scratchy pots on old bass amp - diyable?
 

poss OT but it's DIY :-

I have an old but nice Yamaha bass amp combo which has had scratchy
pots since I bought it years ago - they are nearly all (volume, tone
etc) scratchy to a greater or lesser extent.

How feasible is a DIY repair? I am ok with a soldering iron and would
appreciate any help/pointers as to what to look for/check when finding/
buying new pots to replace the old and from where to buy them.

TIA
JimK

scratchy pots on old bass amp - diyable?
 

On Aug 30, 7:38*pm, jim wrote:
poss OT but it's DIY :-

I have an old but nice Yamaha bass amp combo which has had scratchy
pots since I bought it years ago - they are nearly all (volume, tone
etc) scratchy to a greater or lesser extent.

How feasible is a DIY repair? I am ok with a soldering iron and would
appreciate any help/pointers as to what to look for/check when finding/
buying new pots to replace the old and from where to buy *them.

TIA
JimK

If you can solder its perfectly doable, assuming its not an oddity
with custom pots. I once had an amp with a 4 gang volume pot with
centre taps - no chance of replacement!


NT

scratchy pots on old bass amp - diyable?
 

John Rumm wrote:
Owain wrote:

Probably worth trying a few squirts of cleaner before plugging the
iron in.

Indeed - had a problem with scratchy pots and input selector switch on a
Kenwood hifi amp. Quick squirt with WD40 followed by working the knobs/
switch back and forth a few times restored normal operation.

Now, what can WD 40 _not_ do? ;-)

Dave

scratchy pots on old bass amp - diyable?
 

Dave wrote:
John Rumm wrote:
Owain wrote:

Probably worth trying a few squirts of cleaner before plugging the
iron in.

Indeed - had a problem with scratchy pots and input selector switch on
a Kenwood hifi amp. Quick squirt with WD40 followed by working the
knobs/ switch back and forth a few times restored normal operation.

Now, what can WD 40 _not_ do? ;-)


WD40 is not really the recommended stuff for this, in the longterm.
However, it does work ...

--
Adrian C

scratchy pots on old bass amp - diyable?
 

NT wrote:

If you can solder its perfectly doable, assuming its not an oddity
with custom pots. I once had an amp with a 4 gang volume pot with
centre taps - no chance of replacement!

Ah, ye should have defeated (removed, exorcised, castrated, mullered)
the loudness switch ...

--
Adrian C

scratchy pots on old bass amp - diyable?
 

On Sun, 30 Aug 2009 14:24:52 -0700 (PDT), NT had
this to say:

On Aug 30, 7:38*pm, jim wrote:
poss OT but it's DIY :-

I have an old but nice Yamaha bass amp combo which has had scratchy
pots since I bought it years ago - they are nearly all (volume, tone
etc) scratchy to a greater or lesser extent.

How feasible is a DIY repair? I am ok with a soldering iron and would
appreciate any help/pointers as to what to look for/check when finding/
buying new pots to replace the old and from where to buy *them.

TIA
JimK

If you can solder its perfectly doable, assuming its not an oddity
with custom pots. I once had an amp with a 4 gang volume pot with
centre taps - no chance of replacement!

I once had a custom pot made by Morganite Resistors. It was a dual
gang semi-log and reverse semi-log with a centre click. It cost me
nothing; they were so intrigued by the order :-)

I think I might still have it somewhere - I can't remember ever
getting the correctly-shaped tuit for whatever it was I was going to
build - hell, it was about 30 odd years ago.

--
Frank Erskine

scratchy pots on old bass amp - diyable?
 

On Sun, 30 Aug 2009 11:38:27 -0700, jim wrote:
How feasible is a DIY repair?

Not too bad. A squirt of contact cleaner into them by whatever means is
worth a try. If that doesn't work, they're typically held together by
bent-over metal tabs on the bodies, and you can carefully take them apart,
clean directly, then reassemble.

If they're standard shafts, values and mountings (if direct on a PCB) or
there's room for some (screen) fly wires then you can always replace.

Even if the shafts are something oddball, you may be able to mate the
shafts from the damaged ones to a modern part.

The only time it gets really tricky is when the clearances are too tight
to get an off-the-shelf part in there (oscilloscopes are notorious for
this!) or the part's really oddball.

cheers

Jules

scratchy pots on old bass amp - diyable?
 

John Rumm wrote:
Dave wrote:
John Rumm wrote:
Owain wrote:

Probably worth trying a few squirts of cleaner before plugging the
iron in.

Indeed - had a problem with scratchy pots and input selector switch
on a Kenwood hifi amp. Quick squirt with WD40 followed by working the
knobs/ switch back and forth a few times restored normal operation.

Now, what can WD 40 _not_ do? ;-)

There are better products for this particular job - but it was to hand,
and did the trick...

I would never have expected it to do the job. I always use Super
Servisol 10 switch cleaning lubricant.

