[DistortedDesign]

I have a hobby cnc pro v.1 board. I have had it for a while but never really used it. I have been working on a Joes cnc for a long time. Board worked year and a half ago. I got the machine jogging not much else. I was running 24vdc power supply. I am running 40vdc now. I wanted to double check everything on the board, vref, ect.

Now I only get .2v on the 5v line (Also getting a dead short between them). Checking between the neg on TB6 and 5v pad.

On each of the Vrefs I only get .015v. I have jumper 4 removed like you are suppose to.

I took board inside to check it. I wanted to check the voltage regulators. I hooked it up to a regulated 12v / 1.25a wall wart to check 5v line. It drug the power supply to down to 9v. The voltage regulators got really hot really fast. Within 6 seconds they were hot enough for me to smell them. Lucky for me I was right over the board. No visible damage to any chips. I am assuming the v-regs have gone bad internally.

How do I know if it damaged the driver chips? or U8 or U9? Any way to test the V-regs without power?

[DistortedDesign]

Anyone?

[H500]

Do you have a schematic?

[DistortedDesign]

No, cant find one. The guy who makes the board doesn't seem to be supporting it even on his own message board. I think what is happening is the voltage regulator has a dead short. I got new voltage regs for it. Once i go to replace it and pull ot off the board and see of the short on the 5v line goes away.

[H500]

It sounds like there's a short on your board. LM317 regulators should shut down temporarily if they get too hot. Does it still draw heavy current with no motors attached?

[DistortedDesign]

Yes that is when it got hot. I only gave the board 12v, no motors, and it drug the power supply down to 9v and they got hot enough for me to smell them in 8 seconds.

Sent from my SPH-D710 using Tapatalk 2

[H500]

Although it is not impossible, I think it is unlikely that the regulator is the problem. More likely, one of the driver chips blew and is drawing the current. Find out which one is getting hot, but be careful not to burn yourself. Your only option is to replace the defective chip.

[DistortedDesign]

The regulators were getting super hot. There is no visible damage to the drivers. I have a giant heat sink on all of the driver chips. I am not sure how they would go bad from sitting. I haven't used this board for more than 10 minutes since I had it. It worked fine about a year ago. I will have to remove the heat sink to find out which one is getting hot.

[H500]

Disconnecting the motors with the power applied can kill the chip instantly.

[DistortedDesign]

I did not disconnect the motors with the power applied. I know about the blown chip thing. I disconnected the motors when there was no power for a long time, like a year. I wanted to check everything before I put it back together. I went to check the vref on the motors and i was only getting .025v and .23v on the 5v line.