Gottlieb system 1 - Flipp PI-1/X4 locked coils warning!?

[dudeyds]

Hello, I've been working on my Gottlieb solar ride machine. I've Cleaned up the flippers and replaced all the rubber, I had some issues with the power supply and some issues with driving Coils etc so I went ahead and ordered the Flipp! PI-1/X4.

What a brilliant piece of Kit!

I noticed the CPU controlled coils weren't firing and spotted a blown fuse under the playfield. I replaced that and also saw that there was a missing diode on the target reset coil.
I know the grey line on the diode has to face the positive side, so I took one of the cables off the coil and found the end that connected to the playfield fuse, and soldered the diode with the grey end facing that way. I've attached a picture. Would this be correct?
Unfortuantely it seems I may have made a mistake, I'm now getting an error after the game boots but before I press play (when it's doing coil tests.).
I had a look and this is most often because of faulty transistors? the PI-1/X4 has built in test pads for all it's transistors, I bridged the test point with another point to light up an LED as per page 18 of the manual found here and they all work from what I can see.

I believe I can ignore the wanring and start playing, but I'm quite sure that's not a good idea to try using the test coil feature until this warning stops showing.

If I take the fuse out then the warning no longer comes up, so it has something to do with the coils using that fuse.

I'm quite lost, this is my first pinball and I'm not having much luck so far!

I would really appreciate anyone's help.

 

[ronnie63]

If it would help I'm working on a buck rogers just now I could take a pic of the wiring round that fuse?

 

[drhex]

My interpretation would be that there is continuous current through the coils even when none are driven - seems the new board detects this (there is a coil current status LED on the board to check) and throws an error. As this isn't for a specific coil it must be a short to ground somewhere. Would check if you have connectivity from the fuse to ground with between 30-100 Ohms. If so, you have a short somewhere.

 

[dudeyds]

If it would help I'm working on a buck rogers just now I could take a pic of the wiring round that fuse?

That would be great, thank you!

My interpretation would be that there is continuous current through the coils even when none are driven - seems the new board detects this (there is a coil current status LED on the board to check) and throws an error. As this isn't for a specific coil it must be a short to ground somewhere. Would check if you have connectivity from the fuse to ground with between 30-100 Ohms. If so, you have a short somewhere.

Thanks for your advice here, I just tested from that playfield fuse to ground and the resistance was 182 ohms, could it still be shorting to ground somewhere?
What do you think the next steps should be? disconnect the plug with the coils and try ataching the wires one by one?

I also have a Digital oscilloscope if that will help with troubleshooting.

 

[drhex]

182 Ohms is definitely too low, should be open. First thing is taking the fuse out, measure from the coil side to make sure you're not seeing anything on the supply side. Next thing is disconnecting the coil plug as proposed to see if this is coil side or on the board (latter would be surprising). Then it is about finding the culprit, thorough visual check followed by measuring from the switched side of the coils to ground with the fuse still out. The affected coil is probably shorted to ground directly. May well be what killed the fuse in the first instance.

 

[dudeyds]

182 Ohms is definitely too low, should be open. First thing is taking the fuse out, measure from the coil side to make sure you're not seeing anything on the supply side. Next thing is disconnecting the coil plug as proposed to see if this is coil side or on the board (latter would be surprising). Then it is about finding the culprit, thorough visual check followed by measuring from the switched side of the coils to ground with the fuse still out. The affected coil is probably shorted to ground directly. May well be what killed the fuse in the first instance.

I may have possibly found the culprit?
I removed the fuse, and the multimeter gives 220ohm resistance to ground on the side not connected to the reset coil, 0L (I assume open connection?) on the side with the reset coil.
So I used my multimeter to find out which other coils are using the fuse, one of which I (embarassingly) hadn't noticed before, I think it's the kicker? I do have a parts manual, but it's not very helpful. it's just underneath the right flipper button.
I tried to take a resistance measurement of it, but it gives the same 0L so both sides of the coul are completely disconnected?

 

[ronnie63]

Yeah I get 220 ohms to ground from fuse,

 

[dudeyds]

I really apprecaite everyone's help so far, thank you!

Well, this coil is definitely busted.

I've got a replacement ordered and should be arriving early next week.
Is this what would be causing the warning? or should I still be looking for a short to ground?

is it safe to turn on and see what it says now I've removed the coil?

 

[drhex]

That coil is toast . I don't know the board and the manual is a bit nondescript about the error message. I interpret it as current running without an active coil, i.e. short to ground. 0L is good, it is open circuit, means that you don't have a short to ground while machine is off. If there is no coil pulling constantly when switched on I'd think you're safe and this error pertains to the molten coil. Don't forget to order a liner, too.

 

[Moonraker]

Looks like the coil is for the knocker so you should be able to disconnect it and play a normal game.

 

[dudeyds]

As a quick update. I replaced the knocker coil and this didn't solve the issue.

I have isolated the issue to one Coil, sol8. I replaced every single wire between the power and the transistor, nothing. Same issue.
Out of curiosity, I bridged sol8 and sol7 , with sol8 disconnected from the board, the same error came up. When i bridge sol6 and sol7, no issues and both coils fire at the same time. So I think it's the transistor after all. I've ordered a set from Flipps website, and I'll see if this works!

Thanks for everyone's help so far!

 

[dudeyds]

Final Update!

It was the transistor!
Even though it tested ok, it must have been broken somehow. Replacing the transistor and diode from Flipp worked. I now have my firsrt working pinball machine!!!

Thanks everyone for your help and advice