I’m new the whole pinball realm but somewhat mechanically/electrically inclined. I just picked up a 1979 Flash pinball machine that is in need of some work. It was basically given to me for my son (avid pin head) and I to try and fix.
I am absolutely no expert but I am here to learn how to get this machine working for my son as a father/son project.
The known issue was that the F2 28 VDC 2.5 amp solenoid fuse would blow. This indeed was a problem and I noticed early on that the left slingshot solenoid was actuated constantly. I isolated the wires off of that solenoid and the fuse stop blowing. Shortly after that I noticed that the free game knocker solenoid was noticeably burnt and a wire was disconnected from that. I ordered a couple of solenoids from Marcos along with some more fuses and other items.
The free game knocker solenoid was definitely toast as it read almost a dead short across the two terminals. However, the left slingshot solenoid read about 4.6 ohms across it which is a nominal value. Regardless, I replaced the two solenoids.
Upon turning on the game after the parts replacement we started to test out the solenoids on the Playfield manually. Things were looking good. We had all the sound effects which we didn’t have before. At some point the 2.5 amp fuse blew again. However, it took some time unlike initially when it would blow almost immediately.
We replaced the fuse and tried it again. We noticed that when we dropped the 3 drop targets manually on the bank of 3 that the game crapped out and became unresponsive. We rebooted the game and we tried the three drop targets again. It died again and then we noticed (fortunately) some smoke coming from the driver board at the transistors just below the flipper relay. Immediately turned off power and unplugged the machine.
Upon removing the MPU board and the Driver board as 1 unit (that 40 pin connector looks like an accident waiting to happen) it was apparent that on the backside that the transistor area for the solenoids had gotten hot but more visually noticeable was the dark area around the large resistors for the lighting.
So, now I am at a loss. I’m not sure what I should do. I’ve heard/read a little about the Rottendog replacement board and that seems like a worthy purchase but I am a little concerned that I may have an underlying issue that might smoke that board and I wouldn’t want to do that.
Some items of note:
Reinstalled the boards and the game seems to be fine in attract mode. Lights flashing, looks pretty. Light resistors are getting quite hot to the touch. It also goes into play mode but I didn’t attempt to activate any solenoids for fear of letting out more smoke
When I test the power at the F2 fuse I read about 38 (not 28) volts DC and I think that is above a normal reading but I’m not 100% certain.
Any and all help would be greatly appreciated. Thank you!!!