Live chassis arcade machines

[japlytic]

When I found service information for a Wells-Gardner video monitor (120VAC), it had a live chassis.
This means when the monitor is connected to an arcade board, the arcade board would become live, even though it has its own isolating transformer .
Live chassis arcade monitors were quite common in the 70s to early to mid 80s.
A lot of arcade machines have interlocks too.

[Wizard]

Re: Live chassis arcade machines

TVs are still semi-hot because PSU is not boxed in.

Same with LCD units as well due to some that have internal PSU and inverter.

Cheers, Wizard

[NxB]

Re: Live chassis arcade machines

I've been shocked by both of those.

[Krankshaft]

Re: Live chassis arcade machines

So the game mainboard's power supply is isolated but the monitor itself isn't and is plugged into the mains?

[Wizard]

Re: Live chassis arcade machines

Sorry for confusion.

I define hot as potientially fatal or OWW! that makes you jerk back and injure yourself.
Isolation improves the safety so much but there is still a dangers lurking.

Mains in a hot or semi-hot chassis is exposed on the board (power supply or part of deflection power supply onboard) that can be accidently touched. Pow.

Even there is chassis that have isolated power supply in a box (aka SMPS) and one of the outputs is 130V for the flyback/horizontal deflection circuit. Still kinda dangerous to work on considering the high current (over 500mA, even an amp).

Lamp inverters is also considered hot because of high voltage that make you jerk back because of exposed components solder joints. I got buzzed by this. Not pleasant.

Cheers, Wizard

[Krankshaft]

Re: Live chassis arcade machines

I recently got buzzed by a selenium rectifier in an old tube chassis from my 16mm sound projector.

It was isolated but I accidentally bridged my finger between two of them a little buzz I've had worse.

I had my revenge though I replaced them both with IN4007s I don't care much for cooking rotten eggs .

[Wizard]

Re: Live chassis arcade machines

The stink from selenium rectifier is poisonous to your health, good thing to replace them promptly with soild-state (silicon) diodes.

Cheers, Wizard

[kc8adu]

Re: Live chassis arcade machines

i used to get nice isolation transformers from junked arcade games.
now we fix them up as they are worth something to collectors.
i have seen several nasty accidents with hot chassis monitors in these games. one customer thought he could reach down into the chassis of the monitor in a centipede game to adjust something.it was 95+ in the garage and everyone was sweaty.told him not to try it.he did anyway and when it bit him he jerked his hand back breaking the crt neck and getting badly cut on it.most had isolation though back then.most of the power supplies were linear so were already isolated.

[kc8adu]

Re: Live chassis arcade machines

The stink from selenium rectifier is poisonous to your health, good thing to replace them promptly with soild-state (silicon) diodes.

Cheers, Wizard

and now i think back to highschool where we had a drum full of seleniums from an ncr tube computer.a suicide cord and a pocket full of these meant a smelly time.
1 of them would clear the classroom.

[Krankshaft]

Re: Live chassis arcade machines

he did anyway and when it bit him he jerked his hand back breaking the crt neck and getting badly cut on it.

Well if you want to turn a vacuum tube into a huge glass bottle thats the safest way .