how to bypass dremel tool internal variable speed control?

One of the problems with blowing out electronics with high pressure air is the ultrasonic vibrations that are set up by the air. The vibrations can break the fine junctions on the chip itself.

John

Never heard of a pressure regulator? 15psi air won't damage anything, and except in desert conditions moisture is generally more of a problem with shop air than static charge.

Neaver heard of a pressure regulator, I assume?

I said in disaster recovery situations. After a flood or fire, for instance. Have you ever had a computer go through a fllood or a fire???

Several customers of mine were in the disaster cleanup business. They ROUTINLELY clead computers and electronics i this way.

I alwys recommend at least 4 inches off the floor. Again, you SELECTIVELY read. The "dishwasher" was used for cleanup after fire and flood damage.

One of the WORST culprits for screwing up electronis today is CIGARETTE SMOKE.

Huh? A standard cleaning protocol involved immersion in an ultrasonic freon bath, now replaced by other less-inert solvents; this involved considerably more sonic power than that produced by an air nozzle. Certainly one must exercise care when cleaning around delicate parts such as fine-wire coils without encapsulation, paper parts, etc., but by and large there is little risk in pressurized air cleaning (120 psi) and IMHO the benefits far outweigh any small risks. I've been doing it for far more years than I care to admit with excellent results on industrial, military and consumer electronics. I have also had very good results using high-pressure hot detergent and water for difficult greasy accumulations; the cleaner is much like a dentist's tool or a 'Water Pic' rather than the familiar domestic pressure washer.

The key in wet cleaning of electronics is a proper bake-out protocol to insure that parts (such as transformers) with high-potential connections are dry internally to prevent breakdown before applying power.

Regards,

Michael

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. ;-)

Thank god for gravity, or the vertical surfaces would be equally cluttered.

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