John Navas wrote in
:

Radio Shack doesn't build them. They are sourced from multiple Asian
contract manufacturers.


I knew that. I think Uniden, the CB maker, made these....

On Dec 28, 7:20*pm, Larry wrote:
John Navas wrote :

Radio Shack doesn't build them. *They are sourced from multiple Asian
contract manufacturers.

I knew that. *I think Uniden, the CB maker, made these....

Radio Shack does specify what they want in a product. Some are just
rebranded like the radio shack SM-58 look alikes that have shure
written on the xlr insert. Of course they are 58's that didn't meet
quality control specs for shure...

If radio shack buys tens of thousands of a unit, they damn well can
(but may not) demand robustness in design.They didn't in feature laden
DMM's that fail if you sneeze hard on them.

Larryr wrote in
:

On Dec 28, 7:20*pm, Larry wrote:
John Navas wrote
innews:vi8fl4dvq9el9saob1hj
:

Radio Shack doesn't build them. *They are sourced from multiple
Asian contract manufacturers.

I knew that. *I think Uniden, the CB maker, made these....

Radio Shack does specify what they want in a product. Some are just
rebranded like the radio shack SM-58 look alikes that have shure
written on the xlr insert. Of course they are 58's that didn't meet
quality control specs for shure...

If radio shack buys tens of thousands of a unit, they damn well can
(but may not) demand robustness in design.They didn't in feature laden
DMM's that fail if you sneeze hard on them.


One of the lapel mics failed a couple of months ago. They had plenty of
spares so didn't hand it to me until I was working on the antique Allen
electronic pipe organ that dates back to the very first point-contact
germanium transistors it is full of....one oscillator transistor for
each note it plays...a hartley oscillator with tapped coil for
stability.

Someone forgot to turn off the preamp in the mic and the button watch
battery in the tiny box was dead. I can't believe how long those things
will run or how much abuse they'll take swingin' and swayin' to the
screaming music every Sunday. They all must be deaf. I even have to
replace mid range speakers!

I buy DMMs, in bulk, from Harbor Freight. At $3.99, they're worth it
even if you toss the whole DMM in the trash just for the nice little
test leads that are nicer than RatShacks and half the price with a full
featured DMM with batteries attached! I keep a dozen or so to hand out
to aspiring young technicians and engineers I may need a hand from 10
years from now....mostly to get out of my wheelchair, probably. Give a
curious kid a little DMM and you can ruin his whole life! Serves them
right....it did me.
http://www.youtube.com/watch?v=r9CxjvIAJqc

http://www.harborfreight.com/cpi/cta...emnumber=90899
Darn, they went up a buck!

At $20, this is my favorite DMM:
http://www.harborfreight.com/cpi/cta...emnumber=37772

While were here, every boat should have this 100A battery tester:
http://www.harborfreight.com/cpi/cta...emnumber=90636
It's only $15 and will snoop out those dead cells in 2 minutes flat!

I held my breath and bought the Big Kahuna of battery/alternator
testers:
http://www.harborfreight.com/cpi/cta...emnumber=91129
Wanna see how much power you can get before the belt starts slippin'?
Dis be the beast! 500 amps. If you're going to try for more than a
hundred amps....make damned sure the clamps dig INTO the posts real hard
or this carbon pile load will really smoke them!

It never ceases to amaze me, an old metrologist (calibration technician
USN) how ACCURATE even the cheapest Chinese analog volt or ammeter is
calibrated. It's uncanny! Those little analog VOMs from Ratshack are
DEAD ACCURATE!

Radio Shack SPL meters are damn accurate.
My boat came with a panel mounted digital DC volt meter that reads to .
1
I had a Fluke 187(some crackhead stole it!) that read to .001 and also
read AC on DC so I could see the ripple making it thru the rectifier
on AC Charge. It was fun to watch the voltage come up by the
thousandth.
The panel meter is .2-.3Volts low and is quite upsetting when it says
my 900AH golf cart bank is at 12.0 when It's in the high 12.3 with a
10 amp draw....

My problem with "dispose-a-tools" is that they need to be disposed of
at the most inconvenient times, when you are contorted into a tight
corner having spent a half an hour setting up a 2 minute job they
validate murphy and fail. argggh

Larryr wrote in news:422276b1-0f4b-4462-8db5-
:

The panel meter is .2-.3Volts low and is quite upsetting when it says
my 900AH golf cart bank is at 12.0 when It's in the high 12.3 with a
10 amp draw....



If you would remove the panel meter and take it to a calibration shop that
does analog meters, they will put it in a magnet charger and put an
accurate full scale voltage on it. Then, they will pulse the magnet
charger to bring the meter's permanent magnet up to proper magnetic field,
making the meter read correctly. They will track the meter and if the
tracking from full scale to zero is out of tolerance, they can rescale the
meter scale to read correctly....for more money, of course.

If you tell them you want the meter to be dead accurate at some point on
its scale, say 14.2V for accurate charging, they can calibrate the magnetic
field at that point, instead of full scale.

They'll also test the D'Arsonval's movement jewelled bearings and set the
tension on them, which will have slackened over its lifetime, and make sure
it has the right hairspring tension for good tracking. The hairsprings
slacken tension over their lives, making the meter too sensitive and
spreading the scale inaccurately.

Sure is cheaper than a new, also inaccurately calibrated, meter.

If you're near Houston or Virginia Beach find EIL Instruments and give them
a call. I used to be their mobile calibration van manager, dragging an
office trailer across the country repairing and calibrating CG and FAA test
equipment, on site. Both places had meter calibration facilities to
support commercial and military shipping panel meters, which are still in
use today.

Larry, the panel meter is a no name digital meter. I would rather
take calibration service money and put it towards a battery monitor
system like a link 1000, although I have gotten by without such so
far. Thanks for the info nonetheless.

Larryr wrote in news:b9dee785-7855-441f-933a-
:

Larry, the panel meter is a no name digital meter. I would rather
take calibration service money and put it towards a battery monitor
system like a link 1000, although I have gotten by without such so
far. Thanks for the info nonetheless.


I bet there's a little tiny pot in that kind of meter to calibrate it.
Probably has some fingernail polish holding it fast. Put a known
CALIBRATED meter across the terminals on the back and just adjust the pot
until it reads the same 13.8327 volts the calibrated meter reads.

DVM's aren't rocket science.

Shhhh...don't tell anyone, though. I made quite a comfortable living off
them for many years.....(c;