Adjustment of Cassette Engine Speed in National RX-7000

[BoomboxLover48]

Recommending a novice to disassemble a motor is simply inviting catastrophe. To be useful, such advise should be accompanied with detailed photo step-step otherwise, it's far too easy for someone who has no clue what they are doing to find a pile of tiny parts that can't be reassembled when a brush pops out and prevents reassembly or some such thing.

That is so correct! Words of wisdom!

Just to remove the pulley from the shaft in some cases needs lots of skill and technique.

 

[hopey]

Recommending a novice to disassemble a motor is simply inviting catastrophe. To be useful, such advise should be accompanied with detailed photo step-step otherwise, it's far too easy for someone who has no clue what they are doing to find a pile of tiny parts that can't be reassembled when a brush pops out and prevents reassembly or some such thing.

That is so correct! Words of wisdom!

Just to remove the pulley from the shaft in some cases needs lots of skill and technique.

I said go easy. Happy to post a step by step guide but we're to post?

 

[Superduper]

I said go easy. Happy to post a step by step guide but we're to post?

Sorry Hopey, wasn't trying to be hard on you. This WAS me going ez lol. The OP is obviously a novice based on his questions, so just trying to avoid a situation where we are giving him just enough information to walk him off a cliff. Knowledge is always welcome so it would be great if you can post the step by step here, but it's probably best to start a new thread in the tech section and if you do, if possible, please include detailed step/step accompanied with images so that the reader doesn't have to guess or imagine or maybe misinterpret the instructions.

 

[BoomboxLover48]

Magnum don't have to do this.

This is just some additional info:

There is an easy way to remove the brass pulley from the steel shaft of a motor.

Cover the face of the motor just to expose the pulley with flexible card board with a cut on it, and direct hair drier on it. The cut is to slide the shaft through it.

While the brass pulley is slightly hot, direct compressed air cleaner on the steel shaft and pull the brass pulley out.

It worked for me when I wanted to replace a deck motor.

To put the brass pulley back, heat the brass pulley and quickly slip it in. Keep a spacer in between the motor face and the pulley, or else it will go and hit the motor cover.

In some cases by applying force you can slide it out without any heating!

 

[Superduper]

Hopey was talking about exposing the shaft at the bearing location to clean and polish it. Removing the pulley alone won't expose the shaft where it rides on bearing.

 

[BoomboxLover48]

Hopey was talking about exposing the shaft at the bearing location to clean and polish it. Removing the pulley alone won't expose the shaft where it rides on bearing.

That is correct! I'm so sorry if I misunderstood!

That is is not an easy process.

Very complicated... so easy to make many mistakes!

I won't even attempt, unless I have another working motor with me.

 

[caution]

What's the make/model of the motor? Perhaps someone has an extra.

 

[hopey]

I said go easy. Happy to post a step by step guide but we're to post?

Sorry Hopey, wasn't trying to be hard on you. This WAS me going ez lol. The OP is obviously a novice based on his questions, so just trying to avoid a situation where we are giving him just enough information to walk him off a cliff. Knowledge is always welcome so it would be great if you can post the step by step here, but it's probably best to start a new thread in the tech section and if you do, if possible, please include detailed step/step accompanied with images so that the reader doesn't have to guess or imagine or maybe misinterpret the instructions.

Cheers

Magnum don't have to do this.

This is just some additional info:

There is an easy way to remove the brass pulley from the steel shaft of a motor.

Cover the face of the motor just to expose the pulley with flexible card board with a cut on it, and direct hair drier on it. The cut is to slide the shaft through it.

While the brass pulley is slightly hot, direct compressed air cleaner on the steel shaft and pull the brass pulley out.

It worked for me when I wanted to replace a deck motor.

To put the brass pulley back, heat the brass pulley and quickly slip it in. Keep a spacer in between the motor face and the pulley, or else it will go and hit the motor cover.

In some cases by applying force you can slide it out without any heating!

Good info, but if you do it carefully; I have successfully removed Brass and Plastic pulleys without any heat! I have seen reports of damaging the motor by removing the pulley however this is not my experience.

Hopey was talking about exposing the shaft at the bearing location to clean and polish it. Removing the pulley alone won't expose the shaft where it rides on bearing.

That is correct! I'm so sorry if I misunderstood!

That is is not an easy process.

Very complicated... so easy to make many mistakes!

