Hi all Hitachi M2 is a mini component system comprising HS-M2 speakers, FT-M2 tuner/receiver, HA-M2 amp, and D-M2 cassette deck. It's a cute system and mine is all working except the deck. I have been working on this one on and off for months. The motor speed was 20% too high (3.6kHz using the 3KHz test tape) at its lowest adjustment. I bought a replacement motor at huge expense and can adjust that down to 3.2kHz. My working theories, mostly concocted at sleepless 2am, range from dud electronics in the motor (that's where the adjustment is) to someone fitting the wrong pulley. Before I go further - and arguably a bit late in the day - I need to know I am "barking up the right tree" so... if anyone has the Hitachi D-M2 and is willing to open it up and let me know the motor model number and the diameter of the motor pulley, I would be most grateful. Thanks in advance, Nick.
Lo-D looks like a serious machine, please post some photos of your efforts! I had this exact problem with my (surprisingly, also Hitachi) TRK-5190H. Speed was not adjustable for that model. My cheap'n'dirty fix was 2W resistor: A few weeks ago I bought myself another TRK-5190, it will be interesting to see if it has the same problem. A better but more stressful solution would be to shave motor pulley a little bit. Since you have two motors with pulleys, you have nothing to lose. With motor running, use small file or a piece of fine-grit sandpaper. But if overdone, it will be difficult to increase pulley diameter
The shaving option, I thought of already but there's a complication. The pulley drives the capstan flywheel and the rest of the mechanism with two separate belts running off two separate surfaces (right word?), so to keep things working properly the shaving needs to be done on both surfaces; any discrepancy would have the take-up running at the wrong speed vs. the capstan. I will load some pictures.
do not see much from this angle... except that your Hitachi looks real nice! Should you decide to be that crazy, reduce only capstan/flywheel pulley. Pickup works thru slippage of the reel, the hub itself rotates at higher speed anyway. Forgot to mention two "correct fixes": 1) take motor apart and fix the regulator; check voltage supplied to the motor 2) insert voltage regulator to supply motor with steady 12V. or 9V, or variable voltage
I have no other general photos - I generally just take specific pix to remind me how things fit together - and the machine is now in storage awaiting various rubber bits. I have limited space so things get rotated in and out of storage as parts become available - global postage in the Covid age means a lot of down time! - next I hope is Aiwa L30 deck idlers to complete a most beautiful Series 30 setup with cabinet and speakers. Thanks for the tip on the pulley reduction work. On the voltage side, the motor is 16V nominal and getting 17V off the PCB. I tried running it from off-board supply and it held the same speed all the way down to 7.5V - guessing this an intended effect of the in-motor circuitry; does it simply adjust for "any" incoming voltage/current? BTW I am confident with most of the mechanical aspects of tape deck repairs but I find myself out of my depth quite easily with electronics (but I do know that stab wounds from soldering irons are, at least, self-cauterizing). Thanks again Jorge!
I did not know that, I thought in-motor speed regulator is something more basic! looks like opening the motor and digging out its regulator is your only 'correct' choice. I remember it was doable for JVC El-Diablo motor, it was held together by screws
