Scooba 230 stops early

[czunit]

Ok, interesting problem. I have an out of warranty Scooba 230 that as of late will run for about 5-10 minutes, then stop with water in the tank.

My first error was poking at the tank bladder in the back so it folded and would not fill up. So I tried to use water pressure to fix it. Bad. What had happened is that it put down *no* water so I took off the pump impeller, removed the hose, blew into it and reset some reed valve somewhere, then it worked again. But now it's stopping early but it is putting down fluid.

So what kind of water sensor does this thing have, and can it be tweaked? How is water delivered; is there a reed valve that this thing "burps" with the pump so it puts down a little water at a time?

Chris

[czunit]

Well, after staring at it for awhile I figured "it ain't gonna fix itself". So I got to work.

First job was to take apart the pump again and see what is up. Then I put one end of the hose on the nipple to the tank, the other in my mouth, and blew. Could sort of blow, but when I sucked I barely got anything.

Took apart the bumper and felt in the tank. I can't find the inlet hole, but I know sort of where it is. Anyway I got tired of blowing so I took a can of compressed "air", stuck the straw into the nipple, and let it have it. Why not?

Blew out for a few seconds, hooked up the hose, and tried sucking. No pressure difference between blowing and sucking. Which is good. So I think the root of the problem is that the inlet port was partially clogged with some crud and blowing it out with compressed air cleaned it.

Washed out the bladder, re-assembled, and fired it up. Pumps a *lot* more fluid, out the back jets too. So I think this was the problem.

However now the battery is dead and when I plug it into the charger I don't get a light on the charger. When I plug in the charger with nothing attached the green light flashes twice, but with the scooba nothing.

Terrific. Any ideas on that one? It just stopped with a dead battery, and I really don't want to charge the silly thing manually...

Chris

[vic7767]

The battery voltage may be too low for the charger to detect. You might try a direct charge using an alternate power source for a few minutes and then try the regular charging process using the Scooba.

[czunit]

Well, it looks like the battery has exploded, but it still has enough power to fire up the 230. Very odd, with battery out the charger does the normal flash twice when plugged in, when in nothing.

Is the charge system on the 230 completely passive in the Robot? In other words, does the charger brick itself do all the thinking, and the jack on the back just passes through to the three terminals on the battery?

Chris

[vic7767]

Good question, don't know the answer but there is a battery thermal sensor that is monitored by something. It could be a small charging sub-system internal to the Scooba as well as some smarts in the power supply.

[czunit]

Well, the power supply on the Roomba is a bit interesting. If you look carefully you see that it's got three rings and not the normal two. Given that the logic for charging NiMH is to look for the voltage drop saddle along with the temp going up, my guess is that this information (b+, b-, t+) is sent up those three rings to the charger.

Way to verify is to gut a pack, and ohm things out. I also wonder if the charger itself does not send any voltage down to the plug unless it sees the temp sensor. That would make sense; if you had the charger hanging in a bathroom 24*7 plugged in the electrical current going across wet plugs would corrode the tip (I see this with my Robomower when I leave the charge plug in the dirt).

Once I get my new pack and verify things work I'll give this a shot by taking apart the old one. In the meantime I'll try charging the old pack in my shed with a constant current charge of something like 200ma and an 8.7 volt peak (1.45*6 batteries) for 10 hours.

Chris

[czunit]

Well, so much for that. Ordered a new battery, put it in, Scooba ran for 10 minutes then stopped. Same issue, would not suck in water.

Tried clearing several times with no success. Can't even figure out where the water inlet is in the tank. So I took it "out to the woodshed" to open it up. Could not thread a wire past the 90 degree elbow on the inlet, so I tried removing the elbow. Plastic broke off, scooba is ruined.

So with that out of the way I decided to open it up. A screwdriver took too long, so I used a 12 pound sledgehammer. Opened right up. Ripped open the bag, and I could see that the water inlet is actually a strainer in a plastic relief which was badly clogged. That would do it. Cleaned it under a faucet, now runs clear.

Too bad there was no other way to open the Scooba 230. So the parts of it went into the garbage, first Irobot I have owned that did that. Very annoying.

Will order a new one in the morning. Sad. My main scooba would never do this.

C

[vic7767]

That is disappointing. I hate the use and throw away design of the 230. It's a shame that dis-assembly is impossible on these small models.

[czunit]

Indeed. Well, no one else had any suggestions, and it was becoming annoying to try and troubleshoot around it, so apart it went. At least now I know how the thing pulls water from the tank (via the side, with this fitting to screen interface). Also the inside of the vacuum tank was *filthy*, I can't see buying a used one of these.

So $300 down the drain. I should have the new one next week, in the meantime I'll use the big scooba.

[vic7767]

The reason there were no suggestions is that it is well known the the 230 cannot be dis-assembled and repaired. I donated my first (and last ) 230 to the cause about a year ago and the info posted on this very site. Many folks were disappointed at that discovery including myself.

I'm sticking with the larger models, at least if they quit working they can be fixed.

[czunit]

True, my blue scooba is quite old at this point and has had it's pump replaced and the power button replaced as well. But the key is both parts *could* be replaced, and reasonably.

The trick with the 230 is it can get behind and beside the toilet @ sink. Which has serious amounts of value to be honest, I guess if I hadn't smashed it I might have been able to get it back together, but there is also this time/reward value thing to keep in mind.

On the other hand, if someone else has this problem then they will know what to do. I think taking the hose, hooking it to a syringe full of cleaning fluid, and injecting that up into the tank from underneath, followed by a serious hot water washing could clear the trap. At least I now know that there isn't any back-valve in there or something.

C