1987 Bally Hardbody
When the credit button was pressed the game would ‘try” to start but after the initial splash text on the display. “Muscle beach” would flash and here is where the start of sounds would kick in. but no sound. and SLAM SLAM would show up on the display and the game would reset! Ah! love a challenge! NO Sound When I attained the machine I didn’t realize there was a sound problem. Neither did the seller, who in my opinion is an honest guy. The initial flash sequence didn’t take place. On this soundboard called the T.C.B., it is supposed to have 3 flashes. The more elaborately designed boards such as the ones with dungeons and dragons have 5 flashes. Mainly because the extra Peripheral interface adapter chips PIA 6821 that are check during the flashes. Here I noted the oddity: the memory chip is strangely plugged into the sound card. A 24-pin 6116P SRAM chip is plugged into a 28-pin socket. And get this it is plugged into the lower part of the socket. That is pin one of the chip is in the place of where point 3 would be. So it is moved away from where it would be. Now this isn’t the first time an engineer used a larger socket to mount a smaller chip. It has been done. This confusion came from the schematics, which show clearly the chip is indeed a 28 pin. Or so I thought. Looking up replacements actually gave me a chip that would maybe have worked if there were a need for a 28 pin SRAM chip. But it had 64k of memory on board, which should be okay in this case. But before I started out on this. I decided to check my “former” dungeons and Dragons machine recently sold. After all schematics have been wrong before. Yes, this sound module has two memory chips both mounted oddly the same way. And it works fine. I replaced the chip. Something I need to mention is that it is hard to tell what sort of unholy thing the previous owners have done to a machine to try to fix it. Many don’t know jack about electronics and yet try to fix or “hack” some repairs. So when I saw the chip mounted this way and the schematics supporting a larger 28-pin chip. I thought the worse. The one who own the machine before I, had bought it from a guy who thinks he is a better tech then what he is. This theory of this “other” guys expertise will be proven, when I talk of the next issue wrong with this machine. So.. I put the chip back in this way. It was a scare to think a chip was in then wrong place and that it could mean more problems for the soundboard. But this had to be the right position. I just wonder why the schematics didn’t say anything about that. At one point I had the board out, plugged it back in, and added some screws, because there wasn’t any. Maybe it was a ground problem? I also checked the speaker for 8 ohms, all was set. I started the machine. Ah! 3 flashes! Hmmm..It was a bit colder in the both my garage and the sellers maybe it is a cold solder joint or a connector problem. Or maybe the unsecured board issue had an affect? I don’t spend too much time finding this out when there are too many reasons. It works now that’s what is important. Who knows, all I know is it is getting the flashes now. Something to note is to always check the connectors first in this case. I would have if not for that 24-pin chip issue. Which distracted me from other things. First thing first, now that I found that the chip was in the right place and I got the initial start up flashes on the boards green LED light. Now, where’s the sound? Not start up sound. No new game sound when the game is started. (Later you’ll find it doesn’t start) In the test mode it plays the same tone continually repeating, I put my ear close to the speaker, and could hear something faint. Hmmm. Twisting the control back and forth in the front of the coin door didn’t help. Ah! It is the on board trimmer pot! Kind of scratchy, but the sound kicked in. Used some contact cleaner made for POTs (volume controls) like this. Problem Solved. ISSUE#2 Game crashes at start. The game always went into the attract mode. And should have been ready to play, by adding coins or pressing the credit/start button. Not the case. This would start for a second in the usual way. Sounds and flashing the “muscle beach” text on the display. But then “SLAM SLAM” would follow on the display and it would reset. This happen right when the ball was ejected to the plunger tip. So my first thought was a bad Coil diode on the outhole solenoid coil. The easiest check here was to un solder the wire that fires the coil. Same thing. Not the problem! Now check the slam switch and the tilt switch and the credit button. Diodes and all were okay. Switches were okay. Time to test in the switch test mode. Which is extremely valuable. Pressing the credit button simultaneously latched the new game /credit, slam, two drop targets and a roll over switch. The matrix shows these are all in the same row. Ah! Now we are getting somewhere! The previous owner(s) spoke of random resets before it got to this point. Would make sense if the matrix was shorted somewhere. Now the cabinet switch, though they can be in the same row, all arrive at a different plug. The CPU J3 connector. Clearly labeled cabinet switches. Don’t let this confuse you; it was Bally’s way of organizing the wiring better I suppose. So as the credit and slam switch both are in the same row in the switch matrix, and they both run to J3 instead of j4. Where they meet at strobe zero in the matrix. Something else occurred to tell me more. In the test mode when ANY of the switches in the same “column” as the credit button were engaged, that whole row where each specific switch would simultaneously engage as well. Suspecting matrix zero row, I wanted to test the MPU; since the test tells me strobe zero column must be the problem. One of the things I did to prove the board was okay was I removed the j4 plug and clipped wire 15. And with a diode and some jumper clips I tested all the switches. Watching the display in the test mode, each switch was identified correctly and didn’t show a multiple closure. So the MPU was okay here. The same test was done with J3 touching the clipped wire from strobe zero to each pin that was associated with that matrix column. All tested OK. (This wire comes from the mpu not the playfield; also make sure that the diode is in the right direction.) When the J4 connector was unplugged, the game would start and that cabinet switch worked. So it was one of the playfield switches. The left or right rollover button under the ramps, the right or left sling kicker switch, or the ball outhole switch. The method I did next proved inconclusive and proves that sometimes “the last place you look” is where you find it. I snipped every wire form each component starting at the front of the playfield. And stopped just before the last one, which was the one that was indeed shorted. Which was the right ramp Roll over switch. So it seemed I would never find the problem, yet that last untouched wire was the one I should have clipped first. What are the odds? Well I tes-jumpered a string of test clips from j4’s Strobe zero line from the MPU, to the first three switches. (Left and right sling and outhole) they all worked. So the wire was the problem. To some of you may have been saying. Yeah I already knew that. Well it can fool you sometimes, not a lot of absolutes and never assume anything! Well. Rather than to try to find the wire I started a new wire through the playfield and arrive at the source of the problem last since I started at the front of the PF. The wire was pinched under the flipper assembly. And it was contacting it electrically. So I didn’t need to run another wire. But continued one anyways, just to be sure all was done. Game plays fine now. No random resets. I had to change the 60w bulb, to a 40w to avoid melting the translite or something. This game didn’t need cosmetic surgery or touch-ups like other so it was near ready to go after the right flipper on the upper playfield was set higher and adjusted. The display is a little weaker on the right side. And one entire character is out. While the top segment on another is off as well. Still pending on this. I may test the market first to see if replacing these displays are worth it. But most indications say the right side needs replacing and the left may need a replace decoder/driver chip to fix the missing segment problem.
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