Using the proper technical terms ... :-)
 

Just in. A combo, the job ticket on which says "Low volume. Sounds like
****."

There's hope for the lads behind the counter, yet. How nice to get one with
a perfect owner's description of the problem, rather than some wild guess
that the person who's booked it in has made, based on what the owner said. I
can just see some hairy guitarist lugging it in and saying to whoever booked
it in "Go on lad ! Just write it down, Low volume. Sounds like **** !"

:-)

Arfa

Using the proper technical terms ... :-)
 

On Mon, 26 Jul 2010 18:11:36 +0100, Arfa Daily wrote:

Just in. A combo, the job ticket on which says "Low volume. Sounds like
****."

There's hope for the lads behind the counter, yet. How nice to get one
with a perfect owner's description of the problem, rather than some wild
guess that the person who's booked it in has made, based on what the
owner said. I can just see some hairy guitarist lugging it in and saying
to whoever booked it in "Go on lad ! Just write it down, Low volume.
Sounds like **** !"

:-)

Arfa

LOL!

Using the proper technical terms ... :-)
 

On 26/07/2010 18:11, Arfa Daily wrote:
Just in. A combo, the job ticket on which says "Low volume. Sounds like
****."

There's hope for the lads behind the counter, yet. How nice to get one
with a perfect owner's description of the problem, rather than some wild
guess that the person who's booked it in has made, based on what the
owner said. I can just see some hairy guitarist lugging it in and saying
to whoever booked it in "Go on lad ! Just write it down, Low volume.
Sounds like **** !"

:-)

Arfa

So technically, it's probably fooked

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Using the proper technical terms ... :-)
 

"Arfa Daily" wrote in message
news:blj3o.55085$0e3.52289@hurricane...
Just in. A combo, the job ticket on which says "Low volume. Sounds like
****."

There's hope for the lads behind the counter, yet. How nice to get one
with a perfect owner's description of the problem, rather than some wild
guess that the person who's booked it in has made, based on what the owner
said. I can just see some hairy guitarist lugging it in and saying to
whoever booked it in "Go on lad ! Just write it down, Low volume. Sounds
like **** !"

:-)

**I like it! Much better than when the customer thinks they can diagnose the
fault for you.


--
Trevor Wilson
www.rageaudio.com.au

Using the proper technical terms ... :-)
 

On 26/07/2010 23:01, Trevor Wilson wrote:
"Arfa wrote in message
news:blj3o.55085$0e3.52289@hurricane...
Just in. A combo, the job ticket on which says "Low volume. Sounds like
****."

There's hope for the lads behind the counter, yet. How nice to get one
with a perfect owner's description of the problem, rather than some wild
guess that the person who's booked it in has made, based on what the owner
said. I can just see some hairy guitarist lugging it in and saying to
whoever booked it in "Go on lad ! Just write it down, Low volume. Sounds
like **** !"

:-)

**I like it! Much better than when the customer thinks they can diagnose the
fault for you.


It's probably just a wire off, needs welding...

--
I am using the free version of SPAMfighter.
We are a community of 7 million users fighting spam.
SPAMfighter has removed 1574 of my spam emails to date.
Get the free SPAMfighter he http://www.spamfighter.com/len

The Professional version does not have this message

Using the proper technical terms ... :-)
 

"Ron" wrote in message
...
On 26/07/2010 23:01, Trevor Wilson wrote:
"Arfa wrote in message
news:blj3o.55085$0e3.52289@hurricane...
Just in. A combo, the job ticket on which says "Low volume. Sounds like
****."

There's hope for the lads behind the counter, yet. How nice to get one
with a perfect owner's description of the problem, rather than some wild
guess that the person who's booked it in has made, based on what the
owner
said. I can just see some hairy guitarist lugging it in and saying to
whoever booked it in "Go on lad ! Just write it down, Low volume. Sounds
like **** !"

:-)

**I like it! Much better than when the customer thinks they can diagnose
the
fault for you.


It's probably just a wire off, needs welding...

--


Ah, funny you should mention welding, Ron. Apart from my new Chinese hot air
rework station purporting to be for electronic solder welding ...

