CHAMP ELECTRONICS -" THE VINTAGE VALVE
AMP HOSPITAL"
NOTTINGHAM, ENGLAND
SERVICING OF A GIBSON INVADER GA-30RV
COMBO
AMPLIFIER
Now, this one was
really a mess…..a “rats-nest” again!! Look at the state of this thing as
received!
Simply an
abortion! How can a “so-called” engineer/tech-guy call this a repair or
service!!??
The original
output transformer that was duff and had to be replaced.
God…..what a mess!!
More mess!!
Even more mess! Some
components had been bloodedly replaced plus…..note all the input jacks’ muting
switches were completely open and strained!!
More
bodging!! The replaced “overkill” output transformer; the replaced
[non-original] Fender reverb-drive transformer (fair enough on this one
but…..how about drilling the hole straight and in-line?); The RCA (phono) -
reverb send & return leads were soldered to the Fender reverb drive transformer
but then they were simply held to the chassis with tape as an anchorage!
These have to be some
of the worst-state tube bases I have ever seen!
Bases removed - I
got most of the surface chassis rust off with some fine emery-cloth.
Speakers rewired
neatly. The original Jenson 12” driver had been re-conned and was fine.
However, the matching 8” driver was so bad and beyond repair that it went into
the rubbish bin! The replaced Celestion Super 8 was fine but turned-out to be a
little “too sensitive & harsh”. I later supplied the customer [Keith] with
a nice old 8"/ 8 ohm Elac, which not only suited the amp more, but was more in
keeping as a matching driver for the original Jenson too.
Some replaced
components on the main pre-amp/drive board.
New tube bases and bear-clamps.
Both power and output
transformers rewound. The power transformer was 120 volts only, so it seemed
sensible to rewind this for our British 240 volts whilst the job was being
done.
Believe it or
not, this is the complete power and output stages finished! Just check-out
the difference between this photo and the above photo number three (from the top).
All the input jacks
were far too strained and beyond repair. I have re-tensioned and cleaned jack
sockets many-a-time before but in reality they don’t really last too long…..if
at all. The best bet is to simply change them all for new ones. When doing so,
and especially on a “U-shaped chassis” as this is, it is better and much
easier to build up the sockets on the outside, and them simply swap them to the
inside when finished.
Fitted back
internally and the original shielded cables reconnected.
Now, this is so much
better and more like things should be! I have re-drilled the reverb driver
transformer mounting, in-line now, plus I have used a tag strip and anchored
all four of its wires here too. The rewound output transformer is now back in
place too, along with new cables and proper anchorage all-round.
This unit has been so
badly damp at some point in its life that all four of the potentiometers were
beyond repair/service too. I had to replace them all! Also, notice the re-wire
of the said pots with ribbon cabling….also much tidier too!
Pretty-much finished
here……..phew!
The seller of this
amp had re-covered one of the back panels and some of the main cab
too…..varnishing them to make them look “old and used”!
Now……….a nice and in
good working order amp. Not every customer bothers to send any kind of
e-mail/testimonial but most do always ring with some results/feedback. Keith,
the new owner of this amp did indeed make a phone call and was extremely please
with the final result. I’m not in the least-bit surprised!
