Xantrex/Sorensen/Ametek XPR series service manual?

[Ingineer]

I have a Xantrex branded XPR 300-20.

All I can find online is a operating manual.  Anybody know of a service manual/schematic?

It's got  the HV option, so designed for 480v input, but they have same model designed for 240v, I'm wondering if there is way to convert it back to the LV option?

Thanks!

[coromonadalix]

ko4bb.com  has lots of xantrex but not your series, but sometimes they have lots of similarities ...

[Ingineer]

Thanks, Yeah I found the operating manual there.  He doesn't have the service manual.  I considered looking at other series, but not sure it would be helpful, I guess if I strike out elsewhere, I'll try that.

Really annoying they don't publish the service manuals for pro gear like this, I know this is what the world is coming to.

I'm old enough to remember some consumer gear CAME with a schematic tucked inside!  I remember some GE TV sets had a little plastic cover that had it right on the back!

[coromonadalix]

i would say the opposite, we are lucky they have leaked to the net ....    and they have the right to protect their IP  ....

[Ingineer]

Protect their IP?    For end-of-life older equipment, it's unlikely there is any trade secrets to be protected.   If I was in management, I would make EOL'd service manuals freely available, it creates good will, and enhances the reputation.  If I know a vendor does this, I'm way more likely to buy new equipment from them in the future.

Now it almost seems like most vendors are in such a hurry to ship, they sometimes put out unfinished products, (Especially where software is concerned) and then you are on your own.  Sad!

[coromonadalix]

you have much to learn  ......

[CaptDon]

The old Sorensons came with well documented manuals with schematics, test points and theory of operation. This was true of Tektronix (originally some of the best manuals in the business) and a few other companies. One of the top reasons why we specified buying equipment from those companies. Today, so much equipment is on the cutting edge of technology that the I.P. must be protected, at least until the Chinese buy one and reverse engineer it. As for the new XPS and similar power supplies, there is no hidden magic inside and when I buy something as stupidly simple as a power supply which I can most likely repair on my own I want documents and schematics. (I'll take one of the 80 pound Sorensons over their new crap any day) With thousands of Tek scopes on the surplus market and people parting them out it is easier to fix an old Tek scope today than it was 25 years ago!! And that is one of the reasons equipment companies offer 'buy back' and destroy the old equipment!!! They don't want a surplus of their old well designed last forever gear on the marketplace. They want you to purchase short lived throw away gear. Except for the replacement of a few tantalums and filter caps my old Tek gear works as good today as when it was made and I have the manuals!! The C.R.T.'s are still bright and well focused. Everyone's test gear quality has gone to shit these days with no schematics or parts available and factory repair costs 80% of new!!

[Ingineer]

I was not able to find a manual, but I was able to reverse-engineer the front end and control logic enough to modify it to work on 240v instead of 480v.   There isn't even a microcontroller in here, it's building-block analog and basic 4000 series logic, with only 2 sided PCBs, so relatively easy to figure out.

The 480v option takes the AC into DC and then uses a PFC buck to drop the bus voltage to about 380VDC, whereas on the 240v version it boosts to 380VDC bus.   Since I didn't need the full 6kW capacity on this, I just bypassed the PFC and run a 320VDC bus, and the unit operates well.   Obviously I lose PFC, but not a big deal on residential power and not running it at high power levels.  Re-jiggering the buck to work as a boost would take a lot of work, especially without the schematic.

All I had to do once the buck was bypassed is make the bus voltage monitor happy with a lower voltage so it would enable output and close the precharge relay.   I just replaced a fixed resistor with a 10 turn trimpot and made it adjustable.  To figure this circuit out, I just traced back from the precharge relay.  There is a voltage divider and a comparator, so once the bus voltage comes up enough, it closes the relay and sends an enable output through an optoisolator.   Unit is working!