Smart-UPS MOV replacement

**kc8adu** · 10-27-2011, 06:22 PM

Re: Smart-UPS MOV replacement

http://www.upsclub.org/apcinfo/
trying to go in the front door gives gibberish.you might dig a bit and find it here.

**Maxxarcade** · 10-27-2011, 06:32 PM

Re: Smart-UPS MOV replacement

Originally posted by kc8adu

http://www.upsclub.org/apcinfo/
trying to go in the front door gives gibberish.you might dig a bit and find it here.

Looks like that's all newer stuff than what I have. Mine is all early to mid 90's vintage I think.

I did do some research though, and it looks like I mainly need 130v MOV's in the 20mm size.

**hardwareguy** · 11-04-2011, 12:59 AM

Re: Smart-UPS MOV replacement

Any 130VRMS 20mm MOV will work. Originals were probably Epcos or Litelfuse manufactured.

**Toasty** · 11-04-2011, 02:02 AM

Re: Smart-UPS MOV replacement

This your 1250?

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**hardwareguy** · 11-04-2011, 03:18 AM

Re: Smart-UPS MOV replacement

I got one of those old things in the storage room...just add batteries and the old battle axe is back in business!

The only change I would have made to these would have been an LCD screen and some more MOVs across line and neutral. (oh and yeah...all of them would have been XL units with the external pack connector)

**Toasty** · 11-04-2011, 04:09 AM

Re: Smart-UPS MOV replacement

Sorry. Question was directed at Maxxarcade.

**Maxxarcade** · 11-04-2011, 08:17 AM

Re: Smart-UPS MOV replacement

Originally posted by Toasty

This your 1250?

Yep, looks like that.

I just got in a shipment of 20mm 130v MOV's made by Littlefuse. Hope to start the repairs this weekend.

One thing I did notice, is that the firmware made a noticeable difference in runtime. When I put together the oldest unit and used the batteries from one of the damaged ones, it only ran for about 18 minutes at half load. The others ran for about 22-25. Can I just swap the microcontroller between units if one of the newer ones is burned beyond repair?

**Maxxarcade** · 11-04-2011, 08:19 AM

Re: Smart-UPS MOV replacement

Originally posted by hardwareguy

I got one of those old things in the storage room...just add batteries and the old battle axe is back in business!

The only change I would have made to these would have been an LCD screen and some more MOVs across line and neutral. (oh and yeah...all of them would have been XL units with the external pack connector)

Ya, these older ones still run great with fresh batteries and all the smaller caps replaced. There are a few 22uf ones that are always open. It was causing one of them to act funny and overcharge the batteries.

**Toasty** · 11-04-2011, 01:36 PM

Re: Smart-UPS MOV replacement

Originally posted by Maxxarcade

Yep, looks like that.

I just got in a shipment of 20mm 130v MOV's made by Littlefuse. Hope to start the repairs this weekend.
....

Okay, which caps? I'm assuming the 6 yellow-orange MOV's, yes? Or, the 5 blue one's? Or both/all?

Large white cap?

.

**Maxxarcade** · 11-04-2011, 01:48 PM

Re: Smart-UPS MOV replacement

Originally posted by Toasty

Okay, which caps? I'm assuming the 6 yellow-orange MOV's, yes? Or, the 5 blue one's? Or both/all?

Large white cap?

.

Not sure which MOV's I need to change yet. I hope to have a look this weekend.

If I recall, there is a handful of 22uf caps that need to be changed. There might be a couple others, but I don't remember which ones without looking at it.

**Toasty** · 11-04-2011, 06:19 PM

Re: Smart-UPS MOV replacement

LMK. It's a back-up unit (no pun intended), so I can pull the board out of it and have a good look for you.

**Behemot** · 11-06-2011, 06:05 AM

Re: Smart-UPS MOV replacement

Originally posted by Maxxarcade

One thing I did notice, is that the firmware made a noticeable difference in runtime. When I put together the oldest unit and used the batteries from one of the damaged ones, it only ran for about 18 minutes at half load. The others ran for about 22-25. Can I just swap the microcontroller between units if one of the newer ones is burned beyond repair?

One servicemen told me you should reformat it every tiem with new batteries. Other told me the cheap ones does not need this.

I guess this is one of the UPS which needs it cause the firmware shortens the runtime as the battery deteriorates.

I think you can try it but on the other hand there may be risk that it will actually have lower capacity than the firmware would think it has.

**Maxxarcade** · 11-08-2011, 08:03 AM

Re: Smart-UPS MOV replacement

So far I have been able to fix one of the Back-UPS 600 units. I also had to replace the breaker because it would not reset. I used a 5 amp in place of the 7 amp, because I had it on hand, and I think 7A would be overkill for what I'm using it for anyhow.

The original MOV's appear to be 150 volt. Hopefully the 130v ones don't overheat. My line voltage runs as high as 125v at times.

LittleFuse also makes thermally protected MOV's, but I don't know how they would work in a UPS.

The Smart-UPS 1250's are burned pretty bad. I might be able to fix 1 of the 3 if I can combine enough parts. Really bums me out because the Smart-UPS's are still worth a lot of money in refurbished condition. Everyone seems to think they are so worthless compared to the newer ones, but I found that the run time is about the same as my new SMT1500.

On a side note, these old Gruber batteries in the Back-UPS 600's are still strong after about 4 years. I got about 15 minutes at 150W with one, and another is going on 20 without going into low battery alarm yet.

**hardwareguy** · 11-08-2011, 01:40 PM

Re: Smart-UPS MOV replacement

Thermally protected MOVs (TMOVs) are excellent in these units and add safety that the original design lacked.

Runtime for a 1250 is the same as the 1400 and 1500 units....the batteries are the same, 2x 17Ah 12V SLA. 20Ah is now available in the same case and works great!

One does not need to reflash the firmware for a new set of batteries but you do need to perform a run time calibration. To calibrate, allow the batteries to fully charge (overnight is more than enough) and place a load on the UPS that is at least 30% of the UPS load rating. Unplug the UPS and allow the batteries to discharge fully. Recharge.

**Maxxarcade** · 11-08-2011, 01:43 PM

Re: Smart-UPS MOV replacement

Originally posted by hardwareguy

Thermally protected MOVs (TMOVs) are excellent in these units and add safety that the original design lacked.

Runtime for a 1250 is the same as the 1400 and 1500 units....the batteries are the same, 2x 17Ah 12V SLA. 20Ah is now available in the same case and works great!

One does not need to reflash the firmware for a new set of batteries but you do need to perform a run time calibration. To calibrate, allow the batteries to fully charge (overnight is more than enough) and place a load on the UPS that is at least 30% of the UPS load rating. Unplug the UPS and allow the batteries to discharge fully. Recharge.

Darn, I just ordered regular 150v MOV's about 5 seconds before you replied. I wonder if I can change the order before it ships. As for the calibration, I've done that a few times. I use a power strip to turn off the incoming power, and a 500W halogen light for the load.

**vsmGuy** · 07-28-2012, 08:03 PM

Re: Smart-UPS MOV replacement

I apologize for bringing this thread back from the dead but the circuit board shown by Toasty looks like my own APC UPS.

I am looking to replace the yellow cap to the right of the picture: https://www.badcaps.net/forum/attach...6&d=1177069821

Would appreciate if you guys could have a look here: https://www.badcaps.net/forum/showthread.php?t=21758

Smart-UPS MOV replacement

Smart-UPS MOV replacement

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