On Sun, 05 Jun 2011 10:12:32 +0100, Arfa Daily wrote:

"Arfa Daily" wrote in message
...
A Fender Supersonic combo landed on my bench as an urgent job today.
Ticket said "Power, but no output". The pilot light on the front panel
lit up, but that was about it. There was no sign of the output tubes
being alight at all. When I had removed the chassis from the cabinet,
it was clear that every filament in the whole amp was wired by a single
parallel run, and that this was common with the supply to the pilot
light. There is a 10 amp filament fuse in the line, that looks as
though it might be after the pilot light take off point, but the fuse
was intact. You couldn't immediately see the undersides of the first
few preamp tubes on that wiring run, due to there being a back panel
PCB above them, which carried the effects send and return jacks and a
couple of pots etc. However, you could get to the bottoms of the output
tubes, and there was no voltage at the filament pins of either.

I removed the PCB that was in the way, and it was then apparent what
was wrong. The hand soldering of just about all the tube socket wires,
and especially the thicker and doubled-up filament wires, was
astoundingly poor for a Fender branded product. The solder had not
properly taken to any of the filament pin tags on the tube bases, and
the mechanical appearance of each joint was appalling. The amp was
definitely built using lead-free solder, but it looked as though
nobody had told the hand assembly part of the production line, and
they were trying to make the joints with soldering irons with their
tip temperature set to produce correct joints with lower melting point
leaded solder ...

A reflow of the offending joints with some new solder fed in, restored
the filament supply to the output tubes and those that followed after
them, and the amp then worked just fine.

Other than the normal references to Fender being in California USA, I
could find no indication of where this amp had actually been built.
These amps are not cheap, and I would normally associate the name
Fender with a quality product. In this case, however, I felt very
disappointed for the owner. In order for poor workmanship like this to
find its way out of the factory door, either the QA is non-existent or
poorly structured, or else the QA manager needs his arse firing out of
the job ...

Arfa



"Wild_Bill" wrote in message
...
I've seen numerous examples in my own purchases (since I don't do
regular repair work anymore), where hand soldering has failed just from
opening the cases.

I always open any line voltage operated consumer/imported/China-made
gear to examine all of the hand assembly work.

What appears to be standard procedure is that the leads for attachment
have been tinned previously, so the assembler only needs to hold the
iron on the connection long enough to get the slightest amount of
reflow to take place, before moving on to the next connection.

The result in many cases is a temporary connection.. the way a welder
would tack-weld a part in place to hold it temporarily before doing the
finish weld which actually secures the part.

Good mechanical connections are essentially a thing of the past, rarely
ever performed in low-end equipment anymore.. at most (generally) a
lead might be poked thru a terminal hole before adding solder, but the
leads of the vacuum tube era were nearly always formed tightly around
the terminal before soldering.

Tacking pre-tinned leads to existing soldered connections is the
present standard of quality that's accepted, even by the marketers
(rarely the actual manufacturers) of better quality equipment.

I believe QA is a figment of the imagination any more, as far as
consumer gear goes.. I would expect that the highest priority is placed
on the external appearance of the finished product, and nothing else.

See.. store return policy.

A new consumer market acronym for the old use of MSRP.. Marketer's
store return policy.

--
Cheers,
WB
.............



In general, I would agree, but for the most part, tubed guitar amps,
particularly from the 'big' names, are expensive specialist items, and
subject to limited production runs of hundreds at a time, rather than
the hundreds of thousands of cheap Chinese DVD players, or whatever. It
is quite normal for these amplifiers to have signed production progress
stickers on the chassis, and a final QA test sticker. Sometimes, even a
'musicality' sticker, so I think that for the most part, QA in some form
at least, still exists for the majority of manufacturers of these
products. Apart from this, many examples have adjustable bias for the
output tubes, so as a final or almost final operation, a real person has
to have their hands and eyes inside the chassis to carry out this task.

As to the wires on this one, most were wrapped around the pins in at
least a token fashion, prior to being soldered. The filament wires were
of a rather thicker gauge which certainly *could* have been wrapped
around the pins, but wasn't, presumably because of the extra time that
it would have taken to do it neatly and properly. Or perhaps it was just
an example of a lazy or poorly trained production worker ? There was not
really a *lack* of solder on the joints, just that they were poor, with
the solder having not stuck 'well' to either the wires or the tags on
the bases. I would have to say that it looked to me just typical of a
joint - of any variety of solder - that had been made with an iron that
was either too cold, or not up to the job in terms of tip thermal
inertia. Or again, maybe just a worker that was poorly trained in the
art of soldering. Either way, poor workmanship like this, really should
have been picked up somewhere in the build process ...

Arfa

The absolute most horrible quality construction and solder job on an amp
I've seen was a Trace Elliot Velocette. It took me two painstaking hours
to re-route circuits by hand wiring. And this was a small 20 watt combo
with an 8" speaker.



--
Live Fast Die Young, Leave A Pretty Corpse