MAINTENANCE
Section 17, Page 21 May 2002
6. Continue this process until the receiver will cycle ON and OFF with all the cards left in
the receiver. Send the faulty cards to Zonge Engineering for repair.
If the Crystal LED flashes briefly:
Watch carefully to determine whether the Crystal LED flashes briefly when the power is
cycled. If it does, that is an indication that the electronic circuit breaker is operating and that
there is a problem with BD287. Remove the front panel board (BD287) and inspect the 0.08
ohm resistor (R3) which is next to the fuse (F1). Replace R3 if it shows signs of stress.
If the Crystal LED does not illuminate:
If the Crystal LED appears totally dead, the circuit breaker chip may be damaged. Try
replacing U35 (UC2543) a socketed integrated circuit on BD287 (See Figure 16.4). If this does
not work, see the following discussion on bypassing the electronic circuit breaker, or contact
Zonge Engineering or other authorized service center for repair information.
Bypassing the Electronic Circuit Breaker
Refer to the following instructions on the rare occasion that it may be necessary to bypass the
Electronic Circuit Breaker:
If the circuit breaker chip (U35, UC2543) is okay but the current sense resistor (R3, 0.08 ohm)
is blown, and you do not have a replacement, a piece of small gauge wire can be installed in
place of R3. This will permit operation of the receiver, but the overcurrent turn-off capability
will be lost. The 0.08 ohm resistor should be replaced as soon as possible.
If the circuit breaker chip is not functioning, the following steps may be taken to continue use of
the receiver for a limited period.
Caution: when U35 is removed, as explained below, the receiver will remain in a continuous ON
state. The only way to turn it off is to disconnect the batteries in the battery compartment.
1. Remove the Electronic Circuit Breaker chip from its socket (U35, BD287; See Figure
16.4 for chip location).
2. Cycle the POWER ON/OFF button on the CONTOL I/O Panel. If the Crystal
LED does not illuminate, there is a problem on board BD287. Contact Zonge
Engineering in Tucson.
3. If the Crystal LED on the front panel illuminates, press
ON/OFF
on the Front Panel. If
the MPU board is able to boot up and display the Zonge logo, then the front panel is
probably okay (with the exception of the circuit breaker chip U35 and, possibly R3) and
the fundamental problem lies somewhere else. Or the problem could be a one-time event
generated by a combination of events coupled with a low battery situation.
4. The circuit breaker should immediately be replaced. However, in a pinch, if a problem
has been located and repaired, the GDP-32
II
will operate effectively with the electronic
circuit breaker bypassed.
Caution Again: Once U35 has been removed, the only way to turn off power is to disconnect the
batteries!
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