CT 26 troubleshooting help needed

[madcow]

I posted this in another thread, but I’m also adding it here in case one of you who seems to have had similar problems sees this. I’m not sure what voltage I should see at the motor or at the 2 pin connector (should be the same I think).

I have a CT 26 E that I recently bought used. They were selling it for parts because it only worked intermittently. I plugged it in and it worked. I decided to take it apart and have a look inside to see if there were any lose connections or if it was really dirty.

I cleaned it all out and noticed that the brushes were about half worn. I ordered new brushes and waited. I replaced the brushes and now it won’t power up at all. I checked the voltage at the motor and it’s only getting less than 40V. I should note that I live in the US and therefore have a 120V model. I checked the voltage at the two pin connector on the PCB under the control panel and there is only like 4 V going on those pins in both auto and manual. I’m not sure how much voltage should be going there because those wires are fairly thin and I can’t find any schematics. I don’t want to pay $170 for a new PCB because if it isn’t the problem, Festool won’t let me return it.

I’d appreciate any help anyone can lend me. Thanks.

 

[luvmytoolz]

I can't help you with the board but have you ruled out any issue with the mains cable? The older Midi's had an issue where the copper strands would break at the input clamp junction, so you would get intermittent connection as the cable was flexed/moved.

Maybe it could be a similar issue as some places really abuse tools.

 

[madcow]

Thanks for the reply. The mains cable is solid. I don’t believe it’s a part of the problem because whenever it is plugged in and in auto, the 120V tool plug port has 120V. The previous owner told me the vac was intermittent. When I plugged it in it just worked. I should have just used it until it failed, but I thought it might be something easy like brushes or the motor. Since the motor is reasonably priced, I decided to buy it and then try to troubleshoot it.

I did a little bit more testing today and the results are a bit surprising to me. With the vac plugged in, disconnected the 2 pin connector on the electronics board and measured voltage. 4.8V in manual and 5.8V in auto. I then removed the motor and tested at the motor end of the wiring harness. 38-40V. I looked at the sensor, I’m guessing it’s for thermal overload. I cut the plastic off of it in the hopes that I coug remove the connectors from it. No such luck so I cut the wires and joined the wires to override (disconnect) the sensor. The vac still did not run.

I’m wondering if someone with a working vac could tell me what the voltages should be at the 2 pin connector and the motor. If I had to guess I’d guess 120V since this is a 120V machine and the motor says 120V on it? I could be wrong because it seems like the wires are a bit small for sustained 120V (up to 13A?).

 

[Crispy]

I had something similar with a 36ac a while ago.
The motor worked if you put 240 to it ( im in aus), i dont remember it i had voltage at the front outlet, but it would not power up at all setting it up normally.
The boards are resin covered to stop 'moisture' i think, but the side effect is you cant get to any components if they are U/S.
I ended up having to purchase a board, and have not had any problems since then,

The motor unit will more than likely state 120 on it, mine clearly stated it was 240.
If you motor works when giving it directly 120v, probably find your pc board is toast.
And given its the only item between the power lead and the motor, it will be cheaper to purchase the spare part board as opposed to purchasing a new vacuum.