idler tire for Nak RX-202 square-edged or round?

[Huck]

Hi: I just received two idler tires for my Nak RX-202 and they do not look the same as the "old" one. They seem to have square edges, much like an old style faucet washer,whereas my "old" tire has round edge, like an O-ring.The new tire doesn't want to go on the "wheel" to good and wants to flip over, which forms a "V" for the contact area, which doesn't look right to me. The new ones are the washer type and the old one is the one that looks like an O-ring. Are they suppose to be square or round? I took some pics! Huck

[Acoustic]

On the CR and RX series the tire is the one with the square edges. In the right picture it's the one on the far right. I've changed a few on my decks. The hardest part, for me, was to keep track of the tiny washer. I lost one once and just used a home made one I made out of three layers of scotch tape... cut it to shape and put the hole in it with an ice pick. It's still in one of my machines 'till this day!!

Also.. at first when I changed them I had trouble with them wanted to lay flat on the bottom of the hub like the one in your picture. I just worked it in with a cuticle pusher... I think I got that tip from NakTalk.

[Huck]

On the CR and RX series the tire is the one with the square edges. In the right picture it's the one on the far right. I've changed a few on my decks. The hardest part, for me, was to keep track of the tiny washer. I lost one once and just used a home made one I made out of three layers of scotch tape... cut it to shape and put the hole in it with an ice pick. It's still in one of my machines 'till this day!!

Also.. at first when I changed them I had trouble with them wanted to lay flat on the bottom of the hub like the one in your picture. I just worked it in with a cuticle pusher... I think I got that tip from NakTalk.

Thanks! You were right....I finally got the idler tire on the "right" way, so now the deck does fast-forward and rewind in 82 seconds for a 60 minute tape, which the service manual states FF/RW- 85 seconds! Huck

[Scorpion8]

Good job. As a matter of issue, idler tires are less important than belts and pinch rollers. They are used in FFW/REW and also to take up slack on the take-up reel. I replaced one on a HK 400Xm deck once with an o-ring out of a National O-Ring Service Kit for my car, and it works fine to this day. In fact, it almost works better since it was more pliable/spongy so being slightly oversized it spread out on contact and gripped really well.

[Huck]

Good job. As a matter of issue, idler tires are less important than belts and pinch rollers. They are used in FFW/REW and also to take up slack on the take-up reel. I replaced one on a HK 400Xm deck once with an o-ring out of a National O-Ring Service Kit for my car, and it works fine to this day. In fact, it almost works better since it was more pliable/spongy so being slightly oversized it spread out on contact and gripped really well.

Thanks! There was a little more to changing the idler tire than what is available information-wise on the "net"! Gotta do it yuself to find out! So the idler tire has nothing to do with the "play" mode?. Does it work in conjunction with the capstan drive(motor) to kinda help the capstan drive the tape?.Not sure what does what! Thanks, Huck

[Acoustic]

Thanks! You were right....I finally got the idler tire on the "right" way, so now the deck does fast-forward and rewind in 82 seconds for a 60 minute tape, which the service manual states FF/RW- 85 seconds! Huck

Great! Good to hear you got her goin'.

[Scorpion8]

So the idler tire has nothing to do with the "play" mode?. Does it work in conjunction with the capstan drive(motor) to kinda help the capstan drive the tape?.Not sure what does what! Thanks, Huck

The capstan/pinch roller is what drags the tape across the playback head, but it would all just bunch up if the take-up reel wasn't turning. In PLAY-mode, the takeup reel is driven by the idler drivewheel so it takes up the tape as it comes to it. But it doesn't want to put any tension on "pulling" the tape, which is why it's driven this way. The idler is on a swing arm that swings over by rotational inertia and jams itself between the drive wheel and the tape reel hub of whatever function is occurring, PLAY-FFW or REW. See the attached pics ...

PLAY
http://i127.photobucket.com/albums/p141/Scorpion008/01-IdlerwheelinPLAY-FF.jpg

REW
http://i127.photobucket.com/albums/p141/Scorpion008/02-IdlerWheelinREW.jpg

[Huck]

Thanks! I was not sure if the idler tire had anything to do with the capstan drive when in "play" mode, because when I push "play" with no tape in, the idler tire would turn as well, to drive the take-up reel. I usu assumed that they worked together!! So maybe the Capstan drive control sends a signal to the idler to just "help" the capstan when in "play"?! I never found any washer under my idler tire,so obviously this washer is not a big deal,as the deck was working somewhat when I got it! I was making sure to look for it too! Huck

[Scorpion8]

The idler drive wheel (the small one at the top center as compared to the idler wheel itself- the one that swings back and forth) is driven off a belt from the same pulley (usually) that drives the capstan. That way they turn at the same time and complement each other.

[Huck]

The idler drive wheel (the small one at the top center as compared to the idler wheel itself- the one that swings back and forth) is driven off a belt from the same pulley (usually) that drives the capstan. That way they turn at the same time and complement each other.

Thanks! My RX-202 has two motors, one for the capstan drive and one for the idler tire drive. Huck

[Scorpion8]

Come to think of it, that's usually the way it works. You wouldn't want your capstan changing direction regardless of it if was engaged by the pinch roller or not.