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 8 (click to view)
STANDARD NOTES FOR SERVICING
Circuit Board Indications
a. The output pin of the 3 pin Regulator ICs is indicated as shown. (2) Remove the flat pack-IC with tweezers while applying the hot air. (3) Bottom of the flat pack-IC is fixed with glue to the CBA; when removing entire flat pack-IC, first apply soldering iron to center of the flat pack-IC and heat up. Then remove (glue will be melted). (Fig. S-1-6) (4) Release the flat pack-IC from the CBA using tweezers. (Fig. S-1-6)
Top View Out In Input
Bottom View
b. For other ICs, pin 1 and every fifth pin are indicated as shown.
Caution:
1. Do not supply hot air to the chip parts around the flat pack-IC for over 6 seconds because damage to the chip parts may occur. Put masking tape around the flat pack-IC to protect other parts from damage. (Fig. S-1-2) 2. The flat pack-IC on the CBA is affixed with glue, so be careful not to break or damage the foil of each pin or the solder lands under the IC when removing it.
Hot-air Flat Pack-IC Desoldering Machine
5 Pin 1
10
c. The 1st pin of every male connector is indicated as shown.
Pin 1
CBA
How to Remove / Install Flat Pack-IC
1. Removal
With Hot-Air Flat Pack-IC Desoldering Machine: (1) Prepare the hot-air flat pack-IC desoldering machine, then apply hot air to the Flat Pack-IC (about 5 to 6 seconds). (Fig. S-1-1)
Masking Tape Tweezers Fig. S-1-2 Flat Pack-IC
