A little article about repairing a Woldorf Blofeld with the dead or low output problem. The description was already documented here , you can also try to find the pdf on the web with the filename “blofeld_low_output_repair.pdf”. I thought some german users would appreciate a german repair guide. Well this is just the english version of the german version :-) … maybe you appreciate this article nevertheless.
Audio output and phones has very low or no output at all.
As mentioned above, i am just repeating what is already known: problem is a blown resistor. It’s value is 6.8 Ohm and it can be found near the shift button.
What you need
Soldering station with a fine tip. LED-table light with built in Tischlampe mit eingebauter magnifier. Tweezer. I used leaded soldering wire.
1. open the Blofeld
First reove the 4 screws on the bottm side. The lower half of the case can be removed.
2. desolder power switch
Yeah, rigth. The two wires from the power switch must be desoldered. If you don’t remove the powerswitch you won’t get the pcb out.
3. remove pcb
Remove the 4 distance bolts and the 3 screws in the middle. The pcb can be pulled out of the case easier, if you dial the encoders flat side that they are facing away from the midi jacks. 4. find the broken part and desolder it
On my Blofeld the broken part was broken in the middle! Strange, very strange. I desoldered both halfs, cleaned the pads with some fresh solderwire and a desoldering braid.
5. Soldering the new part
This can come aout a bit tricky. The SMD part is just 3mm long, if are suddenly terrified by something (maybe a big black spider running over the pcb while you look through the magnifier) you might inhale or swallow your spare part. There might be more elegant ways, i did it like this: i put some solder on one pad to form a little hump. With one hand i held the part with the tweezer on this hump, with the other hand i put the iron on th patrs side lying on the hump. The solder under the part quickly gets fluid and the part id lying flat on the pcb. I soldered the other side and that was it. Dont hold the iron on the part for to long, it will easily be desoldered again.
6. Putting it all back together
Point 3 to 1 in opposite direction. Don’t forget to resolder the powerswitch :)