on all inputs. Curt Palme and Mike Parker both mentioned that the RGB switcher board was probably bad. I want to test this before spending a bunch of money on the part and shipping back and forth. I want to try your test described above, but am unsure what this card looks like to swap it. I also need to get the part number off of it. Do you have a digital picture of this board that I can see to verify I am thinking correctly. I believe it is located at the neck of the CRT but I do not know for sure.


Thanks,

Dan
 

·
Registered
Joined
·
445 Posts
Hey Guys -


You're in luck as I was just about to download some weekend pics to a PC and had just enough space to snap off one of the dead board that is sitting right next to me. Just hope I can upload it correctly.


Yep Dan, it is I guess considered a 'neck' board as it is not one of the vertical cards attached to the motherboard. Swapping them means removing them as the 2 multi-pin connectors aren't long enough to reach the other. Make sure the main power is off when doing this. Also, you might want to run this problem by MikeP (EDIT: Oh yeah, ya already did. DOH!) as he has a few spare parts for your unit laying around. This part number is 761750.


Good luck,

Chris
 

·
Registered
Joined
·
667 Posts
Thanks Chris,

Given the information Mike and Curt gave me, I had narrowed it down to that board but I wanted to make sure before I started swapping things. Mike has graciously offered to help me with this, I just wanted to specify where the problem was so he didn't have to carry so many different parts for troubleshooting purposes. I'm so happy to have a guy like Mike close by. His talents are very valuable in this hobby.

Thanks Again for the pic.

Dan
 

·
Registered
Joined
·
667 Posts
Further research has lead me to believe I am on the wrong path. The pic you sent seems to be for an NStage board, which if it was bad would cause severe blooming, a full field of red or a spot on the red tube when powered off. This definitely fits with the thread starters problem but unfortunately, not mine. Mine would be the RGB switcher board with diagnostic LED's onit and it attaches to the main board or the RGB input board. If anyone has pics of these I would greatly appreciate it. This may have been what Mike and Curt were describing and I just missed the boat. Oh well, I am still learning. At least there are guys like them who do know what their doing that can guide us in the right direction. I guess it it board swapping time and time to learn some new skills.

Thanks again for the input.

Dan
 

·
Registered
Joined
·
445 Posts
Quote:
Originally posted by DIZ2
I'm so happy to have a guy like Mike close by. His talents are very valuable in this hobby.
ME TOO!!!



OK, went through the service manual and found a way to upload a page from it with the RGB switching board. Not the best pic, but you should be able to find the part number on it, 761748.


-Chris
 

·
Registered
Joined
·
667 Posts
Thanks Again Chris!!!
 

·
Registered
Joined
·
667 Posts
From the picture it looks like I have more than one of these boards in my PJ. I am assuming probably 3 (RGB). Is this one of those scenarios where I can swap one of the other boards and see if it works? Or do those other similar looking boards do something else.

Thanks,

Dan
 

·
Registered
Joined
·
445 Posts
Dan-


Are you referring to the RGB output boards, or the RGB switcher? There are indeed 3 RGB output boards and they are identical (same part #761750), and can be swapped. However, I quite certain that there is only one RGB switcher board (part # 761748). If you think you see more of the latter, check the stickers (I hope they're still there), for the part numbers. Some of these boards vertically attached to the motherboard do look similar at a glance....but they are not.


-Chris
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #11 ·
ChrisH, Thanks for to info. And so simple to fix that even I can't screw this up.......Well maybe. To everyone a BIG THANKS. I'll swap test and keep you informed.


Tom
 

·
Registered
Joined
·
667 Posts
Chris,

It would most likely be the RGB Switcher board 761748. It looked like several boards in the PJ from that picture that is why I was wondering if there was more than one. Now that I have a better idea of how this thing is laid out and what the symptoms are it should be narrowed don to part number 761748 not the NStage boards 761750. I've been in contact with Mike Parker who is digging around in his spare parts to see if he has one for me.

Thanks Again,

Dan
 

·
Registered
Joined
·
445 Posts
Heck Tom, we just about forgot about ya. Do let us know what happens.


Dan. You mentioned in your first post in this thread that there was no red when using the port 5. Does red work if you use a composite or s-video input?


If Mike cannot find a 761748, I have one in a BG800 (same card) that I may be able to swing by and let you test with. I'm supposed to be running out to Ocean City Wed. night and can probably veer out towards you on my way.


-Chris
 

·
Registered
Joined
·
667 Posts
Chris,


The red tube will turn on using all inputs (using genlocked pattern, even #5). The problem is when I select the source (HTPC) on input #5. I appreciate the offer to stop by Wednesday, but I won't be home until quite late. I have side job to evaluate a computer network Wednesday evening. I should know something from Mike fairly soon. I will keep you posted. Once I get this sqaured away and my Mike Parker modded Radeon 7500 installed I will invite you over to check out my setup since you are so close.

Thanks again for your input (pun intended) :D

Dan
 
1 - 14 of 14 Posts
Status
Not open for further replies.
Top