I have a similar looking power-cycling error on one of my MTK12s (it cycles slower, but is otherwise the same).
I've tested R102 and that's reading at 650K, so I don't think there's an error there even though mild scorching on the PCB shows me it's been pretty hot in the past.
I don't see any bulging or burning on any caps on the board either, so I tested the major resistors. I found R111 reading 0 Ohms.
Does this sound to any of you more experienced with this kind of error, like it could be a cause for this problem?
Big thanks!
R102 should be 75kOhm 2W. It tends to run hot so I replaced mine with a pair of 38kOhm 2W metal film resistors in series bended slightly away from caps in the area to protect them from the heat. If you have a crispy R102, check the smaller caps nearby. My MTK 12 still didn't work after replacing that R102, PSU kept making high-frequency whine when powered up, so I then replaced C103 which didn't show signs of being faulty visually but excess heat had apparently damaged it. And then it started working and it's now been back to rig for a week, no issues whatsoever.
Hilarious. The MTK 12 crew are getting mugged off.
My desk just doesn't power up. There was a time where the light came on very faintly and a little smack would get it to turn on. It's been nearly six months now.
I would greatly appreciate a little video on how to get it working as I have no soldering experience whatsoever. I'll come back when I've opened it up.
Just to confirm, a dead SMPS can be several things, if you are not an experienced technician then think about asking one to look at it for you as these things can give you a shock and, in some circumstances, can hold a charge after removing the power. Repair at your own risk!!
First, check the fuse, if it looks vaporized then you have a serious short, do not replace it without investigating further as it could make matters worse.
R102 often looks discolored due to heat, the part is a 75K 2W resistor but I would recommend changing this to a 82K 3W part, make sure you mount it slightly off the board to help dissipate heat better. This is known as the start-up resistor and is critical to getting the SMPS running.
The other common problem is C103 failing, the part is a 100uF 25v electrolytic capacitor, I replace this with a 35V device but make sure your replacement is marked 105 degrees.
I've had the odd FET fail but this is quite rare, the fixes above will solve more than 90% of the problems.
I purchased mine in 2017, it went down with power supply failure in 2019, sent it in for repair cost $50 shipping... Here we are today with another power supply failure...
Out of warranty repair is a minimum of $230 and $50 return shipping.... The power board costs $140. That is a huge no from me!
They say it is out of warranty and there are no known issues with this mixer... Clearly there is if they same problem keeps happening.. They dont want to annouce the issue or adress it because it will be too costly...
The 2 caps on the power supply next to the resistor are the failure point. That resistor gets too hot and causes the caps to boil...
Bare minimum it needed shielding there.
What a shame becuae this mixer costs as much as a rodecaster pro...
Comments
https://www.ebay.co.uk/itm/100PCS-LOT-1-2W-Carbon-Film-Resistors-5-Error-75K-ohm-75k-Ohm-75KR-Color-Ring/224101570718?hash=item342d7e989e:g:QOEAAOSwpV9fJNfp
Would these do it?
https://www.ebay.co.uk/itm/RESISTOR-75-KOhm-2W-Carbon-Film-Resistor-LOT-OF-10/201604613858?hash=item2ef09246e2:g:G-gAAOSw0vBUmXg8
Or maybe these? These are UK Based so would be easier
You can find more support on FB in the Signature MTK Users Group. More pics and video on the repair. https://www.facebook.com/groups/1980987565348040/
Thanks but i don't have a facebook so unable to see any of that, can anyone confirm if that second ebay link is the correct resistor?
Hey all, sorry to jump on this one, but...
I have a similar looking power-cycling error on one of my MTK12s (it cycles slower, but is otherwise the same).
I've tested R102 and that's reading at 650K, so I don't think there's an error there even though mild scorching on the PCB shows me it's been pretty hot in the past.
I don't see any bulging or burning on any caps on the board either, so I tested the major resistors. I found R111 reading 0 Ohms.
Does this sound to any of you more experienced with this kind of error, like it could be a cause for this problem?
Big thanks!
Hope this helps.
No power! Has anyone done a video on how and what to repair? Thanks!
Hilarious. The MTK 12 crew are getting mugged off.
My desk just doesn't power up. There was a time where the light came on very faintly and a little smack would get it to turn on. It's been nearly six months now.
I would greatly appreciate a little video on how to get it working as I have no soldering experience whatsoever. I'll come back when I've opened it up.
Cheers, M
Hello guys,
Just to confirm, a dead SMPS can be several things, if you are not an experienced technician then think about asking one to look at it for you as these things can give you a shock and, in some circumstances, can hold a charge after removing the power. Repair at your own risk!!
First, check the fuse, if it looks vaporized then you have a serious short, do not replace it without investigating further as it could make matters worse.
R102 often looks discolored due to heat, the part is a 75K 2W resistor but I would recommend changing this to a 82K 3W part, make sure you mount it slightly off the board to help dissipate heat better. This is known as the start-up resistor and is critical to getting the SMPS running.
The other common problem is C103 failing, the part is a 100uF 25v electrolytic capacitor, I replace this with a 35V device but make sure your replacement is marked 105 degrees.
I've had the odd FET fail but this is quite rare, the fixes above will solve more than 90% of the problems.
I purchased mine in 2017, it went down with power supply failure in 2019, sent it in for repair cost $50 shipping... Here we are today with another power supply failure...
Out of warranty repair is a minimum of $230 and $50 return shipping.... The power board costs $140. That is a huge no from me!
They say it is out of warranty and there are no known issues with this mixer... Clearly there is if they same problem keeps happening.. They dont want to annouce the issue or adress it because it will be too costly...
The 2 caps on the power supply next to the resistor are the failure point. That resistor gets too hot and causes the caps to boil...
Bare minimum it needed shielding there.
What a shame becuae this mixer costs as much as a rodecaster pro...
I will be keeping an eye out for the law suit...
https://youtube.com/watch?v=jt3-e0-FigI