by Jizaboz » Wed Feb 10, 2021 9:59 pm
I will definitely be reading the book soon.
Here is an update I just sent "the customer":
Began work on the MPU board today.
First step is neutralizing any acid remnants and corrosion. I spent about an hour and a half hitting it with white vinegar, then filtered water, then 99% iso alcohol before fan-drying it. Tomorrow I will hit it once more with a thick Sno-Bowl toilet cleaner in the bad spots with a toothbrush to remove the rest.
I looked up a way to get the board on a "test bench" like I do for my arcade boards so that I test it without it being in the pinball machine. I have everything I need with exception to a couple of alligator clips and a 9 volt battery to put in-line to the 12v coming off my power supply to give it the 21 volt check that ultimately triggers that 7th green LED blink on boot-up.
Important note: We need to check F4 (fuse 4 on the voltage board underneath the playfield) to make sure it has not burned out. I didn't notice any blown fuses, but it was kinda dark. If it has not, and we check the voltage at the spot before it reaches the connection to resistor 113 on that MPU board, and make sure it reads 43 VDC. R113 actually breaks it down to 21VDC. If the circuit is stuck open like we saw.. it is stuck at too high a voltage and the solenoids never fire
Most likely gonna need parts. Rather than trying to match up random resisters and such I have laying around, I am going ahead and ordering this
https://www.greatplainselectronics.com/ ... Y35-BA-KIT parts kit that was designed years ago to replace all components including those resisters suspect to corrosion and just burning out.
I will say I need at least another week from now to get this board fixed and tested as OK. No charge for any of this of course! Just happy to work on it, learn more, and pay you back for letting me have Bosco. Now I will say though IF for some reason this MPU board is beyond repair.. there is a modern replacement called the "Universal MPU". It's superior, never leaks.. but is neither original or cheap. They go for about 200$ though.. and even if you would like to go with that option, I should at least attempt to get the original going
If this turns out well, I will be thrilled to get this machine going and some elements like the back glass art restored. At least at that point.. if I EVER get a hook up on a Funhouse machine to buy for myself and work on for 3k or less, I won't feel like a complete dumbass who has never worked on a pinball machine.
I will definitely be reading the book soon.
Here is an update I just sent "the customer":
Began work on the MPU board today.
[quote]First step is neutralizing any acid remnants and corrosion. I spent about an hour and a half hitting it with white vinegar, then filtered water, then 99% iso alcohol before fan-drying it. Tomorrow I will hit it once more with a thick Sno-Bowl toilet cleaner in the bad spots with a toothbrush to remove the rest.
I looked up a way to get the board on a "test bench" like I do for my arcade boards so that I test it without it being in the pinball machine. I have everything I need with exception to a couple of alligator clips and a 9 volt battery to put in-line to the 12v coming off my power supply to give it the 21 volt check that ultimately triggers that 7th green LED blink on boot-up.
Important note: We need to check F4 (fuse 4 on the voltage board underneath the playfield) to make sure it has not burned out. I didn't notice any blown fuses, but it was kinda dark. If it has not, and we check the voltage at the spot before it reaches the connection to resistor 113 on that MPU board, and make sure it reads 43 VDC. R113 actually breaks it down to 21VDC. If the circuit is stuck open like we saw.. it is stuck at too high a voltage and the solenoids never fire
Most likely gonna need parts. Rather than trying to match up random resisters and such I have laying around, I am going ahead and ordering this https://www.greatplainselectronics.com/proddetail.asp?prod=BALLY35-BA-KIT parts kit that was designed years ago to replace all components including those resisters suspect to corrosion and just burning out.
I will say I need at least another week from now to get this board fixed and tested as OK. No charge for any of this of course! Just happy to work on it, learn more, and pay you back for letting me have Bosco. Now I will say though IF for some reason this MPU board is beyond repair.. there is a modern replacement called the "Universal MPU". It's superior, never leaks.. but is neither original or cheap. They go for about 200$ though.. and even if you would like to go with that option, I should at least attempt to get the original going[/quote]
If this turns out well, I will be thrilled to get this machine going and some elements like the back glass art restored. At least at that point.. if I EVER get a hook up on a Funhouse machine to buy for myself and work on for 3k or less, I won't feel like a complete dumbass who has never worked on a pinball machine.