Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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Old September 24th 19, 01:58 PM posted to rec.crafts.metalworking
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Default wires are metal ...

** When I got my truck back from our son , lots of things that he just
couldn't be bothered to fix . One thing is the radio power supply . He
did tell me that the radio had "died" , turns out the fuse (in the fuse
block) keeps blowing . I've got the dashboard apart enough to check the
wiring harness and supply wires , can't find any cuts or anything that
looks like damaged insulation ... it works just fine sittin' in the
driveway , but within a few miles driving it blows the fuse . I figured
it was the radio/CD player unit so I got a new one , does the same thing
.. I'm really puzzled by this , from the way the fuse was spattered it's
got to be a dead short to ground . I think it very unlikely that the new
radio/CD unit is bad - the old one did work when I replaced the fuse ,
for a few miles same as the new unit . This is an '86 GMC pickup , I'm
hoping someone here might be aware of a known problem area that I might
check ... I gotta have tunes !

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !


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Old September 24th 19, 03:03 PM posted to rec.crafts.metalworking
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Posts: 1,964
Default wires are metal ...

On Sep 24, 2019, Terry Coombs wrote
(in article ):

When I got my truck back from our son , lots of things that he just
couldn't be bothered to fix . One thing is the radio power supply . He
did tell me that the radio had "died" , turns out the fuse (in the fuse
block) keeps blowing . I've got the dashboard apart enough to check the
wiring harness and supply wires , can't find any cuts or anything that
looks like damaged insulation ... it works just fine sittin' in the
driveway , but within a few miles driving it blows the fuse . I figured
it was the radio/CD player unit so I got a new one , does the same thing
. I'm really puzzled by this , from the way the fuse was spattered it's
got to be a dead short to ground . I think it very unlikely that the new
radio/CD unit is bad - the old one did work when I replaced the fuse ,
for a few miles same as the new unit . This is an '86 GMC pickup , I'm
hoping someone here might be aware of a known problem area that I might
check ... I gotta have tunes !


Its classic for sure. The power wire is bouncing around as you drive, and
over time the wire insulation was worn through, allowing contact between
copper wire and some part of the steel body.When you find the spot, it will
be pretty obvious visually.

Solution is to find out where this is happening, and mechanically prevent
further contact.

Joe Gwinn

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Old September 24th 19, 03:04 PM posted to rec.crafts.metalworking
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Posts: 5,502
Default wires are metal ...

"Terry Coombs" wrote in message
...
When I got my truck back from our son , lots of things that he just
couldn't be bothered to fix . One thing is the radio power supply .
He did tell me that the radio had "died" , turns out the fuse (in
the fuse block) keeps blowing . I've got the dashboard apart enough
to check the wiring harness and supply wires , can't find any cuts
or anything that looks like damaged insulation ... it works just
fine sittin' in the driveway , but within a few miles driving it
blows the fuse . I figured it was the radio/CD player unit so I got
a new one , does the same thing . I'm really puzzled by this , from
the way the fuse was spattered it's got to be a dead short to ground
. I think it very unlikely that the new radio/CD unit is bad - the
old one did work when I replaced the fuse , for a few miles same as
the new unit . This is an '86 GMC pickup , I'm hoping someone here
might be aware of a known problem area that I might check ... I
gotta have tunes !

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !


Check/clean the battery connections.

If connector vibration momentarily disconnects the battery from the
charging circuit, the alternator output voltage will rise until a
protective clamping device somewhere, like in the radio, conducts
enough current to limit it. The voltage regulator tries to cut off the
alternator field current but can't remove the current already flowing
in the field winding.

https://en.wikipedia.org/wiki/Load_dump



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Old September 24th 19, 03:11 PM posted to rec.crafts.metalworking
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First recorded activity by DIYBanter: Feb 2018
Posts: 143
Default wires are metal ...

