582 reel motor cogging - new tyre

[chartz]

Hello,

Do you have any ideas why the reel motor acts like a stepped motor when there is no tape and I press play?
When there's a cassette, it remains very noisy, unless I try to brake it with a finger. The idler is new.
When I test the motor on its own, from another power source, it works fine.
Have any among you experienced such a problem before?
I have tested all the components on page 23 (Q413, 418, 419,420 and C423, 423, 428), and they are fine as well. I haven't tested the 4558 though. FF and REW speeds are normal.

Thanks in advance.
Jacques

[Nakdoc]

Where did you source the idler tire? My opinion is that the tire's inside diameter is larger than the pulley's diameter, allowing the tire to shift as it rotates. I believe a post 2 months ago commented on this problem.

[perry]

Tom and I have discussed idler tire sizes in the past. There are a ton out there, from horrible to excellent. One of the hardest ones to find in the correct size are the classic transport ones. There are at least 2 different idler hubs sizes, and without the correct ID (inner diameter) OD (outer) and width, then all sorts of issues can happen. Too large an ID and the rubber slips and rotates relative to the hub and reel table. That will cause cogging. Too thin, not wide enough, and the rubber walks and is not square to the reel table, that can cause cogging. Too small an OD, and the washer that retains the spring that tensions the idler hub can come in contact with the reel hub, and of course, cause cogging. You can usually SEE what the problem is, with the "beauty plate" (that covers behind the cassette) removed. If it is very noisy, I'd guess idler tire problems. FWIW, I found the tires from "iris_it" on ebay to be an excellent fit. The poorest one was the one from ESL that was a generic replacement (specifically, NOT the OE one) Too thin, too small ID and too small OD. I was surprised Jeff even sold it to me. He claimed they use them if the customer balks at paying $120 for the original tire, and that they are sized for black hubs (which I've still not seen), and that the smaller OD gives higher torque and better grip. I never responded back.

[chartz]

Thank you both.
So you are positive this can't be an electronic problem then?
The idler tyre (sorry, tire) came along with the 582. It has rounded edges! I've already ordered a new one here:

http://cgi.ebay.fr/ws/eBayISAPI.dll?ViewItem&item=170332950691&ssPageName=STRK:MEWAX:IT

Jacques

[perry]

I don't understand..the first post said you already had a new tyre on it? Rounded edges are an indication of old/worn tyre. I've bought idlers from him (Dean Sanborn, a Naktalker)before, but I did not have good luck with the classic transport ones (too big). These 170388618671 were for the Sankyo decks, including Yamahas, and work great.

The best ones for the classic are the ones from iris_it. Here is one of his auctions, just not for idler tyres. 110542824916

[Nakdoc]

Thank you both.
So you are positive this can't be an electronic problem then?
The idler tyre (sorry, tire) came along with the 582. It has rounded edges! I've already ordered a new one here:

http://cgi.ebay.fr/ws/eBayISAPI.dll?ViewItem&item=170332950691&ssPageName=STRK:MEWAX:IT

JacquesI will never say never, but I haven't seen a bad reel motor in the classic mechanism for years. The tire you ordered is from Dean Sanborn.

[chartz]

Hi and thanks for the answers,

I believe original parts on classic mechs are rounded, aren't they? Mine is equipped with a NOS one, it seems. The lady who sold it to me was getting rid of her late husband's stuff...

The tire was not sold as a separate piece by Nakamichi. There are several suppliers of aftermarket replacements, and unfortunately the tires I've sampled are undersized and often fail to work.
A few notes: the classic deck idler had 2 versions over the years with a color change from white to black demarking the transition. The older white tire had rounded edges.
Do not attempt to change the tire yourself unless you are very good at repairs! The job requires a complete mechanism disassembly. Do not change the tire unless you absolutely must (they make noise before they fail). Do not try any DIY instruction that bypass the disassembly. You risk breaking the plastic idler itself.

Therefore I am waiting for Dean's tyre. Let's see what happens!

Iris_it doesn't have them any more.

