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| from page 37 of the 1960 Radio Shack Catalog |
The Realistic Mark 8 improved upon the similar looking "motor unit-stye" Mark 7 in Part 4 of this series by adding a 16 rpm speed and supplying a half pound heavier cast aluminum platter.
I bought this Lafayette PK300 idler-driven turntable because it looked like an improved Shield MO-19 (aka NEAT P58H) with the added feature of an eddy current pitch control as found in the Garrard 301/401 and Thorens TD124.
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| Shield MO-19 vs. Lafayette PK300 |
Comparing them side by side, the PK300 turned out to be proportionately smaller in all dimensions and lighter in weight. Hmmm🤔…let's travel back to the late 50s.
This turntable/tonearm combination has been in my collection for over twenty years. I wired the tonearm for stereo because I particularly enjoy using it with the Shure M3D and M7D.
I couldn't find this in any of the Radio Shack Catalogs issued from the late 50s to the early 60s unless it escaped my tired, old eyes.
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| from page 2 of the 1957 Radio Shack Sale Flyer |
However, the A-3 tonearm, which is essentially a Calrad SV12/Musicmaster Model 12/Velvet Touch sibling, was featured in the 1957 sale flyer above.
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| from page 4 of the 1958 Radio Shack Sale Flyer |
This is the Mark 7 turntable recorded in the Radio Shack Catalog Vault.
Based on the shape of the chassis, this Mark 7 is perhaps the younger of the two since it looks very similar to the succeeding Mark 8, which I will discuss in a future installment.
Although not quite as heavy and massive as a QRK or Russco, the cast aluminum chassis is very rigid on both units. The earlier MK7 chassis above is configured to accommodate a 9"-10" tonearm, while the later MK7 below was designed as a "motor unit" like the Garrard 301 and 401.
The speed selector linkage to the idler wheel in both are similar, but due to a slight difference in the motor mounting layout, the idler arm and idler wheels are not interchangeable.
Except for the paint color, this hysteresis motor is exactly the same unit fitted to my NEAT P58H, which I covered in Part 2 of this series. Click here for motor servicing information.
The main bearing is an oil lubricated design, which supports a 3-lb. cast aluminum platter.
Before moving on, the younger MK7 depicted above had a serious issue - the motor has a bent rotor spindle!😔 Will I be able to save it by adapting the motor from another Lafayette PK245 (don't ask my wife how many turntables I own 😆) with a warped platter?🤔
While planning the motor transplant, I examined the MK7 idler wheel condition and decided it might be worth rejuvenating.
So I mounted it on a handheld drill, deglazed the rolling surface with 400 grit sandpaper, and soaked it in brake fluid for over a week. This was suggested to me decades ago by a kind soul who visited the Rek-O-Kut Tips page in my old website. It has worked with two other Japanese idler wheels but I've never tried it on a Lenco or Rek O Kut. Back in those days, it was more convenient to just send Lenco and ROK wheels to Ed Crockett, RIP 😞 or Terry Witt 👍, who's still catering to the needs of audio DIYers.
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| The above idler wheel was resurfaced by Gary of VoM. 👍 |
Even if the rubber motor mounts were still supple, I replaced them with springs. A nice lesson I learned from servicing my NEAT P58H.
To my ears, the spring mounted motor + 8 mm ball bearing/nylon countersunk washer thrust pad help lower the noise floor.
Realistic Mark 7 stepped pulley specs
I have a close affinity for the Mark-7 + A3 since this was the very first Japanese idler-driven turntable I acquired.
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| Page 12 of the 1958 Lafayette Radio Catalog |
...and 1/2" x 0.72" 302 stainless steel springs 😊 from Grainger. IIRC, it was part number 1NDJ1.🤔
After further listening tests, I determined that the rubber shock mounts used in the Gray Research turntable were better suited to this design. They can be sourced from Surplus Sales of Nebraska, part number RPS 426-0001.
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Happy tinkering and listening!
