Fwd: item for the AMRAD tacos news letter
mcfadyenusa at yahoo.com
Mon Oct 3 14:18:00 CDT 2005
Forwarding this to the Tacos list as requested:
--- Michael Chisena <ka2zev at yahoo.com> wrote:
> Date: Mon, 3 Oct 2005 08:25:54 -0700 (PDT)
> From: Michael Chisena <ka2zev at yahoo.com>
> Subject: item for the AMRAD tacos news letter
> Could you please foward this to the Taco's crew.
> Im fixing some very old stuff. These are Army motor controlers for air
> conditioners. They take any kind of 220 power and convert it to three phase
> 220 power at 61hz. Up to 18k btu.
> One of the last problems up is two eproms that hold the program for the
> digital card.
> Im mostly a high voltage analog guy, and diden't work much on the digital
> side of the house.
> This digital card is about as complex as an old pin ball game. But it's
> loaded with subtle things.
> I need to make copies of two proms. They are of the same type, the number is
> 2764 .
> There are also questions as to if these can be 'locked' so a prom reader and
> burner can't be used. Ive never heard of such a thing. Please teach me the
> Im also in the market for a prom burner gizmo. Anybody have one for sale? If
> not, can one be mail ordered and a recomendation made.
> My laptop has a 232 output (9 pin) if that's any help.
> I would also like to buy a TTL data book, and or a CMOS data book. Just for
> pin outs and stuff.
> One thing about these motor controlers you might get a charge out of.
> We get some 'rough operation' from them depending on which 'digital' card is
> loaded into the test jig. I got the problem knocked today. This is wild.
> Seems the cards that work the best, make nice clean square waves and pulses.
> No hash on the wave tops.
> The digital outputs are optocoupled to several stages of transistor
> amplification up to the huge power transistors that push the voltage down to
> the motor. Seems any noise on the tops of the wave forms, cause the opto
> couplers to fire a tad hotter, and all that gain sends a high speed slug of
> voltage all the way into the motor, saturating a winding and making the
> motor sound like there is a marble traped in the works. This was a wild one.
> Been changing working parts that show this hash on the wave tops, with new
> parts. Guess what, the test motor turns clean now. Is that wild or what?
> Ive done about 8 or 9 cards this way, and it has worked each time.
> Later guys
> Mike Chisena aka KA2ZEV in Kuwait.
> ka2zev at yahoo.com
> "You are, what you do, when it counts"
> The Masso
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