On Tue, 24 Sep 2019 07:58:47 -0500
Terry Coombs wrote:

** When I got my truck back from our son , lots of things that he just
couldn't be bothered to fix . One thing is the radio power supply . He
did tell me that the radio had "died" , turns out the fuse (in the fuse
block) keeps blowing . I've got the dashboard apart enough to check the
wiring harness and supply wires , can't find any cuts or anything that
looks like damaged insulation ... it works just fine sittin' in the
driveway , but within a few miles driving it blows the fuse . I figured
it was the radio/CD player unit so I got a new one , does the same thing
. I'm really puzzled by this , from the way the fuse was spattered it's
got to be a dead short to ground . I think it very unlikely that the new
radio/CD unit is bad - the old one did work when I replaced the fuse ,
for a few miles same as the new unit . This is an '86 GMC pickup , I'm
hoping someone here might be aware of a known problem area that I might
check ... I gotta have tunes !


Just some random ideas... Does it have a power antenna? (doubtful)

Check the fuse schematic and see if anything else uses the same fuse?

Any kind of work/replacement done than might have pinched a wire
underneath or shot a new screw threw a wire?

Some speaker systems run "hot leads" and do not behave well
if a lead gets grounded...

--
Leon Fisk
Grand Rapids MI

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Old September 24th 19, 03:44 PM posted to rec.crafts.metalworking
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First recorded activity by DIYBanter: Jun 2011
Posts: 5,502
Default wires are metal ...

"Leon Fisk" wrote in message
...
On Tue, 24 Sep 2019 07:58:47 -0500
Terry Coombs wrote:

When I got my truck back from our son , lots of things that he just
couldn't be bothered to fix . One thing is the radio power supply .
He
did tell me that the radio had "died" , turns out the fuse (in the
fuse
block) keeps blowing . I've got the dashboard apart enough to check
the
wiring harness and supply wires , can't find any cuts or anything
that
looks like damaged insulation ... it works just fine sittin' in the
driveway , but within a few miles driving it blows the fuse . I
figured
it was the radio/CD player unit so I got a new one , does the same
thing
. I'm really puzzled by this , from the way the fuse was spattered
it's
got to be a dead short to ground . I think it very unlikely that the
new
radio/CD unit is bad - the old one did work when I replaced the fuse
,
for a few miles same as the new unit . This is an '86 GMC pickup ,
I'm
hoping someone here might be aware of a known problem area that I
might
check ... I gotta have tunes !


Just some random ideas... Does it have a power antenna? (doubtful)

Check the fuse schematic and see if anything else uses the same fuse?

Any kind of work/replacement done than might have pinched a wire
underneath or shot a new screw threw a wire?

Some speaker systems run "hot leads" and do not behave well
if a lead gets grounded...

--
Leon Fisk
Grand Rapids MI

=====================
Good suggestion.

I prioritize my troubleshooting sequence partly by how quick and easy
the tests are with available equipment. How would you check for an
intermittent speaker wire short to ground?






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Old September 24th 19, 03:50 PM posted to rec.crafts.metalworking
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First recorded activity by DIYBanter: Oct 2012
Posts: 3,028
Default wires are metal ...

On 9/24/2019 9:03 AM, Joseph Gwinn wrote:
On Sep 24, 2019, Terry Coombs wrote
(in article ):

When I got my truck back from our son , lots of things that he just
couldn't be bothered to fix . One thing is the radio power supply . He
did tell me that the radio had "died" , turns out the fuse (in the fuse
block) keeps blowing . I've got the dashboard apart enough to check the
wiring harness and supply wires , can't find any cuts or anything that
looks like damaged insulation ... it works just fine sittin' in the
driveway , but within a few miles driving it blows the fuse . I figured
it was the radio/CD player unit so I got a new one , does the same thing
. I'm really puzzled by this , from the way the fuse was spattered it's
got to be a dead short to ground . I think it very unlikely that the new
radio/CD unit is bad - the old one did work when I replaced the fuse ,
for a few miles same as the new unit . This is an '86 GMC pickup , I'm
hoping someone here might be aware of a known problem area that I might
check ... I gotta have tunes !

It´s classic for sure. The power wire is bouncing around as you drive, and
over time the wire insulation was worn through, allowing contact between
copper wire and some part of the steel body.When you find the spot, it will
be pretty obvious visually.

Solution is to find out where this is happening, and mechanically prevent
further contact.

