Power on problem with my arcade monitors

[ckong]

First: I don't have a lot of technical/electrical skills and or knowledge. I just like to try out a lot of things. Mostly it goes allright, sometimes it goes wrong (Latest failure: soldering a chip in a Wii, the first one went right, the second one terribly wrong which forced me to buy a refurbished drive  )

But there are bounderies which I don't like to cross, mostly because of safety reasons.

So, my problem: About 4 years ago I bought two old 19" arcade monitors from a bloke who said they were in good order. The monitors have a Hantarex circuit board (MTC 900). I did not test it back then (I know, that's stupid). The monitors have been in my shed since then, until today. I stumbled upon them and wanted to test them right away. So I hooked one up to the jamma connector (RGB connector and power connector) in my existing cab and I switched the cab on. But at the same moment the lights in half the house went out, including all electrical equipment!! One main fuse in the house electrical cabinet (good English?) was blown.  So I disconnected the jamma connectors from the monitor, switched on the main fuse again (Haleluja, there is light again), connected the second monitor and switched the cab on a second time. But the same thing happened with the second monitor!! 

I know I have to be very carefull with monitors, I don't want to get fried! Therefore I hesitate to try some things out myself. But perhaps someone can give me a clue what the problem could be?

Oh, and another thing. One of the monitors has a little breakout circuit with a red push button and two adjustable (turning) knobs on it. Where are they for?

[Ken Layton]

Here in the USA, Hantarex MTC900 series monitors are designed for operation on 120 volts AC from an isolation transformer.

Storing monitors in an outdoor shed is never a good idea. Moisture, wide temperature swings, rodents, and insects all can damage a monitor even though it may look alright.

[Kevin Mullins]

Here in the USA, Hantarex MTC900 series monitors are designed for operation on 120 volts AC from an isolation transformer.

Bingo......

"Isolation Transformer"

You may have just damaged both of those monitors if you wired them straight up without using an isolation transformer. (did you?)

[grantspain]

if you wired to the mains direct then you just fired 230vac into a chassis that is 120vac,you have probably taken out some of the following
F1
F2
D1,2,3 AND 4
C11

you need to get a 230v to 120v stepdown transformer to power these chassis

the two pots and red button are brightness,contrast and degauss switch

[ckong]

Thanks for the replies. both monitors operate on  230V (I am sure of thta because I checked it), and that't what they got (I live in Europe). I don't know what an isolation tranformer is, but this is what I did: I have an arcade cab with an arcade monitor (working properly).  From that monitor chassis I took the power connection (2wires, white and black) and the RGB connection (5 wires), and I just stuck them in the two monitors from the shed (I know, not a good storage facility). Then I turned on the power switch of the cabinet. That's it.

[grantspain]

trust me,mtc900 run 120v for chassis with a seperate 220v for degauss-same as mtc9000(unless u.s issue)
if you have polo chassis then it will run direct from wall socket
what about providing some photos

[Kevin Mullins]

What kind of monitor is in the cab that you used to test with?
(curious as to if it requires an isolation transformer)