Mesa/Boogie MARK 1 - Manual (Page 9)

PAGE 5
REAR PANEL:
FUSE
3A
FUSE
3A GROUND
FX LEVEL
POWER / TWEED SWITCH: Continued From hard rock to insane metal, the MARK I can be your essential ingredient to
achieving any tone imaginable! Those players who want that British “crunch” tone can try replacing the output tubes with four
European - style EL34 power tubes. Greatly enhanced, shredding top end and the grinding lows so important to a great metal sound
result from this tube change. And yet all the fluid, spongy feel remains intact for those hammer-ons, pull-offs, or those two-handed
fingering lines that become noticeably effortless as the gain controls are increased. With EL34 power tubes in place, rated power is
roughly 80 watts in the switch up ( 100 watt ) position and about half of that in the switch down ( 60 watt ) position. It is easy to obtain
the right grind at virtually any volume level. A metal player’s dream, the
MARK I boasts gain and tone that put the “Modified” British
heads to shame and it does so reliably and consistently!
AC RECEPTACLE: This grounded outlet provides A.C. power for effects and other powered devices that require 117 volts. It is
active whenever the amplifier’s A.C. power cord is plugged into the wall and is not affected by the POWER /
TWEED switch located on the Front Panel.
FUSE: This is the A.C. line fuse for your Boogie . Should the fuse ever blow, be sure to replace it with the same rating in a SLO-BLO
type package. Domestic U.S. versions of the MARK I , require a 3 amp SLO-BLO Fuse. By far the most common cause of a blown
fuse is a bad power tube. Always follow the cold start procedure mentioned earlier in the ON / STANDBY switch section and watch the
power tubes as you flip the STANDBY switch to the ON position. If a power tube is going bad or is
arcing you will see it! Flip the STANDBY switch to standby immediately and replace the faulty power
tube (s) and the fuse if necessary. If you see nothing abnormal as you lift the STANDBY switch, it is
possible that a power tube shorted temporarily and blew the Fuse. If this is the case it may work
again normally. To be extra safe you may want to replace all power tubes in the “shotgun” trouble-
shooting tradition and save the replaced set as spares. Always carry along a few extra fuses and
tubes, they could be worth their weight in gold when needed.
GROUND: This three position switch reverses the ground of your Boogie . It is often helpful in reducing annoying buzz and hum
which originate in the A.C. power wiring outside the amplifier. We recommend leaving the switch in it’s center ( OFF ) position, unless
position A or B definitely helps cure noise problems. In the center OFF position, your
Boogie cannot be the source of annoying microphone “ground shocks”.
FRONT PANEL:
(Continued)