[sdiy] L7912ACV puts out -16.3 volts

[Dave Krooshof]

__________Stability issues:____________
used a few dozen of 78xx's, still behave perfectly too.
They're so standard, Harry would complain monthly if they'd realy suck.

__________Wrong output voltage:___________
>> Could suspect bad/leaky caps perhaps...
>> App notes... Prolly a must to troubleshoot this type of thing too... Perhaps
>> the load is very capacitive? I wouldn't suspect this as a problem, but you
>> never know till you are knee deep..
>>
>> Rob
>
> I remember having "fun" with helping debug a PSU over email.
>Sure he checked the polarity of the big elcos a hundred times, nothing
>wrong there. It was a real mystery till it turned out he used tantalum
>types for the 100n caps 8(
>
>Theo
!!!!!!!!!!!!!!!
One of the 104's on the bad side _does_ have a slightly different colour.
I'll see if I can find a oker (yellowish) replacement. I do not DIY enough
at home, but I started noticing the advantages of having a complete
collection of caps and resistors.


__________late night issue that'll disappear in daylight________

My next problem to get rid of is:
why is there 9 volts AC between my synth's ground
and my mixer's ground, even when the power is off
and the circuit is disconnected from the supply.
Older projects still work fine. ODD.
But I guess, to solve this one, a good night of sleep
will solve all, tomorrow I'll instantly notice what the problem is.

I disconnected my complete gear drom the mains today,
after a Shostakovich live concert on TV on which the rolling
of thunder was very audible :-)
Then the thunderstorm kicked the tv off air twice, my
mac's monitors were flikkering...
Now the earth of the televisioncable is some 20 volts AC
different from the mains earth. Hummmmmm....
Tomorrow I'll see on which planet I wake up, and what the
local current is.


Dave
(hummed out for today)

----- >^v< ---------------------------------------
Dave Krooshof http://www.xs4all.nl/~krooshof
geluidstechnicus @ http://www.ahk.nl/the
webmaster: http://www.popronde.nl
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