The idea is to remove the load from the output transistors. They should not
be able to burn out if they aren't driving anything...but you must not
unplug the output transistors as then the drivers are unbalanced and can be
damaged.
Another trick I sometimes use to avoid major smoke is to put a 15 - 25 watt
light bulb in series with the power transformer for transistor amplifiers
(and this is a simple transistor stereo amp after all). If the lamp stays
glowing brightly then something is wrong, if it starts bright and rapidly
dims to a faint glow, then the system is fine, plus if you have no input
the voltages will be somewhat close to normal operating levels, yet the
light bulb is working as a current limiter...saving those expensive
outputs. This test can be done with the yoke in place as a static burn-in
test. If the lamp stays dim after the monitor is banged around a bit (the
Thump test monitors require before passing into the burn-in stage) then I
figure the monitor is probably OK and ready for signal testing.
John :-#)#
At 10:46 AM 13/05/2002 -0400, Christopher X. Candreva wrote:
>On Sun, 12 May 2002, John Robertson wrote:
>
> > STOP!!!!! TURN OFF THE POWER!!!! YOU ARE DESTROYING THE DRIVER
> > TRANSISTORS!!!! NEVER EVER EVER RUN A VECTOR MONITOR WITH THE OUTPUT
> > TRANSISTORS UNPLUGGED!!!!
>
>Would this hold if there was no INPUT also ? As in ,powering just a
>deflection board with no input ?
>
>I'm thinking of the times I've isntalled an LV2000, where if I recall the
>docs say to check it by doing just that. Then again, if everything is
>unplugged, I guess the yoke is off too.
>
>-Chris
>
>==========================================================
>Chris Candreva -- chris@westnet.com -- (914) 967-7816
>WestNet Internet Services of Westchester
>http://www.westnet.com/
>
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Received on Mon May 13 10:20:05 2002
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