The Triac is a Q6004L4 ...

http://www.teccor.com/cgi-bin/r.cgi/en/ ... HuuuOmFXvg

I looked at the specs and think this part will work as a replacement

http://www.digikey.com/scripts/DkSearch ... 60&Site=US

Its instock at Digikey for 1.40

I have to save your VERY brave to be pulling out the the main power board!

As for strings arrays and configurations, your incorrect in your thinking, in a single series string, the loss of a panel to shading only lowers the total available voltage, as the bypass diode kicks in. As long as the total vmp voltage is above the inverters minimum, full available power is still harvested from the remaining unshaded panels


Now if you have TWO or more series strings, and you shade a single panel in only one of the strings, you now have mismatched series strings and the losses will be more than a single panel ... so you should wire the panels panels so the shading is common to the parralell strings in this case

The only plus for 48V nominal strings (Suntie) is you can have a system with as little as 2 24V panels, otherwise in everyway the GT is a better product and to get one for 999 is a steal, you should be thankful Xantrex is willing to offer this deal for an out-of-warranty unit

Ya know I thought about the Triac being bad but I just am not an expert on those, Fet's, Bipolar (ancient history), power stuff I am good at. Xantrex led me to believe the problem was upstream from that. Leaky Triac ? Wasn't sure bout those but hey its just another semiconductor, I will try that and if it works I can rip the bandaids off. I have an old ST2500 I got cheap from a friend and I spent a little time studying it, doing a block diagram and replacing blown caps and it works but still thinks the voltage is above 264 from time to time, I don't know if this is typical for the old units but a couple of guys at Xantrex did give me thermister part numbers and help me a bit getting it this far. (It was wierd, it was like they were going out on a limb to help me. The employees seem great but xantrex policies seem hard on people who want to help). I meant it that unit as a spare. The UPG is great when it is workin. I did consider Xantrex's offer but I also have an Outback unit which is meant for another string, but it handled everything fine. The loss in batteries is considerable. Anyway When I get back from my trip to the seattle area I'll tell you more, I really appreciate the correspondance...If I have time I am going to stop by Outback and Midnight Solar and say Hi. Thanks

You have found a case where it isn't?, I have had NO reports of functional issues with the UPG's

My STXR2500 is back from Xantrex. I shipped it on June second and it returned on the twentieth. Considering that it spent about eight days in shipping each way, that's very good turn around. Still for me, that's twenty days with zero production. The packing list noted:

REPLACED MAIN BOARD AND SENSOR BOARD.
REPLACED FAN.
FULL TEST, NO OTHER PROBLEM.

I wired it back in last night and it came up this morning with no issues. The fan is working and it's putting out good power for this time of day. I'll need to watch it this afternoon, when it's hotter, to confirm the derating problem has been fixed. But, so far, so good.

Sounds like you will be good to go for a very long time with everything replaced, I'm pleased to hear you can still get UPG's repaired

If you have time, please upload some pictures of your setup

I just curious. Maybe Xantrex only has parts for the 2500 but when I called in with a problem with my 1500 they just shipped me a new GT2.5. That's why I originally said there was no RMA on these old units, just deals on replacements.

Do you have any suggestions on how to get a reasonably sized picture? I previewed a couple and they were so big!

In windows, right mouse click on the picture and select "open with", select "paint"

Once in paint, select Image-> stretch/skew and set to 50% for both H&V

Then save as a new file name ... once or twice thru this and you'll get the feel for it

Good luck!

I have two ST2500 UPGs. I ended up on this web site because the fan no longer works on one of them. I looked up the spec's on the Q6004L4 and found it rated at 600 volts. Well, the 246 volts showing on my display amounts to 695 volts peak-to-peak.

I have disassembled it yet, but I'm assuming the fan is running on the 240. I think I'll go with the sister part #Q8008LH4 (800 volt) from digikey ($1.71)

True, the peak voltage is RMS/.707 or approximately 340 volts. Peak-to-peak, allowing for the other half Sine excursion is twice that, or 680 volts.

http://en.wikipedia.org/wiki/Alternating_current