The AKAI 1720 model reel to reel tape recorder described in this Manual is quite an old unit - circa late 1960's. As a consequence, the description of the mechanical details - and adjustments thereof - is quite critical. The manual does this quite well. The schematics are also well presented and have detailed PCB overlays. Probably the only negative is that some half-tone detail has been lost from the original manual as it has been scanned in simple B&W.
Text excerpt from page 5 (click to view)
SERVICE NOTE
1. POWER SUPPLY DURING REPAIRS
In this unit, about 10 seconds after power is supplied (8.4V) to the battery terminal using the service power cord (J-6082-223-A), the power is shut off so that the unit cannot operate. This following two methods are available to prevent this. Take note of which to use during repairs. Method 1. Connect the servicing remote commander RM-95 (J-6082-053-B) to the LANC jack, and set the remote commander switch to the �ADJ� side. Method 2. Press the battery switch of the battery terminal using adhesive tape, etc. Method 3. Use the DC IN terminal. (Use the AC power adaptor.)
DC IN terminal Battery SIG terminal Battery terminal �
Battery switch
Battery terminal �
2. TO TAKE OUT A CASSETTE WHEN NOT EJECT (FORCE EJECT)
1 Refer to 2-1. to remove the front panel assembly. 2 Refer to 2-3. to remove the cabinet (R) assembly. 3 Refer to 2-10. to remove the battery panel assembly. 4 Refer to 2-10. to remove the cabinet (L) assembly. 5 Add +5V from the DC POWER SUPPLY and unload with a pressing the cassette lid.
6
Pull the timing belt in the direction of arrow A with a pinsette while pressing the cassette lid (take care not to damage) to adjust the bending of a tape.
A
Pinsette
Press the cassette lid not to rise the cassette compartment [DC power supply] (+5V)
Timing belt
7
Let go your hold the cassette lid and rise the cassette compartment to take out a cassette.