Jacques

[perry]

I know he doesn't list them on ebay, but I have always emailed him direct to ask in the past, and he's had them. He always said he had plenty, and ships promptly from Italy. When did you email him? Dang.....I guess I should start looking for another source.

[chartz]

I have just sent him an email.
Since I am still suspecting a bad 4558, I will try that too. I'll keep you informed of course.
Thank you for your time and ideas.

Jacques

[chartz]

Hello,

New tyre, no luck (as expected)...
The thing is the voltage at the reel motor is way out of specs. When FF or RW there are 9V; worse, when playing it goes from 3.5V to 6V alternatively, which explains the "cogging". The PSU is okay, the 4558 is fine as well, all transistors are tested OK and I replaced the capacitors. The motor itself is good. Any ideas please?

Jacques

[chartz]

Found it!

R473 had gone up to 20Ω! It should be 2.2Ω...

Reel motor now works normally... yeah!

[scan80269]

Excellent troubleshooting!

Bad resistor is a lot easier to deal with than a bad motor.

[chartz]

Thanks. However, another slight problem has now arisen.
When the idler wheel takes its working position, the lever goes askew towards the front of the mechanism, so that the (new) idler is never in optimal position, with a higher noise level than is desirable.
What next then? Do you think a tire with an outer diametre that is slightly too small may cause this?
Apart from that the deck runs and sounds great.

Jacques

[perry]

Good job. That's something you don't see too often. When you said you checked the components in the first post, I'd have thought you would have checked the voltage at the motor too. I should have asked.

Not sure what you mean about the idler tire lever? Tire is going towards the end of the brass hub and closer to the cassette on the reel tables? Is the diameter of the new one much smaller than the older? If it's all rubber touching, then it shouldn't matter where it is, it should be quiet. Too small, and when it skews like that, the plastic of the hub can intermittently contact the reel hub. Is that what you mean?

[chartz]

Tire is going towards the end of the brass hub and closer to the cassette on the reel tables?

Exactly. A little beyond the felt pad even. It isn't square at all! There is a lot of leeway there... The hub is very free to move in all directions, although there is no play in the bearings themselves. The plastic is very soft and the hub wants to travel towards the edges of the reels, as if drawn by some mechanical force.

The tyre is indeed smaller but there is no contact on the plastic hub at all.
Anyway, I'm waiting for yet another new tyre from Dean Sanborn which he tells me will be a better fit!

Jacques

[Nakdoc]

When that resistor burns it indicates that the reel motor intermittently stalls.
I'd say the deviation of the idler arm is normal. It is the one consistently sloppy part found in classic mechanisms.

[perry]

Does the 582 idler hub have the same small washer over the large washer over the spring as the other classics? If so, are you sure the spring end is seated between the 2 small nibs in the well of the hub? Tom is right they can be sloppy. Some people have added a small slip washer to the pivot to reduce the slop.

[chartz]

-Does the 582 idler hub have the same small washer over the large washer over the spring as the other classics?
-If so, are you sure the spring end is seated between the 2 small nibs in the well of the hub?

Yes, and yes!
So the "traveling" idler arm is normal then. I hope the new tyre will do its job correctly... Also, the brass axle of the reel motor looks a bit too shiny where the tyre has run for years and I was thinking of sanding it. Any thoughts?

As regards the resistor Nakdoc, your hypothesis seems logical to me, although it was not burnt at all. This now works normally, the resistor doesn't even get warm.

Thank you both.

Jacques

[perry]

I always clean the brass idler pulley with a very small piece of 1500 grit emory paper, while holding a vac nozzle over it to suck up any powder. Trust me, don't omit the vac. Takes literally 2 seconds when its running. I find it improves the noise and grip. Then clean the dust off the pulley and idler tire with some American Recorder 721.

Remember, the smaller the tire, the more torque that is applied. A larger tire may reduce the hub skew. But what a royal PITA to change, eh?

[chartz]

But what a royal PITA to change, eh?

Oh yes... But I am quite trained for that (!) and it is not that difficult once you know what to do (thank you people who allow us to download the service manuals). Just one small issue I had to solve was a bad solder joint at the PCB big connector (last pin at right) which prevented the capstan motor to work at all!