Joe Gwinn


* I kinda figure you're right , there's a place where it's worn thru .
The problem is finding that spot ... if it was obvious I'd have found it
by now . I've looked and felt as much of that harness as is available to
check , nothing so far . I'm starting to wonder if it's in/near the fuse
block , maybe where the under-dash wiring comes from behind the block .
But it's raining today , and I'll be too busy to look into it further
until Friday or Saturday .

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

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Old September 24th 19, 03:52 PM posted to rec.crafts.metalworking
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First recorded activity by DIYBanter: Oct 2012
Posts: 3,028
Default wires are metal ...

On 9/24/2019 9:04 AM, Jim Wilkins wrote:
"Terry Coombs" wrote in message
...
When I got my truck back from our son , lots of things that he just
couldn't be bothered to fix . One thing is the radio power supply .
He did tell me that the radio had "died" , turns out the fuse (in
the fuse block) keeps blowing . I've got the dashboard apart enough
to check the wiring harness and supply wires , can't find any cuts
or anything that looks like damaged insulation ... it works just
fine sittin' in the driveway , but within a few miles driving it
blows the fuse . I figured it was the radio/CD player unit so I got
a new one , does the same thing . I'm really puzzled by this , from
the way the fuse was spattered it's got to be a dead short to ground
. I think it very unlikely that the new radio/CD unit is bad - the
old one did work when I replaced the fuse , for a few miles same as
the new unit . This is an '86 GMC pickup , I'm hoping someone here
might be aware of a known problem area that I might check ... I
gotta have tunes !

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

Check/clean the battery connections.

If connector vibration momentarily disconnects the battery from the
charging circuit, the alternator output voltage will rise until a
protective clamping device somewhere, like in the radio, conducts
enough current to limit it. The voltage regulator tries to cut off the
alternator field current but can't remove the current already flowing
in the field winding.

https://en.wikipedia.org/wiki/Load_dump




* Wouldn't that blow the smaller fuse in the radio itself before the 15
amp supply fuse ?

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

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Old September 24th 19, 04:06 PM posted to rec.crafts.metalworking
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First recorded activity by DIYBanter: Oct 2012
Posts: 3,028
Default wires are metal ...

On 9/24/2019 9:11 AM, Leon Fisk wrote:
On Tue, 24 Sep 2019 07:58:47 -0500
Terry Coombs wrote:

** When I got my truck back from our son , lots of things that he just
couldn't be bothered to fix . One thing is the radio power supply . He
did tell me that the radio had "died" , turns out the fuse (in the fuse
block) keeps blowing . I've got the dashboard apart enough to check the
wiring harness and supply wires , can't find any cuts or anything that
looks like damaged insulation ... it works just fine sittin' in the
driveway , but within a few miles driving it blows the fuse . I figured
it was the radio/CD player unit so I got a new one , does the same thing
. I'm really puzzled by this , from the way the fuse was spattered it's
got to be a dead short to ground . I think it very unlikely that the new
radio/CD unit is bad - the old one did work when I replaced the fuse ,
for a few miles same as the new unit . This is an '86 GMC pickup , I'm
hoping someone here might be aware of a known problem area that I might
check ... I gotta have tunes !

Just some random ideas... Does it have a power antenna? (doubtful)


* Nope , no power antenna .


Check the fuse schematic and see if anything else uses the same fuse?


* As far as I can tell it's only the radio , nothing else goes dead .


Any kind of work/replacement done than might have pinched a wire
underneath or shot a new screw threw a wire?


** Nope , no other work besides a transmission replacement . I don't
think the power lead for the radio goes anywhere there .

Some speaker systems run "hot leads" and do not behave well
if a lead gets grounded...


* No powered speakers , basic stock 4 speaker system , I have some
bigger speakers in a box behind the seat . I've never had any problems
with the stereo system in the 12 years I've had this truck - until I
loaned it to my son "for a few weeks" that turned into a year and a half
.. In fact , the only problems I've had were normal wear-n-tear stuff
that happens with over 120k on the odometer .

