JRDG Coherence II; Battery Display Issue

Stew, if you determine that your batteries last significantly less than prior to the blackout, you may want to cycle the charge completely several times. The operation may restore some of their original charge capacity. If you require new batteries, call JRDG at (719) 473-1181,, extension 4. G.

Stew, as mentioned in my PM, there is an entry in the JRDG knowledge base that suggests that one of your batteries may have failed and may need replacement. See:

http://jeffrowlandgroup.com/kb/questions.php?questionid=464

The Coherence II manual at

http://jeffrowlandgroup.com/kb/questions.php?questionid=488

discusses battery operations in the following paragraphs:

A MODE SELECT push button: Momentarily pressing this button switches
the power supply between AC and BATT operational modes. Either the
BATT lamp or the AC lamp will be illuminated. Note: BATT mode is not
allowed unless the batteries have achieved sufficient charge capacity.

...

Upon initially connecting AC power, it may be necessary to press and hold
down the MODE button (2) for five (5) seconds to initially boot-up or
reset the charge management system located within the Power Supply. In
a few seconds, the AC mode lamp will light and the Preamplifier INPUT 1
And RECORD 1 lamps will illuminate.
The Coherence Preamplifier is designed to be powered from the AC mains
which automatically initiates battery charging as necessary and is indicated
by the illumination of the AC mode lamp. However, the Preamplifier is still
powered by the internal batteries. AC mains power is disconnected from
the power supply internally whenever the BATT mode is selected using
the MODE push button. Under this operating condition, the preamplifier
operates exclusively from the internal batteries. Up to fifteen (15) hours of
operation in this mode is possible depending upon the initial state of
charge of the internal batteries.
If the Preamplifier is not used for an extended period of time and/or a
source of AC power will not be available, AC power should be removed
and the MODE push button should be pressed and held down for
approximately five seconds. A slight click will be heard. No lamps should
be illuminated. This feature allows the preamplifier to be stored or
shipped without discharging the internal batteries.

If the FULL charge lamp is illuminated, the battery capacity will range
between 50-100% of full charge. This lamp will not illuminate shortly after
the BATT mode is selected.
If the LOW charge lamp is illuminated, the battery is significantly
discharged and will automatically switch back to AC mode to commence
charging. If AC mains power is not available under these conditions, then
the Power Supply will automatically switch off, thus preventing the
batteries from becoming overly discharged.
The Power Supply is intended to operate connected to active AC mains at
all times. The charge management system only permits operation at the
voltage indicated on the rear panel. If an incorrect AC line voltage is used,
all of the Power Supply front panel lamps will flash on and off simultaneously
approximately four times per second.

...

Battery Complement 2 each 12 volt, 7.2 amp/hour
user replaceable sealed, lead calcium,
maintenance-free batteries
Battery Service Life 5-8 years
AC Unassisted Run Time 14-18 hours based upon
initial battery full charge

G.

There are 2 JRDG-authorized repair shops in New York State. They are both listed on the JRDG Knowledge base at:

http://jeffrowlandgroup.com/kb/questions.php?questionid=483

Uck.... Looks like the 3 days long battery drain zeroed the battery and possibly inverted their polarity as well. Remember to apply a touch of vaseline or similar lubricant onto the walls of the battery compartment, to prevent the fresh set from ever getting stuck inside. There is a specific JRDG bulletin, which states....

"placement Battery Installation

The replacement batteries for the Coherence and Coherence II preamplifiers are chosen specifically to fit into the holes cut into the preamplifier power supply chassis.

To install the batteries, please observe the following precautions:

• Unplug the power supply from the AC outlet.
• Disconnect the preamplifier from the power supply.
• Using a cloth or paper towel, rub a light coating of Vaseline or petroleum jelly on the inner walls of the battery pockets of the power supply chassis. This will prevent the batteries from becoming stuck in the future if there is any sort of swelling or shape increase. Note: Do not place the petroleum jelly directly on the battery, as it may cause you to lose control of the battery and drop it during installation."

Magfan, the JRDG literature is not terribly specific. It states only that excessive drain may damage the Lead-Calcium batteries of Coherence. Actual polarity inversion is a pure fruit of my own guesswork. Needless to say, the application of a non manufacturer-supplied battery cell to an electronic device like Coherence II is a recepy for expensive, and sometimes fumiginously stinky fireworks. G.

Stew, it is likely that your depleted batteries did not deliver an optimum voltage to Coherence any longer.... Hence a comparatively more dynamic performance with fresh batteries. G.

All, if anyone needs replacement screw fasteners for Coherence top and back plates, the correct type is:

#6-40 BUTTON HEAD SOCKET CAP SCREW x 3/8".

Please note that these are not common 4-40 screws, and they may not be stocked by all consumer-grade hardware outlets. G.
We'll put a few in the mail to the address below.