VM 1245 for my Motorola SK-111 console

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stbasil
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VM 1245 for my Motorola SK-111 console

Post: # 24268Post stbasil »

When I first tried to crank up this beauty, it had what I have learned are the typical problems. The cartridge, a Sonotone 9T was present, but loose and missing a stylus. I held off ordering that until I made sure I didn't need to order anything else. A basic service video by Jordan Pier was my guide: https://www.youtube.com/watch?v=B-HqO_m ... JordanPier

After accomplishing that work, it still had issues. For one, the turntable would stall or slow down during a cycle. I found that the 10" sensor leaf spring was bent and dragging a bit on the changer base, but after fixing that, stall was still present.
10 inch sensor leaf spring
10 inch sensor leaf spring
10 inch sensor.jpg (33.58 KiB) Viewed 689 times
The rubber on the idler wheel, though having a small dent, didn't seem to be too hardened, so I thought maybe it's tension spring was too weak. Even after cleaning the wheel and inside the platter with alcohol, and even acetone, it still stalled. After reading up on methods of refurbishing the idler wheel, I thought I would try reconditioning the rubber before resorting to turning it on a lathe (still might do that at some point). I found this video which described using wintergreen essential oil mixed with isopropyl alcohol: https://www.youtube.com/watch?v=G7w-AkZ ... %27sCloset

It worked! I soaked for about 2 days, cleaned off the wheel with acetone, and put it back on. I have run it for several hours, and the dent seems to have reduced itself, and, no stalling! That has been over a week ago, and the changer still runs without stalling, and is totally silent.
idler before
idler before
dented idler.jpg (35.57 KiB) Viewed 689 times
Idler after
Idler after
idler-mount.jpg (67.67 KiB) Viewed 689 times
I'm sure the small dent has some effect, but I think after running it for a longer time, it will slowly go away. If not, I can always mount the idler in a lathe and shave it down a little. Interestingly, in this design, the size of the idler will not affect the speed of the turntable (not my determination, but found that out after reading up on it). Here is the result of an RPM measurement app, it shows it running a little slow, not sure how to judge that wow measurement, but it sounds OK to me on piano music :
RPM
RPM
RPM.png (14.76 KiB) Viewed 689 times
The motor mounts were in worse shape than I realized, which was contributing to the poor contact with the motor spindle. Unfortunately, I had already ordered the new stylus from Gary, and I did not want to place a $3 order and pay postage for new mounts! So, I put a steel washer on the top of each mount to take up the slack, the mounts are still pliable enough apparently, since things are working as expected. You can see one of the washers underneath the clip in the "after" idler wheel picture above.

Finally, from the topside, I had to drop a little clock oil into the 12" sensor pivot, and the record stabilizer shaft to let it drop down all the way (it was not sensing that the record had dropped). Also, I squirted a little WD40 in the tone arm pivots and all those black lever thingies at the tone arm base since I did not take that all apart earlier. The changer works like a champ!
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William
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Re: VM 1245 for my Motorola SK-111 console

Post: # 24270Post William »

It sounds like you bought some time but eventually you really should replace the 3 motor mounts and the idler wheel. I work on enough VM changers that I keep a few sets of motor mounts handy just so I have them when I need them and I am not waiting for an order from Gary. The other thing that I would suggest is the next time you order something from Gary ask him to send you the VM lube information. It tells and shows where VM really wants the lube and not where we think it should go. I am just finishing up a VM1245 and I swear this one someone previously lube it with 50 weight oil and tar, it was a gummed up mess. It also has a Euphonics cartridge that is junk so at some point I will need to order a replacement. No hurry, it is one of my changers so I will order it the next time I order parts from Gary.

Bill
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Re: VM 1245 for my Motorola SK-111 console

Post: # 24272Post electra225 »

What Bill said. Been there, done that. Kluges never work very long. Bill tried to tell ME when I started working on changers, yet I tried short cuts. New drive tires and motor mounts are the only long-term cures for stalling. Digging the changer back out of a done instrument to fix it right is not something you are likely to forget next time. Good luck.... ;) ;)
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Re: VM 1245 for my Motorola SK-111 console

Post: # 24273Post TC Chris »

I have found that the easiest way to improve a used idler wheel is to use an appropriately-sized axle--nail, etc.-- and then hold the idler against a moving sanding surface like a sanding disc or belt. If you rotate the axle slightly so it's not just rolling with the abrasive surface, but "skidding" slightly, you will abrade the surface rubber evenly. This will work on glazed surfaces. If the rubber is petrified or cracked badly, nothing is going to do much good for it.

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Re: VM 1245 for my Motorola SK-111 console

Post: # 24277Post stbasil »

Yeah, I'm buying time, but really, it's for personal use, and if I do have to pull it out in a few months or years, it would not be a problem, especially if I start doing more of this as a hobby!
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Re: VM 1245 for my Motorola SK-111 console

Post: # 24600Post hermitcrab »

Ah yes ... the bane of all VM changers... the idler wheel .... wintergreen and alcohol does give you a temporary fix but it will harden up again... but I can't blame you ... with the increase in prices for them and if it will be mostly a shelf queen, the price is not worth the repair ... I have been messing around with the 3D printer and made one with a rubber O ring to drive the platter, and it works ... but all I have is PLA plastic, I guess the better stuff for an application like this would be the PET plastic ... still experimenting ...
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Re: VM 1245 for my Motorola SK-111 console

Post: # 24602Post hermitcrab »

here is a pic of my homemade printed idler
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Idler wheel

Post: # 24603Post stbasil »

Yep, the wintergreen trick doesn't last very long. The dent never worked itself out, probably was burned in, and it was evident by a regular thumping in the bass. I removed the wheel and noticed that it was hardening up again, but it still ran without slipping. I sanded down the dent with a flat piece of 220 grit sandpaper by mounting the wheel in a drill press, making sure it ran true. Also cleaned the motor spindle steps with emory paper. No more thumping; the speed and wow/flutter is still good.

