My father recently gave me several family audio recordings.  These
were recorded in the late 1960's or early 1970's on a consumer
reel-to-reel magnetic tape recorder.  They mostly contain voice
discussion (with a few painful episodes of bad singing).

I want to extract the recordings, and digitize them onto my PC for
safe keeping.

Unfortunately, the tape recorder these tapes were recorded on no
longer works reliably.  I was considering purchasing a used tape
player, but I know nothing about tape formats, so I don't know what
players might be compatible, cautions, etc.

So, before I do anything, I wanted to have someone get me oriented.  I
have four questions:

(1) Format Identification --- Is it possible to surmise the likely
magnetic tape format, so I can buy a replacement tape player on EBay,
etc?  Here's what I know:
  * The tape appears to be 1/4" wide in a 3.25" diameter spool.
  * The recorder was a PHILCO solid-state recorder and has a switch
for 3 3/4 and 1 7/8 tape speeds, but no obvious switch for
mono/stereo.
  * Tape spools have a spindle diameter around 5/16" and three
diagonal slots spaced 60 degrees apart from each other
  * I have photographs of the recorder I can send if it helps (I can't
see a way to attach photos to this question).

What is the likely format?
Should I assume 1 track on the A side, and 1 on the B side?
How would I describe this format to someone else, so they properly
understood the type of tape format?

(2) Compatibility --- What are the odds that a tape recorded on this
recorder would play on another player from the same era that looked
similar?  Would the recorder alignments/etc. be too different to allow
proper playback?

(3) Transfer Advice --- What is smart general advice about doing
tape->PC transfer of vintage home audio tapes?  I was just going to
connect a player to my sound card input jack and record it, but are
there better ways?

(4) Restoration --- Is there software available that can clean up the
tape speed warbling, noise, etc.?  Are there professional firms that
can do this restoration?

Firstly I am no expert nor am I a google researcher but I did used to
have a similar recorder (In fact several) so am failry certain of this
advice:
The recorder is almost certainly mono - stereo ones were quite rare in
those days.
Everything you describe sounds competely standard and most machines
should play the tapes - even stereo machines as these can playback
mono tapes. Tapes and tape machine swere designed to interchange with
each other, even then. One exception: the tapes could have been
recorded at either of the selected speeds - although at the slower
speed the quality would be fairly poor. Ok for speech but not ideal
for music. Nevertheless you must get hold of a machine that runs at
either speed just in case. Not every tape machine will run at the
slower of the two speeds.

As for head alignement, a properly adjusted machine should play the
tapes ok - but if required, adjustment is usually straightforward - a
couple of screws on the tape head. Try tweaking them very slightly as
the machine plays and see if it improves the sound quality.

Warbling - was not as bad on reel to reel as you would get on an old
cassette machine. Cleaning the pinch rollers works wonders.
Have a look at this, it may help:
http://www.dantiques.com/tapedecks/1965catalog/index.htm

Don't sue me if everything above is off the mark!

playitagainsam, thanks for the comment.  I suspect you're right on the mark.

Hey, thanks for taking the time to share this info!