I put that amp on the bench this morning, and indeed, it did have low
volume, and it did sound like **** - but not all of the time ... If you
plugged a guitar in it, and gave it a good 'clang', it produced a horrible
grating distortion, almost as though something was arcing, and how right
that turned out to be ! Plugging a generator into it, and with a reasonable
set of front panel settings on the amp, you could wind the generator level
up, and all of a sudden, the output would go from a nice clean sine wave, to
something resembling a distorted square wave, with 'sparky-looking'
interference on the top.

Nothing was shifting - HT was clean, bias was clean, outputs from the phase
splitter were clean, and drive right on the grids of the O/P tubes was
clean, but both anodes (plates) were 'dirty'. I was beginning to suspect
that the O/P Tx was breaking down when there was a large peak - peak drive
across it, but thought that I'd better try a replacement pair of 6L6's in
it, just in case. No change. I managed to get the generator set to a level
where it was consistently producing the bad output, and was just about to
carry out some more 'scope checks, when something caught my eye. It was a
little firestorm going on around one of the output jacks, which on this amp
are in the bottom of the chassis pointing down, and are open frame types.
The one for an extension speaker has an open contact set on it. Where the
contact 'loops' out of the front of the socket, it is quite close to the
chassis, and there, wedged between the contact and the chassis, was a screw,
merrily arcing away. I shut off and pried the screw out with a screwdriver
tip, and then, stupidly, picked it up and burnt my fingers :-(

The screw was a black plated type, so I guess not a brilliant conductor -
not enough to actually put a full short across the output, anyway. However,
once there was a high enough p-p output voltage across there, the plating
was breaking down enough to cause the sparks, and upset the output stage.
The screw was actually one of the ones that secures the main board to the
chassis. Given that these combos are built as portable gigging items, I' m
surprised that a company like Fender, doesn't put a paint seal, or a bit of
thread-lock on these screws. Still, they've all got a liberal coat of nail
polish on them now, so hopefully should prevent a similar occurrence in the
future.

Nice to get an 'odd' fault that can actually be pinned to a definite
problem, with a definite fix, for a change ...

Arfa

Using the proper technical terms ... :-)
 

On 27/07/2010 14:17, Arfa Daily wrote:


"Ron" wrote in message
...
On 26/07/2010 23:01, Trevor Wilson wrote:
"Arfa wrote in message
news:blj3o.55085$0e3.52289@hurricane...
Just in. A combo, the job ticket on which says "Low volume. Sounds like
****."

There's hope for the lads behind the counter, yet. How nice to get one
with a perfect owner's description of the problem, rather than some
wild
guess that the person who's booked it in has made, based on what the
owner
said. I can just see some hairy guitarist lugging it in and saying to
whoever booked it in "Go on lad ! Just write it down, Low volume.
Sounds
like **** !"

:-)

**I like it! Much better than when the customer thinks they can
diagnose the
fault for you.


It's probably just a wire off, needs welding...

--


Ah, funny you should mention welding, Ron. Apart from my new Chinese hot
air rework station purporting to be for electronic solder welding ...

I put that amp on the bench this morning, and indeed, it did have low
volume, and it did sound like **** - but not all of the time ... If you
plugged a guitar in it, and gave it a good 'clang', it produced a
horrible grating distortion, almost as though something was arcing, and
how right that turned out to be ! Plugging a generator into it, and with
a reasonable set of front panel settings on the amp, you could wind the
generator level up, and all of a sudden, the output would go from a nice
clean sine wave, to something resembling a distorted square wave, with
'sparky-looking' interference on the top.

Nothing was shifting - HT was clean, bias was clean, outputs from the
phase splitter were clean, and drive right on the grids of the O/P tubes
was clean, but both anodes (plates) were 'dirty'. I was beginning to
suspect that the O/P Tx was breaking down when there was a large peak -
peak drive across it, but thought that I'd better try a replacement pair
of 6L6's in it, just in case. No change. I managed to get the generator
set to a level where it was consistently producing the bad output, and
was just about to carry out some more 'scope checks, when something
caught my eye. It was a little firestorm going on around one of the
output jacks, which on this amp are in the bottom of the chassis
pointing down, and are open frame types. The one for an extension
speaker has an open contact set on it. Where the contact 'loops' out of
the front of the socket, it is quite close to the chassis, and there,
wedged between the contact and the chassis, was a screw, merrily arcing
away. I shut off and pried the screw out with a screwdriver tip, and
then, stupidly, picked it up and burnt my fingers :-(

