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 Post subject: Shure P90B Crystal Cartridge Replacement Options
PostPosted: Nov Thu 09, 2017 4:02 am 
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Joined: Jan Mon 18, 2016 5:49 pm
Posts: 53
Location: Cedar Falls, Iowa
I'm repairing a Philco 47-1227 radio / phonograph console and while the radio has been recapped and is working fine, I'm having a heck of a time with the phonograph (which only plays at 78 rpm and therefore only plays 78's).

The cartridge on the tonearm is a Shure P90B crystal cartridge. The needle was broken off.

Attachment:
ShureP90B.jpg
ShureP90B.jpg [ 151.04 KiB | Viewed 364 times ]


As I understand it, this model cartridge had a built in needle that was not interchangeable like other cartridges. So I began looking for replacement cartridges.

Luckily, there is a replacement manual online that offers many options.
Shure W58A
Astatic L-22A, L-25A, L-27A, L-32A, L-41A, L-70, L-71, L-75, L-76
Webster E4, E9, F2P, F4P, F6P, GX-82, N1-N, N2, N3, N4, N6, N7, N8, N9, N10, N11P, X-82, Y-82

These are all near impossible to find at reasonable prices - Does anyone know of anywhere to find these? Also, as I understand it, even getting an NOS cartridge doesn't guarantee that it will still be working. I found an NOS Webster Q3 at a local vintage electronics store which I installed and tried - but it was DOA.

An alternate idea: Can a modern cartridge be used? I understand the original cartridge has an output of 1.6v - while a modern cartridge like the Shure M78S outputs 0.004v. Could one insert a preamp in between the cartridge and the phono input on the Philco console?

I have seen instructions on how to "rebuild" the crystal cartridge with a piezo element- but I'm a little leery of this. Has anyone done it successfully?


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 Post subject: Re: Shure P90B Crystal Cartridge Replacement Options
PostPosted: Nov Thu 09, 2017 4:38 am 
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Joined: Jan Wed 16, 2013 12:04 am
Posts: 1084
Location: 77001
There are some relatively high output ceramic
carts that are still available.
Sonotone 2-T, Astatic (Powerpoint) 81/89T, E-V 76 (Powerpoint) , E-V 154 (crystal) e.g.
(Edit: you will need to also find the mounting bracket for the 81/89T or E-V 76)

Gary at thevoiceofmusic .com guarantees the nos crystal
carts. Best prices, too.

You will have to modify how the new cartridge is mounted
in the tonearm.
This is done routinely for the 45 RPM record players from
the late 1940's to 1950's.
Some folks keep 1/2 of the old crystal cartridge shell as a mounting
frame to epoxy the new cartridge onto.
One thing that may be a problem is that your Shure cart had
a fairly heavy tracking force. Not sure if a lighter tracking cart
will let the tonearm trip at the end of a 78 record correctly.


Search for threads on the piezo rebuild here on ARF and you tube.
Hotwax


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 Post subject: Re: Shure P90B Crystal Cartridge Replacement Options
PostPosted: Nov Thu 09, 2017 5:19 am 
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Joined: Apr Mon 04, 2011 4:23 am
Posts: 440
Location: SW PA
There's no way a Shure M78S would work in that heavy of an arm. The maximum tracking force is only 3 grams. They aren't even that great in a modern turntable when playing warped or off center records.


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 Post subject: Re: Shure P90B Crystal Cartridge Replacement Options
PostPosted: Nov Thu 09, 2017 6:09 am 
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Joined: Jan Mon 18, 2016 5:49 pm
Posts: 53
Location: Cedar Falls, Iowa
beat_truck wrote:
There's no way a Shure M78S would work in that heavy of an arm. The maximum tracking force is only 3 grams.


Yeah, min needle force on the Shure cart is 1 oz - about 28-29 g!

Do you think an old stock ceramic cartridge might work? They require tracking force of 8-10g - perhaps with a lil' counterweight? ^_^

Otherwise - looks like I find an old stock crystal cartridge that works or attempt to rebuild this one.


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 Post subject: Re: Shure P90B Crystal Cartridge Replacement Options
PostPosted: Nov Fri 10, 2017 3:46 pm 
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Joined: Aug Sun 23, 2015 6:01 pm
Posts: 531
Location: South Jersey East of Philly
Quote:
looks like I find an old stock crystal cartridge that works or attempt to rebuild this one.

Chances are 99.9% a NOS cartridge will be dead. If you want to stay original, send it to West-Tech for rebuild, if they can do that one. Runs about $50-$60.


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 Post subject: Re: Shure P90B Crystal Cartridge Replacement Options
PostPosted: Nov Mon 13, 2017 6:19 am 
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Joined: Jan Mon 18, 2016 5:49 pm
Posts: 53
Location: Cedar Falls, Iowa
Tbirdkid wrote:
Quote:
looks like I find an old stock crystal cartridge that works or attempt to rebuild this one.

Chances are 99.9% a NOS cartridge will be dead. If you want to stay original, send it to West-Tech for rebuild, if they can do that one. Runs about $50-$60.


Thanks - I will check West-Tech out.


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