No sooner was one 414 about to be going out of the door, another was coming in!
The customer of the Tascam 414 LED metering noise problem on the previous fix, had a friend with a 414 having the exact same problem, so brought it along to receive the same fix.
Confirmed the same symptoms before doing anything further – yep – same “noisy LED” issue! This one had seen a little bit more use and a fair bit of dust/grime and the sliders were quite gritty, but whilst it was apart may as well use the opportunity to clean it up a bit.
Horribly it had warranty void stickers over almost all the screw holes though which was a right royal PITA to remove, but got there in the end.
Visual inspection of heads and mechanics looked fine just perhaps a bit of cleaning to do…
Removal of all the knobs to get access to the mixer board for the required modifications. When the cover is off will be the ideal time to clean it – leaving the intentional pitch control markers in place of course! Quite dusty top panel:
Once mixer board was unscrewed (shield removed etc first and screws all organised to go back the same way), the meter bypass capacitor modification was completed (including the resistor and larger LED V+ supply cap):
Noticed the capstan shaft and motor were a bit dry (capstan sounded a little noisy off load) so lubrication added to the phosphor bronze bearings with a small application of Mobil DTE Light:
Whilst underneath the mechanism, checked belts and were in good condition… Also cleaned up pinch roller somewhat and the capstan shaft with naptha:
After the main fixes done, set about alignment/calibration, things had drifted somewhat, so first the bias/erase frequency brought back to 85KHz spec:
More details on the alignment procedure are in the previous 414 post, just a few more iterations were required on this machine to get things spot on, and the fader sliders needed a bit of extra work to help with the stiffness/grittiness. Noisy pots were treated with Deoxit F5.
After reassembly and cleaning this newly revived 414 was ready to go back to it’s owner for hopefully some renewed joy !
