CTL 26 circuitboard diagrams

[Coen]

I have a 230V CTL 26 E, build year 2020 that when turned on, gave some arcing and a puff of white smoke and doesn't give a sign of life ever since.

I have taken out the circuit board and found nothing visibly wrong. No blown caps, no burned parts. The problem however... is that it is encased in epoxy (?). I have removed a bunch of it with a soldering iron, however, the PCB has some holes in it and the epoxy has flown underneath too, so I don't know how to free the board from it's 'basket'.

The potentiometer behind the main switch did have a funny smell. I have removed the epoxy around it and removed it's cap. It is from PIHER (probaby a PT15) and market 50K842M. I cannot match that to their naming topology however. I did measure the potentiometer and it ranges from 0 Ohm to about 14 kOhm. That is however 'in circuit', so that will most likely distort the measurement. Otherwise I would have expect 0 to 50 kOhm. This potentiometer tell the CTL to either be in auto or manual-on.

The problem is however, I don't have a diagram and the epoxy makes it impossible to draw one myself. So if anyone has it, or has had a similar problem before (and a solution) I would be happy to hear it.

I do have another (older) 230V CTL 26 E that I can compare measurements with. However, I am somewhat reluctant to swap out the PCB 1:1 in case the motor blew the PCB. The older PCB does have significantly less epoxy on it, but the entire surface is still invisible.

I could of course just buy a new PCB at €125 but for my wallet' and environments sake I'd rather just replace the broken parts. Like that potentiometer is only ~70 cents.

This is where I am at now;
[attachimg=1]

 

[luvmytoolz]

Coen, it would be a simple matter to pull the existing pot out and wire in a new 50Kohm one to try, but are you sure it's the switch between auto/manual? Doesn't make sense to me to use a variable component as a switch, unless it's not a pot?

 

[hdv]

A few weeks ago the exact same thing happened to my CTL 26 E AC. If I am not mistaken I posted about it here on the forum.

By the way, that puff of white smoke was really obnoxious. I suspect it must have been bad for your health to breath in whatever that stuff was. Luckily I managed to evade most of it. I hope for you you did too.

After inspection of the board I couldn't find the cause of it either. There was no visible damage at all. In the end I gave in and sent the machine to Festool to repair it. They replaced part 203974 (Electronic CTL AC 230V FL VP) and after that the machine was OK again. The part cost €128 excluding VAT (but I reckon you already knew that). The total cost for the repair was just above €200, including VAT.

If you do find out which component it was, then I'd be interested to know. It still bugs me I couldn't find out.

 

[Coen]

Coen, it would be a simple matter to pull the existing pot out and wire in a new 50Kohm one to try, but are you sure it's the switch between auto/manual? Doesn't make sense to me to use a variable component as a switch, unless it's not a pot?

Not so simple because the underside of the PCB isn't accessible because the epoxy also went underneath it so it's pretty much 'glued' over a huge portion of it's bottom surface. So unsoldering the pot will probably result in it being destroyed. Then putting in a new one... maybe with a small pool of solder on each of the three holes, using three irons, then drop it in. Or I have to just cut a hole in the basket so I can reach the underside of the PCB near the pot.

Yeah, it makes no sense to me either, but since the main switch just does the same in both manual and auto (close the 2 poles) the potentiometer has got to be the thing that makes it able to distinguish between 'on' and 'auto'. Btw, the connector from the main switch has six poles and five wires; four to the switch and one goes straight to another contact on the same connector.

Also makes no sense to me that my working one gives between 40 and 50 Vac in both 'on' and 'auto' on the connector to the motor when you take the cable to the motor off. Once connected it's 230V on full blast and 113V on the lowest setting.

A few weeks ago the exact same thing happened to my CTL 26 E AC. If I am not mistaken I posted about it here on the forum.

By the way, that puff of white smoke was really obnoxious. I suspect it must have been bad for your health to breath in whatever that stuff was. Luckily I managed to evade most of it. I hope for you you did too.

After inspection of the board I couldn't find the cause of it either. There was no visible damage at all. In the end I gave in and sent the machine to Festool to repair it. They replaced part 203974 (Electronic CTL AC 230V FL VP) and after that the machine was OK again. The part cost €128 excluding VAT (but I reckon you already knew that). The total cost for the repair was just above €200, including VAT.

If you do find out which component it was, then I'd be interested to know. It still bugs me I couldn't find out.

It's not really my CTL 26, but my brother's. But for simplicity in writing it became mine  [tongue]. It died in a flooded basement. Most likely took some water on the front before when some spilled from the CT-VA-20 when it was being emptied.

Did you get the old PCB back? And did you do a smell test on the PCB? If so I would be interested in just completely cutting it out of it's epoxy

 

[luvmytoolz]

Not so simple because the underside of the PCB isn't accessible because the epoxy also went underneath it so it's pretty much 'glued' over a huge portion of it's bottom surface.

Yeah, it makes no sense to me either, but since the main switch just does the same in both manual and auto (close the 2 poles) the potentiometer has got to be the thing that makes it able to distinguish between 'on' and 'auto'. Btw, the connector from the main switch has six poles and five wires; four to the switch and one goes straight to another contact on the same connector.

You could just cut it out and solder to the legs from the top to try a replacement. You'd then be able to confirm the value out of circuit.

 

[hdv]

Sadly, I did not get the replaced part back. Otherwise I could have sent it to you to scavenge for parts. Sorry.

 

[etds4u]

I posted a photo of the schematic that shipped with my CT26 replacement circuit board in the following thread: https://www.festoolownersgroup.com/...ps-turning-off-in-manual/msg657988/#msg657988