Easy to test with a voltmeter

Your transformer could have a shorted winding, which is causing it to pull a ton of current...which causes the fuse or breaker to blow / trip.

If you dont have a solid background in electrical theory or electronics, this might be a hard one for you. DON'T keep plugging it in to the wall socket. Find someone with a variac or experience testing circuits.

If this were mine, I would disconnect the transformer primary [where AC wall connects] and supply a lower AC voltage with a variac and start measuring AC output. Or reverse feed the transformer secondaries with low voltages and see how things measure.

I'd Nerd out and use my impedance bridge too.

Check your hot, neutral and ground from your power cord and make sure someone didn't tie something together incorrectly. Easy stuff first.

In my experience transformers are rarely the problem unless someone physically damaged them which is usually very obvious. Yours has some aged paper insulation but that says nothing about it’s electrical condition.

Test, test, test but understand you are working with full line voltage.

I wish I could remember what it's called but it's not the transformer. It's the silver box that the power cord goes to before the transformer.

These short out and blow house breaker.

Edit just realized it's a em. Dont think em's have this. It's a line filter.
20200421_190214 (resized).jpg

You are in Norway, I think.
Has this game been used in your country before?
Could this be a 120 vs. 240 setup issue?

I agree. However, I have had a transformer with an open winding and another with a shorted winding. Both on the secondary side. Not pinball transformers. It happens.

This is a '72 Bally Fireball schematic.....the transformer part # is E 122-95
16bb93058c5cc9e63197624735474ac075f9431e (resized).jpg

Hi all and thanks for your input!

I was the one who tested this for @axl. I have not worked much on EMs yet, but I am eager to learn!

To recap, the problem is that it blows the mains the instant I plug it in. I checked the power chord and the power switch to be ok. I checked the 8 amp line fuse to be ok. I unplugged all other fuses in the game, and although I might be wrong this should mean that I am testing the transformer without load. Power in, no power out. It still blows the mains. Once the mains blow, there is a whiff of burning smell coming from the transformer - I might be imagining this though, as I cannot trust my sense of smell anymore. I am old.

The transformer appears to be wired correctly. Norway is 220V, and the wires go to the correct lug on the transformer.

Since the mains blow instantly, I cannot test any output whatsoever. So I came up with the idea of testing the transformer for continuity. Looking at the attached schems, it seems to me that lugs 1,3 and 5 should have continuity. The same applies to 7 and 8. What puzzles me, however, is that ALL the mentioned lugs buzz. Is this how it should be? I would imagine that bank 1,3,5 would be separated from bank 7,8 - especially since the fuses in the game are removed. The lower lugs do not, however, buzz with the upper lugs 2,4,8,10 - which I guess is good news.

Am I doing it wrong? Is there an approach to test the transformer under the given conditions? I would prefer not removing it from the game.

st (resized).png

trafo (resized).png

Are you getting a continuity reading across the two prongs of the plug? That's the most basic way to start looking...

The schematic shows primary windings 1-3-5 and 7-9 separated, but the wiring instructions do not comply with that.

Sounds crazy, but did you check your plug on the cord (where you plug it into the wall) to make sure it is wired correctly. I am assuming it has a 'screw on plug' and not a molded plastic plug.

If you ohm or meter a transformer, you are going to measure low resistances because it merely is a coil of wire from one side to the other (hot to neutral). Yes, there will be separation between the primary input and secondary output. You need to find a variac or impedance bridge to test this properly.

If you do find that it is bad I have a spare out of a bally night rider.

Does your mains still blow if you have the on/off toggle switch in the OFF position?

Ait, found it! Seems this old line filter is shorted. I cut one wire at the on-off-switch and there was still a buzz when testing. What is the best way to replace this? Is there any modern equivalent?

A5D1059A-DE4D-4A4A-93F7-5A7FC673446F (resized).jpeg

C5E898F7-FBF8-4571-BCDD-5A4225995D75 (resized).jpeg

I don't know export games (outside the USA), but that might be a filter someone added and not Bally. Others can confirm. Those line filters were / are used on solid state games. Inside are resistors and capacitors that can go bad.

You can order replacements from Farnell or DigiKey. Those are European suppliers. You just need to spec your AC voltage and current of the game. A 3 to 5 Amp filter would be plenty.

The mystery box seems to be an "Radio Interference Filter" which I'm not sure is needed at all. Seems that it was just a requirement for German games at the time. Can I just remove it and connect the mains on either side without messing anything up?

Yes.

I'd open up the filter and take a look at what's going. The filter is just an LC (inductor/capacitor) low pass filter. Maybe it has MOV in there too.

Hey Axl,

Mind opening up the EMI filter and shooting a few pictures to post so we can see what is going on? Curious minds (me) would like to know. No biggie if you are busy.

Thanks for the post. Boy, they did button it up well!