Hey, first time poster here.
I have a xenon pinball machine and when I turn it on 5 or 6 solinoids lock on immediately. I had everything working and went to repin J1 on the sound plus board to get some of the scratch out the speakers. Everything ran fine for maybe 10 credits and then I went to turn it on the next day and blam everything went screwy. Locked solinoids and no background sound. If I press the test button for sound she speaks and chimes up clear and fine.

I replaced repined j3 on my solenoid driver board.
If I remove j5 I get 7 flashes on my mpu
I quickly checked a few of my transistors- not all and I was getting .5 and 0 from them
My voltage on tp2 is way high 230vdc

I though it would be my transistors or capacitors but the ones I checked were okay for its age. I get low voltage out of my power supply board for tp1 5v instead on 6 or 7.

Anyone know why my solinoids lock on power up? I can provide any more detail you need to help just ask.

The solinoids that lock on are right and left slingshot and middle/lower thumper bumper. Four locked solinoids when I throw the power switch.

No everything is mostly original from first sale in 1980. A few solinoids and nick nads like bumpers and balls have been replaced. I have taken readings on the caps and they are doing fine.
Yeah tp2 is reading 230vDC and it does not change in accordance to the potentiometer. I’ll take the SDB out and take some more readings.
I found the components injunction with the faulty solinoids and the transistors read good on each leg. So do the rest on the lines on each.

I thought it could have been something flopping out at the sound board because that was the last thing touched.

I’m thinking I might just take all the circuit boards out test each component and freshen up the boards. Then when I put them back in re wire the whole thing.

I read hard wiring grounds on the SDB is a good idea. Although I am not one to want change anything from its original state and if need I would rebuild a board from scratch. Could flowing the SDB with “mods” fix my problem?

I have the right fuse in the play field it blew once along with half my power supply board fuses. I replaced them all and haven’t had an issue. If j5 is removed I get 7 flashes on my mpu and the locked solinoids don’t energize i can use the flippers but no sound.

I don’t have any solder mistakes but my pining may be funky. When I repined j1 on my sound plus board I didn’t notice but I have an extra wire. And I slightly remember my grandfather saying he had it worked on once and the guy wired it to work not to the schematics

So I ground on the tab and test my legs with an ohm meter for the transistors. Looking for 0 to .7.

I also don’t think it is my solinoids driver board. I might have a power issue causing the machine to send singles to whatever it can but I don’t have have extras to test them. I have a feeling it is my sound plus board getting the wrong voltage and using the voltage making the SDB act funny.

I appreciate the feed back and have decided to take my time through each component on each board individually and in sequence. I might even build a bench test system.
I will let you know what I find wrong on SDB and or if my sound plus board is running away with power. Incase someone else finds this and has the same problem.

So I found the issue with all but one solinoid. The left sling shot, middle, and lower thumper. None of the transistors were bad when I took out the board I freshened up the solder confections on j3 and repined the female connection to it. I also freshened up some of the high voltage components which made the problem stop. Now I’m only stuck with one solinoid, right slingshot, that is locked on I found a old post on a search and it said it could be from someone monkey around with the machine wiring it to work not to schematics.
I know I need all new components for my 190vdc and 230vdc in the SDB-everything between and near the 2 caps looks worn and blackened.
I still have to re wire the back box to how the schematics say because I can not find out why or what the extra wires are doing there. The extra wires run to the sound plus board and SDB.
I’ll keep you updated when I find what is up with the extra wires I’m finding and how it was rigged so anyone else can undo something like what I’ve seen without redoing everything like I’m about to do.

Hey guys big oops back at square one! I replaced a transistor for the right sling shot, found out it went bad after turning it off and on constantly to check things. So now when I put the SDB back in everything is energized again!
- left/right sling shot
-middle/lower thumper bumper
At a loss on what to do...
The SDB has no bad components. The solinoids are reading 10ohm on my meter.
I get 43.7v.

The thing that is weird and I know I probably shouldn’t be doing this but on the solinoid driver board j3-25u I remove single (u) pins. I found if I remove u25 the solinoids don’t energize.

Can anyone help me with this? I read the zero cross circuit is something but I am getting 7 flashes on my mpu led

Sorry to skip over that comment, I bought the kit for the pins and when i take everything out for re wiring I will re pin both ends like you mentioned. Thanks!