The screw was a black plated type, so I guess not a brilliant conductor
- not enough to actually put a full short across the output, anyway.
However, once there was a high enough p-p output voltage across there,
the plating was breaking down enough to cause the sparks, and upset the
output stage. The screw was actually one of the ones that secures the
main board to the chassis. Given that these combos are built as portable
gigging items, I' m surprised that a company like Fender, doesn't put a
paint seal, or a bit of thread-lock on these screws. Still, they've all
got a liberal coat of nail polish on them now, so hopefully should
prevent a similar occurrence in the future.

Nice to get an 'odd' fault that can actually be pinned to a definite
problem, with a definite fix, for a change ...

Arfa

So I was almost right, it wasn't fooked, it was screwed!

Ron

--
I am using the free version of SPAMfighter.
We are a community of 7 million users fighting spam.
SPAMfighter has removed 1574 of my spam emails to date.
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The Professional version does not have this message

Using the proper technical terms ... :-)
 

"Ron" wrote in message
...
On 27/07/2010 14:17, Arfa Daily wrote:


"Ron" wrote in message
...
On 26/07/2010 23:01, Trevor Wilson wrote:
"Arfa wrote in message
news:blj3o.55085$0e3.52289@hurricane...
Just in. A combo, the job ticket on which says "Low volume. Sounds
like
****."

There's hope for the lads behind the counter, yet. How nice to get one
with a perfect owner's description of the problem, rather than some
wild
guess that the person who's booked it in has made, based on what the
owner
said. I can just see some hairy guitarist lugging it in and saying to
whoever booked it in "Go on lad ! Just write it down, Low volume.
Sounds
like **** !"

:-)

**I like it! Much better than when the customer thinks they can
diagnose the
fault for you.


It's probably just a wire off, needs welding...

--


Ah, funny you should mention welding, Ron. Apart from my new Chinese hot
air rework station purporting to be for electronic solder welding ...

I put that amp on the bench this morning, and indeed, it did have low
volume, and it did sound like **** - but not all of the time ... If you
plugged a guitar in it, and gave it a good 'clang', it produced a
horrible grating distortion, almost as though something was arcing, and
how right that turned out to be ! Plugging a generator into it, and with
a reasonable set of front panel settings on the amp, you could wind the
generator level up, and all of a sudden, the output would go from a nice
clean sine wave, to something resembling a distorted square wave, with
'sparky-looking' interference on the top.

Nothing was shifting - HT was clean, bias was clean, outputs from the
phase splitter were clean, and drive right on the grids of the O/P tubes
was clean, but both anodes (plates) were 'dirty'. I was beginning to
suspect that the O/P Tx was breaking down when there was a large peak -
peak drive across it, but thought that I'd better try a replacement pair
of 6L6's in it, just in case. No change. I managed to get the generator
set to a level where it was consistently producing the bad output, and
was just about to carry out some more 'scope checks, when something
caught my eye. It was a little firestorm going on around one of the
output jacks, which on this amp are in the bottom of the chassis
pointing down, and are open frame types. The one for an extension
speaker has an open contact set on it. Where the contact 'loops' out of
the front of the socket, it is quite close to the chassis, and there,
wedged between the contact and the chassis, was a screw, merrily arcing
away. I shut off and pried the screw out with a screwdriver tip, and
then, stupidly, picked it up and burnt my fingers :-(

The screw was a black plated type, so I guess not a brilliant conductor
- not enough to actually put a full short across the output, anyway.
However, once there was a high enough p-p output voltage across there,
the plating was breaking down enough to cause the sparks, and upset the
output stage. The screw was actually one of the ones that secures the
main board to the chassis. Given that these combos are built as portable
gigging items, I' m surprised that a company like Fender, doesn't put a
paint seal, or a bit of thread-lock on these screws. Still, they've all
got a liberal coat of nail polish on them now, so hopefully should
prevent a similar occurrence in the future.

Nice to get an 'odd' fault that can actually be pinned to a definite
problem, with a definite fix, for a change ...

