Battery Board Repair on a Old Coney Island Machine

[Officepot]

As title states, just got in a Old Coney Island Machine that is in really good shape besides battery leakage. All damage has been repaired but need some help identifying replacement ICs that were sacrificed to the battery acid god. I think I have identified one via schematic, it is labeled as "339", "SYL B130" it says on the chip, I think an equivalent is a LM339? The other one is a bit trickier, it is labeled "C32" in the schematic, the label on the chip is impossible to read. I have attached photos of the chips in the schematic. Please let me know if you think i am on the right path for the LM339, and any help finding a replacement for "C32" is greatly appreciated!

 

[Officepot]

I have realized the parts catalog does list all individual components... if anyone is interested, "339" is a LM339 and "C32" is a 74C32 IC

 

[JakesArcade]

Hah, funny I just finished repairing my old Coney Island board yesterday. let me know if you have any other issues, I'm putting together my repair log now. I bought a whole bunch of chips I didn't need when the root issue was the bypass caps.

 

[Officepot]

Hah, funny I just finished repairing my old Coney Island board yesterday. let me know if you have any other issues, I'm putting together my repair log now. I bought a whole bunch of chips I didn't need when the root issue was the bypass caps.

I just got everything plugged in today, after getting my new chips in the mail. I get no lights on the MPU board. I get a loud boot up song and then a very faint song playing in the background. Assuming I need to program some new ROMs or I take the shotgun approach of replacing all the socketed components... (I do not have a programmer but the one ROM was pretty corroded). Tell me more about these bypass caps so I can check mine ;-)

 

[JakesArcade]

For me I had zero light flashes, sound board would do a frequency sweep sound and a constant buzz.

Bypass caps are all the big green ones. They are trash just replace them all with 103 ceramics. Check the 5v at the ceramic capacitor just after the battery charge circuit. In my case it was reading 0v, removing the capacitor caused the game to boot but freeze after 30 min, removing the ram chips I still found the voltage to drop to zero after about 30 min, the only other thing in that part of the circuit was the 74c82, replacing that fixed the problem permanently, see attached, the parts I circled all have to do with that part of the circuit.

Is your board still using the original roms or eeproms? I converted mine to EPROMs when I initially thought it might have been a rom issue, I can send my originals to you at shipping cost if you want.

 

[Officepot]

For me I had zero light flashes, sound board would do a frequency sweep sound and a constant buzz.

Bypass caps are all the big green ones. They are trash just replace them all with 103 ceramics. Check the 5v at the ceramic capacitor just after the battery charge circuit. In my case it was reading 0v, removing the capacitor caused the game to boot but freeze after 30 min, removing the ram chips I still found the voltage to drop to zero after about 30 min, the only other thing in that part of the circuit was the 74c82, replacing that fixed the problem permanently, see attached, the parts I circled all have to do with that part of the circuit.

Is your board still using the original roms or eeproms? I converted mine to EPROMs when I initially thought it might have been a rom issue, I can send my originals to you at shipping cost if you want.

Jake, I have the same exact sound then. You are much better at describing it! Mine is using the original ROMs, I will check your problem areas and report back. I did replace both of those diodes and resistors next to the battery that you circled in the second photo. (mine still had the original battery installed YIKES, it was a full day of trace cleanup yours is much cleaner!)

 

[JakesArcade]

Good luck!

What's your plan for replacing the battery? Seems like everything has its pros and cons, I'm debating trying something new and buying a small li ion charge controller/ protection board and use a 18650 battery, Ofcourse isolating it using a diode like all other battery solutions. If not that then I'm still torn between a button cell and 3 AA batteries.

Pardon Our Interruption...

 

[Officepot]

Good luck!

What's your plan for replacing the battery? Seems like everything has its pros and cons, I'm debating trying something new and buying a small li ion charge controller/ protection board and use a 18650 battery, Ofcourse isolating it using a diode like all other battery solutions. If not that then I'm still torn between a button cell and 3 AA batteries.

Pardon Our Interruption...

