Marshall JCM 2000

N

N_Cook

Guest
Latching switch types ok for VCRs etc, with tight clearances but not here. 2
DPDT worn , leading to snap crackle and pop etc unless you hold the knob in
or out. There is about 2mm of play between the knobs and the holes in the
metal of the front/rear panels. Replace those 2 plus 2 more with same
flimsey 0.1 inch pin spacing switches and try and find or make larger knobs
? Replace with heavier duty switches, larger footprint , requiring
re-positioning/drilling/wiring-in ?
The 2 off 4PDT switches maybe more resilient to off axis loading so will
leave as is , unless anyone knows better.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
 
N_Cook wrote:
Latching switch types ok for VCRs etc, with tight clearances but not here. 2
DPDT worn , leading to snap crackle and pop etc unless you hold the knob in
or out. There is about 2mm of play between the knobs and the holes in the
metal of the front/rear panels. Replace those 2 plus 2 more with same
flimsey 0.1 inch pin spacing switches and try and find or make larger knobs
? Replace with heavier duty switches, larger footprint , requiring
re-positioning/drilling/wiring-in ?
The 2 off 4PDT switches maybe more resilient to off axis loading so will
leave as is , unless anyone knows better.
Click to expand...
They may well be chinese pattern copies of ALP`s switches, replace them
with genuine ALPS parts and they will be fine

Ron
 
Ron Johnson <ron@lunevalleyaudio.com> wrote in message
news:y-6dnb4l6OpxirnUnZ2dnUVZ8tSdnZ2d@bt.com...
N_Cook wrote:
Latching switch types ok for VCRs etc, with tight clearances but not
here. 2
DPDT worn , leading to snap crackle and pop etc unless you hold the knob
in
or out. There is about 2mm of play between the knobs and the holes in
the
metal of the front/rear panels. Replace those 2 plus 2 more with same
flimsey 0.1 inch pin spacing switches and try and find or make larger
knobs
? Replace with heavier duty switches, larger footprint , requiring
re-positioning/drilling/wiring-in ?
The 2 off 4PDT switches maybe more resilient to off axis loading so will
leave as is , unless anyone knows better.

They may well be chinese pattern copies of ALP`s switches, replace them
with genuine ALPS parts and they will be fine

Ron
Click to expand...

Actually 3.5 mm pin spacing, yellow stem "angle logo", found 4 ALPS marked
ones, blue stem replacements and some slightly larger diameter knobs.
Required slightly opening out the "gold" fascia holes but not the underlying
panel and unfortunately red in colour. Permanent black felt marker over them
, cooked in with hot air and repeated again sorted out that aesthetic
problem.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
 
N_Cook wrote:
Ron Johnson <ron@lunevalleyaudio.com> wrote in message
news:y-6dnb4l6OpxirnUnZ2dnUVZ8tSdnZ2d@bt.com...
N_Cook wrote:
Latching switch types ok for VCRs etc, with tight clearances but not
here. 2
DPDT worn , leading to snap crackle and pop etc unless you hold the knob
in
or out. There is about 2mm of play between the knobs and the holes in
the
metal of the front/rear panels. Replace those 2 plus 2 more with same
flimsey 0.1 inch pin spacing switches and try and find or make larger
knobs
? Replace with heavier duty switches, larger footprint , requiring
re-positioning/drilling/wiring-in ?
The 2 off 4PDT switches maybe more resilient to off axis loading so will
leave as is , unless anyone knows better.
They may well be chinese pattern copies of ALP`s switches, replace them
with genuine ALPS parts and they will be fine

Ron


Actually 3.5 mm pin spacing, yellow stem "angle logo", found 4 ALPS marked
ones, blue stem replacements and some slightly larger diameter knobs.
Required slightly opening out the "gold" fascia holes but not the underlying
panel and unfortunately red in colour. Permanent black felt marker over them
, cooked in with hot air and repeated again sorted out that aesthetic
problem.
Click to expand...
The ALPS 'blue' range are pretty universal on many major brands of pro
quality mixing desks tec, and are very reliable.

Ron
 
"N_Cook" <diverse@tcp.co.uk> wrote in message
news:gg1c3c$tmc$1@news.motzarella.org...
Ron Johnson <ron@lunevalleyaudio.com> wrote in message
news:y-6dnb4l6OpxirnUnZ2dnUVZ8tSdnZ2d@bt.com...
N_Cook wrote:
Latching switch types ok for VCRs etc, with tight clearances but not
here. 2
DPDT worn , leading to snap crackle and pop etc unless you hold the
knob
in
or out. There is about 2mm of play between the knobs and the holes in
the
metal of the front/rear panels. Replace those 2 plus 2 more with same
flimsey 0.1 inch pin spacing switches and try and find or make larger
knobs
? Replace with heavier duty switches, larger footprint , requiring
re-positioning/drilling/wiring-in ?
The 2 off 4PDT switches maybe more resilient to off axis loading so
will
leave as is , unless anyone knows better.

They may well be chinese pattern copies of ALP`s switches, replace them
with genuine ALPS parts and they will be fine

Ron


Actually 3.5 mm pin spacing, yellow stem "angle logo", found 4 ALPS marked
ones, blue stem replacements and some slightly larger diameter knobs.
Required slightly opening out the "gold" fascia holes but not the
underlying
panel and unfortunately red in colour. Permanent black felt marker over
them
, cooked in with hot air and repeated again sorted out that aesthetic
problem.
Click to expand...


