I though it would be a good idea to discuss this topic after member BoomboxLover48 completed a successful repair on the deck on his M80. Royce is a true Boomboxery asset. 
Usually, when we get a new blaster with a non-working deck, we just go ahead and order a new set of belts. Sometimes, this is only 1/2 of the problem. Without properly functioning idlers and clutches, our decks are simply decorative.
Idlers and clutches are the mechanisms that drive the take-up reels.
If your clutch or idler is not properly engaging, one of two things will most likely happen:
1.) The auto-stop will engage immediately (usually on soft-touch and full logic decks).
2.) The deck will "eat" the tape (get a pen ready).
The principle is that the take-up reel needs to spin just fast enough to apply light tension to the tape as it passes through the capstan and pinch roller. If there is too much tension, the idler or clutch will slip, causing the auto-stop to engage if equipped.This is why we can rewind and fast-forward to the end of a cassette without breaking it. It also allows the take-up reel to spin at the proper RPM, as it changes as the reel fills or is depleated.
Common problems with idlers:
1.) Excess cleaner/lubricant
2.) Flat spots (usually from long-term storage without use)
3.) Wear from use
4.) "Goo" syndrome, often found in belts as well
Common problems with clutches:
1.) Excess cleaner/lubricant
2.) Wear fom use
3.) Mis-aligned engagement mechanism
Example of an Idler:
Example of a Clutch:
Here are two threads about repairing each type of mechanism:
https://boomboxery.com/forum/index.php?/topic/18802-jvc-rc-m80-belts/
https://boomboxery.com/forum/index.php?/topic/17960-sanyo-m9990-deck-repair/
I hope this thread helps others get their decks up and running. If anyone has anything to add, please do.
We are the reason many of these units still exist.
Usually, when we get a new blaster with a non-working deck, we just go ahead and order a new set of belts. Sometimes, this is only 1/2 of the problem. Without properly functioning idlers and clutches, our decks are simply decorative.
Idlers and clutches are the mechanisms that drive the take-up reels.
If your clutch or idler is not properly engaging, one of two things will most likely happen:
1.) The auto-stop will engage immediately (usually on soft-touch and full logic decks).
2.) The deck will "eat" the tape (get a pen ready).
The principle is that the take-up reel needs to spin just fast enough to apply light tension to the tape as it passes through the capstan and pinch roller. If there is too much tension, the idler or clutch will slip, causing the auto-stop to engage if equipped.This is why we can rewind and fast-forward to the end of a cassette without breaking it. It also allows the take-up reel to spin at the proper RPM, as it changes as the reel fills or is depleated.
Common problems with idlers:
1.) Excess cleaner/lubricant
2.) Flat spots (usually from long-term storage without use)
3.) Wear from use
4.) "Goo" syndrome, often found in belts as well
Common problems with clutches:
1.) Excess cleaner/lubricant
2.) Wear fom use
3.) Mis-aligned engagement mechanism
Example of an Idler:
Example of a Clutch:
Here are two threads about repairing each type of mechanism:
https://boomboxery.com/forum/index.php?/topic/18802-jvc-rc-m80-belts/
https://boomboxery.com/forum/index.php?/topic/17960-sanyo-m9990-deck-repair/
I hope this thread helps others get their decks up and running. If anyone has anything to add, please do.
We are the reason many of these units still exist.
, :jason: , or :ebay: . Then they can do more of 
!
