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Stereo cassette deck AD-F70 (AIWA)

[Outline] [Front view] [Front view 2] [Inside view] [Trouble-shoots]

Fig.1 Overview

• Wow & flatter is 0.04% ( WRMS )
• 2 motors full logic controll ( without any logic IC ).
• Use FG servo mortors for capstan & FF.
• Cue & review controll are available.
• Dolby B type noise reduction system using NE545, first Dorby B IC.
• Bias fine adjust for LH,FeCr,CrO2 position.
• Peak level LED Indicator & analog VU meter.
• Tape remain time display.

Trouble	Cause	Repair
Capstan, reel, FF, REW and tape counter were not driven correctly at all.	The belts and roller had been all damaged.	Replace capstan belt, idler belt, idler roller and counter belt.
Peak level display (LED) didn't hold the peak level.	The timer IC ( NE555 ) to hold the LED for few seconds was failed.	Replace the timer IC.
A digit of the peak level display was always lighted on.	Increase the leakage current from the output pin of the peak level controller IC.	Add the resister at the output pin to vss to bypass the increased leakage current.
FG servo controller didn't correctly drive the capstan motor.	Increase the leakage current of a capacitor of the FG servo controller.	Replace the capacitor.
No cover at the cassette holder.	When I got this deck, there was no cover.	Attach the cover for AD-F60 which is almost same design.
Capstan motor speed went slow down and stopped.	The commutators of the armature were shorted.	Remove the couductive piece between commutators.