I won't even attempt, unless I have another working motor with me.

I understand your concern, I would conclude that the motor requires a service or replacement. Your current motor isn't going to get any better so if you have a crack at fixing it there is little to loose.

Did you change the Pinch roller as this is crucial to obtaining the correct tape transport speed, this could make you think the motor is too slow?

Despite comments I have read about these Japanese motors, they are very reliable and most are serviceable; as long as you can remove the back plate!

 

[BoomboxLover48]

What's the make/model of the motor? Perhaps someone has an extra.

That makes sense to me...unless it is something else !

Good suggestion Eric!

 

[baddboybill]

Something I noticed that was said by Magnum in first post was that when he records on Panny the speed is fast on other machines but when he has recorded on other machines that are slow on Panny. That seems kinda fishy!!!!

 

[BoomboxLover48]

Something I noticed that was said by Magnum in first post was that when he records on Panny the speed is fast on other machines but when he has recorded on other machines that are slow on Panny. That seems kinda fishy!!!!

Bill, If the motor is slow on Magnum RX7000, the recorded music on it will sound faster on a normal tape player, and prerecorded tapes will play slower on Magnum RX7000. Make sense to me!

 

[Magnum]

Ok thanks to all the feedback!

I have to say I really didn't expect so much feedback. I know this must sound alarming to the specialists here that a novice is trying to open a so-called holy grail. The most recent feedback doesn't exactly help me with my own nervousness abot the whole thing.

But I try to be as cautious as I possibly can. That's also why I'm moving forward like a turtle with this project. It was on 'standby" for the past days because:

a) I had to repair a laptop. Worked out fine!
b) I had to buy a tool in order to remove the 2 nuts on the front side. First I bought the wrong tool BECAUSE these nuts are not 8 and 9 mm in diameter (as claimed in the service manual) but 11mm.

Now the nuts are removed.

Next step: Removal of the screws on the back.

I keep you all in the loop.

Thanks again for your support and interest.

 

[BoomboxLover48]

9.0 mm nut? I am going nuts!

In the RX7000 disassembly?

 

[Magnum]

Yes they are on the front cabinet behind two knobs.

 

[BoomboxLover48]

Yes they are on the front cabinet behind two knobs.

But...... there is no need to remove those. They are the nuts holding the pots on the metal chassis.

 

[baddboybill]

Something I noticed that was said by Magnum in first post was that when he records on Panny the speed is fast on other machines but when he has recorded on other machines that are slow on Panny. That seems kinda fishy!!!!

Bill, If the motor is slow on Magnum RX7000, the recorded music on it will sound faster on a normal tape player, and prerecorded tapes will play slower on Magnum RX7000. Make sense to me!

Lol. OMG. It was way past my bedtime and I again wasn't paying attention to what I was reading. Lol 😆. Thank god I wasn't working on a box. Lol 😆

 

[Magnum]

Ok, next time they will stay.

 

[Superduper]

Yes they are on the front cabinet behind two knobs.

But...... there is no need to remove those. They are the nuts holding the pots on the metal chassis.

Royce, that is incorrect. On a virgin unmolested RX-7000, those two nuts need to be removed or the front shell will not come off. It is not uncommon to find examples that have been previously serviced with those nuts missing, which in my opinion is sloppy work or oversight on the technician.

 

[BoomboxLover48]

Royce, that is incorrect. On a virgin unmolested RX-7000, those two nuts need to be removed or the front shell will not come off. It is not uncommon to find examples that have been previously serviced with those nuts missing, which in my opinion is sloppy work or oversight on the technician.


Hi Norm,

Then mine was missing it to begin with. My mistake! My Apologies....

I've never seen something like that on a Panasonic, only on Japanese cars...

Magnum, I love to see a pic of that nut.


~Royce

 

[Superduper]

Then mine was missing it to begin with.

Magnum, I love to see a pic of that nut.

Alot of times, when the front shell has been removed for an extended period of time, the technician forgets that they removed that nut to begin with, or they see the nut in the fastener pile but doesn't know where it goes since every pot already has a nut. I have seen this on many examples as I've worked on many RX-7000. If it's never been opened before, it has it. If it's been worked on before, a lot of time it's missing.

There's nothing special about it. It's just a double stack nut. One to hold the pot to the chassis, and another one stacks on top after the front shell is replaced. Oh and this is not the case for all the pots. Only 2 of the pots have this extra fastener.