Re: 556 problems

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "David Sharpe by way of Terry Fritz <twftesla-at-qwest-dot-net>" <sccr4us-at-erols-dot-com>

Matt

Need a schematic to help you.   8 volts out with a 14 V supply
means something is seriously overloading the supply. May have
a bad totem transistor, or bad/damaged 556.  Make
sure your voltages are to the correct points on the 555/556.
Direct power connections to certain points (discharge comes
to mind) will detonate a 555.  It will catch fire.  Is anything
running hot (if you can't hold your finger on it more then a
second, its TOO HOT).  Also make sure to bypass each end
of 555/556 with 1uF +0.1uF ceramic disk.  A soft power
supply will cause ground bounce and can "confuse" the timer.

Visually check board for workmanship and solder bridges,
that may expalin where the power supply overloading is
coming from.

Regards
Dave Sharpe, TCBOR
Chestefield, VA. USA

Tesla list wrote:

> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Fucian-at-aol-dot-com>
>
> Hi all, i am having some freaky 556 timer problems.I am using a standard 556
> and using one timer to pulse the second timer.They both are in 50% duty cycle
> mode.It seems to work fine when on the solderless breadboard but once i
> solder it all too a Radio Shack IC board, it doesnt work right.The voltage is
> like 8 volts out with a 14volt regulated supply.WHY!??Both timers use bare
> miniumum components.A pot and a timing capacitor each.The output of the
> staccato one goes to the reset pin of the second timer.The output from the
> second timer goes to a totem pole transistor pair.What could be wrong?Ive
> triple checked EVERYTHING.Ive built and rebuilt the circuit several times on
> a new board each time.Maybe evil radio shack spirits?
>
> Thanks,
> Matt