WTH Servo Dynamics amp repairman, or WTB rebuilt SD amp

[Mario]

I have a milling machine that has blown three Servo Dynamics PWM SD3030 amplifiers. (Some people
call this amp a SD3030-16, but the full name is SD1-3030-163-1. It is very similar to an amp called
the SD3060.) Now that I have figured out the power problem that was causing these amps to blow, I am
now looking to repair one of them - maybe two if the price is right. This amp drives the 6hp
peak/4.3hp continous DC spindle motor on my mill.

If you have the knowledge and experience to repair these amps, please let me know (especially if you
are in the Dallas/Fort Worth area). If you can recommend a repair shop that can fix this amp, or if
you know of a shop that is selling rebuilt Servo Dynamic amps, I would appreciate knowing about that
as well.

Since I have more than one of these amps, I think I can make it easier for someone to fix them by
swapping out parts from one unit to the next. I am hoping to find a solution this week (the week of
May30 - June 5) so I can get my machine running soon.

Thanks a lot for your input!

 

[Ned Simmons]

I have a milling machine that has blown three Servo Dynamics PWM SD3030 amplifiers. (Some people
call this amp a SD3030-16, but the full name is SD1-3030-163-1. It is very similar to an amp called
the SD3060.) Now that I have figured out the power problem that was causing these amps to blow, I am
now looking to repair one of them - maybe two if the price is right. This amp drives the 6hp
peak/4.3hp continous DC spindle motor on my mill.

If you have the knowledge and experience to repair these amps, please let me know (especially if you
are in the Dallas/Fort Worth area). If you can recommend a repair shop that can fix this amp, or if
you know of a shop that is selling rebuilt Servo Dynamic amps, I would appreciate knowing about that
as well.

Since I have more than one of these amps, I think I can make it easier for someone to fix them by
swapping out parts from one unit to the next. I am hoping to find a solution this week (the week of
May30 - June 5) so I can get my machine running soon.

There are quite a few businesses that repair and rebuild industrial
electronics, but they're not cheap and I don't have any recent
experience so can't make a recommendation.

I'm assuming these amps are obsolete. If so, have you considered
replacing them with a current model? If you have brush type motors it
should be dead simple. A bit more complicated if you have brushless
motors and/or tach feedback to the amp. You could check with Copley or
AMC to see if they're familiar with your amp and can make a
recommendation on a replacement. I personally prefer dealing with
Copley, but both are good.

http://www.copleycontrols.com/

http://www.a-m-c.com/

Ned Simmons

 

[Cliff]

Since I have more than one of these amps, I think I can make it easier for someone to fix them by
swapping out parts from one unit to the next.

Probably all failed the same way.

 

[Mario]

In addition to the two local repair shops I mentioned, I have contacted several repair companies that are
not local. They all want at least $420 to start, plus parts or whatever else. Plus shipping, plus a two
week wait time (unless you pay for them to rush yor order)... so I was hoping to find a local electronics
guy who fixes these for a living and who would give me a better deal than going through these comapnies.
Also, so will not quote until you send them the unit.

The amp does receive feedback from the tach. However, I just found a local company (in Irving, Tx), where
it looks like the guy is going to give me a better price than anywhere else, so I am going to try him out.
I'll let you guys know how he does if anyone is interested.

Thanks Ned!

 

[Mario]

I know that the fisrt one failed from a problem on the circuit board: there are a few burned resistors
that seem to indicated that the big power regulating transistors are fused closed. The second one died
when the big cigar sized 10ohm resistors that dump voltage striaght to ground (in order to slow down
the spindle) started glowing red like toaster elements! So that seems to indicated that a smaller board
that regulates this voltage dumping is the item that blew the second time.

After the second amp blew, I decided to call in some professional help. So an experienced E.E. came
over to help me do some rewiring on the machine. THese amps are kind of weird in that they are designed
to accept 110VAC 3 phase power. THats right - 3 phase 110 (But you can just drop the third leg of 110
power to this amp, and it really does not affect the amps performance. Found out that tidbit from
another friend who has the same machine.) . But during our rewiring project, we accidentally wired the
amp to accept 220v. It did not like that. It made that fact very clear to us when the big capacitor
(shaped like a coke can, but bigger) went BOOM! (Those big capacitors make for awfully expensive
fireworks.) So basically, all three amps died in different ways.

But anyway, I once I have just one of these amps fixed, I should be back on track with this machine.
Thanks Cliff.

 

[Cliff]

In addition to the two local repair shops I mentioned, I have contacted several repair companies that are
not local. They all want at least $420 to start, plus parts or whatever else. Plus shipping, plus a two
week wait time (unless you pay for them to rush yor order)... so I was hoping to find a local electronics
guy who fixes these for a living and who would give me a better deal than going through these comapnies.
Also, so will not quote until you send them the unit.

The amp does receive feedback from the tach. However, I just found a local company (in Irving, Tx), where
it looks like the guy is going to give me a better price than anywhere else, so I am going to try him out.
I'll let you guys know how he does if anyone is interested.

Have any trade schools that teach electronics nearby?
Call & ask for such instructors if so ... either they or a hungry
student or class project ...