My first jamma cab... (newbie post)

[Shep]

Hi folks...

A long time lurker, but first time poster here - and the reason I'm posting is, I just got my hands on my first cabinet (w00t!). It's a no-name generic jamma cab... and the innards look a bit like this...



Before hacking, drilling, renovating + mame-ing, I wanted to double-check with the experts here that some of my assumptions are correct...

So:

(1) The box at the bottom right takes _all_ incoming power to the cabinet, and looks like a transformer. There are two yellow wires coming out of it, and two red wires. I'm assuming this is a combination isolation + and step-down transformer. (should probably have mentioned that I'm in the UK)

(2) The black box on the right is fed by the two yellow wires from (1), and there are 12v and 5v outputs. So, the no-brainer answer is that this is the cabinet PSU. It has no high-voltage outputs.

Therefore, by process of elimination, I'm assuming that the 2 RED wires from (1) are the monitor power supply. The path that the wiring takes to the monitor is partly concealed, and I'm kind of wary about sticking continuity testers on monitor traces to test this theory out... (I like to think I have a healthy fear of poking around in monitors) but there are 2 red wires amongst the monitor inputs, so this scenario seems pretty likely, right?

The ground on the cabinet seems good... I've been testing whatever points seemed obvious.

So... my battle plan is to disconnect the yellow wires at the isolation/step-down transformer end (to disable the main cabinet PSU, but hopefully leave the monitor connected), stick a J-PAC into the jamma connector, and cross my fingers...

Does this seem sensible?

The cabinet has come from an unheated warehouse to a heated room in a house... how long should I leave it standing to minimise the risk of condensation zapping something? I'm really eager to fire this sucker up

Thanks in advance,

Oh... one other thing... I'm using a rather dated J-Pac (bought several years ago - it's actually labelled a "Jamma I-Pac". Looks kind of similar to the current one, except it has a pass-through VGA socket. (I assume this will be active when the synch rate is out of range for the cabinet monitor?) ...any "gotchas" to be aware of with this "older" model?

Shep.

[bowza]

Where in the UK are you?

I am to in my early stages of my first cabinet, I have just converted mine to run on 240 volts, I had to replace the monitor anyway so was not to bad.

Bowza

[Shep]

Where in the UK are you?

Northumberland.

Update: I decided to go with my gut feelings, disconnected the yellow wires, and fired everything up to see what happened...

The keyboard controller on the J-Pac works a treat; all buttons working fine. The video, I've been less successful with. The monitor is powering up OK - the back of the CRT is glowing, and the monitor is making "warm" noises... but no picture. I'm using an old ATI rage card, salvaged from an ancient PC... when I start mame in arcade monitor mode, the SYNCH OK led illuminates on the JPAC (which I presume means I'm producing a scan at the correct frequency) - but nothing appears on the monitor

I'm wondering if something got damaged in transit (the monitor was demonstrated working when I collected it) - but it does seem to be pretty ancient. Looks like I might need a replacement