how to bypass dremel tool internal variable speed control?

I guess most of us have handled CMOS in this fashion, and I did so myself until made aware that failure rates of such treated equipment was much higher than good procedure.

As a test, I directly applied standard 5kv 1/50 impulses to 800 PIV diodes, and found that it was simple to get measurable change in characteristic, but usually took several applications to produce an actually unuseable diode.

So the warning is there, that you may not stop the device from working, but it may not be the same as when the manufacturer provided it to you, and certainly I would safely guarantee that any change will not be for an improvement..

Peter Dettmann

I suppose you've never heard of a special nozzle made for electronics. It has a radioactive isotope to prevent static problems. Microdyne leased two of them for the production floor, because the manufacturer didn't sell them.

Central Florida isn't a desert, but I suppose you've never seen a commercial air compressor with a dryer?

If you install a bigger fan it will either remove all of the cat's hair, or suck it into the computer. ;-)

I prefer to put a mini regulator and gauge by whatever tool I'm using, to get a constant pressure.

I don't think there's room for my cat inside my computer ;-)

One of my tower cases HAD to sit on the desk, because it was taller than the desk. It had 12 drive bays, and room for several cats.

No matter how big my desk is (or how many) there is never enough space on it[*]. I generally put the towers on a shelf beside the desk. Even a foot off the ground is enough to keep them from constantly vacuuming the floor.

I guess they haven't. Static *is* still a problem.

No, but if it ever were I'd simply salvage the data off the disk and replace the hardware. I can't believe anyone would spend real money to salvage *cheap* hardware, particularly an insurance company.

Not that I don't believe you, but...

Shouldn't be too bad today. Twenty years ago, when people smoked in office buildings... Even so, hardware is cheap. Labor isn't.

"It" being the cat, I assume you mean. ...makes too much noise. ;-)

On older circuit boards when ic's were first introduced it was not recommended to use high pressure air on the boards. One of the main failure points on early chips was the bonding of the leads to the chip. This has since been solved but I still remember having boards fail after they were blown off with high pressure air.

John

Interesting. What package types were susceptible to this (or did it matter)? Metal can TO-x ICs seemed to be the most reliable (RTL, HLL, some DTL, etc.) but I found a lot of early ceramic packages suffered from bad seals and permitted fungi to enter and grow inside (this in equipment that had never been wet, just from operating environmental conditions). These parts seemed also to lack proper passivation internally.

Regards,

Michael

The ceramic Ic's were supposed to be more reliable but in fact as you said they had a higher failure rate. The sealant that they used was not too good since in many instances the tops would come off the IC . I bet the sealant was probably a little corrosive too.

The first generation of IC's had a very high failure rate in compared to todays products. They were very heat sensitive and would act up above 100 degrees F even though the rating was higher. If I found one bad ic I would just change out every IC on the whole board that had the same date code and install a second generation ic with the same number. On some equipment you would automaticly change out a couple of parts and it was fixed. One company insisted on using the cheapest parts available but their advertising sold a lot of equipment in spite of the poor reliablity of the product. Today ic's and transistors , other than high power transistors, almost never fail unless something external blows them out. The industry has come a long way since the fifties when I first started in electronics.

John

Check the front of the refrigerator. Gerry :-)} London, Canada

Then, thank God for magnetism, too. d8-)

-- Ed Huntress

Air is also capable of introducing an ESD event. The tribo-electric effect.

Air is an insulator. Drag molecules of it across an isolated device (read blow), be it conductor or otherwise, and it WILL gain charge. Touch to ground, and there is a discharge.

Nearly every "air station" one will find in a proper electronics manufacturing facility will be at an ESD, properly grounded workstation so that such discharges only occur at a slow rate. The "air tool" operator is also supposed to remain grounded through a properly constructed ESD grounding system. Either heal straps on an ESD matting or floor set-up, or wrist or smock strap versions.

Silver filled epoxy is the main chip bonding media. The air must be evacuated from it in proper use. The surface of it will "tarnish" after application.

We use "humiseal" on our applications.

Epoxies have come a long way since the sixties.

Don't know if I would have gone that far, but whatever.

The first IC chips were in the sixties. TI made them for Fairchild, and they went into missiles. Ten transistor elements.

Now, we have 200 Million plus transistor elements on a single die.

I think we are doing pretty good..

Thank god for a lot of things...

According to krw :

Including the labor of re-entering or re-creating lost data. Of course, proper backup procedures can minimize this.

Enjoy, DoN.