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Found it! dpdt relay
- Thread starter rockhouse
- Start date
Give it a clean, nothing to lose. These tend to be reasonably reliable. Reflow the solder too. Getting the cover off in one piece is quite "fun" though... 
If it ain't broke, fix it until it is.if it dont come off with a screwdriver hit it with a hammer
If you do break it I'm positive I have a spare expander board with relay mounted Pm me if you find you need it
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Good tip @Moonraker. Because @rockhouse said it worked when the relay was bypassed I assumed he'd narrowed it down to that being the point of failure.
To take the cover off you'll need a couple of small pry tools or small, thin flat screwdrivers. There are 3 one-way push-fit tabs that hold the clear cover on the relay. You need to pull the cover whilst gently levering one of the tabs and keep pulling gently as you work on the other 2 tabs. If you don't keep pulling the cover will snap back down and lock into place. The "tabs" and just small square holes along the bottom of the clear cover and it's very easy to over do it and crack the cover. Gently does it!
To take the cover off you'll need a couple of small pry tools or small, thin flat screwdrivers. There are 3 one-way push-fit tabs that hold the clear cover on the relay. You need to pull the cover whilst gently levering one of the tabs and keep pulling gently as you work on the other 2 tabs. If you don't keep pulling the cover will snap back down and lock into place. The "tabs" and just small square holes along the bottom of the clear cover and it's very easy to over do it and crack the cover. Gently does it!
The relay activation/control feed goes through J3...
that Bally system was rock solid. everything since has gone down hill.
The tracks on Bally boards are so woefully inadequate for the current they carry it's a joke.
Some very rough measurements using digital calipers show that the copper on my AS-2518-22 board is 0.03 to 0.04mm thick, making it similar to contemporary standard PCB copper which is 35um or 0.035mm, commonly known as 1oz. But if you're making PCBs for power boards you should use thicker copper, either 2oz or 4oz, and the tracks should be of an appropriate width proportional to the current demands.
Punching in some rough values, Bally flipper coils work on +43VDC and the low resistance "flip" coil has a resistance of about 10 Ohms, so pulls about 4 to 5 Amps. It's very brief but it's still 4 to 5 Amps. For 1oz copper (0.035mm) on a PCB the track should be at least 2.25mm wide to carry that much current. A quick measure on my board makes them around 1.75mm, so undersized for the job at about 75% of the required width.
They got away with this size because the high current only flows for a few fractions of a second as the flipper is activated so the track doesn't over heat. The holding current is much lower, only around 0.1 Amps. But if the EOS switch fails to cut in the high resistance "hold" coil then that 4 to 5 Amps is going to keep flowing as long as the flipper button is held in.
Mmm... I love the smell of burning PCBs in the morning!
Funnily enough, look what I found on the back of one of my spare solenoid driver boards:
Some very rough measurements using digital calipers show that the copper on my AS-2518-22 board is 0.03 to 0.04mm thick, making it similar to contemporary standard PCB copper which is 35um or 0.035mm, commonly known as 1oz. But if you're making PCBs for power boards you should use thicker copper, either 2oz or 4oz, and the tracks should be of an appropriate width proportional to the current demands.
Punching in some rough values, Bally flipper coils work on +43VDC and the low resistance "flip" coil has a resistance of about 10 Ohms, so pulls about 4 to 5 Amps. It's very brief but it's still 4 to 5 Amps. For 1oz copper (0.035mm) on a PCB the track should be at least 2.25mm wide to carry that much current. A quick measure on my board makes them around 1.75mm, so undersized for the job at about 75% of the required width.
They got away with this size because the high current only flows for a few fractions of a second as the flipper is activated so the track doesn't over heat. The holding current is much lower, only around 0.1 Amps. But if the EOS switch fails to cut in the high resistance "hold" coil then that 4 to 5 Amps is going to keep flowing as long as the flipper button is held in.
Mmm... I love the smell of burning PCBs in the morning!
Funnily enough, look what I found on the back of one of my spare solenoid driver boards: