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The MARK IV uses a removable I.E.C. type power cord to supply the A.C. power. The power cord supplied with your unit should
be used whenever possible as we chose it for its snug fit. Because this type of RECEPTACLE is somewhat universal and used in
many products both in and out of electronic musical instrument domain, you may use other cords of this
type when the one supplied is not available. Should this become necessary, check that the cord is seated all
the way into the RECEPTACLE to insure an uninterrupted performance. In the U.S., the proper voltage is
117 volts A.C. (110-120). Always be sure to connect the MARK IV to its rated voltage to avoid damaging
internal circuitry.
The FUSE should be a 3 amp Slo-Blo for use with 100 or 117 volt A.C. Mains. Should the FUSE blow, replace it with a similar type and
rating, then watch the power tubes as you start the amp back up again.
Warm up the tubes first with the amplifier in STANDBY mode, then, watching them carefully, flip the STANDBY
switch to ON. If you see a tube arc or spark inside, that is definitely the problem and can be remedied by an
easy power tube replacement. In many cases though, the bad tube will only fail intermittently. Watch for a
while and if any tubes start to run red-hot, this is the cause of your original problem.
If everything appears OK, tap on each power tube to reveal the faulty one, because a blown fuse is nearly
always caused by a bad power tube (s). Running the amp in TWEED power will very likely offer a temporary
remedy and let you get through the gig. If the FUSE blows immediately when switching on the A.C. power (in
the STANDBY mode), then some other problem is the cause, most likely a failed rectifier diode. (See the section on tube maintenance
further back in this manual for more assistance and helpful hints on how to maintain the life of the power tubes).
REAR PANEL MKIV
A.C. RECEPTACLE:
FUSE:
3A SB
FUSE
117 VOLTS
60 HZ
4 AMPS
3A SB
FUSE
RECORDING
SLAVE (D.I.)
POWER AMP
TRIODE SIMUL-CLASS HARMONICS
PENTODE
CLASS A
SPEAKERS
8 OHM
4 OHM
4 OHM
MID GAIN
LEAD VOICING
LEVEL OUT
117 VOLTS
60 HZ
4 AMPS
EXTERNAL SWITCHING JACKS
RHYTHM 1
RHYTHM 2
LEAD
CLASS A/ SIMUL FX LOOP
EQ
REV FTSW.
SATELLITE EQ
SATELLITE SEND
SATELLITE
AUTO
RHY 2
AUTO
RHY 1
FX LOOP ON
FULL TIME
FX LOOP
SWITCHING
RHY 2
LEAD
AUTO ASSIGN SWITCHES
FX SEND
RETURN
RETURN
LEFT
(STEREO)
RIGHT
(MONO)
SIG.
PATH
MODE SELECT
LEAD
EX SW
FT SW
RHY 1
RHY 2
HANDBUILT IN PETALUMA CALIFORNIA
2
3
4
5
6
7
8
9
1
0
10
GRAPHIC EQ
ON OFFAUTO R2
REMOTE
REVERB
2
3
4
5
6
7
8
9
1
0
10
2
3
4
5
6
7
8
9
1
0
10
REST AREA
3A SB
FUSE
117 VOLTS
60 HZ
4 AMPS