My ancient shop light has 2 mammoth ballasts with 4 starters for the 40w tubes
and I'd like to be able to know for sure what's at fault before I begin
replacing parts. Is there a procedure for bench testing ballasts using a
Next, is there any reason to replace a ballast,if one is needed, with the
original type, or can I adapt a modern smaller ballast that doesn't use
Frankly they are better because they are smaller. Being smaller keeps
the heat in the lamp better and they work more efficiently. Most also come
with modern electronic ballast and will work well at very cold temperatures
without any of the annoying buzz.
Lamps are measured in`1/8's of an inch.. Do not ask me why, I do not know
where this came from. T-8's are 1 inch in diameter and are smaller than the
standard T-12's. The T-8's also can produce more light for less energy.
There are also some high output T-5's available.
Personally I would throw away the ballasts and starters and buy new. Either
electronic or magnetic ballasts your choice. Wear gloves when your replacing
the old ballasts, they are probably full of PCB's. Do not burn them.
And if you spend much time in the shop I'd recommend springing the extra
few bucks for some wide spectrum bulbs; sometimes referred to a
"daylight" bulbs. The light from them makes a big difference in your
general viewing pleasure and in many cases they seem to brighten up a
sagging mood just like going outside on the first sunny day of spring.
I've switched to those kinds of bulbs everywhere I can in our home, my
home workshop and our office.
Jeff Wisnia (W1BSV + Brass Rat '57 EE)
"My luck is so bad that if I bought a cemetery, people would stop dying."
While you're at it, since it's that old and parts like starters and sockets are
sure to begin failing, why not replace all of the electrical components with a
4-light electronic ballast, 8 new sockets and 4 new day-light spectrum lamps?
It may be cheaper to just buy a whole new fixture and swap the whole electrical
Is the shop heated? Or actually, can you say "it never gets too
cold in there"?
If it's a reasonably warm room, you can get away with a new
fixture that uses cheaper tubes (35 or 38W, it's late, can't
remember right now) and you could buy a fixture and a case of
10 tubes for less than you would likely pay for replacement
parts for an "ancient" fixture and 4 new 40W tubes.
Sometimes, $tuff just ain't worth trying to fix.
No more big'uns for me, now I'm a 'Venture Capitalist'.
I've learned to totally appreciate 'Small Firms'.
half the lampholders, so I did pretty much what you suggested and just went
with a new light.
BUT.......I'd still like to know if there;s a simple way to bench-test a
ballast , or test it in place.
Thanks to all for the help.
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