Isolation Transformer for Arcade monitors

[vanwatson]

What is the Isolation transformer used for Arcade monitors?

The Isolation transformer has the 120VAC on the primary and the secondary of the transformer goes to the flyback?

[shrunkenmaster]

Have a look on this page dude, lots of information for you:

http://www.ultimarc.com/monfaq.html

[lilshawn]

older monitors use an electronic regulator to supply voltage to the electronics of the monitor. it needs to be isolated from the line voltage with a transformer (120volts in, 120 volts out or a 1:1 transformer) hooking one of these type monitors directly to the line voltage results in the regulator blowing up. it must be powered through the isolation (or 1:1) transformer to isolate it from the line.

newer monitors use a switch mode power supply to power the electronics, these newer monitors don't need isolation and can be hooked directly to the line.

[vanwatson]

That doesn't make sense if the 1:1 transformer is 120VAC on both sides and it doesn't blows the regulator chip?

If I hook up the 120VAC direct to the regulator chip it will blow it up , but if I hook up a transformer 1:1 at 120VAC on both sides primary and secondary it doesn't blow up the regulator chip.

The Regulator is getting a 120VAC input either way if it's isolated or not.

The Isolation does what to the 120VAC? the Isolation does what to the regulator?

It needs to be isolated from the line because of why?

[ed12]

man u need to read up

it is a self explantory term >isolaiton<
it isolate's the chassic from ground....
thus when u hook a :hot: ground refrence board or video source or probe to it
it will not go :puff: and or :magic smoke: which ever term u like
it in it's simple term's isolate's the chassic from ground..

ed

[lilshawn]

That doesn't make sense if the 1:1 transformer is 120VAC on both sides and it doesn't blows the regulator chip?

yes, 120 volts AC in and 120 volts AC out (sometimes 100 or 130 volts AC out)

If I hook up the 120VAC direct to the regulator chip it will blow it up , but if I hook up a transformer 1:1 at 120VAC on both sides primary and secondary it doesn't blow up the regulator chip.

yes.

The Regulator is getting a 120VAC input either way if it's isolated or not.

yes and no.

The Isolation does what to the 120VAC? the Isolation does what to the regulator?

the isolation transformer isolates the power regulator from the line voltage to have it's own power source independent from the line voltage with which it comes from.

It needs to be isolated from the line because of why?

quick and dirty NON TECHNICAL EXPLANATION

the regulator uses electrical difference to achieve it's high current high voltage output. this ground is not the same as earth ground. the neutral on your house wiring is connected to earth ground. this causes the monitor to have part of it's output shorted to ground. result: blown regulator (and likely other stuff too)

using an isolation transformer removes the neutral from ground and allows the regulator to operate.

[vanwatson]

So you're saying that the Monitor circuit board is "Floating" from earth ground or doesn't have an earth ground, it's an isolation ground.

Any reasons why they want the monitor circuit to be floating or not have an earth ground?

yes it isolates the chassis from earth ground, but any reason why they would want to do this?

To filter out the 60hz ripple, hum and noise out of the monitor circuit?

[ed12]

no
the tech term is called "hot" chassic
which mean's the steel of the chassic is 1 side of the line power >120vac<,
which they refer to as ground,this is normaly the white return wire..

so to protect your-self and any electronic's u hook up to it u isolate it.

ed

[vanwatson]

My Oscilloscope has a 3 prong ac plug with earth ground. If I probe my Oscilloscope on the monitor circuit board or deflection board it will be tied to the Oscilloscopes earth ground with I'm probing. You're saying it will short out and damage the monitor circuit boards components. The oscilloscope probe has a ground clip which goes thur the oscilloscope 3 probe ac plug that gets earth grounded.

[ed12]

if u do not isolate the chassic. yes u will damage your scope and the chassic..2 bird's
with 1 stone..because the chassic's nuteral >white wire< is tied as ground
the scope with it's 3rd >green< wire will act as a dead short to earth ground..
if the chassic is isolated this no longer become's a problem as the chassic can never see earth ground pre-say..

ed

[vanwatson]

But the Monitor is earth grounded from the braided ground wire that attaches to all the AC grounds in all the circuit boards, transformers, AC line filter, etc. So the Monitor is AC grounded to earth from the braided ground.


Plus I don't why they have 3 series pass transistors on heatsinks in the power supply , what such big series pass transistors on heatsinks, it's only +5 volts at 11amps

I'm guessing the Series pass transistors increase the amps to 11 amps at 5 volts

[ed12]

series pass

ed