Dead power supply?

[Mayo]

I was cutting a job and stepped into my back yard for a minute and when I came back in, the job file was done however the bit was still within the material and it had not completed the entire file.

I have a 2001 PRT with board 2.07

Tried to move the motors with keyboard but nothing moves even though the screen makes the X,Y,Z locations move as if the gantry is moving.

Shut everything off, rebooted, started up control box and software but I still get no motion from the motors.

Inspecting the control box, the computer power supply at the top of the box is getting power and the fan is blowing. The 45v power supply does not have the fan blowing however I understand it only turns on when needed from heat.

What can I check to determine if it's the 45v power supply?

As these things usually happen, I have to complete this job and ship it tomorrow for it to arrive in time for an event - but now it looks like I'll have to pay big bux to Fedex the order next day on Monday.

[Mayo]

Further info - I just checked and the power supply has 45v at the screw terminals where the red and black wires from the control board connect to the power supply.

This is not looking good - I had hoped I could just get another 45v power supply locally. It may be another component on the board.

[srwtlc]

Mayo, are your motors locked in when everything is powered up or are they loose? Is that one hooked up with a serial cable from the serial port on the computer?

[ssflyer]

Hi Mayo,

I don't have a PRT, so these are just guesses...

I've had that happen to me on my PRS, with a couple of SB3 versions, but it never persisted through a power cycle.

Since the control spftware thinks it's moving, and you have the 45v from the PS, the first thing I'd try is a re-install of SB3 and firmware. Only takes a couple of minutes, and eliminates one possibility...

EDIT: I see Scott beat me to a reply! He has a great idea, that I didn't think of - if you can move the machine by hand, then you don't have power to the steppers. However, I wouldn't think you'd lose all the drivers. I haven't delved into the actual circuit, though...

[Chuck Keysor]

Mayo, its a good thing you live in South Elgin and I live in Elgin. You can cut your stuff on my machine if you want. Chuck

[Mayo]

I brought my control box to someone that can actually work on electronics at the component level, and he determined that the diode was bad on the under side of the control board (opposite the 45v connection).

An interesting thing about the 45v power supply -
When the red and black wires from it are connected to the control board, it does not light up the green LED inside, nor does it read 45v at the screw terminals. However when you remove the red and black wire plug from the control board, the green LED lights up solid green and 45v is present at the screw terminals. I assume this is some kind of built in protection. Or the blown diode causes this. Or both.

Unfortunately he didn't have a diode to replace it with and the closest store that would have one (ten miles away from him) was already closed.

He also mentioned I could probably use it temporarily with the blown diode removed, but if the 45v power supply was the original problem, it could possibly damage the board further by not having a fresh diode on that connection. I don't think I'll take the chance.

I have found the part from various sources online priced anywhere from 69 cents to $3.99 but I'm going to try and get one locally so I don't have to wait for shipping. Amazingly even I can solder something this simple.

If I have no luck with finding the diode, I may be bringing some foam over to your place Chuck, since you were gracious and offered use of your machine!

[Mayo]

OK the "local" part was almost an hour drive one way to get but thankfully they had them in stock and they were the only store that had them in stock so I picked up two diodes today. One for a spare just in case.

Soldered the new one in place, reconnected everything and it worked perfectly.

To justify the drive I had to also buy the new release of Wolfenstein The New Order but that's a different story...


Thank you to Frank from Shopbot for emailing after hours and follow up.