FSP EP1000, too low output voltage.

[warsztat]

Hi, I have ups fsp ep1000, his output voltage got too low.
In power socket 235V his otput is 203V, in program "View Power Monitor System" output voltage is ok but input voltage shows 245V. I think voltage measurement circuit is bad but I do not have a schematic to identify elements.
I need schematic or indication elements.
All the best all.

[stj]

Re: FSP EP1000, too low output voltage.

????
i have never seen a system that reads the input voltage.

[warsztat]

Re: FSP EP1000, too low output voltage.

Maybe I'm misunderstood, sorry my bad english.
One picture instead of a thousand words.

[stj]

Re: FSP EP1000, too low output voltage.

ah, i see.
probably a bad op-amp or voltage reference chip (tl431?)

[kaboom]

Re: FSP EP1000, too low output voltage.

ah, i see.
probably a bad op-amp or voltage reference chip (tl431?)

Or a drifted-high resistor on the topside of a voltage divider.

[PeteS in CA]

Re: FSP EP1000, too low output voltage.

ah, i see.
probably a bad op-amp or voltage reference chip (tl431?)

Or noise.

Many server PSUs have microcontrollers on both sides of the pri-sec barrier, with communication between. These report to the server the input and output voltages and currents to the server.

Back in 1981 or so an engineer at Boschert predicted that a time would come when power supplies would be controlled by Z80 microprocessors. I laughed at the idea. Well, it took 2 or 3 decades, and the actual parts are not literally Z80 microprocessors, but that time has come, for servers at least.

[warsztat]

Re: FSP EP1000, too low output voltage.

Good discussion, I still need a schematic. I use a lot of time for repair without a schema. UPS is measuring badly so it gives bad outage voltage, it works on a transformer that heats up.

[Stefan Payne]

Re: FSP EP1000, too low output voltage.

Back in 1981 or so an engineer at Boschert predicted that a time would come when power supplies would be controlled by Z80 microprocessors. I laughed at the idea. Well, it took 2 or 3 decades, and the actual parts are not literally Z80 microprocessors, but that time has come, for servers at least.

First one I've seen is from 2003 or so with a PIC16 Micro and was made by NMB, dual PCB WTX. The one Fujitsu-Siemens used in the Celsius 670.

[warsztat]

Re: FSP EP1000, too low output voltage.

Hello, I found some time and solved my problem.
I replace capacitor C6 and add resistor 100kohm in measure input voltage circuit.





Now is ok



Regards for all.

[stj]

Re: FSP EP1000, too low output voltage.

it may get worse, you didnt find the fault - you adapted the circuit.

[warsztat]

Re: FSP EP1000, too low output voltage.

After replace capacitor voltage measurements stabilized (differences before in time between indicating UPS and measuring with a multimeter).
Resistor add because of my power supply network that floats near to the stabilization value of UPS. The relay knocked too often. I have reduced the measurement to about 5V and there is finally silence . Otherwise, it would be enough to replace the C6.

Sorry my bad english.