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Electronics => Repair => Topic started by: prot_brot on December 25, 2017, 05:38:19 am

Title: APC Smart UPS - Need help with EEPROM contents
Post by: prot_brot on December 25, 2017, 05:38:19 am
Merry Christmas everyone!

I just got an SUA1000I unit that behaves strangely. When I plug it to AC power UPS immediately turns on, I can't turn the power off unless I remove AC power first and let it running on battery, AVR trim LED always lights up, battery bar always drops to 1 whenever it performs self test or running off inverter.
APC Fix clearly shows that there is something wrong with EEPROM values. I tried to change the firmware/model and some of the variables using hyperterm according to this article I found http://blog.inceweb.com/adrian/2014/05/24/programming-the-apc-smart-ups-700/ (http://blog.inceweb.com/adrian/2014/05/24/programming-the-apc-smart-ups-700/). But pressing b and +/- brings me to manual input for the first 3 characters of the firmware instead of cycling trough firmware versions. My free APC Fix won't let me change anything either.

Now I'd just pull out the EEPROM and reprogram it. So I wonder if anyone had experience with Smart UPSes or knowing where's the value for correct firmware/model selection, please let me know. Better yet if you could share dumps from working unit, I would really appreciate it. Not necessarily from exact same model, just anything I can make comparison will be fine.
Title: Re: APC Smart UPS - Need help with EEPROM contents
Post by: EHT on December 28, 2017, 09:43:37 am
Hi. I can tell you how I updated the firmware on a Smart-Ups 750 which I have. It wasn't as straightforward as i expected.

I have one which is the older model with no LCD, just rows of LEDs and one which is newer with LCD display. I think the latter is the SUA750I so like yours. This is the one i updated. The reason I updated it was that the original firmware version didnt work with apcupsd over USB. That was unexpected since the older model did, with no fiddling around.

The LCD model shows the following in apcupsd:
APC: 001,039,0909
VERSION: 3.14.14 (31 May 2016) mingw
MODEL: Smart-UPS 750
FIRMWARE: UPS 09.3 / 00.4

I had to get it onto the latest f/w to use the MODBUS driver. It would NOT update the f/w over USB so I had to use serial. Problem was a) APC used a custom wired cable, b) neither of my PCs had an external port. Anyway I managed to find a schematic of the cable and got it working. If you need, i may be able to find the info.

APC had a freely available piece of s/w which allowed updating the f/w over serial, and this tool downloads/installs the f/w for you. I got it to do this and now it works in apcupsd, so i'm happy with that.

On a different note, I wonder how long these old UPSs will work for since they are always on... I'm thinking of the electrolytics etc. I've replaced the batteries in both of those UPSs.

Good luck.

PS Windows ME !?  :scared:

 


Title: Re: APC Smart UPS - Need help with EEPROM contents
Post by: prot_brot on December 29, 2017, 09:11:44 pm
Hi EHT, thanks for your reply. Are you sure you're not confusing the old model (SUA750I) with the new SMT750I?

Mine is the older model without LCD, doesn't have upgradeable firmware. It has an Intel OTP micro, and a 93C56 EEPROM that stores UPS model, calibration data, serial number, etc. Seems like APC only made one firmware for the entire line of Smart UPSes. The UPS type is stated in the EEPROM, so if that value is changed, it will not only affects the model number and their behavior but all voltages, frequency, battery capacity, etc will be in wrong value.

The EEPROM contents in this UPS is screwed. Most data is read as FFh, so I will have to start experimenting with the hex values. (Hopefully it won't blow up :P)

Quote
PS Windows ME !?  :scared:
yep.  ;)  That's the only laptop I got that has a serial port.

Oh, and the caps... It mostly depends on temperature, the quality of the capacitor itself, and luck ;). If your UPS is old enough, you may want to change the electrolytics with better brands, just in case... And there are only a few of them anyways. My unit was manufactured in 2001 and all the caps are still fine, but as a precaution I'll change them when I managed to sort out this EEPROM problem.
Title: Re: APC Smart UPS - Need help with EEPROM contents
Post by: EHT on December 30, 2017, 12:22:42 am
Hi, ah yes, I have one of each of those UPSs and you are correct it is the SMT750 which I updated. PM me if you know there is a way i can dump the contents of the SUA750 EEPROM for you. It is in use so I'd rather not disassemble it though. How did you do it?
Title: Re: APC Smart UPS - Need help with EEPROM contents
Post by: shakalnokturn on January 08, 2018, 08:15:37 am
I have a SC1500i, would a dump of the 93C46 (IC6) be any use to you?
Title: Re: APC Smart UPS - Need help with EEPROM contents
Post by: prot_brot on January 22, 2018, 07:59:15 pm
Sorry for the late reply, I've been very busy. Unfortunately, the only way to fix this thing is to pull out the EEPROM and reprogram it. Last time I played with the values and made it clicking relays like mad when it tries to switch from inverter to AC power.

I have a SC1500i, would a dump of the 93C46 (IC6) be any use to you?

Shakalnokturn, that would be very helpful  :D