Re: SMK-1 Questions

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From: George Gingell (k3tks@u1.abs.net)
Date: Sun May 21 2000 - 00:54:53 EDT


Hi Craig,

While I can't help you with the info on the replacement IC, I am sure that
you have the info now from Dave and others.

Actually, this is kind of a Me Too! kind of note.

As soon as I read your question, I immediately thought of going for My
Dremel Moto-Tool and Cutoff Wheels.

I have several of them as they are extremely useful in the Locksmith Trade
as well as in the Ham Radio Workshop.

In addition to the Standard Cut-off wheels, I have an assortment of Steel
Saw blades, grinders and Diamond surfaced cutters.

In most cases I prefer the Newer Heavy Duty Fiber Reinforced wheels. They
are much less shatter resistant and seem to last longer.

I generally use the DUBRO Brand name Disks which I purchase at the local
HobbyTown store. (Model Airplaane & Boat Store).

As with all of these tools, extreme care must be used.
ALWAYS WEAR EYE PROTECTION! Secure your work in a vise or clamp it to the
workbench. Go slow, don't force it, just let the cutting wheel do its job.

I also recommend the use of a flexible shaft tool with the Dremel as this
gives much better control when working in tight quarters.

When removing Standard Dip Chips, It is best to cut the leads right where
they enter the chip. No danger of heat messing up nearby components.

One Trick which I have used in the past when doing a Repair job, is to Cut
the Pins Right at the chip as just mentioned, then take a New IC Socket
and trim its leads to about 1/2 length, straighten them and tin them them
put the socket in place of the removed chip. It is then possiable to just
apply a bit of heat to each leg, along with a bit of extra solder where
the old and new legs overlap. If needed you can also apply a bit of
pressure on the leg with an awl or Wooden Skewer until it cools.

This trick is also useful when using RECYCLED IC's.

In earlier times I used the CutOff wheels to remove IC's from Computer
Circuit Boards, TV's, Etc.

I have also been known to Use a Propane torch to unsolder Large quantities
of IC's from PCBs. This is done only outside and when you are not
concerned with saving the PCB :^)

I have also used the CutOff wheel to Remove Selected Circuits from a PCB
for later use intact or to more carefully remove a Large Computer Chip.

Need an AUDIO Stage, an Oscillator or an IF filter? Just trace out the
circuit, Mark your CUTOUT AREA with a Black "SHARPIE PEN" and cut away..

OBTW One more thing I almost forgot. It is generally a good Idea to Use a
"Resistive WRIST STRAP" for yourself and one from the PCB to Workbench
GROUND.

This is very important if you are working on the extraction/repair of
STATIC SENSITIVE DEVICES. The friction and heat from the cutting wheels
can generate a bit of static charge.

People are always amazed when they see the light from a bit of scotch tape
being pulled from the roll in the dark.

Plastic and its relatives have lots of unseen danger for our toys.

Hope some of this is useful to you and the gang on the list.

ONE Last note. If you haven't used these methods or tools much before, I
would recommend practice on an Old Computer PCB. Lots of free ones at any
hamfest or Trash Day :^)

Sir George, The First :^)

72 ES
QRP DX TU (C) 1986, G. "Danny" Gingell, K3TKS@ abs.net
QRP A.R.C.I. Net Manager and Board of Director Member.
Gingell & Company, Ltd. Small Business Telephone Systems
Notary Public and Locksmith Services
George D. Gingell, Jr. 3052 Fairland Road, Silver Spring, MD 20904-7117
Maryland Milliwatt Club QRP Reference Library, (301)572-6789
Maryland Milliwatt Club Founder and Trustee of Club Station - WQ3RP -
Grid Square FM19mb 76.94 W - 39.06 N Silver Spring, MD 20904 QRPea.A.


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