You knew that, didn't you ;-)


Dave

scratchy pots on old bass amp - diyable?
 

dave wrote:

switch cleaner. afaik WD40 is a moisture displacer.

Water dispersant, to give it its right title. Hence the WD in its name.

Dave

scratchy pots on old bass amp - diyable?
 

"Dave" wrote in message
...
I would never have expected it to do the job. I always use Super Servisol
10 switch cleaning lubricant.

I once used switchcleaner on the pots in a Unaohm spectrum analyser. They
froze solid and had to be replaced.

Bill

scratchy pots on old bass amp - diyable?
 

If you use Electrolube {obtainable from Radiospares } it will both clean and
lubricate, did the job on my Hitachi volume control

Sam
"Dave" wrote in message
...
dave wrote:

switch cleaner. afaik WD40 is a moisture displacer.

Water dispersant, to give it its right title. Hence the WD in its name.

Dave

scratchy pots on old bass amp - diyable?
 

jim wrote:
poss OT but it's DIY :-

I have an old but nice Yamaha bass amp combo which has had scratchy
pots since I bought it years ago - they are nearly all (volume, tone
etc) scratchy to a greater or lesser extent.

How feasible is a DIY repair? I am ok with a soldering iron and would
appreciate any help/pointers as to what to look for/check when finding/
buying new pots to replace the old and from where to buy them.


It sdepends if they are on the board, or connected by wires. If the
latter its a tricvial excecrise..mut do take pictures of which wires go
where.

If the latter its a bit harder.

As clearing solder from the pins and breaking them out of the board is a
bit more skilled. If they are being replaced, cut them off and remove
the leftovers.


Replacements hafe to physically fit, be the same value, be log or linear
taper, and have the same shaft to fit the knobs (round, round-with flat,
or splined)

Apart from that, butyy moulded track if you can find them. Lats longher.

Try a spray of contact cleaner first tho. It may be just dust..

TIA
JimK

scratchy pots on old bass amp - diyable?
 

John Rumm wrote:
Owain wrote:

Probably worth trying a few squirts of cleaner before plugging the
iron in.

Indeed - had a problem with scratchy pots and input selector switch
on a Kenwood hifi amp. Quick squirt with WD40 followed by working the
knobs/ switch back and forth a few times restored normal operation.

Yahoo!


--
Dave - WD40 Liberation Front.

scratchy pots on old bass amp - diyable?
 

On 31 Aug, 16:19, dave wrote:
On Mon, 31 Aug 2009 09:12:29 +0100, The Natural Philosopher



wrote:
jim wrote:
poss OT but it's DIY :-

I have an old but nice Yamaha bass amp combo which has had scratchy
pots since I bought it years ago - they are nearly all (volume, tone
etc) scratchy to a greater or lesser extent.

How feasible is a DIY repair? I am ok with a soldering iron and would
appreciate any help/pointers as to what to look for/check when finding/
buying new pots to replace the old and from where to buy them.

It sdepends if they are on the board, or connected by wires. If the
latter its a tricvial excecrise..mut do take pictures of which wires go
where.

If the latter its a bit harder.

As clearing solder from the pins and breaking them out of the board is a
bit more skilled. If they are being replaced, cut them off and remove
the leftovers.

Replacements hafe to physically fit, be the same value, be log or linear
taper, and have the same shaft to fit the knobs (round, round-with flat,
or splined)

Apart from that, butyy moulded track if you can find them. Lats longher.

Try a spray of contact cleaner first tho. It may be just dust..

TIA
JimK

I thought I was the typo King:-)
Just to add, that on my Trace amp there are some sensitive custom IC's
- be careful you know how to de-solder if the pot is soldered to the
board. Replacing one of those chips is much harder - and may be
difficult to find anyway.

ah can you refresh me on how to desolder please?
I was imagining using a desolder pump thingy I have or cutting the
legs off the old pots (a la Natural Philosopher) and then taking the
remaining "feet"? out one at a time...

JimK

scratchy pots on old bass amp - diyable?
 

Bill Wright wrote:
"Dave" wrote in message
...
I would never have expected it to do the job. I always use Super Servisol
10 switch cleaning lubricant.

I once used switchcleaner on the pots in a Unaohm spectrum analyser. They
froze solid and had to be replaced.

Nasty! I'll bet that made parts of your anatomy twitch :-)

Dave

scratchy pots on old bass amp - diyable?
 

John Rumm wrote:
jim wrote:

ah can you refresh me on how to desolder please?
I was imagining using a desolder pump thingy I have or cutting the
legs off the old pots (a la Natural Philosopher) and then taking the
remaining "feet"? out one at a time...

For something like a through hole PCB mounted pot, then you can desolder
each contact with a soldering iron and desolder pump.

