several incorrect statements in Don Nichols review of phonograph technology

on older wind up units, the failure I have seen most often is hardened
grease - it won't work because it's all glued togethr - clean and it's fine

on tube units, most common failure is one or more capacitors,



"DoN. Nichols" wrote in message
...
On 2010-09-25, Ignoramus10035 wrote:
Today...

Bought a pintle hook adapter for $5, similar to this:


http://www.amazon.com/Buyers-Pintle-.../dp/B0000AX57E

I needed it badly to tow that M105A2 that I won in the miiltary
auction. Very happy about it.

K.O. Lee valve grinder for $40, like this:

http://ef.algebra.com/e/360254563637

but with a big box and a bunch of accessories.

Super old phonograph with some kids music included for $15. This might
not work and I may need to throw it out.

Depends on what you mean by "super old".

If it is old enough, the most likely failure will be the spring which
drives the turntable. (Wind up style.) The other thing is you will
need some consumables (needles -- cactus needles work nicely -- steel
ones have to be replaced more often or they start to grind away the
music from the grooves. Of course this is purely deadly to stereo
recordings. :-) But the playback is purely acoustic -- no electronics or
electrics. Be warned -- the spring is a flat clock spring type, but 1"
wide and thick -- a killer if it gets loose. Usually, the failure is
where it hooks to either the center shaft or the outer cage, and it is
possible to make a new hole at the cost of some play time by shortening
the spring.

Later -- you would find electric motors turning the turntable,
but still an acoustic playback unit -- especially on kid's phonographs.
Most likely failure here is the rubber tire which transfers motion from
the motor shaft to the inner rim of the turntable.

Then we get to electric motors and tube amplifiers. Tubes are
the major failure mode here. Needles get a bit fancier -- but are only
sometimes called "styli".

Then to solid state amplifiers. Back to the needle/stylus and
the drive rubber as the most likely failure modes.

There is *one* out there somewhere -- built from a kid's
portable phonograph to demonstrate a flexible mosfet power transistor
printed on a mylar film. Full power for the amplifier was a single
1-1/2 V D cell. The speaker and the cartridge were hooked directly to
the power mosfet.

It was stolen from the research scientist's car, and he looked
forward to the time the battery died and the thief took it in for
repair, and the repairman would say "You have *got* to be kidding me.
You say this worked?" :-)

Then ones new enough so you are unlikely to be calling them
"very old", so I won't mention them.

Enjoy,
DoN.

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