I Need Help With Motorola SH18N Speed Control!!

Hi everyone,

I just acquired a completely restored 1959 Motorola SH18N, the three-channel stereo portable. It sounds utterly amazing and I am so grateful to have such a wonderful machine in my collection! However, on every speed, the AC motor turns too fast and it will play a record a half-step higher than what it was recorded at (eg a 45 recorded in the key of F will play back at F#). And yes, the motor has been degreased and relubed/oiled, so there is nothing wrong with the motor itself, nor with the idler wheel.

I was wondering if there is some kind of variable power transformer for a wall outlet I could buy that would allow me to adjust the level of supply frequency for the motor (in other words, a device that I would plug into the wall, attach the power cord to, and turn down the supply frequency until the motor slows down enough where it rotates at the correct speed. It would probably affect how loud the amplifier can go, but I don't really listen to my music at full blast so it wouldn't affect me much). Does this kind of thing exist? If it does, where can I get it? And finally, would repeated use of this device damage the player in any way? Right now, the player is set to run on standard 117 V, 60 Hz.

Again, there is no "defect" with the motor itself...it's just set to run a little too fast and there are no speed pots or speed control I can adjust to bring the speed back down. Thanks!!

Indeed there IS a "defect" since the speed is off as you say.
As far as being "completely restored" - that is meaningless to me, I've seen the horror stories pertaining to that.
I've properly repaired plenty of already "restored" units.
Though I'm an experienced technician of these things, I cannot accurately troubleshoot something that is not on my workbench.
However most likely the motor mounts are defective by this time or incorrectly installed.
This could allow the motor to sag and be out of alignment causing speed issues.
Quite possibly the motor/idler assembly is incorrectly serviced and causing issues.... backyard mechanics always do this.

Another thing to understand is that these mass-produced players are not High Fidelity units with exacting precision - people who bought them were not expecting, nor paying for such quality, and many were slightly off-speed by design.

No, there is no outboard speed control solution for these things.
If you want precise accurate speeds, invest in a higher-quality machine is my advice.

MattTech wrote:Indeed there IS a "defect" since the speed is off as you say.
Though I'm an experienced technician of these things, I cannot accurately troubleshoot something that is not on my workbench.
However most likely the motor mounts are defective by this time or incorrectly installed.
This could allow the motor to sag and be out of alignment causing speed issues.
Quite possibly the motor/idler assembly is incorrectly serviced and causing issues.... backyard mechanics always do this.

Another thing to understand is that these mass-produced players are not High Fidelity units with exacting precision - people who bought them were not expecting, nor paying for such quality, and many were slightly off-speed by design.

No, there is no outboard speed control solution for these things.
If you want precise accurate speeds, invest in a higher-quality machine is my advice.

Actually, this phonograph WAS a hi-fi, audiophile-level unit back in 1959, and the people who bought them would not have plunked down $200 ($1,500 in today's money) for it if it wasn't. There's a good video on YouTube demonstrating this unit and you can see for yourself how high-quality of a player it is. And the place I took it to get it restored were no "backyard" mechanics - they make their living repairing vintage audio equipment!

That being said, since there's no outboard solution to this, would it be possible to install some kind of audio oscillator in this to control the speed? It would certainly be a weird retrofit but I can only imagine there's some kind of solution for this...otherwise how would people use record players designed for 50 Hz in the US when it runs 60 Hz??

http://www.youtube.com/watch?v=2Wmnqq8U3DM

You're preaching to the choir about High Fidelity.
I own some respectable equipment.

That unit uses a common design V-M (Voice of Music brand) record changer.
Motorola branded it "Golden Voice", and it's mass-produced mediocre machinery compared to high fi..
The best I've seen them, they're always slightly off speed.
Weak 2-pole motors overspeeded to compensate for a heavy stack of records.

I don't need demonstrations - I've seen and serviced plenty of them over the decades to know.

Get a stroboscope and check the speeds - wandering strobe lines forward slightly is tolerable and normal for these machines.

Oh, and lest I forget - that changer uses a dual ring idler, and if it's been ground down by some professional, (dirty fix) it's likely one reason for the speed issue.
The proper repair would be to replace the idler with a quality rebuilt one, as I would.
None of my customers ever complained about speed issues to me.

MattTech wrote:You're preaching to the choir about High Fidelity.
I own some respectable equipment.

That unit uses a common design V-M (Voice of Music brand) record changer.
Motorola branded it "Golden Voice", and it's mass-produced mediocre machinery compared to high fi..
The best I've seen them, they're always slightly off speed.
Weak 2-pole motors overspeeded to compensate for a heavy stack of records.

