Thanks for the reactions! The pictures give some information about the construction, but unfortunately its is not possible to see if the connection to the 'top' capsules is fixed (a wire) or a slider contact.
It seems it is rather tricky to open the headbasket of a SM69.
Klaus Heyne:
"Disassembling the SM69 head is tricky and not recommended for the faint of heart. The small black plastic dot indicating 0� (front) on the upper basket needs to be pried out; then, through the opening created, the first of two compression spring clips needs to be pushed in, while slightly tilting the upper basket upwards, to free, and then remove, the spring clip. Then the basket needs to be pushed back down to its original position, and rotated 180�, to free and remove the second spring clip through the same procedure.
Now you can lift off the upper basket and inspect the rotating mechanism for wear, play, or breakage.
Reassembly is in reverse order, though the upper basket will be positioned and remain in its 0� setting: insert the rear spring clip into the bottom basket's slit first, and guide the top basket over it, until it is flush in the rear with the bottom basket. Now position and push the front clip in until you can slip the upper basket over the clip, into the top basket�s groove, until it clicks into position. Rotate slightly, to confirm locking.
Careful: the plastic guide nipples on top of the head assembly mentioned in my previous post will break if you misalign and then push the basket down during reassembly. The capsule assembly must stay perfectly on its center axis during this procedure-even a slight tilt may crack the nipples. Bottom line to consider: Everything needs to fit smoothly and can be assembled without force. If it does not, and resistance is felt, stop, and re-position the head until it�s lined up perfectly straight over the capsule assembly, before pushing the basket down into its final position. "
And on the Neumann forum Martin Schneider writes:
"I don't do disassemble SM69 heads, even after 20 years at Neumann. I leave that to my colleagues in Service.
By the way, e.g. the circular springs are selected in thickness as to make them fit snuggly. You need a full selection of them to find the correct ones."
I already tried to push the spring, but I suppose you will have to use a lot of force to push it in!
I will think about it and wait until I have enough courage! ;D
