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 211 (click to view)
(3) DV EQ ADJ Move the cursor to �DV EQ ADJ� which is displayed with a white background using the [ENTRY] (�), [AUTO|EDIT] (�) keys. 1. Press the [OUT] (�) key to enter the adjustment mode.
2. Playback the alignment tape XH4-1A/XH4-1AP. Select �E� in the parentheses ( ) in the top right with the [OUT] (�) key and select PHASE with the [OUT] (�) key at the same time. Perform adjustment until the data becomes nearly the minimum value (000X) using the [ENTRY] (�), [AUTO|EDIT] (�) keys.
3. Playback the alignment tape XH4-1A/XH4-1AP. Select �E� in the parentheses ( ) in the top right with the [OUT] (�) key and select COS with the [OUT] (�) key at the same time. Perform adjustment until the data becomes nearly the minimum value (000X) using the [ENTRY] (�), [AUTO|EDIT] (�) keys.
4. Playback the alignment tape XH4-1A/XH4-1AP. Select �E� in the parentheses ( ) in the top right with the [OUT] (�) key and select AGC with the [OUT] (�) key at the same time. Perform adjustment until the data becomes nearly the minimum value (000X) using the [ENTRY] (�), [AUTO|EDIT] (�) keys.