Oktava Mk-012 microphones

[N_Cook]

Expensive Russian mics. Is there any pitfalls about getting inside the
XLR barrels? eg threadlock on the obvious screws, twist the wrong way
and some 70swg wire breaks or something like that?
One barrel has something acoustically , not electronically, loose
sliding around inside and the other has a bad electrical connection of
some sort

 

[N_Cook]

On 14/07/2014 12:28, N_Cook wrote:

Expensive Russian mics. Is there any pitfalls about getting inside the
XLR barrels? eg threadlock on the obvious screws, twist the wrong way
and some 70swg wire breaks or something like that?
One barrel has something acoustically , not electronically, loose
sliding around inside and the other has a bad electrical connection of
some sort

according to a utube bod, looks too easy

 

[N_Cook]

Now I've got inside may as well find some sort of info/equivalent for
the 3BF1 and 3107E transistors. With blue electros like the Philips ones
of 1960s, looks like 1960s inside but for the glass+polyester pcb

 

[N_Cook]

schematic on
http://taperssection.com/index.php?topic=141868.30

 

[N_Cook]

In one a loose screw , needs nail varnish on these screws.
The other one looks like a cracked die in a transistor from being dropped.
I'll have to go with these www refs
FET ABM7 = ( 3BF1?) = 2SK170BL
PNP Si marked 3107e = BC179AP
for the moment.
Then the usual conundrum as a matched pair of mics with 3 inserts each,
will have to make the desicion of replacing with the same matching
transistor replacement in the broken one only or both mic stems

 

[N_Cook]

Probably a mechanical problem. The insert end core is not firmly held
transverse to the pcb, and so poor contact between the mic central pin
and the sprung pip contact in that core disc. At least plenty of space
in that area to add a plastic brace, to farther back along the track
side of the pcb