Nakamichi 480 intermittent play, fast forward and rewind

[Dalegoodman]

Hi. I recently picked up a Nakamichi 480 cassette deck for $40. Powered up but not working at all. Opened it up.Two belts were stretched out. Replaced all belts and to my astonishment, the unit operated and sounded great! Two hours later.....when I push play, the control cam turns, the backs off and the tape won't play. When I push fast forward or rewind, the tape will move for about a second in either direction, then stop. Any suggestions would be greatly appreciated.

 

[zedex]

Yup. The transport is seizing up not allowing the headblock to rise. Your most likely culprit is the pinch roller arms. They always are almost frozen solid due to hardened grease. 30 years sitting in a closet you would be seized too. The arms are spring loaded so moving them by hand they should move freely.

 

[Dalegoodman]

Would you degrease it or just spray some lubricant in that area? I don’t think spraying Deoxit, the cure all, is a good idea as it leaves a residue...

Thank you for your quick reply!

 

[zedex]

The arms generally have to come off. You may be able to work them free. If you do take the arms off they have to go back on exactly the same height otherwise you need a special gauge to measure roller height. Make sure that is the problem first.

 

[zedex]

Re reading your first post. Your idler tire is most likely toast. If its the original tire it will be hard as a rock and cause the same symptoms your experiencing.

 

[TWTRTECH]

The cam motor shaft, also can have dried grease on it. I would check that first. if so you would have to remove it to properly clean out the dried grease then relube with lithium grease.

 

[Dalegoodman]

The tire doesn't seem too bad. The tape will FF and RR for about a second until the cam reverses and shuts the mechanism down. Play does not move the tape at all. Almost as if the mechanism is out of synch. I don't think I upset the mechanism when I used the service manual to to a belt change with everything OK for a few hours following the belt change. Gear have no broken teeth.

 

[zedex]

Oh. When you hit play without a tape, does the headblock rise as well as the pinch rollers. Truth be told that mech needs a teardown and clean/ lube. Idler tire/belts. I have done many and they all wont go unless . Try this. Take off the cover,hit play,and help that big white ish gear with your finger. See if the headblock will go up all the way and stop .

 

[Dalegoodman]

The headblock does not rise when play is pushed without a tape in. It does rise when play is pushed with a tape inserted, but once the large white gear turns about 90 degrees, the large white gear rotates back and the mechanism shuts down.

 

[zedex]

You replaced all belts? All belts meaning 2? There is another belt and the deck wont operate without it. Counter belt behind the beauty plate.That would explain how you got 2 hours out of it.

 

[Dalegoodman]

I replaced 4 belts with some generic belts listed below. The counter does not move at all during the 1 second FF and RW that the brief operation allows. On inspection, the main long belt seems a bit floppy in my opinion. Maybe I should order the Mars belts? I think the counter belt is intact, but if it is broken, the player should operate, right?

 

[zedex]

The deck wont work without the counter belt. Other than capstan belt, no other belt is crucial so you don't need a marrs belt. And i wouldn't suggest getting anything from Marrs.

Also. There is no possible way that the idler tire is any good. It will be hard as a rock. And changing that is NO FUN . Its fun on any other machine but since the 480 is old, the plastic display housing is extremely brittle/delicate borderline rotten. Tabs break off. Falls apart. It has to swing away to get at screws etc.

 

[Dalegoodman]

Sounds like a great weekend project. Would you kindly suggest a source for the idler tire please?

 

[zedex]

I hear these are good but have not tried them.

https://www.audiolabga.com/data_html/STC.7874.html

I used to use Red Star tires and got on the red star band wagon, and still have a bunch but they are too damn grippy and cause the tire to chatter.

 

[Dalegoodman]

Is this the diagram that I’ll be working from to get to the idler tire?

 

[zedex]

yup