Troubleshooting Steelman 3RP6U phonograph

Electrically amplified phonographs or radio/phonographs and related components (approx. 1928-1990).


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newshirt
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Troubleshooting Steelman 3RP6U phonograph

by newshirt » Fri Apr 18, 2014 4:30 am

My "new" Steelman 3RP6U phonograph does not produce sound from the stylus. (See attached photos) Fortunately, the built-in AM radio works so I know the amp and speakers are good.

Here is what I have tried so far: (All very gently and deliberately)
1. Replaced the stylus with a "Astatic T Stylus" from Needle Doctor. Didn't help.
2. Replaced the stylus with a steel needle from a Victrola. Don't laugh. Didn't help.
3. Measured the resistance of the cartridge leads with an ohmmeter. Open circuit. Infinite ohms.
4. Replaced cartridge with modern microphone to see if I could get any sound. None.
5. Touched the cartridge wires with my finger. Static is produced in the speaker!
6. Dragged my finger over the stylus. Static is sometimes produced in the speaker!

My conclusion is that the cartridge is bad. If so... can I...

1. Buy another original exactly like this?
2. Carefully grind off the rivets and repair it?
3. Find an ugly substitute? (Needle Doc says no.)
4. Rig something up to test the circuitry? (Like a modern mic???)

Thanks in advance! And any misc info about this model is greatly appreciated!!!
Attachments
cartridge side.jpg
Side view
cartridge side.jpg (93.23 KiB) Viewed 679 times
cartridge bottom.jpg
Cartridge
cartridge bottom.jpg (114.03 KiB) Viewed 679 times
cartridge underside.jpg
Under the tone arm
cartridge underside.jpg (190.75 KiB) Viewed 679 times
steelman.jpg
Steelman 3RP6U
steelman.jpg (163.56 KiB) Viewed 679 times
Ray White


Ron Rich
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Re: Troubleshooting Steelman 3RP6U phonograph

by Ron Rich » Fri Apr 18, 2014 4:49 am

Ray,
Try contacting Ed Crockett at Vintage Electronics 601 264-4755 M-Friday -- 8 to 5PM CT only.
He will most likely be able to solve this problem. Ron Rich


Rob-NYC
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Re: Troubleshooting Steelman 3RP6U phonograph

by Rob-NYC » Fri Apr 18, 2014 9:15 am

Pardon my emphasis but...UGH! If you value your records..even 78's do NOT attempt to reuse that grinder of a tonearm.

At the very least replace that cart with something slightly less destructive.

Check the mounting hole spacing. If they are 1/2 in you can use a variety of newer ceramic carts.

The poster below had suggested this: http://all-unique.com/califone-0291-rep ... p-251.html as replacement in his Califone and I could see this as viable in your case. it is stereo so you will need to connect the channels in parallel and modern ceramics have lower output than that ancient crystal cart, so you'll turn the phono up a bit more. But the sound is better and won't ruin your records as quickly.

If that is not doable you might consider a "new" arm similar to this:

http://www.ebay.com/itm/Vintage-Record- ... 1272726785 Though any old arm will probably still need a new cart.

It might also be necessary to replace a capacitor or two in the 'amplifier" for safe operation.

As for connecting a mic, the original cart has an output on the order of 2 volts. A mic will typically be minus 55-60db or around 5 millivolts. A preamp is needed.

Rob/NYC
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Record-changer
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Re: Troubleshooting Steelman 3RP6U phonograph

by Record-changer » Mon Apr 21, 2014 9:02 pm

That is a crystal cartridge. It has the following properties:

- A good one reads open on an ohmmeter (or tens of millions of ohms).
- It puts out a higher voltage than any modern microphone.
- A modern dynamic microphone would not have a chance of working a crystal phono cartridge input.
- They go bad over time as the crystals absorb water from the air.
- The fact that it males noises sometimes indicates that it has cracked.
- They wear records more than any pickup type except acoustic.
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Re: Troubleshooting Steelman 3RP6U phonograph

by newshirt » Sat May 03, 2014 12:05 am

Got it working!!! Sorry or the delay in responding.

Ed Crockett from Vintage Electronics got me set up with a ceramic cartridge with sapphire needle to replace the old crystal cart. Perfect fit! Nice and loud after the vacuum tubes warm up.

I don't like the modern appearance, but you can only tell when you look under the tone arm.

I wonder if a modern ceramic cartridge could be rigged inside the old crystal case. Blasphemy? Well, I want the vintage look but the modern reliability. Is that possible?

Thanks for all the help!
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cartridge_sm.jpg
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Re: Troubleshooting Steelman 3RP6U phonograph

by Ron Rich » Sat May 03, 2014 1:23 am

Ray,
Glad Ed was able to help ! My "further advise", is "if it ain't broke, don't fizz on it, no more !
Ron Rich

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