Neat trick using a 3D printer! I guess you intend it as a low-hours part, since the "bearing" is just a hole in the plastic (unless you figured out how to put a brass insert in!)
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Re: VM 1245 for my Motorola SK-111 console

Post: # 24604Post William »

3D printers sound cool, i would love to watch one work sometime.

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Re: VM 1245 for my Motorola SK-111 console

Post: # 24606Post TC Chris »

I have an old Lenco turntable, the device with continuously-variable speed and an idler that runs vertically under the platter. The rubber was beyond salvation. I peeled it off and substituted an O-ring. It worked especially well in this application because the Lenco idler used an inverted-V rubber tire. Bottom line: if possible, use an O-ring.

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Re: Idler wheel

Post: # 24628Post hermitcrab »

stbasil wrote: Sat Jan 18, 2025 5:12 pm Yep, the wintergreen trick doesn't last very long. The dent never worked itself out, probably was burned in, and it was evident by a regular thumping in the bass. I removed the wheel and noticed that it was hardening up again, but it still ran without slipping. I sanded down the dent with a flat piece of 220 grit sandpaper by mounting the wheel in a drill press, making sure it ran true. Also cleaned the motor spindle steps with emory paper. No more thumping; the speed and wow/flutter is still good.

Neat trick using a 3D printer! I guess you intend it as a low-hours part, since the "bearing" is just a hole in the plastic (unless you figured out how to put a brass insert in!)
PET plastic is supposedly made for rough applications... supposed to be of the same type of plastic they made gears out of for VCR's transports ... but I think a brass insert would be easy enough to make for a plastic idler... I am a long way from giving Gary @ VM any competition on them... :D
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Re: VM 1245 for my Motorola SK-111 console

Post: # 24629Post hermitcrab »

William wrote: Sat Jan 18, 2025 5:15 pm 3D printers sound cool, i would love to watch one work sometime.

Bill
They are cool.... when they work right... setting them up to print is a exercise in patience .... the plastic injector nozzle has to be perfect across the whole hotbed about .01mm or the thickness of an ordinary sheet of paper , or the foundation layer will not stick to the hotbed and it will fail... then you have to find tune the temps of the plastic and the hotbed usually the nozzle is 200 C or around 390 F ... hotbed is around 60 C or about 140 F ...since the printer is in the basement , the temps are below 70, so I have an enclosure to retain the heat , otherwise jobs will not stick to the bed , they are that finicky ... basically a 3D printer is a fancy hot glue gun, but uses plastic instead of glue , I was given mine from my son... glad I didn't buy it... a few times of trying to get it to print right I got so frustrated I felt like reenacting the scene out of office space with the fax machine and a baseball bat in the field ... :lol:
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Re: VM 1245 for my Motorola SK-111 console

Post: # 24631Post hermitcrab »

here is an example of when the printer works.... and when it doesn't .....printed up some reels for the R2R... some came out great ... others not so much, the half reel is an example of when the foundation layer fails to stick to the bed... also the box in the picture failed right at the end of the print which takes about 3.5 hours :evil: ....
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Re: VM 1245 for my Motorola SK-111 console

Post: # 24633Post William »

Not sure I would have the patience for that, I barely have the patience for this hobby.

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45 Adapter clean-up

Post: # 24765Post stbasil »

When started to clean up the 45 adapter, I used lacquer thinner which removed the very scratched-up gold paint, revealing nice shiny metal underneath! So, I applied some wax and it looks like it matches the rest of the silver stuff on the changer! So far, it still looks good, so I'm hoping it won't rust.
45 adapter.jpg
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Re: VM 1245 for my Motorola SK-111 console

Post: # 24772Post TC Chris »

Probably pot metal of some sort, non-ferrous.

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New motor mounts make a huge difference in LF turntable noise!

Post: # 24995Post stbasil »

So I was making a video of the finished Motorola SK-111 and when listening to the video, I could hear a low frequency hum immediately when the needle landed in the starting groove and before the music (loud drums) began. This was especially noticeable due to a "boomy" sound track on the video, due I suppose to the room acoustics and the unidirectional characteristics of the phone's mic.

I figured it was due to the poor isolation of motor noise from the changer chassis due to the hardened mounts. My kludge described above fixed the instability of the motor, but made the mounts even less effective in isolation. :oops:

So I immediately ordered replacements from Gary, and after a quick swap, the noise disappeared! Lesson learned!
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Re: VM 1245 for my Motorola SK-111 console

Post: # 25001Post William »

Idler wheels and motor mounts are a must if one wants it to work like the factory had intended. Sometimes you can get away without replacing the idler, but motor mounts not so much.

Bill
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