since I first encountered "high-end" audio in the early 1970s I was
always impressed by the VERY expensive reel-to-reel tape recorders that
dominated the-best-of-the-best. The quality of the sound recording and
playback exceeded any other media at the time and would continue to do
so until the rise of digital "high resolution audio" around 2010.
1974 while working as a technician in a high-end audio shop, the cost
of such magnificent machines was equivalent to about 6 months wages so
it was not until the late 1980's that I acquired a second hand
machine from a coworker. but I had the chance to work on a few of these
gems on the service bench and to borrow one for field recordings.
December of 2018 I happened to be window shopping on eBay and ran
across a Teac A3300SX-2T up for auction. This model was among the
best and a "master recorder" (used for making the final copy of
studio recordings to go to music production companies). The unit had
spent most of its life in an FM radio station in Virginia (USA)
and was obviously significantly worn. It had also been in cold storage
for years and showed some environment damage but the current bid price
reflected its condition. In the last minute of the auction I
threw in a very modest bid and won the unit at a very reasonable price.
I thought restoring the Teac would be a good winter's project.
Two weeks later the Teac arrived and an initial assessment showed a number of problems
(headphone jack broken - input channel strong in but output extremely low - too much wow & flutter)
Initial work included lubricating the mechanical components, replacing the headphone jack, and cleaning the switches.
decided to tackle the "wow and flutter" (tape speed instability) first
and get all the mechanical parts of the deck working properly.
Considering its age, amount of use, and poor storage, this turned out
to be a major rebuild!
The motor was in descent condition and just in need of cleaning and fresh lubrication.
By the time I got to the mechanical linkages, I had most of the machine apart!
I had to straighten the capstan shaft, rejuvenate all rubber parts, and clean and lube all moving parts.
so many hundreds of little parts laying around I was quite relieved
when it went back together with no missing parts and none left over!
With a few new parts arriving, I replaced the headphone jack.
Then took a bunch apart to get at the tiny VU meter lamps, one in each meter.
Looks better now!
heads (erase, record, and play) were badly worn (as I knew before I
purchased the unit) and I wasn't about to pay nearly $300US to have
them professionally lapped (resurfaced) so I ordered an assortment of
emery paper from 400 grit to 3,000 grit to have at it myself.
the abrasive sheets came in I decided to have a go at the heads
and get rid of the trapezoid shaped flat spots on each head.
stated with 400 grit to bring the face of the head even using a glass
plate under the abrasive and a slight rolling motion of the wrist to
keep the face perpendicular to the base and keep some curve.
went to progressively finer grits while each time extending the
parabolic face and finally finishing up with 3000 grit and oil the full
width of the face. It took less than an hour per head but I did have to
rest my eyes between heads LOL! (Having an illuminated magnifying glass
and a jeweller's loupe helps to assess the condition of the head in
The end result is better than I expected!
Well 2 steps forward and one step back!
lapping the heads and doing the preliminary head alignment, and after
replacing the pressure roller, playing back a tape recorded on another
machine the VU levels are right up where they should be and the sound
quality is great. The wow & flutter is greatly reduced - haven't
measured it yet but it is not noticeable now.
the record problem(s) I was setting up the transport mechanics -
brakes, back tension, etc. The brakes set up fine but when I got to
tensions I noticed the left reel brake doesn't release in PLAY so the
back tension is the full braking force (1200g) rather than tension set
by the back-tension resistor! So the capstan is pulling against the
brake. Unfortunately the schematic I have is a P.O.S. that's almost
impossible to read and very incomplete. (Downloadable manuals, even if "free", aren't worth what you pay for them!)
(I wonder if the left brake has not been working for years and may be why the heads were so badly worn!)
trying to set the tensions, something else has gone awry - either a
sticky relay contact or a bad connection. After PLAY and then STOP, it
will not play again unless I give the machine a solid bump. In this
state, if I press the REC button, the PAUSE light comes on. After the
bump, this doesn't happen and the PLAY works again.
I have a better service manual coming from the UK and I am kind of stuck until it comes in.
waiting for the service manual I noticed one of the mic jacks was
broken - I already replaced the headphone jack. It looked like it had
been broken before and somebody glued it back together.
I ordered two new jacks and installed them so ALL the jacks are new.
replacing the jacks, I was able to complete the mechanical setup,
solved the brake not releasing on the left spool in play mode and
the problem with not going into PLAY a second time - the two were
a factory service manual and a calibration tape having arrived
from overseas it was back to work on the tape deck only to find that
the high frequency response was non-existent :(
the problem for a week I finally induced a strong magnetic signal into
the playback head that confirmed the electronics were working and that
the problem must be with the worn-out head.
So the project is suspended unless or until I can find replacement heads.
*** to be continued (I hope) ***