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HARD-starting KILLS electronics!!!
The older the caps & the longer they've
been unused, the worse the problem.




How To ReForm Electrolytic Capacitors

(never operate a TUBE amp without a load)

Electrolytics dry out when not biased.
If your equipment hasn't been used
recently, especially if over 10 yrs old,
following this simple procedure will
improve sound & delay costly repairs.

You will need a "portable" VARIAC
and a "True-RMS " AC Voltmeter
(if meter is not marked "True-RMS,"
the reading may not be accurate).

1)  Cleaning and a thorough inspection
of all internal parts (especially capacitors -
look for signs of heat-damage, deformation
and leakage) and verification of correct
mains-voltage & fuse-value is essential
before operating equipment.
Consult a qualified technician.

2)  Measure line voltage going into VARIAC.

3)  Measure output voltage of VARIAC.

4)  Mark scale at UNITY-voltage
(INput voltage equals OUTput voltage).

5)  Mark scale at 120 Volts
(or 100-220-230-240 for your location).
Best to measure late at night
when line-voltage is highest.

6)  While reading OUTput voltage (analog meter
is better for this purpose), rotate very slowly
over full range and make sure there are
no "dead" spots on the autoformer wiper.

7)  Turn VARIAC control full-CCW to Zero-Volts.
Switch VARIAC ON and leave it ON.
Plug component-under-test into VARIAC
and switch Component ON.

8)  S-L-O-W-L-Y and S-M-O-O-T-H-L-Y,
bring voltage up to around 50% of line voltage.
Increase slowly and smoothly 5 Volts at
30-minute intervals (or longer, depending on age
of equipment and how long it hasn't been used)
until you reach your mains-voltage.

* Note: It's the exception, but some equipment
(i.e., some Sony) do not like to be run at low
voltage. In this case, bring up initial voltage
to 70% of line & increase s-l-o-w-l-y from there.
If in doubt, consult Manufacturer's Service
Manual or Service Department.

9)  After you reach the target max-voltage,
let it run for 24 hrs (or longer) on the VARIAC.
When finished, dial VARIAC down to Zero before
switching off the Component (not the VARIAC!).
Unplug component from VARIAC, plug directly
into wall outlet (or Balanced Mains Transformer),
switch ON, let it warm up for 72 hrs, and enjoy.

* Check
AllegroKnowledgeBase for
How To Determine Best AC-plug Polarity.

* Be aware that [stock] VARIACs allow OUTput
voltage to go way above your line-voltage;
be very careful not to exceed your nominal
line voltage; keep a plastic cup over the
Control knob to prevent inadvertent operation.

* Design-center for US electronics is 117 VAC
("110" Volts-AC went the way of the Victrola).
120 is MAXimum voltage you ever want.
Alas, most power companies are delivering
more than this, as it spins your meter faster
(it is not a true ampmeter as they claim),
and they skate by with less transformers.

* Some functions may not work properly
when line voltage is brought up slowly
(Nak Dragon is one such example).
When re-forming is complete and the
VARIAC removed, the component will
function normally when hard-started.




Electrolytic capacitors over 20 years old
should be replaced to improve performance
and avoid catastrophic failure.




So what's inside that can?
An electrolytic capacitor is composed of an anode foil,
a cathode foil, and a separator plate, wrapped and impregnated
with an electrolyte comprised of a solvent, such as ethylene glycol,
and a solute, such as ammonium borate, sealed in aluminum can;
the end-seal is made of rubber, rubber-backed phenolic,
molded phenolic-resin, or polyphylenesulfide; over time,
the electrolyte evaporates through this seal; as the volume
of the electrolyte decreases, the ESR of the capacitor increases
and its capacitance decreases; the increase in ESR leads to
increased heating which leads to further evaporation of
electrolyte, and so on until it eventually fails :-(




Soft-starting all electronics with
a VARIAC avoids costly repairs.



quid pro quo

AllegroSound
−  Established 1973  −
"love what you listen with"
Los Angeles, California USA
Rick@AllegroSound.com
FOR SALE - TRADE           

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AllegroSound
−  Established 1973  −
"love what you listen with"
Los Angeles, California USA
Rick@AllegroSound.com
telephone 323.960.5014

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