Not sure yet, I did come across this post that used a memory cap. I might take you up on that ROM offer after replacing all the bypass caps, if the issue is unchanged. That post I referenced says to change the "Z80 CPU (U11), Z80 CTC (U10), 8255 PIA (U17), ROMs (U12, U13 and most times U26, depending upon the game), 6810 (U8) and 6551s (U6 & U7.)" all right out of the gate... I figure thats an expensive fix and like I said, I would have to get a programmer. I will start with the bypass caps and see if that gets me anywhere, after that, might go for the part cannon if it isn't too costly.

 

[Officepot]

@JakesArcade I went ahead and replaced all of the bypass caps.. no luck. I did have 5V on the battery charge line. I sent you a PM about the ROMs I figure I will give those a shot. Thanks again

 

[JakesArcade]

One other thing you can try while waiting for those roms to arrive is short out pins 25 and 26 on the CPU to see if you get any life, this will force the reset circuit to go high and allow the cpu to attempt to boot. See the flash codes section here for more info on how the watchdog circuit works. Do you have a scope? It doesn't hurt to probe the reset line or the data/address lines to see if it's doing anything.

 

[Officepot]

One other thing you can try while waiting for those roms to arrive is short out pins 25 and 26 on the CPU to see if you get any life, this will force the reset circuit to go high and allow the cpu to attempt to boot. See the flash codes section here for more info on how the watchdog circuit works. Do you have a scope? It doesn't hurt to probe the reset line or the data/address lines to see if it's doing anything.

Thanks for the link, I will try this tonight. Yes I do have a scope, I will see if there is any activity on the data line.

 

[Officepot]

@JakesArcade Okay not the update I wanted to give butttt, I have replaced the ROMs as well as the CPU, and all other socketed components. No change. No light blinks on MPU at all. I see 5v on the battery rail, I see 12v and 5v on both the test points the schematic says i should see them. I see a clock signal on the CPU. I see a very frantic 2-5v swing on the reset rail. It is like it is constantly in reset mode? Not sure, I am going to do some further testing this weekend. I have replaced both capacitors on the board, as well as all the tantalum chips and the 3 transistors on the reset line. I have not replaced the final transistor as I do not have one, that one is QD. Words on what to check next appreciated!

 

[JakesArcade]

I see a very frantic 2-5v swing on the reset rail.

Did you try shorting pins 25 and 26 together to force the cpu out of reset? While shorted you may get the flashes telling you that the board is working but there is something wrong with the reset circuit.

Also were you able to distinguish between the two roms that looked very similar? Perhaps they need to be flipped around.

 

[Officepot]

Did you try shorting pins 25 and 26 together to force the cpu out of reset? While shorted you may get the flashes telling you that the board is working but there is something wrong with the reset circuit.

Also were you able to distinguish between the two roms that looked very similar? Perhaps they need to be flipped around.

Shorting pins 25 and 26 does not seem to do anything. Still no lights. I tried the ROMs in both configurations and it also did not change anything. I see a signal on pin 26, but shorting this does not seem to make the circuit do anything. This is with a new CPU and PIA.

 

[JakesArcade]

Hmm, are you running it on a bench or inside the machine? Check with the scope all data and address pins on the chips, make sure everything is getting a good signal.

 

[Officepot]

I have went through and replaced A LOTTAAA chips in an attempt to find this issue (if i do many more I might end up replacing the all)... Anyways I have determined that if I left out pin 13 in U2 which is one of the AND gates that gets the 5v to the reset line, I get a constant 5v on my reset. Otherwise my reset floats between 1-3v continuously and constantly resets. Even with my reset at 5V I never get any LED blinks on my circuit board though. If I put a new chip in U2 we go back to the constant up and down voltage on the reset line. I have replaced almost every single chip in the reset circuit. All of the transistors, all of the socketed chips, U14, U1, U2, the zener diode, all tantalum as well, the only one I have not done yet is U5 and that one is in the mail.... I am starting to think I have a trace issue somewhere in the reset circuit and will be tracking that down soon. I have the power supply and the MPU board out on the bench for easy testing. As I understand that one J2 i think it is, is the only connector i need to get LED flashes. I am understanding now why these Game Plan MPUs are a nightmare! I am starting to grow ever suspicious of the 74C32 but I have already replaced that once.... I might start taking chips out and seeing if it will boot with a few removed, like the ram etc. I am following the MPU guide linked and it is very helpful but I am getting to the end and still have no LEDS!