Absurd, right? The 30 foot phone line

I guess nichrome wire wound around a ceramic core, then coated with
(maybe?) epoxy. my biggest question: I assumed the resistance wire was
originally UNcoated, bare wire, wrapped with each turn touching the next.

BUT

if it IS bare wire, then the makers either must keep each turn from
touching the next turn over (with a very small clearance), *OR* the wire
is coated -prior- to the winding process. otherwise, the 'resistance per
turn' wouldn't be controllable - right? I mean like if one turn, near
the middle of a wirewound resistor, was 'shorted' to the next winding
mid-turn...

like in these things:

http://machines.scienceontheweb.net/shocker/photos/photo23.html
wirewound03.jpg

thanks for info, guys :)

bubba here is kind of contemplating making a rheostat...this recipe
calls for a 6 ohm, 11.1 amp type (see bottom right of page 2)

http://www.countryplans.com/vintage_farm//metalshop/AutoArcWelder.pdf
AutoArcWelder.pdf (application/pdf Object)

of course, i have this ol' powerstat, but it's a 5 amp model

http://machines.scienceontheweb.net/shocker/photos/photo16.html
powerstat07.jpg
 
tx7123@yahoo.com wrote:

Well just when I thought everything was fixed...
The receiver had worked flawlessly for over 3 weeks.
Then suddenly today the radio went dead again.
I took it apart and this time reheated one of the solder
joints on the questionable transistor (d313e).
Anyway everything is back together and working.
Hopefully this will permanently fix the problem.
The plastic tabs that hold the board in place are disintegrating.
Anybody know where I can get similar tabs?
Thnaks.


On May 10, 6:11 pm, tx7...@yahoo.com wrote:

On May 3, 5:19 pm, "Mark D. Zacharias" <mzachar...@nonsense.net
wrote:






tx7...@yahoo.com> wrote in message

news:92dc789c-7188-460c-aed3-e3df24b80df4@x41g2000hsb.googlegroups.com...
I have left the case open, and have the thing sitting on a shelf
vertically.
It worked flawlessly for about 3 days, then spontaneouslt theradio
went dead again.
I ever so gently tapped the heatsink that this transistor is on, and
once
again everything is fine. I have not lifted the board yet to look at
the solder
underneath. However I'm beginning to think that it is the transistor
itself
that is the problem. Can I find the exact replacement atradioshack?
If I'm going to lift the board, I'm thinking it's probably makes sense
to replace the
device.

Thanks

On Apr 29, 2:32 am, "JANA" <j...@NOSPAMca.inter.net> wrote:

I strongly suggest you find and fix the cold solder connection that
caused the fault. Or if the transistor is intermittant, replace it.

--

JANA
_____

tx7...@yahoo.com> wrote in message

news:a60fee7d-739c-427d-bf6c-301464aa4ceb@k37g2000hsf.googlegroups.com...
OK I took the thing apart and sure enough, there was a sanyo 313E
mounted on a V shaped piece of metal(heatsink?). When I tapped
gently on the metal, everything now works fine.
The small board in question is AWR-011A, which according
to the schematic is the power supply unit.
I would think that if this was the roblem it would effect
everything, not just theradio.
Anyway I will run it for awhile with the case open,
and see if the problem recurs.

On Apr 26, 11:50 am, "Bob Shuman" <no_spam_...@sbcglobal.net> wrote:

Sounds like something is intermittent in theradiosection (assumes
amplifier/auxiliary input/tape/etc. all are still working fine). I'd
start
by looking for cold/broken solder connections under a magnifying. Or
alternatively, if that does not work and you can get at the board
safely
while the unit is powered up, you can try pushing at various points
with a
wooden dowel or similar non-conductive item. This may help you isolate
the
area to take a closer look.

If these do not help, then you'll either need a schematic, a volt
meter,
scope, and some troubleshooting skills to check the power supply
voltages at
key points and then follow the signal through theradiosection or
take it
to someone to do the work for you.

Bob

tx7...@yahoo.com> wrote in message

news:facbbdcd-1b25-4648-a91b-6c409b7924d8@56g2000hsm.googlegroups.com...

I have apioneersx-727receiver, I'm the original owner (33 years).
Recently theradiostopped working.
Everything else works great.
FM, AM no difference does NOT work.
The tuning meter does not move as I turn the tuning dial.
If I turn the volume up, I can hear some static thru the speakers.
Occasionally theradiowill spontaneously work for a while,
and then return to this dead mode.
All the other inputs cd, turntable work fine.
Any ideas what the problem might be?
Thanks.- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

Just resolder the transistor. You will see that the solder connections there
have ring cracks from age and heating / cooling over the course of time.
Common problem.

Mark Z.- Hide quoted text -

- Show quoted text -

Hi ,

I decided to lift the board and look at the solder for the device
sanyo 313e.
Before I could do anything the V shaped metal (heatsink?) attached to
the
device just fell off. The plastic screw holding it had just cracked in
half.
There also is a thin piece of plastic between the device and the
heatsink.
I'm assuming that they do want the device to touch the metal.
I could not find a another plastic screw, so I use a metal one with
an
insulating washer. I hope that is ok. Why does the device need to be
insulated from the metal heatsink. Is it strictly pecautionary, in
case
the heatsink comes in contact with something else. Would it be ok
to put some cpu grease between the device and the plastic insulator?
Anyway after all this the solder looked ok, so I did not resolder.
I wonder if my problem all along was that the heatsink
was just hanging on by a thread.
Anyway it seems to work ok. I'll run it for a while with the case
open
as a precaution.

Thanks- Hide quoted text -

- Show quoted text -


You mean nylon stand offs?
Click to expand...
places like Mouser, Digikey etc.. have hard things like that.


--
"I'd rather have a bottle in front of me than a frontal lobotomy"

"Daily Thought:

SOME PEOPLE ARE LIKE SLINKIES. NOT REALLY GOOD FOR ANYTHING BUT
THEY BRING A SMILE TO YOUR FACE WHEN PUSHED DOWN THE STAIRS.
http://webpages.charter.net/jamie_5"
 
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Michael Kennedy wrote:
"jakdedert" <jakdedert@bellsouth.net> wrote in message
news:SRj0k.8522$vP5.2612@bignews6.bellsouth.net...
PhattyMo wrote:
Franc Zabkar wrote:
On Thu, 29 May 2008 12:27:02 +0100, "N_Cook" <diverse@tcp.co.uk> put
finger to keyboard and composed:

Twice in 2 weeks, faults caused just by normal handling of kit, ...
Just about every battery compartment lid on any battery powered
equipment ...

- Franc Zabkar
Grrrr!!!! That damn little tab always breaks off,and the batteries fall
out!! *sigh*
I've seen some large CRT TV sets, where if you set them down in a
forward-tilted position (IOW set the front edge down first), the front of
the plastic base breaks off. To me that's ridiculous, to require handling
so carefully that one must set the unit down almost perfectly flat or
something will break off....

jak

Thats that wonderful chinese engineering and construction. ;-)


Probably 'construction', but the last time this happened to me, it was a
Click to expand...
Sony Trinitron 30(?)". I assume this was designed in Japan.

jak
 
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