Hi Guys,
I have a 1995 VMC15, 7500rpm 15hp. The problem is I will throw the main power switch and and the electrics in the rear panel will come on but I push the green on/brownout button and the controller will not come on. I checked continuity on the switch, fine. I don't see any of the LED lights in the side panel coming on. all the fuses look good. Could it be the 12v power supply is shot? Wouldn't I still hear the relay snap on when I hit the green button even if the 12v power supply was bad or is that interlocked to it?
Any help is appreciated.
Josh

Yes these conditions usually mean a bad DC power supply. Just check the 110 volts going to the DC power supply board, the fuse on that board and connections.

Does the power supply have "tri-mag" label (looks like the power supply from a PC) If it has this style power supply and it is bad, I know a very cheap repair.

I recently had a similar issue on my trm (it was intermittant). I would turn on the power and everything would come on but I could not tog the machine or do anything else for that matter. It turned out to be (I think, it is working fine now) the relays on the power dist. board. If I tapped them while the machine was on (when it was acting up) they would energize and the machine would work fine. Not sure if thats your problem but it was mine.

Mark

Yes these conditions usually mean a bad DC power supply. Just check the 110 volts going to the DC power supply board, the fuse on that board and connections.

Does the power supply have "tri-mag" label (looks like the power supply from a PC) If it has this style power supply and it is bad, I know a very cheap repair.

Yes it is a Tri-Mag power supply. I was thinking of trying to use a pc power supply but havent found the schematics for it yet to see if it would work.

How do you test the relays on the power dist. board? continuity I would guess, but over what terminals?

I just tapped them with my hand and they would energize. I replaced them and have had no problems since.

I just tapped them with my hand and they would energize. I replaced them and have had no problems since.

While holding the power button in? How much juice is flowing thru them, maybe use a stick?

sounds like your problem is different to mine. I opened the back panel (to have access to the boards) and turned on the main power switch. My machine could no jog or anything, in fact upon powering up I could not hear the relays clichk on. I simple tapped on the plastic shell of the 24v relay(s) on the power distro board and the relay(s) energized and my machine worked as it should. I have now replaced the 4 relays and have not had that problem re-occur.

Mark

Yes it is a Tri-Mag power supply. I was thinking of trying to use a pc power supply but havent found the schematics for it yet to see if it would work.

You don't need a schematic. It is a PC power supply. Chop the wires down, and match up the colors. Check the machine schematics to make sure you have the right voltages running to the right place. Its been a while since I changed ours out, but it was really easy. Cheap PC power supply VS. $240 from Fadal. If all you can get is a switching power supply (99.9% of all new ones) I think you jump the green to the gray or something like that and it stays on. You can even swap out the panels of the power supply so that it looks "original".

I'm not sure if thats your problem, but if it is, its a cheap and easy fix.

I guess I will try to test the power supply again just to make sure power is getting that far, thanks for the input guys, will be nice if it is a simple power supply swap.

we have a 2216 and we have the same problem. Sometimes it wont start when i push the green button but after i turn the main power on and off a couple of times it usually works? Does yours start occasionally?

Dont forget that there is a solid state (SS) relay on the Tri-Mag power supply that must energize before anything will come up, and that includes the power that runs the small icecube relays in the back panel. You can pull the SS relay on the Tri-Mag supply, short the output of the relay (be careful that you are shorting the correct holes in the board where the relay plugs in) and press or short the leads on the green "on" button to see if if starts. You should at least have the +5 and such from the Tri-Mag at this point if the Tri-Mag is good. If so, the problem is indeed with your ice cube relays in the rear panel most likely.

Yes, a normal pc power supply will work, in place of a tri-mag, however you may have to change how it mounts to the cabinet.

To get the power supply to work, usually it needs the dark green wire to be gounded to a black wire. Just connect these two wires together permantly, use the same color wires you need for the DC voltages
(5+ red,12+ yellow,12-blue, ground black) and tape up the wires that are not needed.

Here's a link for pc power supply connections.

http://www.helpwithpcs.com/courses/power-supply-basics-inc-pinouts.htm#connectors

Well once I get plowed out and can get up to the shop I will check all the things you guys have mentioned. CNCzone ROCKS!!!

Ok, I replaced the power supply and I am back up and running!! wooHoo!!
Thanks for the help guys!