Arfa

So I was almost right, it wasn't fooked, it was screwed!


Haha, it's only a matter of semantics.

Good story though.


tm



--- news://freenews.netfront.net/ - complaints: ---

Using the proper technical terms ... :-)
 

"Ron" wrote in message
...
On 27/07/2010 14:17, Arfa Daily wrote:


"Ron" wrote in message
...
On 26/07/2010 23:01, Trevor Wilson wrote:
"Arfa wrote in message
news:blj3o.55085$0e3.52289@hurricane...
Just in. A combo, the job ticket on which says "Low volume. Sounds
like
****."

There's hope for the lads behind the counter, yet. How nice to get one
with a perfect owner's description of the problem, rather than some
wild
guess that the person who's booked it in has made, based on what the
owner
said. I can just see some hairy guitarist lugging it in and saying to
whoever booked it in "Go on lad ! Just write it down, Low volume.
Sounds
like **** !"

:-)

**I like it! Much better than when the customer thinks they can
diagnose the
fault for you.


It's probably just a wire off, needs welding...

--


Ah, funny you should mention welding, Ron. Apart from my new Chinese hot
air rework station purporting to be for electronic solder welding ...

I put that amp on the bench this morning, and indeed, it did have low
volume, and it did sound like **** - but not all of the time ... If you
plugged a guitar in it, and gave it a good 'clang', it produced a
horrible grating distortion, almost as though something was arcing, and
how right that turned out to be ! Plugging a generator into it, and with
a reasonable set of front panel settings on the amp, you could wind the
generator level up, and all of a sudden, the output would go from a nice
clean sine wave, to something resembling a distorted square wave, with
'sparky-looking' interference on the top.

Nothing was shifting - HT was clean, bias was clean, outputs from the
phase splitter were clean, and drive right on the grids of the O/P tubes
was clean, but both anodes (plates) were 'dirty'. I was beginning to
suspect that the O/P Tx was breaking down when there was a large peak -
peak drive across it, but thought that I'd better try a replacement pair
of 6L6's in it, just in case. No change. I managed to get the generator
set to a level where it was consistently producing the bad output, and
was just about to carry out some more 'scope checks, when something
caught my eye. It was a little firestorm going on around one of the
output jacks, which on this amp are in the bottom of the chassis
pointing down, and are open frame types. The one for an extension
speaker has an open contact set on it. Where the contact 'loops' out of
the front of the socket, it is quite close to the chassis, and there,
wedged between the contact and the chassis, was a screw, merrily arcing
away. I shut off and pried the screw out with a screwdriver tip, and
then, stupidly, picked it up and burnt my fingers :-(

The screw was a black plated type, so I guess not a brilliant conductor
- not enough to actually put a full short across the output, anyway.
However, once there was a high enough p-p output voltage across there,
the plating was breaking down enough to cause the sparks, and upset the
output stage. The screw was actually one of the ones that secures the
main board to the chassis. Given that these combos are built as portable
gigging items, I' m surprised that a company like Fender, doesn't put a
paint seal, or a bit of thread-lock on these screws. Still, they've all
got a liberal coat of nail polish on them now, so hopefully should
prevent a similar occurrence in the future.

Nice to get an 'odd' fault that can actually be pinned to a definite
problem, with a definite fix, for a change ...

Arfa

So I was almost right, it wasn't fooked, it was screwed!

Ron



Or not ... :-)

Arfa

Using the proper technical terms ... :-)
 

Still, nice to see a bit of kit that, even with almost a direct short
on, didn't blow up the o/p stage or get otherwise BER.
-B

Using the proper technical terms ... :-)
 

"b" wrote in message
...
Still, nice to see a bit of kit that, even with almost a direct short
on, didn't blow up the o/p stage or get otherwise BER.
-B


Well, to some extent, that's the nature of the beast with tube amps.
Obviously, if you run something like a continuous sine with a direct short
across the output, given time, you're going to **** the output transformer,
but the general rule, for normal music running through an amp, is that
semiconductor amps don't like a short, but don't mind an open, and the
opposite case for tube amps, as without any primary-side damping from
secondary side load, the p-p voltages that appear across the primary, can
cause internal flashover of the tubes, and insulation breakdown in the
transformer.

Arfa