I have a Nakamichi BX300E on the workshop table, and after completing the service I discovered a faint howling/squealing sound from the drive. The frequency of the sound changes up and down when the pitch knob is turned. The sound seems to be produced by something mechanical - perhaps the flywheel? Has anyone observed a similar phenomenon? And what was the reason?
I haven't worked on this particular deck but could it be the idler belt?
Hugo
Hugo
Thanks Hugo. It could be, however the belt is quite new (app. 3 month), and the sound hasn't been there before. I notised the noise after fixing a cam wheel issue.....
It's not simple to apply the stethoscope - screwdriver method on moving parts but does it squeal in FF or REW or PLAY without cassette?
Might give you a clue...
I understand it's not easy to localise such a problem on these small parts. You'll need fingerspitzengefühl. 🙂
Might give you a clue...
I understand it's not easy to localise such a problem on these small parts. You'll need fingerspitzengefühl. 🙂
Netlist; It's constantly howling/squealing when flywheel is turning - stops if I stop the flywheel from turning with my finger.....
Might be the belt, but I can't figure out why it suddenly should start making trouble.
Might be the belt, but I can't figure out why it suddenly should start making trouble.
If you can take off the belt and turn the flywheel by hand, that would exclude the belt and the motor.
Flywheel should run very smooth.
But I'm sure I'm telling you the obvious. 🙂
Flywheel should run very smooth.
But I'm sure I'm telling you the obvious. 🙂
Did you remove the transport and lubricated the Capstan Shaft bearings? check whether you also have the plastic washer on the Bearing face mating the flywheel end. Finally check the clearance between DD motor and the Flywheel face/ plastic part that mating the Flywheel center - need lubricant.
hope these things help .
hope these things help .
I did a quick service on it app. 3 month ago incl. replacing the belts. I didn't remove the capstan or other parts. Just loosen the back of transport to clean the flywheel and to get new belt in place. It was noiseless then. I will try removing the belt and see/hear the result......
Jan, I feel your pain.
It's very annoying to find out a repair that doesn't behave in the final tests after service.
It's very annoying to find out a repair that doesn't behave in the final tests after service.
To squeak, it needs to move slowly, so I do not think it is the flywheel, it sounds like maybe a pinch roller that is not lubricated.
A piece of tape twisted somewhere? Pinch rollers are primary targets for that.
Left it On for some hours and it started squeaking again. Ordered a new set of belt. Don't know what else to try.....
So, the flywheels/capstans bearings are newly lubricated? Has this machine been converted to gear drive to the hubs, as opposed to the original rubber idler drive (both by Sanyo)?
All good fortune,
Chris
All good fortune,
Chris
Chris; Yes they are lubricated. The machine has the old rubber idler wheel, but this is not in action, when machine is only powered On and in STOP mode.
Then the only other point of high enough pressure to make noise is the capstan motor's "top" sleeve bearing. IIRC the bottom bearing is just a thrust plate with dry lube. If a small drop of oil, allowed time to soak down, doesn't cure it, removing the capstan belt and running the capstan motor alone might give more information.
All good fortune,
Chris
ps: or I could be wrong about the bottom bearing - it's been a few decades
All good fortune,
Chris
ps: or I could be wrong about the bottom bearing - it's been a few decades