On Sep 3, 1:36Â*pm, "J. Clarke" wrote:
On 9/3/2010 12:46 PM, DerbyDad03 wrote:



On Sep 3, 11:55 am, "Michael A.
wrote:
DerbyDad03 wrote:

"when something stops working when you put the lid on, that tells
me the lid is somehow binding something up or shorting something out."

In a much earlier life, I used to install and repair Radio Shack
TRS-80 workstations. My company also used the Storage Expansion Unit
which could house up to three additional 8€³ drives as shown he

http://www.trs-80.com/wordpress/trs-...line/model-ii/

These expansion bays were notorious for not working once you put the
cover back on. You'd repair the unit or add a drive, test all three
drives with the cover off and then install the cover and the 84,000
screws that kept it on. Invariably, one of the drives (it would be
random as to which one) would no longer be accessible.

You had to loosen screws, tweak the cover, slap the box, whatever, to
get it working.

With hundreds of these workstations installed in everything from
offices to chemical processing areas, you can be sure that we did a
lot of bench work trying to determine what the problem was in an
effort to make our on-site work easier. We never figured it out and
were thrilled when they started replacing them with the original IBM
PC.

Â* Â* They cut one corner too many by tin plating the edge connectors, then
plugging them into connectors with gold plated contacts. Â*At one time
there was a special connector sold that you soldered to the tin plate,
and had gold plated contacts to mate with the ribbon cables.

--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

"At one time there was a special connector sold that you soldered
to the tin plate, and had gold plated contacts to mate with the ribbon
cables."

Trust me, I know all about the many corners they cut! ;-)

However, how would this particular connector issue be impacted by the
installation of the case? The case had no connectors, it was just a
metal shell.

Just a guess but tightening the crews could distort the case enough to
put stress on the drives, altering their alignment thus they (especially
with the old stepper-motor drives) no longer have proper track
alignment. Â*Solution would be to leave the drive mounting screws on one
side a little loose so they support the drive but don't put any load on
it--a little Loctite would keep them from working loose in service.

P.S. Before installing the TRS-80's, we opened up every keyboard and
ran a wire from the circuit board ground to the plastic case. Before
we did that, weird things would happen when the user touched the
keyboard.

The worst was seeing the disk drive light turn on and knowing that the
program and/or data disk was now corrupt. The least was hearing the
daisy wheel printer print out a single character.

We had some users that were so paranoid about their data that they
wired a grounding bracelet to the sprinkler system and would hook
themselves up before they touched the system.

Many times we just left half the screws out altogether!