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Main => Monitor/Video Forum => Topic started by: newmanfamilyvlogs on October 27, 2010, 11:06:03 am

Title: P719 neckboard "extra" components
Post by: newmanfamilyvlogs on October 27, 2010, 11:06:03 am
I'm getting ready to replace the transistors on a P719 neckboard for a K7400. I noticed there are two additional capacitors that have been added to the back of the board, one of which connects to a transistor I plan on replacing.

I don't see these on another P719 board I have. What would the purpose be? The one in question is printed as:
CM
470K
X5F

It ties Q504's base to ground.

Title: Re: P719 neckboard "extra" components
Post by: Ken Layton on October 27, 2010, 11:42:09 am
Probably part of Wells-Gardner's many UNDOCUMENTED production improvements/changes.

DON'T TOUCH THOSE PARTS. LEAVE THEM ALONE.

If you have to unsolder them to replace that transistor, make note of what connected where and reconnect as you found it.
Title: Re: P719 neckboard "extra" components
Post by: newmanfamilyvlogs on October 27, 2010, 01:29:13 pm
Awesome. Thanks.
Title: Re: P719 neckboard "extra" components
Post by: MKFan4Life on October 27, 2010, 07:40:44 pm
Oh man I feel for you.  Those traces ARE kind of bad eh?  This is the one you spoke about that you are putting the original part-numbered transistors back into, right?

Mine is still running with the ones I bought from Mouser with zero problems at all (at the moment).  Ran all day last weekend when I had a LAN party here.

Let me know if it improves your display as compared to the Mouser transistors if that is what you're doing.
Title: Re: P719 neckboard "extra" components
Post by: newmanfamilyvlogs on October 27, 2010, 10:14:33 pm
Yes, I planned on posting in your thread as well as one of my own with any differences between the two.

Both of the boards I have are horrible like that as far as the traces are concerned.

My transistors should be in tomorrow so perhaps I'll have time to swap them soon and post results.
Title: Re: P719 neckboard "extra" components
Post by: MKFan4Life on October 27, 2010, 10:16:39 pm
Cool.  I still would like to do that fan mod for my transistors... but I have a full plate and taking a little vacation in 2 days, so it'll have to wait for a week or so, lol!
Title: Re: P719 neckboard "extra" components
Post by: newmanfamilyvlogs on October 27, 2010, 10:53:36 pm
I've got a small pc chipset fan to use. Should be tiny enough to not produce EM garbage to mess with the screen.

Wouldn't it be cool if you could induct the 5V from an HV lead and only have it hooked to ground :P
Title: Re: P719 neckboard "extra" components
Post by: MKFan4Life on October 27, 2010, 11:20:43 pm
Sure.  I was wondering where I could get the 5V from.  I have a similar fan that came off the back of one of those removable IDE hard drive 5 1/4" bays.  It's really brand new since the bay was never used.  I just junked the bay and kept the fan and some wiring from the bay a while back.