genesmasher
Active Member
Cross-posting on this forum to hopefully get some ideas.
I have a CD491 with what seems to be a logic issue with tape transport. Here are two videos: ONE and TWO. Basically, when the tape is inserted (or tape sensor switch engaged like in the videos), it immediately starts going through endless random cycles of Play/Pause (it also goes to Rew at first for a short time). Never stops by itself. Play and Pause button lights blink, all other lights are dark. I can stop the cycling by holding down the Stop button. If I press and hold FF or REW, it starts FF or REW, but as soon as I let go of the button, it resumes the same erratic cycling.
I already checked the common culprits - cam motor and cam leaf switches. The switches are clean (resistance is under 1 Ohm when closed). All wires to switches have continuity all the way to the power board, solder joints are intact. Cam motor (taken out) is spinning freely and continuously in both directions with DC voltage applied as low as 1.5V. I also re-flown solder joints to the Play and Pause buttons and recapped the power supply board. Pin 37 on the main controller IC (Pause signal) is perpetually high (11V), even when other functions are engaged (Stop, Play, FF/REW).
Any ideas what I should test next?
I have a CD491 with what seems to be a logic issue with tape transport. Here are two videos: ONE and TWO. Basically, when the tape is inserted (or tape sensor switch engaged like in the videos), it immediately starts going through endless random cycles of Play/Pause (it also goes to Rew at first for a short time). Never stops by itself. Play and Pause button lights blink, all other lights are dark. I can stop the cycling by holding down the Stop button. If I press and hold FF or REW, it starts FF or REW, but as soon as I let go of the button, it resumes the same erratic cycling.
I already checked the common culprits - cam motor and cam leaf switches. The switches are clean (resistance is under 1 Ohm when closed). All wires to switches have continuity all the way to the power board, solder joints are intact. Cam motor (taken out) is spinning freely and continuously in both directions with DC voltage applied as low as 1.5V. I also re-flown solder joints to the Play and Pause buttons and recapped the power supply board. Pin 37 on the main controller IC (Pause signal) is perpetually high (11V), even when other functions are engaged (Stop, Play, FF/REW).
Any ideas what I should test next?
