Help with Neo 4-25 (ver. 3)

Hi Guys, I have a few questions so without hesitating I'll cut to the chase.
OK, I have a dedicated 4-25 (ver. 3) which I'm having a few problems with.
Firstly I have some monitor issues; When the main power is turned on and the ac power is switched to on I get coin led's on, and an audio hum, but no monitor picture at all. I've tried it with a four slot and one slot but still nothing, the previous owner did say it takes a little while to work and there's no need to worry - but I haven't really seen anything at all yet.
Also there seems to be a high pitched ringing coming from somewhere, but I can't locate it.
Secondly; there is a ram error on the board, when I purchased it recently I was well aware of it but have been unable to view what it says on screen; I did get a breif image up on screen for a few seconds but it seemed to just go.
Also, when the previous owner purchased it from the original arcade it was set to freeplay but still had the coin mechs in the cash box for change over, one of them seems to work, but i can't get the other to; basically p1 seems to work but p2 doesn't, even if i swap the connectors around.

So, what I am asking is the following;

Firstly, I'm assuming the monitor needs to be changed out, what would be a suitable replacement, where from and how much? And what is the ringing from? No lock on the coin door? something inconsequential?

Secondly, if I remember correctly; long before I signed up, when I still lurked - I'm sure I remember someone fixing the ram chips for the price of shipping/eeproms - does anyone still do this sort of thing?

Lastly; would the coin mech be easily changed, why is it only p1 seems to be working? what would be a suitable replacement if need be?

With the monitor, are you getting glow in the neck of the tube? You want to make sure the monitor is bad before replacing it.

Barrel locks can be bought at most hardware stores, I usually replace all the locks at one time and have them keyed alike.

Coin mechs are pretty much universal. switch it with the other one and see if the problem changes to the other slot, if not, its a wiring issue. In fact, check all the wiring for breaks and damage.

I had a similar issue with a "high pitched ringing" and the issue was with the EL paper bulbs in the marque.

They may be bad, or about to go bad. You may notice a difference if you disconnect them from the power supply.

That's the great advice a member gave me not too long ago. Glad to pass it on - hope it helps.

When disconnecting the EL panels to get rid of the high-pitch whine/ringing, do NOT (just) disconnect the EL panels from the inverter board, disconnect the inverter board from the rest of the system. If the inverter board is powered but the panels are disconnected, it'll burn itself up eventually.

Coin mechs are basically universal, as I understand it any mech designed to fit a Happ-style coin door should do the job...and that's just about every arcade coin mech you'll find that isn't a standalone coin mech/slot.

For getting the bad SRAM chips replaced (if that is in fact the root of the problem), refer to channelmaniac's thread for his fees and a description of his services.

As for the monitor... It shouldn't be hard to tell if the monitor is 'on' but just isn't getting an image from the game board, or is simply dead/un-powered. Check and double-check all the connections before undertaking a monitor replacement. Though, as you got your hands on a full cabinet, I'm guessing a replacement monitor isn't as much trouble as it would be for someone like me, who has no local source and would have to have it shipped in for god-knows how much.

You're looking, obviously, for a 25 inch monitor, standard resolution (Not VGA) and that can run you in the neighborhood of $350 new. Price for used is all over the place and probably the more budget-conscious option if you can swing it. (Hell, you might even get lucky and score a whole used cab for less than a monitor and it'll have your coin mechs too! )