APC UPS1400 help

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dacflyer
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APC UPS1400 help

Post by dacflyer » Fri May 21, 2021 6:58 pm

I have an APC UPS1400 ( 1400VA / 950W )
I been using this in a small solar set up for a while in constant battery mode. been doing great for over a year now.
But the other day i noticed the fan has died. But it's not the fan,. the circuit that controls the fan is my issue. I have tried to bug it out, but i'm running into a brick wall.
Would anyone happen to have a schematic on this unit ?
If i cannot fix the issue soon, I'll most likely just hot wire the fan..But i'd like to fix it properly, if possible..

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Janitor Tzap
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Re: APC UPS1400 help

Post by Janitor Tzap » Fri May 21, 2021 9:16 pm

Have you tried resetting the unit?

Here's a video on how to do it.
https://www.youtube.com/watch?v=Q4-0lAVBATM

If that doesn't help......
You should check the other videos that go about repair of the APC UPS Models.
I gave them a quick scan, {Though there were quite a few that I probably skipped over.}
and didn't see anything regarding a "Dead Fan".
But A few videos with the subject of "Fans that run constantly".

In one video, the guy contacted APC about a schematic.
Or if they would repair the UPS.
They simply said that they don't repair them.
Thus, they don't have any schematics, throw the dead unit away.
:(


Signed: Janitor Tzap

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haklesup
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Re: APC UPS1400 help

Post by haklesup » Tue May 25, 2021 1:25 pm

the fan is probably controlled by a thermocouple. It may be open or inaccurate and not allowing the fan to turn on or the PWM fan controller is dead. If yu want to keep variable speed, an easier fix might to be to hotwire the fan with an off the shelf Fan controller intended to be installed in a PC. Lots of them to choose from to find a useful size and connector configuration. Or if running at full speed full time is OK, then as you suggested, just hotwire it to an available supply voltage or strap one on externally.

The thermocouple may be wired out to the battery pack or it may be on the board. If its not doing the job of monitoring battery temp, it might be wiser to scrap it. though SLA batteries shouldn't go into melt down.

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dacflyer
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Re: APC UPS1400 help

Post by dacflyer » Mon Jun 07, 2021 2:06 pm

found the issue... APC is weird..
the drive transistors ( 2 paralleled ) were open.. tiny SMT types, i replaced both with 1 beefier transistor,
there is also 2 blocking dioads in parallel as well.. anyway, the issue is fixed..I also took the opportunity to add in another fan with stand alone thermal control using an op-amp and thermister and a junkbox mosfet. minimal parts and works great...comes on only when needed..the Main one runs all the time when in Back up power mode.

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