You may find that the yellow stem switches have solder tags on the metal
cover, giving a mounting arrangement that the blue Alps switches do not
have, being all plastic. IME though, the yellow switches are way inferior.

The blue Alps ones are indeed universal and are found in many pretty decent
recording and live consoles, where they give a pretty decent lifespan. They
do not tend to break, unlike the yellow ones, but just wear out. I would go
with Ron's advice and replace with the blue.



Gareth.
 
Another solution I tried, padding out the gap with cut 5mm LED clips or cut
down 8mm clips and they would work with the original knobs but the fascia
would need opening up a bit also.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
 
"N_Cook" <diverse@tcp.co.uk> wrote in message
news:gg1491$bck$1@news.motzarella.org...
Latching switch types ok for VCRs etc, with tight clearances but not here.
2
DPDT worn , leading to snap crackle and pop etc unless you hold the knob
in
or out. There is about 2mm of play between the knobs and the holes in the
metal of the front/rear panels. Replace those 2 plus 2 more with same
flimsey 0.1 inch pin spacing switches and try and find or make larger
knobs
? Replace with heavier duty switches, larger footprint , requiring
re-positioning/drilling/wiring-in ?
The 2 off 4PDT switches maybe more resilient to off axis loading so will
leave as is , unless anyone knows better.


--
Click to expand...

Actually, after re-reading your post more carefully, you are right about the
problem.

I changed one of those yellow switches on a Marshall TSL100 about 4 o'clock
this afternoon. There is indeed far too much play in the knob / chassis
hole arrangement, so maybe this is more the problem rather than the switches
themselves being inferior.

I would still replace them with the blue ones, even though the one I
replaced this afternoon was a Marshall stock yellow one. (Only because I
didn't have a blue one and the guy needs the amp tomorrow, but ..... what to
do?)

I think you will find the blue ones negate the need for faffing too much
with the oversize hole problem.


Gareth.
 
Gareth Magennis <gareth.magennis@ntlworld.com> wrote in message
news:Xy0Vk.3944$iQ2.2666@newsfe23.ams2...
"N_Cook" <diverse@tcp.co.uk> wrote in message
news:gg1491$bck$1@news.motzarella.org...
Latching switch types ok for VCRs etc, with tight clearances but not
here.
2
DPDT worn , leading to snap crackle and pop etc unless you hold the knob
in
or out. There is about 2mm of play between the knobs and the holes in
the
metal of the front/rear panels. Replace those 2 plus 2 more with same
flimsey 0.1 inch pin spacing switches and try and find or make larger
knobs
? Replace with heavier duty switches, larger footprint , requiring
re-positioning/drilling/wiring-in ?
The 2 off 4PDT switches maybe more resilient to off axis loading so will
leave as is , unless anyone knows better.


--


Actually, after re-reading your post more carefully, you are right about
the
problem.

I changed one of those yellow switches on a Marshall TSL100 about 4
o'clock
this afternoon. There is indeed far too much play in the knob / chassis
hole arrangement, so maybe this is more the problem rather than the
switches
themselves being inferior.

I would still replace them with the blue ones, even though the one I
replaced this afternoon was a Marshall stock yellow one. (Only because I
didn't have a blue one and the guy needs the amp tomorrow, but ..... what
to
do?)

I think you will find the blue ones negate the need for faffing too much
with the oversize hole problem.


Gareth.
Click to expand...

The easy fudge would be peripheral cut a 5mm LED clip or 8mm with a section
removed fitted in the gap , but enlarging the fascia hole a bit, and
gluing-in the clips internally. The other problem is the black knobs seem to
be pushed on the shafts, hot, rather than gummy glued on , so do not come
off easily. I could only remove one with (too much) hot air heating. Those
black knobs, there is an axial seem that is somehow disguised, becoming
apparent on heating, so will try finding the seem on another and knifing
axially at that point to remove


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
 
Gareth Magennis <gareth.magennis@ntlworld.com> wrote in message
news:Xy0Vk.3944$iQ2.2666@newsfe23.ams2...
"N_Cook" <diverse@tcp.co.uk> wrote in message
news:gg1491$bck$1@news.motzarella.org...
Latching switch types ok for VCRs etc, with tight clearances but not
here.
2
DPDT worn , leading to snap crackle and pop etc unless you hold the knob
in
or out. There is about 2mm of play between the knobs and the holes in
the
metal of the front/rear panels. Replace those 2 plus 2 more with same
flimsey 0.1 inch pin spacing switches and try and find or make larger
knobs
? Replace with heavier duty switches, larger footprint , requiring
re-positioning/drilling/wiring-in ?
The 2 off 4PDT switches maybe more resilient to off axis loading so will
leave as is , unless anyone knows better.


--


Actually, after re-reading your post more carefully, you are right about
the
problem.

I changed one of those yellow switches on a Marshall TSL100 about 4
o'clock
this afternoon. There is indeed far too much play in the knob / chassis
hole arrangement, so maybe this is more the problem rather than the
switches
themselves being inferior.

I would still replace them with the blue ones, even though the one I
replaced this afternoon was a Marshall stock yellow one. (Only because I
didn't have a blue one and the guy needs the amp tomorrow, but ..... what
to
do?)

I think you will find the blue ones negate the need for faffing too much
with the oversize hole problem.


Gareth.
Click to expand...
the way to remove the knobs is to squash slightly in a flat jawed vice,
diagonally relative to the square stems. To break the melt between black and
yellow. Always leaves a crack or undisguised seam, cannot decide which


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
 
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