Adcom GFA-5400, Service Manual

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5
PARTS EXCLUSIVE TO VERSION ONE OF THE GFA-5400
(VERSION WITHOUT STANDBY POWER SUPPLY AND LM 555 PROTECTION CIRCUITRY)
SCHEMATIC ADCOM PART NUMBER DESCRIPTION
LOCATION
D605,D606
16000082 DIODE 8.2V ZENER
R615,R616 27004300 RESISTOR 15K
R621,R622 27004200 RESISTOR 10K
PJ1,PJ2 22001370 INPUT JACK, Board Mount
30001045 SPEAKER POST RED
30001035 SPEAKER POST BLACK
Q639,Q640 33002362 TRANSISTOR 2SC2362
T1 24005400 POWER TRANSFORMER
* Note 1: Matched IRFP240 and IRFP9240. Due to manufacturing variations in the turn on voltage of
these devices, these parts must be replaced in matched sets of 3. If any one of the output devices fails,
all three must be replaced. For example, if Q616 fails in the right channel, then all 3 of the N-channel
IRFP240 devices must be replaced in that channel (Q616, Q618, Q620). When ordering these parts,
specify a matched set of 3. Failure to use matched devices will cause "current hogging" by one of the
output devices. Proper bias alignment will not be possible in this circumstance leading to incorrect and,
possibly, unreliable operation.