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

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Old September 24th 19, 04:07 PM posted to rec.crafts.metalworking
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First recorded activity by DIYBanter: Jun 2011
Posts: 5,502
Default wires are metal ...

"Terry Coombs" wrote in message
...
On 9/24/2019 9:03 AM, Joseph Gwinn wrote:
On Sep 24, 2019, Terry Coombs wrote
(in article ):

When I got my truck back from our son , lots of things that he
just
couldn't be bothered to fix . One thing is the radio power supply
. He
did tell me that the radio had "died" , turns out the fuse (in the
fuse
block) keeps blowing . I've got the dashboard apart enough to
check the
wiring harness and supply wires , can't find any cuts or anything
that
looks like damaged insulation ... it works just fine sittin' in
the
driveway , but within a few miles driving it blows the fuse . I
figured
it was the radio/CD player unit so I got a new one , does the same
thing
. I'm really puzzled by this , from the way the fuse was spattered
it's
got to be a dead short to ground . I think it very unlikely that
the new
radio/CD unit is bad - the old one did work when I replaced the
fuse ,
for a few miles same as the new unit . This is an '86 GMC pickup ,
I'm
hoping someone here might be aware of a known problem area that I
might
check ... I gotta have tunes !

Its classic for sure. The power wire is bouncing around as you
drive, and
over time the wire insulation was worn through, allowing contact
between
copper wire and some part of the steel body.When you find the spot,
it will
be pretty obvious visually.

Solution is to find out where this is happening, and mechanically
prevent
further contact.

Joe Gwinn


I kinda figure you're right , there's a place where it's worn thru
. The problem is finding that spot ... if it was obvious I'd have
found it by now . I've looked and felt as much of that harness as is
available to check , nothing so far . I'm starting to wonder if it's
in/near the fuse block , maybe where the under-dash wiring comes
from behind the block . But it's raining today , and I'll be too
busy to look into it further until Friday or Saturday .

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !


Taping possible contact areas may help.

This has been useful when there are no voltage-sensitive components at
risk, like older appliances:
https://www.amazon.com/dp/B00975X2FY..._26725410_item

Battery-powered ones are more convenient, but don't stop generating if
you get shocked.


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Old September 24th 19, 04:28 PM posted to rec.crafts.metalworking
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First recorded activity by DIYBanter: Jun 2011
Posts: 5,502
Default wires are metal ...

"Terry Coombs" wrote in message
...
On 9/24/2019 9:04 AM, Jim Wilkins wrote:
"Terry Coombs" wrote in message
...
When I got my truck back from our son , lots of things that he
just
couldn't be bothered to fix . One thing is the radio power supply
.
He did tell me that the radio had "died" , turns out the fuse (in
the fuse block) keeps blowing . I've got the dashboard apart
enough
to check the wiring harness and supply wires , can't find any cuts
or anything that looks like damaged insulation ... it works just
fine sittin' in the driveway , but within a few miles driving it
blows the fuse . I figured it was the radio/CD player unit so I
got
a new one , does the same thing . I'm really puzzled by this ,
from
the way the fuse was spattered it's got to be a dead short to
ground
. I think it very unlikely that the new radio/CD unit is bad - the
old one did work when I replaced the fuse , for a few miles same
as
the new unit . This is an '86 GMC pickup , I'm hoping someone here
might be aware of a known problem area that I might check ... I
gotta have tunes !

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

Check/clean the battery connections.

If connector vibration momentarily disconnects the battery from the
charging circuit, the alternator output voltage will rise until a
protective clamping device somewhere, like in the radio, conducts
enough current to limit it. The voltage regulator tries to cut off
the
alternator field current but can't remove the current already
flowing
in the field winding.

https://en.wikipedia.org/wiki/Load_dump




Wouldn't that blow the smaller fuse in the radio itself before the
15 amp supply fuse ?

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !


Hard to say without looking. Some fuses blow immediately, others have
a time delay to allow high-current startup surges like charging the
power supply capacitors. For example I can pull 70A for about 10
seconds through the 30A output circuit breaker on my home brew 24V
battery charger.

Cleaning the battery connections is a good idea whether or not it
helps here.




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