Revox B-710 repair: faulty rewind

Archived from groups: rec.audio.tech (More info?)

"Max" <maxrf@telus.net> wrote in message
news:c183f680.0505020133.3bdb38af@posting.google.com...
> Hello,
> My Revox B-710 cassette deck has a problem with rewinding. From the
> end of a tape ,it will start out fine, but when it is almost at the
> beginning, it stops. Pressing rewind again will start it but it will
> keep in stopping after a few seconds of rewinding, or at the beginning
> of the tape. Fast-forward and play do not have this issue, only
> rewind. Sometimes it will even finish rewinding a whole side on its
> own. I have not opened up this unit yet, (I have a CD-ROM service
> manual on the way from www.beersoft.de in Switzerland (I have their
> Revox A-77 & B-77 manuals)), but if someone knowledgeable knows of
> this problem or can point me in the right direction, that would be of
> great help.
> Thanks and Cheers, Max.

Is this something it has always done, or has it just started to do this ?
If it has not always done this then clearly it is a problem, and I do not
know the answer. However, if it has always done it then perhaps what it is
doing is stopping at the start of each song. The rewind in the tape deck in
my car does this, and I thought there was something wrong with it or that my
tapes were getting tangled, since I had to keep pressing the rewind button
to completely rewind a tape. Then I noticed it always stopped at the start
of a song, and sure enough that is the way it was designed.

This may have nothing to do with your particular problem, but I mention it
just in case.

Archived from groups: rec.audio.tech (More info?)

"Chuck" <ch@deja.net> wrote in message
news:u8oc71d4gtb97eqbii8v3pg7uqfmgf5aj9@4ax.com...
> On Mon, 2 May 2005 09:11:48 -0400, "Robert McLean"
> <robert.mclean1@sympatico.ca> wrote:
>
> >
> >"Max" <maxrf@telus.net> wrote in message
> >news:c183f680.0505020133.3bdb38af@posting.google.com...
> >> Hello,
> >> My Revox B-710 cassette deck has a problem with rewinding. From the
> >> end of a tape ,it will start out fine, but when it is almost at the
> >> beginning, it stops. Pressing rewind again will start it but it will
> >> keep in stopping after a few seconds of rewinding, or at the beginning
> >> of the tape. Fast-forward and play do not have this issue, only
> >> rewind. Sometimes it will even finish rewinding a whole side on its
> >> own. I have not opened up this unit yet, (I have a CD-ROM service
> >> manual on the way from www.beersoft.de in Switzerland (I have their
> >> Revox A-77 & B-77 manuals)), but if someone knowledgeable knows of
> >> this problem or can point me in the right direction, that would be of
> >> great help.
> >> Thanks and Cheers, Max.
> >
> >Is this something it has always done, or has it just started to do this ?
> >If it has not always done this then clearly it is a problem, and I do not
> >know the answer. However, if it has always done it then perhaps what it
is
> >doing is stopping at the start of each song. The rewind in the tape deck
in
> >my car does this, and I thought there was something wrong with it or that
my
> >tapes were getting tangled, since I had to keep pressing the rewind
button
> >to completely rewind a tape. Then I noticed it always stopped at the
start
> >of a song, and sure enough that is the way it was designed.
> >
> >This may have nothing to do with your particular problem, but I mention
it
> >just in case.
>
>
>
> These decks have a chuck on the reel tables that loosen up from the
> motor shaft. I can't remember if they can be tightened or have to be
> replaced. I hope someone else who used to repair these remembers.
> Chuck
I've got a B710 Mk2 and mine had exactly the same problem but in reverse. If
I wanted to wind from beginning to end (so that I could turn the tape over
and be ready to go from the start) it would stop about 90% through. Each
touch on the rewind button made it wind on for about 10 seconds & then stop.
This repeated each time you did this.
The fix - I talked to the Revox service guru at Syntec in Sydney, Australia
( a guy called Brian Murphy , who has since retired) and he told me the
likely cause was the two small spooling motors. The bearings in these are
bronze bushes and over time, they wear oval and create a lot of drag,
especially when they are under load. He told me to replace the bearings. I
replaced mine with ball race types which I got from a local engineering
outlet and they were only about US$8 each - you'll need 4 of them for the
front & rear bearings in each motor. They were a push fit into the existing
housings. Getting the motors apart was a tricky job as you are dealing with
precision micro engineering. Time and patience are the key....
I also replaced the spooling tables as the originals were loose. The later
ones have a locking collar whereas the early ones were a friction fit.
End result was no more stalling on rewind. You may want to try this -
alternatively, talk to the Revox agent in Tenesseee? I think they are called
J & M Technical Arts.