I don't need demonstrations - I've seen and serviced plenty of them over the decades to know.

Get a stroboscope and check the speeds - wandering strobe lines forward slightly is tolerable and normal for these machines.

Oh, and lest I forget - that changer uses a dual ring idler, and if it's been ground down by some professional, (dirty fix) it's likely one reason for the speed issue.
The proper repair would be to replace the idler with a quality rebuilt one, as I would.
None of my customers ever complained about speed issues to me.

Thanks so much for that helpful advice. As far as the unit being mediocre, I can't comment on that because it's mediocre compared to WHAT?? A Dual from 1984? A Garrard from 1972? A Callaro from 1957? Certainly high-end consumers in 1959 didn't think this was mediocre, so please enlighten me...

I also got a strobe disc to test your hypothesis. The lines do indeed move forward, and after a stack of records is placed on them it slows down just a hair...certainly not enough that your ear would really notice the difference, though - I'm talking only by about 1%, maybe 2% max. And the idler wheel has been replaced since the place I took it to has a whole cabinet full of new and rebuilt idlers for just about every machine you can think of (including VM changers) so there are no issues there. Since it's only a half-step it's still very listenable and is certainly not a deal-breaker for me in the slightest. But I will just have to remember not to tune my guitar to my tuning record on this machine!

If you want a "tunable" unit, go with something with a pitch control, like a Dual, Miracord, Garrard, etc. = high fidelity quality.
Never expect these mass-produced record changers to be able in that department.
As far as "high end consumers" in 1959, they purchased turntables like Rek-o-Kut, Thorens, among other brands, that were capable of satisfying their picky needs.

All-in-one (budget) phonographs were, and only are, for casual listening and convenience.

I do have a Dual 505 turntable that I use for tuning anyway, so that's why I mentioned that the speed shift on the Motorola isn't that big a deal to me. However, if I'm not mistaken, RCA, Motorola and Zenith were the first to offer phonographs (consoles, table models or portables) that were specifically designed for stereo as early as 1958 while Rek-o-Cut, Thorens, etc. didn't introduce their line of stereophonic players until the early 1960s.

If your Thorens had more than one speaker I'm sure you could just get a stereo-compatible cartridge and play the new stereo records that way. But I would think that for the high-end consumer of 1959, a quality player designed for the new, cool stereo records would be very appealing. That would, of course, limit your choices to the three brands previously mentioned. (That could also be why a surprising number of these early Motorola stereo systems sold so well, even with their hefty price tag when there were other mono systems that could have easily been obtained for $125 or less back then and were of the same quality.)

Your original post was a concern about speed issues on a common record player.
I answered as best I can.
I don't undestand your shifting to a whole 'nother subject.
High quality turntables were around years before stereophonic sound was brought to the public.
Studio-quality and home versions, geared towards people with money.

As far as Motorola's popularity, it didn't sell any better or worse than other "home" brands.
it wasn't any better or worse in quality either...... it was just "another brand".
Oh, and RCA Victor basically pioneered consumer products with stereo sound by the way.
While each manufacturer had different "tiers" of quality in their product lines, the plethora of such units that I've seen cannot obtain true "high fidelity" status and never will.
They just weren't designed that way..... even tweaking is limited, and I've done that as well.
What you've got is a typical suitcase portable, certainly worthy of playing records, but not high fidelity, and not "high-end".
That status is tacked on many units as a sales tactic to people who don't understand or know better.

MusicMan93 , this is the reality of consumer grade phonos, especially changers from the 50's -straight through the early 80's when the all electronic tables took over and most had vernier adjustment.

My family got an early KLH portable stereo in fall 1963. It has a full sized Garrard changer that ran faster than the radio station (who always pitched up a bit), In fact the only consumer table that didn't run fast is the Collaro changer in our 1965 Magnavox console. It seemed slow by contrast to everything else.

The first thing to check is to see if a deposit of rubber from the idler puck has formed around the motor shaft, This will increase it's diameter and speed things up. If so, soften it up with alcohol and scrape it off while the motor turns using a plastic card or even your fingernail.

If no rubber deposit:

There is a fix which I have done dozens of times, primarily on Rowe/AMI jukeboxes which ran notoriously fast.

It requires grinding --slightly-- the diameter of the motor shaft.

As follows:

Determine which speed "step" on the motor pulley is the one you want to reduce.

Make a "bib" around the motor shaft out of pieces of masking tape or similar material. The idea is to keep filings out of the motor bearing.

Start motor running and keep the rubber "puck" away from the shaft'

Then you use a fine file help gently against that step in the pulley for no more than a few seconds. use just enough pressure so as to slow the motor a bit.