Perry I found your post regarding idler tyres... I'm waiting for two more of these: one from n4229k (low expectations then) and one from Friedhard in Germany, who says his are fine (he's Gianni's—aka Iris_it—supplier, same price). He even sent me a photo of it with a ruler atop to show dimensions and it seems about right (a little over 19mm or 3/4 inch OD, about 13 mm or 1/2 inch ID), thickness about 3mm.

Jacques

PS. Thanks for the hoover tip! And another PITA is to have to wait for you guys across the big pond to wake up! *fit* *grin*

[perry]

Tres bien! I did not know Gianni got his stuff from Friedhard! Small world. The ones I got from Gianni are almost a perfect fit for the clasic transport with white hubs. Almost. The ID could be 0.25mm smaller, but that's being really picky. They are the best size of the 6 different places I've tried, and a nice resilient rubber. Dean Sanborn's (n4229k) are a harder rubber, and the ones he sent me were too large an OD. I wondered if he sent me ones for a 480, which I read WERE larger. If they are too small, like the non-OE ones I got from ESL, then they stretch too much when installed and are not perfectly round. Useless waste of $. Between belts and idlers, I waste a bit of $$ buying a few possibilities in order to compare them direct when I do the work, a hard earned lesson. But, it's just not worth $10 to take everything apart again when I find a better part, so I try to line up the solutions in advance. Let me know what you find, please!

[chartz]

Let me know what you find, please!

I will!

Jacques

[Nakdoc]

I do not advise sanding the brass pulley. If you do so your flutter will increase measureably. The pulley is designed to slip easily if it needs to. Sanding transforms the process to stick-slip. Any excessive slipping is easily remedied with a new tire.
Resistor that change value have been overheated. This is flameproof and is designed not to burn.

[chartz]

Okay, got that. My main concern is the wrong position the hub takes. At rest it is about square but it moves considerably forward when running, so that only the edge of the tyre is in contact with both pulley and reels.

So I thought insufficient grip or wrong tyre OD. Is this a just bad design then? Why is the hub plastic so supple?

Jacques

[chartz]

Hi,

I received the idler tyre from Dean Sanborn this morning.
Unfortunately, it looks more like a plumber's gasket with a very rough surface and it is much too thick... it won't fit! One for nothing! *headache*

Let's see whether Friedhard's tyre is what it should be...

[perry]

That's what I said about the n4229k ones. Not even close. I don't get it. I have to send mine back to him and get a refund. Tom, I did say 1500 emory for 2 seconds, and I meant it. Do not sand it, or polish it. Brass will oxidize in short order (a few days), but the 30+ year old build up of rubber glaze, that cleaner will not remove, comes right off. Haven't had any flutter increases, but you have way more experience than I, so everyone, try this at your own risk!!!. I can only note that it's helped some of my decks, measurably, where the hub was very dirty and cleaning made no difference. I've even used the same emory for a few turns of the reel hubs as well.

[chartz]

Oh well...

Just a small question: when I run the calibration process, the needles are perfectly stable with the 400Hz signal but they are not very stable on the 15kHz signal (Dolby out of course). On my CR-4 the bias LED flickers. The recordings are fine nonetheless after calibration.
Is this an issue? The user's manuals don't say anything about this.

Jacques

[perry]

How much is "not very stable"? A db either way at 15khz and up is normal. 3 db is not. 8k and under is usually dead stable.

[chartz]

I'd say about 0.5 dB. At 400 Hz it is dead stable.

[chartz]

Hi,

I received Friedhard's tyre (ordered on Saturday! but then I live 140 miles away from Germany) this morning. Perfect, period. Dean's tyre was completely out of specs and very hard, Friedhard's is an exact replica and the rubber is of excellent quality. Definitely not an O-ring!
I will buy from him from now on, possibly not via Ebay.

Jacques

Edit.: the new tyre works perfectly... I am about to get for free a Nak 682ZX which plays fine but can't record!