STA-235  (310-2065)         Care and Maintenance       Faxback Doc. # 16066

TAPE RECORDER CARE

A clean, demagnetized recorder will give its best performance for many
years, while a dirty recorder can mangle or ruin pre-recorded tapes in a
very short time.

An inexpensive demagnetizer (degausser) removes residual magnetism from the
tape heads.  This will insure the lowest possible hiss and distortion and
the best possible high frequency response.  Always clean and demagnetize
the recorder before making critical recordings.  Under normal conditions
you should demagnetize the recorder after every 10-15 hours of play.

With normal use you should clean the heads and metal tape guides once or
twice a month with a special solvent such as Realistic Recorder Cleaner
(catalog number 44-1010).  Moisten a clean cotton swab with the fluid and
rub the heads with short circular movements.  Then, clean oxide deposits
from all metal tape guides.  There are also a number of cloth cleaning
tapes which can be played like a tape for fast, easy cleaning.

You can even use the demagnetizer to help remove oxide particles trapped
deep in the head gaps.  Place a cleaner-moistened cotton swab over the gap
and bring the demagnetizer into contact with it.  Move the swab and
demagnetizer in short, circular sweeps.  Gradually withdraw the
demagnetizer and remove the dirty swab.

Yearly preventative maintenance by an authorized technician reduces the
possibility of expensive major breakdown and keeps the recorder in peak
operating condition.

RECORD & PHONO CARE

Even a small record library is a large investment, which, with proper care,
can give years of full-fidelity musical enjoyment.

Generally speaking the best way to reduce record wear is to decrease the
stylus force - but only if the cartridge and tonearm are designed for light
tracking.  If the force is less than the cartridge or tonearm is designed
for, the needle will bounce around in the groove.  This causes breakup,
distortion, skipping and excessive wear.  Always track your cartridge
within the range suggested by the manufacturer.  If you play mostly rock or
classical records (typically recorded at high volume) you should use one
the heavier suggested tracking forces.

Records often carry dust-attracting static charges and should be cleaned
before use.  Playing a dirty record grinds dust against the record walls
until it wears away the high frequencies and increases background noise. 
The most effective cleaners use an ionizing formula to remove the static
charge and a cut velvet pad to lift particles from the groove.

Occasionally you will need to remove dust and dirt from the needle.  For
best results trim the bristles of a #2 or smaller camel's hair brush and
then dip in rubbing alcohol and touch the needle lightly.  Brush forward
very gently to remove the dust.  CAUTION:  Brushing from front-to-back or
side-to-side may cause permanent damage.

To reduce record wear and maintain top performance, you should examine the
stylus carefully every 6 months.  You can take it to the nearest Radio
Shack store for a free checkup.  While you're there, look over the wide
selection of record care accessories.

CARING FOR THE RECEIVER

The STA-235 is built for a lifetime of precision musical reproduction.  The
receiver's wood case should be polished periodically with lemon oil.

NOTE:  Wax produces a glossier finish but may eventually cause a dull wax
       buildup.)  If the front panel requires cleaning use a soft, damp
       cloth (DO NOT use solvents).

Speaker Protection Relay Circuit

You may have noticed some stereo systems which produce a loud "pop" in the
speakers when power is turned "on".  This "pop" noise has been known to
blow speakers - especially with high-power amplifiers such as the STA-235.

But don't worry - it won't happen with this Receiver.  We've built in a
special relay-protection circuit to prevent such damage.  The high-power
output stages are kept off for a couple of seconds after power is turned
on, till the power supply circuit and audio preamp stages have had a chance
to stabilize - then the relay circuit switches in power to the audio output
stages.  Of course, this means you don't hear sound for a couple of seconds
after power is first turned on - but you won't mind that, now that you know
the speakers are protected!

Overload Protection

We've got another important protection circuit - which protects the
Receiver from overload.  If too much current flows in the output circuit
(from excessively low impedance [combinations less than 4 ohms], shorted
speaker terminals, etc.) a protection circuit activates immediately and the
output connections and the speaker impedance (don't use 4 ohm speakers if
you use more than one pair).

Thermal Protection

The Receiver has built-in thermal overload protection.  That means that it
can not become abnormally hot and damage some portion of the circuitry.  If
internal temperatures do rise abnormally, the Receiver will automatically
silence itself.  If this happens, check to be sure you have not placed
something over the ventilation holes - if you have, remove it.  If you are
using speakers with excessively low impedance, the amplifier circuit may be
over-driven and thus producing excessive heat.  This can be caused by using
4 ohm speakers on main and remote - if you use remote with main speakers,
be sure to use either 8 or 16 ohm speakers.

In any case, if the Receiver does turn itself off, set POWER to off, check
ventilation and then check to be sure the speakers are properly connected
and that you are not using a combination of 4 ohm speakers for both main
and remote.  The protective circuit is triggered by temperature, thus it
may take a few minutes for the circuitry to cool down and allow the unit
to come back on.  If everything is OK, turn power back on.  If the Receiver
does not come back on, you may have to wait a few more minutes for
everything to cool adequately - it should never take more than about 20-30
minutes for this cool down cycle, or, check the fuse (4A) on the rear
panel.  Replace only with the same size and rating.


(llg/all-07/21/95)