Seeburg HF100R - Low Voltage Shock

Odd question....
I jut picked up an original, unrestored HF100r last week. There are many mechanical issues I am working through, yes I have the manual and troubleshooting guide. I have spent years rebuilding old Gottlieb Wedge Head pinball machines from the early 60's so I do have experience with coils, solenoids, and wire tracing via schematics, as well as general troubleshooting.

While waiting for parts to come I have been trying to figure out another problem.... While working in front of the machine the other day, I kneeled down on my concrete garage floor and my arm happen to brush the front chrome bezel and was given a low voltage shock, compare it to 9v battery. So I have spent the past few hour tracing and pulling sections out of the mix to try and pin point where this may be coming from, so far nothing.

So I am trying to get suggestions from people to see what could cause a low voltage shock by touching the frame in the front of the machine. I will do more in depth troubleshooting tomorrow, like pulling out the entire mechanism, as I need to clean the pinbank, and I will see if I still get a shock with that removed.

Thank you, this is a great project... Cant wait for the trip solenoid to come in as thats what holding me from moving forward. Will not pick up or reject a 45, all contacts have been cleaned and adjusted, as per the manual, and the Pins are opening when a selection is made and the carriage is moving but will not pickup. Playing manually sounds great, down 1 12" front speaker, but will not reject the 45 either. But the low level shock is something I need to fix asap, not sure if it is a grounding issue or not. I replaced the power cords, as the originals were badly deteriorated and I get the shock if I use the courtesy outlets in the case or just use the hardwired plug from the receiver.

This is pretty common with older electronics in-general.

I don't worry about it. For commercial installations I replace the existing two-wire cord-plug with a grounded one. Before turning it over to the public I first lift the ground connection on the plug that goes into the wall (3 wire) using an adapter. I measure what leakage is present on exterior metal and then replug the internal (2 wire from selection receiver) at the polarity that gives little or no leakage and then plug the 3-wire straight into a grounded outlet.

Unless there is significant current behind the leakage -which indicates a fault, the method I described will kill any leakage and not cause problems.

If you want to actually track down the leakage simply connect a mater from the chassis of the selection receiver to ground and in-turn, remove the mech plugs and then the amp. My guess is that you'll have to deal with this via polarization and grounding as I described.

BTW: Have the amp and receiver been recapped?

Rob/NYC

Thank you for your reply...
I replaced the 2 prong cord for the receiver that connects to the convenience outlet in the cabinet and I replaced the cord for the convenience outlet with a 3 prong ground version and ran the ground wire to one of the wheels. I have taken the convenience outlet out of the equation and just plugged in the 2 prong cord from the receiver into the wall and I still have the low voltage leak. I will try trial and error and remove different connections until I can narrow it it down. I had the same problem with one of my pinball machines years ago, drove me crazy.

They have not been recapped yet, on the list of things to do. I have ordered the cap kit just waiting for it to show with the other parts I ordered.

You have to connect the external ground (3 prong) to the selection receiver chassis. All points in the machine center there. The cabinet wheels are of no use here -they are in wood and not connected to metal.

Use the polarity of the internal two-wire plug that shows the least leakage to the external ground, Then reconnect the external ground to chassis kill any remaining leakage.

Rob

Are you suggesting that I should try switching the polarity of the 2 prong outlet that is hardwired in the receiver? Switching black & white to see which has less leakage?

SorrY, I am not sure what you were suggesting.

Correct. Choose the polarity of the two wire plug from the selection receiver into your cabinet outlet that shows lowest leakage to ground and then attach the external ground wire (your 3 prong plug's green lead) to the selection receiver chassis. This just to eliminate any residual leakage and prevent any future hazard.

Rob

Hi Ron,
I don't know about New Jersey, but here in California, it is NOT legal to replace a two wire cord, with a three wire cord, unless you re-submit the item to UL for testing. When I run across this, I find, and fix the source of the problem. Often it is a lamp ballast. Also, I do replace both power cords with polarized cords, making sure they are correctly connected. Worst case, it' a leaky transformer--which IMHO, should be replaced. As a "safety" I also often install a GFIC in place of the convenience outlet, or instruct that the phonograph be only plugged into a GFIC. Ron Rich

Well running the ground wire from the 3 wire cord I have connected to the convenience outlets inside the cabinet to the frame of the receiver eliminated the low voltage shock. I can try replacing the 3 wire cord with a 2 wire polarized cord for the outlets in the cabinet to see it if changes anything but I tried using a 2 prong adapter on the 3 prong plug to remove the ground and was still getting a low level shock from the cabinet.