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Arcade Collecting => Pinball => Topic started by: More Cowbell on October 21, 2009, 11:50:02 am

Title: Black Knight issue
Post by: More Cowbell on October 21, 2009, 11:50:02 am
I have a Black Knight in great shape that played perfectly for a long time. Now when I turn it on, the bell rings, a ball kicks into the trough, and the number 2500 appears in the P1 score area. If I shoot the ball, the flippers work and the bumpers bump, but when the ball drains, the game stops cold. Can't credit it or play any further. I have found if I cycle through the audit functions a time or two, it will reset to attract mode and can then be played like normal. The only problem with this is that all of the high scores are reset, and any settings are reset as well each time I do this. Ideas?
Title: Re: Black Knight issue
Post by: ChadTower on October 21, 2009, 12:52:04 pm

...assuming that he doesn't have battery corrosion all over the memory circuit and the left side of the 40pin.

Does this game still have the original battery holder on the CPU board?  Has that ever had leaky batteries?

It's definitely that circuit, could easily be the 5101, but it could also be the blocking diode, the battery holder, acid damage to a trace, etc.
Title: Re: Black Knight issue
Post by: More Cowbell on October 21, 2009, 01:05:22 pm
I just put new batteries in last year and there was no corrosion at the time. I'll take a look. Hopefully it is as easy as replacing the 5101. Thanks for giving me some things to look at guys.
Title: Re: Black Knight issue
Post by: ChadTower on October 21, 2009, 01:33:40 pm
Well, if he can reset it and it goes back to normal I don't think he's dealing with corrosion....

Mine acted that way before I cleaned it all up.  Then it worked properly again.  Of course, that could have been just from reseating the 5101 in a new socket, because now it's back to having to clear the audits every time I turn it on.

You can do the powercycle reset if the 5101 is only sorta bad.  It worked on my Laser Cue and it worked on my BK for a bit.  I think once the 5101 is totally gone it no longer works.

If the boards are clean it could easily be your 5101 or the socket if it's socketed.
Title: Re: Black Knight issue
Post by: More Cowbell on October 21, 2009, 09:39:32 pm
All right, making a little progress. The batteries are fine. I replaced them just in case and tested them in the battery holder. They seem fine there. When I test them at the 5101 pin 22 as mentioned here http://www.pinrepair.com/sys37/index1.htm#battery (http://www.pinrepair.com/sys37/index1.htm#battery) (thanks whammoed) I get a reading of around 2.5v. Not sure where I'm losing power but pinrepair says it will boot into audit mode at anything less than 3.6v. So does that mean the diode is bad or a trace is bad? Or could the 5101 still be bad. In any case, I tried the flicking power off and on (with the door open) and it worked. Tis is fine for the short term, but I'd like it to be right, not to mention I like to keep high scores and I like 5 ball play (ok I'm not a purist. I have kids that would play for about a minute before losing all of their balls in a 3 ball game). I would simply order a new 5101 to try it but my 5101 is soldered in place so it's not an easy swap. I don't want to mess things up for a fix that may not work. Other ideas? I'm wondering about the loss of power to the 5101. What could cause that?
Title: Re: Black Knight issue
Post by: ChadTower on October 21, 2009, 10:20:30 pm

Same paragraph says to measure the voltage right at the battery holder.  If that is low you know it's not getting enough straight out of the batteries.  I could see that being the case if one of the battery contacts is dirty, corroded, or a little broken.  Those original battery holders pretty much need to be swapped now on all but the cleanest boards.
Title: Re: Black Knight issue
Post by: More Cowbell on October 22, 2009, 10:11:21 am
Weird. After messing with it for a while last night I decided to play a few games since it was on and working and I hadn't played in a while. After I finished I turned it off, waited 10 seconds or so and turned it back on. Worked! No audit mode. I figured it was an anomoly and would test it again in the morning. Turned it on this morning, worked! The only thing I actually did last night was change the batteries but when I turned it on immediately after installing the new ones, it still booted into audit mode. Could it need time to juice up from the batteries? Who knows, it may go back to audit mode this evening when I test it. That's the frustrating thing about miraculous fixes, they could miraculously break again at any time because the problem probably isn't really resolved.