Mesa/Boogie Mark IV Amplifier manual Receptacle, Internal circuitry, Fuse

REST AREA

REAR PANEL MKIV

FUSE

3A SB

117VOLTS 60 HZ

4 AMPS

							REV FTSW.	FX LOOP ON
								FULL TIME
REVERB	1	0	10
	2
					9
	3				8
	4			7
	5	6
								FX LOOP
GRAPHICEQ						SATELLITE		SWITCHING
							SIG.	LEFT
							SATELLITE EQ	(STEREO)
ON OFFAUTO R2							PATH
	REMOTE					SATELLITE SEND		RETURN

AUTO		AUTO
RHY 1	RHY 2
RHY 2		LEAD

AUTO ASSIGN SWITCHES

RIGHT

(MONO)

FX SEND

RETURN

RECORDING

(D.I.) SLAVE

					TRIODE	SIMUL-CLASS	HARMONICS
1	0	10			AMP		VOICING
					POWER
5							LEAD
	6		7	9
2
3				8
4
					PENTODE	CLASS A	MID GAIN
LEVEL					OUT
4	0			8	SPEAKERS
1		10
2				9
3			7
5	6				8 OHM	4 OHM	4 OHM

	RHY 2
RHY 1	LEAD
FT SW	EX SW

MODE SELECT

HANDBUILT IN PETALUMA CALIFORNIA

CLASS A/ SIMUL FX LOOP EQ

EXTERNAL SWITCHING JACKS

RHYTHM 1 RHYTHM 2 LEAD

A.C. RECEPTACLE:

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
FUSE	the way into the RECEPTACLE to insure an uninterrupted performance. In the U.S., the proper voltage is
3A SB	117 volts A.C. (110-120). Always be sure to connect the MARK IV to its rated voltage to avoid damaging
	internal circuitry.

117VOLTS 60 HZ

4 AMPS

FUSE:

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
FUSE	switch to ON. If you see a tube arc or spark inside, that is definitely the problem and can be remedied by an
3A SB	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.

117VOLTS 60 HZ

4 AMPS

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).

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