Next, clean away filings on the pulley, I use alcohol, then free the puck and replace the turntable and use you strobe disk and ears to check your progress.

You should let it run for a minute or so before deciding if it need more filing. the reason is that the puck will slip slightly when it first touches the newly filed surface and in so doing it will deposit a little rubber to add traction thus speeding it up a bit.


You will have to do this procedure several times and I recommend leaving it slightly fast if you are going to ever stack records.

I know what you mean about this being a bit irritating, I grew up going to live classical concerts and later worked in theater as a TD, pitch errors on most consumer stuff is always noticeable to me.

Be careful, good luck.


Rob/NYC

Rob-NYC wrote:MusicMan93 , this is the reality of consumer grade phonos, especially changers from the 50's -straight through the early 80's when the all electronic tables took over and most had vernier adjustment.

My family got an early KLH portable stereo in fall 1963. It has a full sized Garrard changer that ran faster than the radio station (who always pitched up a bit), In fact the only consumer table that didn't run fast is the Collaro changer in our 1965 Magnavox console. It seemed slow by contrast to everything else.

The first thing to check is to see if a deposit of rubber from the idler puck has formed around the motor shaft, This will increase it's diameter and speed things up. If so, soften it up with alcohol and scrape it off while the motor turns using a plastic card or even your fingernail.

If no rubber deposit:

There is a fix which I have done dozens of times, primarily on Rowe/AMI jukeboxes which ran notoriously fast.

It requires grinding --slightly-- the diameter of the motor shaft.

As follows:

Determine which speed "step" on the motor pulley is the one you want to reduce.

Make a "bib" around the motor shaft out of pieces of masking tape or similar material. The idea is to keep filings out of the motor bearing.

Start motor running and keep the rubber "puck" away from the shaft'

Then you use a fine file help gently against that step in the pulley for no more than a few seconds. use just enough pressure so as to slow the motor a bit.

Next, clean away filings on the pulley, I use alcohol, then free the puck and replace the turntable and use you strobe disk and ears to check your progress.

You should let it run for a minute or so before deciding if it need more filing. the reason is that the puck will slip slightly when it first touches the newly filed surface and in so doing it will deposit a little rubber to add traction thus speeding it up a bit.


You will have to do this procedure several times and I recommend leaving it slightly fast if you are going to ever stack records.

I know what you mean about this being a bit irritating, I grew up going to live classical concerts and later worked in theater as a TD, pitch errors on most consumer stuff is always noticeable to me.

Be careful, good luck.


Rob/NYC

Thank you!! This is probably best answer I have received so far as to how I should go about correcting the speed. I think I can find some time this weekend where I can really focus on doing this and getting it right.

Rob, I wouldn't recommend filing down the motor shaft to anyone.
It's too critical and polished to mess with by amateurs, inviting more damage than it's worth.
Just let things be, and accept the fact that these changers are not designed for critical listening.
I've already discussed the aternatives.

Excuse me, but Rob said that this is a solution that works on several different phonographs, and he seems to have the necessary qualifications for making such advice after reading his profile. Even if I don't end up doing that repair myself, I will certainly keep it in mind for if and when I come across something like an old Califone with a speed error, considering it looks like it's damn near impossible to vary the speed on these old AC motors.

Matt, I understand where you are coming from..but, this isn't open-heart surgery -it's a record player.

If the fellow follows instructions, uses common sense and patience, he'll get the results he wants to make the machine more enjoyable.

Rob

Every 2-pole V-M changer made in the 1950s and 1960s I have ever repaired or used has run fast. When I repaired them, I always checked the speed with a stroboscope. The speed was always 1 or 2 % fast with one record, but 1 or 2 % slow with eight 12" 78s. The 2-pole Webcor and Philco changers behaved similarly.

The 4-pole V-M changers were somewhat better, saying within 1 %. But they were rare (I once had one).

The only consoles I ever found with exact speed were:

- Magnavox consoles with Collaro changers made after 1962 with their combo induction and synchronous motor (4 years before Garrard had this)

- Rare ones with Garrard, Dual, or Miracord changers made in the 1960s or 1970s

I have built speed controls for record changers that run fast. The black knob in the upper left corner of my avatar is one of these.

I use a 25 ohm 20 watt rheostat and a 3-amp 600V silicon rectifier connected in parallel. This assembly is connected between the power switch and the motor. It introduces a DC component into the motor that slows it down. Adjust it for exact speed.

But on a two pole motor, the motor does not have enough power to run a V-M change cycle with the speed control connected. Adding an extra leaf to the muting switch to short out the speed control during the change cycle fixed this. But it slows down even more with a heavy record stack.