wrote in message
...

That kinda rings a bell. Also, in working on TVs which all have switched
mode power supplies now, you usually can't use a variac.

How to try to keep the smoke in ? I have thought of that and the answer
might be to remove the main filter off the line recifiers. Temporarily
replace it with about a 33 uF. Then a modded light bulb tester, like with
two higher wattage bulbs in parallel.

With some timkering you can probably find some comfortable values that'll
allow the circuit to power up fairly normally but yet keep the fire brigade
away.

I remember a certain model of Sony TV, didn't have a switch mode but it used
a startup cap from the main B+ down to about a 20 vlt source to run the
horizontal osxcillator which was then powered off the flyback. No way to
start those on a variac either. Also Zeniths that had the A-11345 startup
module would not slow start. I'm pretty sure RCAs from CTC 88 through 92
wouldn't either.

I don't like it when manufacturers do that but whaddya gonna do ?

Well I know what we're going to do, outsmartem and fix their **** so they
don't sell more of it ! LOL




I really don't like SMPS's because I don't know enough about them, I am way
out of my comfort zone here.

But, most modern audio equipment (I only know audio equipment) using SMPS's
use small IC's as the controller, which are designed to tolerate almost
anything thrown at it.
They will only attempt to power up once they have enough voltage to do so,
and will shut down if excessive current draw occurs, without destroying
anything.

You can usually power them up with a Variac and lightbulb, but with the
JBL's you can't, because I believe they have added some relay circuitry that
makes this not possible.
I'd just like to know what that is.




Gareth.