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 65 (click to view)
ELECTRICAL TROUBLESHOOTING GUIDE -11/17 3. Y/C CIRCUIT (3) When the C(Color) signal doesn�t appear on the screen in PB Mode,
Is 5.2VT/5.4VA applied to the IC301 Pins 24, 42, 55, 72, 91. YES Is the Color Rotary signal applied to the IC301 Pin 70? YES Is Color Rotary "H" about 3.4V? YES Does the Color signal appear at the IC301 Pin 25 ? NO Does the X301(4.43MHZ) oscillate? NO Replace the X301. NO Check the Color Rotary level. (Check the R303) NO Check the Color Rotary Circuit. (IC501 pin 99 ) NO Check the line of the 5.2VT/ 5.4VA Line. (Power Circuit)
YES
Does the Color signal appear at the IC301 Pin 21? YES
