Re: TI-H: TI-86 Slowdown problem, more info
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Re: TI-H: TI-86 Slowdown problem, more info
Measure the frequency of the ripple that the inverter is adding to the
power supply. I can see about figuring out the capacitor and
choke(coil, inducter, etc) that you'll need to filter it out.
The way I figure it, you've got a bad inverter there, as it shouldn't be
putting that kind of stuff on its power supply.
-Adam
dknaack@hotmail.com wrote:
> Ok, I picked up the 'scope last night and did some testing
> in the calc.
>
> The interter output looks something like this:
>
> --
> --
> --
> --
> --
> --
> ---- -----------
>
> The wave runs at 400 cycles per second, 85 volts.
> It is actually stepped like that, but a little more
> curved, and with more steps than I have show here,
> about 12 steps in 5ms.
>
> The voltage at the power supply when the inverter
> is running looks something like this:
>
> _/ / / / / /
> _/
> ____/ ________
>
> You can see it ramp up at the beginning of each
> cycle, then peak out for the remainder of each
> cycle.
>
> The system oscillator (taken from the driven
> contact where the turbo capacitor is) looks a bit
> like this:
>
> _________________ _________________
> | | | | | | | | XXXX| | | | | | | | |XXXX
>
> The "XXXX" parts are just kind of solid, fat
> bands, I can't get any better resolution with
> my scope, so I don't know what exactly is happening
> there.
> The "|" characters are where there is a very brief,
> very regular dip in the voltage.
> Unfortuanately I can't remember the timing info here,
> I'll get it again to night (I wasn't taking notes).
>
> If the inverter is switched on, the clock goes
> to the "XXXX" mode only, just a big, fat line on
> the scope, and the calc slows down.
> Curiously, when the inverter goes off, the scope
> does not change, but the calc speeds back up!?
>
> I put a big electrolytic across the leads of the
> inverter as a filter, which smoothed out some of
> the ripple a bit, but it didn't help with the
> slowdown.
> Can someone suggest some other filtering techniques
> which might help?
> I'll post timing data and (hopefully), some scans
> of the acutal waveforms.
>
> I really need to get this solved people, I've got
> a TI-86 here that I'm sure the owner would really
> like to get back, thanks for anything you might
> be able to suggest!!
>
> DK
>
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