Folks,

Looking for a bit of help on this. I've tried to search and read every other BK speech issue thread I can find and still am not sure what to try next. I will readily admit I'm no expert here but am pretty good at basic troubleshooting and following instructions.

I acquired a BK that needs plenty of TLC. The game mostly works but I have never had any speech. I get the rest of the sound effects during game play but no speech. I get sound effects when I use the diagnostic tests (using the coin door switches) but again no speech.

When I use the diagnostic test on the sound board I get three sounds which loop. In other threads guys are asking if there is a pause before the sounds repeat. My game just keeps looping continuously without a pause.

I have tried to follow the thread that cody_chunn started - https://pinside.com/pinball/forum/topic/black-knight-sound-board-repair. All the cables are fine, the jumpers are set properly, I've reseated all the ROMs, I've checked continuity from the ROM legs to the solder pads on the back of the boards, I've checked the continuity of the ribbon cable. I've checked voltages with a DMM (accidentally blew up a trace on the board which I've now jumpered). Some voltages were a bit high (20V instead of 18V and 14V instead of 12V) but I don't think that would cause a speech-only problem.

I also have a Firepower that works perfectly. I swapped the speech board (but not the sound board) between the machines and switched the ROMs over. Both boards worked in FP as expected but behaved the same way in BK.

The most peculiar thing is that the only way to get sound of any type is to set the sound board dip switch 1 to on (pushed left) and dip switch 2 to off (pushed right) which is the opposite of what the proper settings should be and opposite of what my FP switches are set to.

So if anyone has any great ideas, let me know. I think I'm going to check the jumpers on my FP sound board and see if it's set up the same way and try another swap. Also, I'm about to order new capacitors for the boards just for preventive maintenance.

I'm open to suggestions at this point! Also, appreciate the info that HHaase has already given me!

Thanks,

Dino Z.

I tested the dip switches for resistance when I had the board out but I will check it again. I was told that if all is right with the speech board, I should be able to plug it into Firepower and hit the sound board diagnostic and hear all the speech on the BK ROMs. I'm pretty sure I already tried that but I will give it another shot. I will compare jumper settings between the two sound boards to make sure I'm comparing apples to apples.

Unfortunately at this point I don't have a logic probe but I'm thinking it might be time to get one.

Will test a few things and report back. I'm tempted to just get a new set of ROMs but don't want to throw away money if I don't have to!

So I swapped the sound board from BK with my Firepower sound board. I swapped the sound ROM as well. I checked that all the same jumpers were set. After plugging everything back in, I couldn't even get the diagnostics on the sound board to work. I was going to unplug the speech board and put the jumper back in to W1 just to test but have decided to get a new set of ROMs for the speech board and see if that fixes the issue.

I also have a basic logic probe on order from Amazon. Once I get everything here I will let you know what I find. Fingers are crossed that it's something as simple as a bad ROM.

Just a quick update...

I've replaced the appropriate caps, re-pinned all the headers on the board and put in new ROMs. The logic probe arrived so I followed the instructions in this post - https://pinside.com/pinball/forum/topic/black-knight-sound-board-repair

When I got to testing IC10 (6821 PIA) pins 26 through 33 were pulsing but pins 2 through 9 are locked on high indicating there is a problem with the chip. Lucky for me someone already soldered in a socket so all I need to do is pop out the bad chip and put in a good one. I will see if my local tech has a working 6821 chip and do the swap.

Will report back soon!

So good news and bad news.

Bad news first. I swapped the PIA with a new one. Followed all the steps to test with, exactly the same results. Crap! So out of frustration, I decided that I would pull the speech board from Firepower and swap it with the one from BK to see if I could isolate which board it was. I hate removing and replacing ROMs but I needed to figure out which board was causing the issue. And of course when I put the speech board into FP, it worked just fine. So it looks like both speech boards are okay.

The good news is that when I swapped the sound boards between the two games and put a speech board board into BK with the new ROMs, I finally got BK working! Sounds and speech are fine! Yay! I could swear I did this at some point already but I never got the knight to speak!

The bad news is that I now have a non-working sound board in FP! The good news is that both sound boards have been recapped and repinned now.

So I will continue investigating what the issue is with the sound board installed in FP and report my findings!

The saga continues...

Winner, winner, chicken dinner! Finally!

Following the steps in the post by @cody_chunn, I got to the point where I was testing IC12 (sound ROM) and checking pins 1 through 8 with the logic probe for pulsing. Pin 8 was giving me nothing but when I touched the solder pad on the board, I got pulsing as expected. So I decided to twist the chip in the socket a bit and test the pin again. Sure enough, it started pulsing while other pins I had previously tested successfully were no longer giving me any kind of reading.

Conclusion - bad IC socket! Just as Luzur and Schwaggs had suggested! So after a quick replacement with a new IC socket and the re-installation of the sound ROM, sound and speech is now working!

While the smart thing would have been to replace the sockets right off the bat, this was a great learning experience. I now have some basic understanding of schematics and how to use a logic probe. And my soldering skills are getting better all the time.

Hope this helps someone else in a similar situation! Thanks for the help guys!