Its performance exceeded my expectations! So instead of relegating it exclusively for mono hifi playback duties, I also enjoy using it fitted with high quality tonearms like the Audio-Technica AT1501-II, Denon DA305, Grace G540L, Fidelity Research FR54 and others for stereo LPs.
I got this NEAT P58H + Tokyo Sound ST900 tonearm when Tish and I returned to the States in 2016. It wasn't as well kept as the MO-19 and required a bit more fettling.
The turntable is built on a heavy duty cast chassis with a 1.5 kg cast aluminum platter. Aside from a few discussions in audio forums, the only literature I've found about this particular model is the 1960 NEAT catalog available for download at vinylengine.com.
Everything I've done to my NEAT P58H and Shield MO-19 is documented below.
The rubber on this NEAT P58H idler wheel was in good condition except for a pinch, which couldn't be removed by minor grinding. So I sent it to Terry E. Witt for new rubber.
Terry of Terry's Rubber Rollers did a great job rejuvenating the P58H idler wheel (above left) + another wheel for my ROK L34 Rondine Jr.
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| Idler wheel installation sequence |
The idler wheel should spin freely and quietly after a drop or two of blue 3-In-One SAE 20 motor oil.
Idler arm reassembly sequence
The idler wheel arm action should be snappy. If it isn't, back off the nut a bit and/or add a bit of light oil to the sliding surfaces.
A good balance between speed accuracy, torque, and low noise can be achieved by adjusting the idler wheel contact pressure to the inner rim of the platter.
While the turntable is disconnected from the AC source and the speed selector set at 33 rpm, I set a 1-1.5mm clearance so that the idler wheel doesn't touch the shoulder of the 45 rpm step.
With the speed selector at the 78 rpm setting, make sure there's no clearance between the tip of the set screw and the piston which raises and lowers the idler wheel arm mechanism.
Before we move on, how about a track from Style Council?
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The turntable is powered by a fairly substantial 4-pole hysteresis synchronous motor.
It's not as hefty as American-made Ashlands and Bodines, but bigger than the TD124's E50 and comparable to those fitted to the Garrard 301, 401, and the ROK B12GH's Papst Aussenläufer.
Through the years I've gotten requests for a schematic because some of these turntables were hastily pulled out of installations by flippers for quick bucks on eBay.
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| Top view of the motor + sub-chassis |
The deteriorated bottom rubber mounts (red arrows) can be replaced with rubber grommets.
To remove the motor, unsolder the motor wires from their respective connections. Use my hand drawn schematic above as a guide. Then, remove the four nuts marked with blue arrows.
Before pulling out the motor entirely, I marked its orientation (black arrows) in the sub-chassis for easier reassembly.
Motor parts ID
The top and bottom shells house the sintered bearing well and are almost identical in construction except for an exit hole on top for the motor spindle. I marked the partially visible sintered bearings (or bushings) with blue arrows. To access the bearings for cleaning, remove the spring clips marked with green arrows.
To access the motor bearing, remove the bottom cover, which is held by three small screws + lock washers. Be careful not to lose the tiny 3mm ball bearing. Clean all the components with either Naphtha or IPA. The numbers indicate the sequence for reassembly.
The motor should now be whisper quiet in operation.
Let's take a break and hear a tune from Sinatra at the Sands LP.
These are the main bearing components after cleaning (soaked in solvent overnight). They're ready for fresh grease and reassembly. I used Phil Wood grease left over from my Raleigh 20 restomod folding bike project.
The Garrard 301 grease bearing makes the NEAT P58H bearing look diminutive.
Although innovative in its own right, the various pictures show that the mechanical design and manufacturing quality of the NEAT P58H/Shield MO-19 isn't quite as sophisticated as the illustrious Garrard 301, 401, or Thorens TD124. I never envisioned it to equal those revered models in terms of performance. However, IMHO and experience, a reconditioned NEAT P58H is a worthy alternative to a restored Lenco or Rek O Kut.
