mikeyB
Well-known member
Hi All,
Been asked by a client to repair a pair of Telefu*k - en M60s.
Very erratic behaviour - intermittent ticking etc.
Absolutely no info on web and no other problem mics that I can find????
Build quality is good, capsule look outstanding! The only thing I thought wrong was very little solder used on joints.
Had a go at soldering half a dozen joints or so, reassembled and bingo!! now works. Proceed to secure with 3 tiny retainer screws, try again, BAH faulty again.
There is about 10 resistors, a polysty cap from the capsule and a few elec caps. Transformer output. The only active device is a dual fet LSK389. Is it likely the intermittency of the pcb is spiking the FET to death? The mic has a faint distorted output when subject to a high spl but nothing otherwise.
To me that sounds like biasing is way off (probably if the biasing is intermittent).
I'll try and trace out the cct, resolder all the joints and try again.
(I am using antistatic precautions while testing)
It is difficult to bench test as the outer body holds the capsule in place.
The mics were sent to Telefunken for repair just out of warranty, worked for approx 2 month then faulty again, sent back again but they insisted they were working fine!!! and returned to my client, again, not working!!
Any advice greatly appreciated.
Been asked by a client to repair a pair of Telefu*k - en M60s.
Very erratic behaviour - intermittent ticking etc.
Absolutely no info on web and no other problem mics that I can find????
Build quality is good, capsule look outstanding! The only thing I thought wrong was very little solder used on joints.
Had a go at soldering half a dozen joints or so, reassembled and bingo!! now works. Proceed to secure with 3 tiny retainer screws, try again, BAH faulty again.
There is about 10 resistors, a polysty cap from the capsule and a few elec caps. Transformer output. The only active device is a dual fet LSK389. Is it likely the intermittency of the pcb is spiking the FET to death? The mic has a faint distorted output when subject to a high spl but nothing otherwise.
To me that sounds like biasing is way off (probably if the biasing is intermittent).
I'll try and trace out the cct, resolder all the joints and try again.
(I am using antistatic precautions while testing)
It is difficult to bench test as the outer body holds the capsule in place.
The mics were sent to Telefunken for repair just out of warranty, worked for approx 2 month then faulty again, sent back again but they insisted they were working fine!!! and returned to my client, again, not working!!
Any advice greatly appreciated.