5
DANGER
HIGH VOLTAGE
MAY BE PRESENT
ON FILTER CAPACITORS
DO NOT TOUCH!
SAFETY
Tube amps operate at high voltages that have the potential to injure and kill. Please remember the following
when working on this project.
Only work on the amp when you are wide awake and sober.
Do not plug the amp in until you have gone through all of the instructions, checking and re-checking
each step.
Do not turn the amp on until you have connected it to a speaker cabinet.
Be aware that tubes become very hot when the amp is on and can take up to 10 minutes to cool down
after power is turned off.
Work in a ventilated area when soldering.
Always follow the one hand rule when working with an amp that is connected to power or may have
voltage present.
(Any amp that has been plugged in at one time, may have high voltage present).
ON
STANDBY
The one hand rule
(pictured below): is a safety precaution for working on an amp that is
plugged in or could potentially have high voltages present. Using alligator clips with your
DMM, clip the ground side to the chassis and use the other side to probe at various test points
with one hand.
This prevents a fatal shock which can result from current passing through the
heart.
(Many people even put their other hand in their pocket or behind their back).
Always probe the amp for dangerous voltages at several test points before working on it, even if it has been turned
off and unplugged for months.
Test points include:
Each positive end of polarized filter caps
Visit
www.modkitsdiy.com
if you have any problems when first turning on your amp for
troubleshooting help. If you
smell
or
see
smoke,
hear
something pop, or the chassis becomes too
hot to
touch
, turn off power and unplug immediately.
