Well, this is different. Or not...maybe this is the definition of strobing...? My newly acquired Dracula has a flickering credit/BIP display. No big deal there. The weird part is the player score displays. The digits are 'fading in and out' in a coordinated manner. So, the zero digit and thousands digit fade out together on each player display. As they start to come back on, the tens and the thousands digit start to fade out, and so on with the hundreds and hundred thousands, and this cycle repeats. Other than that, the game plays perfectly. All functions behave exactly as they should. Any thoughts or suggestions greatly appreciated!! In the meantime, I'll be doing some more cleaning, and switch out some known working displays, reflowing solder on the displays, etc...

Thanks!!

Reseating connectors did not change anything.

Thanks Jack - It's definitely MPU related. Swapped in a working MPU, no more funky fading in and out. So....I'm way out of school here, and completely without an oscilloscope, so if you can recall more specifically what you did, that would be a huge help. The 4049 is at U18.

Thanks!!

OK, so here's where I'm at. Long story, but a while back, I ended up with an extra working Bally MPU with Stern ROMs on it, and an Alltek board that is currently running a Stern Pinball. I used the Alltek to test Dracula last night. I put the Bally board in just now, and the game fired up, no problem. Of course, with a different ROM, the coils are crazy. So, I switched out the ROMs, and then the Bally board refused to boot up. LED does not flash, just a solid light immediately on power up. I thought I might have somehow damaged the ROMs, but putting them back on the original Dracula board and reinstalling it gets me right back where I started. Crap!

There's a local electronics store with 4049s in stock, and I have what appear to be a couple of properly functioning 4049s on this working Bally board. So, while the next steps seem pretty obvious, I'm still hung up on why the Bally board would boot with one set of ROMs, but not the other. This kind of stuff drives me nuts...

Well...geez. Yes, it finally dawned on me that I should have enough working boards to make all machines happy at the moment. Put Magic's original board in Magic. It plays fine. Moved the Alltek over to Dracula. It plays fine and displays are solid, and I've still got a couple of spare MPUs that are at least close to working to fiddle around with and see if I can make work. Crawling back into my hole now....

That didn't take long. I tested a couple things with the Alltek in place, and rebooted a couple of times. Now the sound is screwed up. Loud, discordant electronic hum as soon as it finishes booting up. I suspect the connectors between the sound board and MPU. I verified that they are connected correctly. Dammit. I've done enough damage for one day. Dammit.

It does get weirder, though better. I did pause to think to myself...'jumpers,' but haven't researched whether that's at the core of the non-booting MPU issue. Wanting to do something else pin-productive, I decided to reflow the solder on the displays. Even I can't screw that up, right? So now all five displays have shiny new solder on the male connector pins. And the electronic hum vanished. Okaaaaaaaaaay. I'll take it.