SL-10 overload

Went to turn on my HAAS SL-10 (2004) this morning and nothing. The electrical cabinet revealed 2 slow burn 500ma fuses blown for the voltage overload protection. ( a board in the right middle area of the cabinet ) Replaced them and blown again. Before the problem with my machine happened a transformer outside was tripped from 2 unfortunate birds. Both the VF-2's and VF-4 as well as compressor and other items are up and running fine so I wonder if a surge only got the lathe as it is first in line on the breaker panel. Thinking the board is toast but unsure! HAAS is 3-4 days delayed to get a service tech out as they are very busy. Had a board shipped to arrive tomorrow to give it a go on my own as I am in a rush to get it up and running again. Anyone have or heard of a similar situation? Thanks in advance!

short

It sounds like you have a short some were. You may want to ohm out the axis motors before putting the new card in. They should ohm out to 1.5 ohms. The problem could be just the card, but better to be sure

On the board is another area that looks like it lights up for a possible short but that may be a short for other wired areas. I will check the motors and get an ohm reading. Where is a good area to get the reading using a meter? Thinking I could possibly avoid having to pull the covers off and check from the electrical cabinet.

Nope, likely big problem inside the machine.
In fact it should be a less than $5 fix.
On that board you will 6 MOV-s, labeled VR1 - 6.
They are the over voltage protection devices, which are designed to short out ( yes, I did say SHORT OUT ) whenever an over voltage condition exist.
They are actually wired between L1-G, L2-G, L3-G, L1-L2, L2-L3 and L1-L3.
By shorting out, they are the very very first device that will activate the fuses, thereby protecting all other internal components.
IOW when installed and new, they are an open condition. WHen over voltage occures, ( not over-current!!! ) they short out, effectively short any of the legs to any of the other legs ( or ground ) which in turn activate the fuse, which then immediately shuts off the main contactor.

Now, how to solve it:
a: For this morning and if you REALLY need the machine, you can find the defective MOV ( it will likely be all black and smoked up), nip it off with wire cutters, replace the fuse and go to work.

b: Immediately go to a local electronic supply house OR get onto DigiKey's website and order the appropriate MOV from them, and get a pack of 10 while at it. They are maybe a buck or two apiece.
Solder them in, replace the fuse and you're good to go.


If you choose option a, please note that you now have effectively 0 protection against overvoltage condition, so choose this only if you absolutely MUST have the machine up!

Is this MOV originally blue in color and round like the size of a nickel? None of them or anything on the board is discolored but one of the blue devices looks like it is split and the blue rubber coating is coming off. Its # is VR1. Wondering if a continuity test would shed some light on the problem MOV. Make any sense? Thanks for the info!

Yup, them are it.
Being split and coating coming off likely means it has got cooked.

You may need to de-solder it, but once you do and it shows continuity, then it is dead.
While at it, you may also want to ohm out all the others as they do tend to go in pairs.

Got ya! Thanks for the help and great instructions!

Wow! You certainly called that one Seymour. I'm constantly amazed by how knowledgeable the members on this site are. It's funny (in a hmmm way, not a haha way) that Haas' service center didn't know about the MOV's and how they function.