Warning, power supply mod to 220volts blows fuse!

[rj5555]

There is a new revission power supply, the original voltage mod will not work, it will blow the fuse with a bang if attempted!

The solution is simple, I'm in the process of rewriting the original how to I will append it in this thread when finished.

Robin

[rj5555]

iRobot made a change in the power supply unit, they added a Zinc Oxide Varistor to protect the unit from power spikes, this new part ( SAS-271KD10) is rated 175Vac and it WILL blow when you connect your PSU to 220volts. The simplest solution is just to remove the new part and carry out the original voltage mod (located here)
If you wish to replace the part to should buy a Metal Oxide Varistor rated around 360 volts like the "VAR360V04W" from Fuji Semiconductor.

If you're not sure you have a new revision look the photo's below

New revision, you need to remove or replace the part labeled VR1:


Old revision, there is no VR1:


I'm not sure if you can see the difference between the revisions from the outside, the serial number from my new type PSU started with an "A" while the serial number from the old PSU was all numeric. I also noted a "R" printed on the case itself of the new unit.

[Gordon]

That is useful reporting, Robin! Similarly, I have been into Scooba's Power Supply (seeing what differences there might be, compared to the Disco's Fast-Charger), and want to report the Scooba circuit also uses a varistor shunt in the HV section.
On the PWB, the locator is silk-screened as "RV1" (probably should have been 'VR1'). The varistor is the same one you reported above. While I was looking at it, the thought about its voltage rating being too low to support up-conversion to 220VAC mains, ran through my mind, hence your post came along at a good time. I'll pass it along to Rog.

[rj5555]

Gordon,

Do you have pictures of the inside of the Scooba psu?

Robin

[Gordon]

Hi Robin:
Yes, I have five pix of the interior. I could stuff them in an exe-slide-show file, zip it and mail to you. I will be going back inside the PSU today (060111) to see why three wires feed out the 22Vdc-cable. After you see the pix I have taken, let me know If you want another view (the set I initially took, was not meant to be 'all inclusive'). I'll hold the box open for another day -- just in case you don't soon see this reply.
You can PM me on this board, or find my addy at the roombausers List (assuming you don't use Digest).

[Guest]

That is useful reporting, Robin! Similarly, I have been into Scooba's Power Supply (seeing what differences there might be, compared to the Disco's Fast-Charger), and want to report the Scooba circuit also uses a varistor shunt in the HV section.
On the PWB, the locator is silk-screened as "RV1" (probably should have been 'VR1'). The device had been installed with its P/N data closely facing the big 0.22uF cap, so I could not read the varistor's information. While I was looking at it, the thought about its voltage rating being too low to support up-conversion to 220VAC mains, ran through my mind, hence your post came along at a good time. I'll pass it along to Rog.

[ISANBER]

good work rj555. I send a p.m. to you


buen trabajo rj5555, te env?o un privado

[Curtis Newton]

Hi, I make every changes, but forget to remove the VR1 so it blows with the fuse.

I finally remove the VR1 and replace the PCB fuse.

There is power, but not enough to charge the roomba.

So I decide to go back to the original PSU without the VR1.

Still the same not enough power.

Do you have any ideo of where the problem can coming from?

Thanks

[juanpa74]

there is another revision. My Power supply model number says: 17062.
Input Power 33W.
Output: 22.5 VDC 1.25A

I just got the Roomba 560 and there are two more capacitors near the Varistor and also an IC with code 1200P60 CPDN. What is that?
Any ideas what is the funtion of those capacitors and the IC? They are named on the PCB C4 & C20.
C4 being 82uF/25v and C20 1uF/50v

There is a picture here: http://bp2.blogger.com/_Qa6M9BTHPv0/R7g ... _1987b.jpg

picture belongs to this blog entry http://abecemod.blogspot.com/2008/02/ir ... 0240v.html

I plugged my power supply ignoring it was just 120v AC Input...
the varistor exploded. I guess the fuse is down too. This capacitors (C4 & C20) and the IC are a bit dark. Not sure if they were affected.