You will probably need to apply some fresh solder to the tip of the iron
to tin it, and allow for more rapid heat transfer to the tab. Reflow the
joint and then suck it clean with the pump. You may need a couple of
bites at each to get rid of all the visible solder. Once all the pins
are desoldered you may find they are still "stuck" by a thin film of
solder. A gentle wiggle of each should free it. Sometimes a bit of
lateral pressure on the end of the tab with a flat bladed screw driver
will free it. (a handy knack to practice is to hold the tab away from
the sides of the hole in the PCB with the tip of the desolder pump as it
cools - that prevents it getting stuck back into the film of solder)

(Note that If you are dealing with very fine PCB traces, a small hole
annulus, or anything surface mount, then it is probably safer for the
board to run a sharp knife down the contacts and cut the device away
first. Each remaining leg can then be flicked off with a hot iron with
very little risk to the board).


Note that if pumpless, the outer sheath of coax if stripped makes a fine
braid to attract solder onto.


HOWEVER, having worked in the game many years, the best way to strip a
component KNOWN to be bad is to cut its legs of and remove them one by
one with fine pliers and a soldering iron, and redrill the holes if you
haven't got desoldering equipment.

It also works well for politicians, but is sadly illegal.#

scratchy pots on old bass amp - diyable?
 

"John Rumm" wrote in message
o.uk...
Arfa Daily wrote:

Normally John, I would hang on every word that you would have to say on
this group, but not this time. Please please don't recommend that DIYers
bring WD40 anywhere near electronic equipment. It is not designed as a
switch

I have already said its not the best thing for the job, what more do you
want, blood? ;-)


OK, fair enough, but I actually posted that reply before you said that there
were better products. The order that posts appear depend on how quickly they
arrive at the servers.



cleaner / lubricant chemical, and whilst in some very few instances it
may be effective in providing an apparent cure to some electronic ill, in
the vast majority of places that owners try it - for cleaning and
lubricating CD drives, tape decks etc - it spells instant and
irreversible death. I have lost count over the many years that I have
been involved in electronic service, of how many owners' pride and joy
items have been wrecked by use of WD40. My heart sinks every time one
appears on my bench with that characteristic smell wafting up from it ...

Indeed, and I would not suggest it for that application either. However
the one case of a wiping contact as in a pot - I have had some success
with.


I don't doubt it. It's just that WD40 is nasty stuff when it comes to
electronic equipment, and I would rather that DIYers don't get the idea that
it is ok to use it *anywhere* in such items of equipment. It's not just that
there are "better" chemicals for the job. It's more a case of there being
correct ones, and unsuitable ones, and WD40 is a singularly unsuitable one.
It's not even a good lubricant when it comes to plastic, and many pots have
plastic component parts.

Sorry to harp on about this, and it's not particularly a dig at you John.
You've been more than helpful to me over the years, on questions that I have
asked here. It's just that I have seen so much irrepairable damage done to
equipment by people that believe WD40 to be a magic cure-all, that I always
get upset when I see anyone recommending it for tasks such as this.

Arfa



--
Cheers,

John.

scratchy pots on old bass amp - diyable?
 

Arfa Daily wrote:
It's just that WD40 is nasty stuff when it comes to electronic
equipment, and I would rather that DIYers don't get the idea that it is
ok to use it *anywhere* in such items of equipment. It's not just that
there are "better" chemicals for the job. It's more a case of there
being correct ones, and unsuitable ones, and WD40 is a singularly
unsuitable one. It's not even a good lubricant when it comes to
plastic, and many pots have plastic component parts.

Sorry to harp on about this, and it's not particularly a dig at you
John. You've been more than helpful to me over the years, on questions
that I have asked here. It's just that I have seen so much irrepairable
damage done to equipment by people that believe WD40 to be a magic
cure-all, that I always get upset when I see anyone recommending it for
tasks such as this.

Yes, we can see that...

The point about "correct" solvents for electronics work is that they
have been specifically formulated not to attack the large majority of
components. That is the main reason for using those particular solvents.

There are still no guarantees, but with any other solvents you're
completely on your own.

Arfa, I hesitate to ask this... but please could you be more specific
about the kinds of damage that WD40 can do?



--
Ian White

scratchy pots on old bass amp - diyable?
 

Arfa Daily wrote:
Please please don't recommend that
DIYers bring WD40 anywhere near electronic equipment. It is not
designed as a switch cleaner / lubricant chemical, and whilst in some
very few instances it may be effective in providing an apparent cure
to some electronic ill, in the vast majority of places that owners
try it - for cleaning and lubricating CD drives, tape decks etc - it
spells instant and irreversible death. I have lost count over the
many years that I have been involved in electronic service, of how
many owners' pride and joy items have been wrecked by use of WD40. My
heart sinks every time one appears on my bench with that
characteristic smell wafting up from it ...

So, given that we don't know the exact ingredients, but have a rough idea
http://en.wikipedia.org/wiki/WD-40 what is it that makes WD40 so evil &
wicked?

I love the stuff, use it all the time.


--
Dave - WD40 Liberation Front.

scratchy pots on old bass amp - diyable?
 

On 30 Aug, 19:56, Owain wrote:

Open up. Identify pots. Values should be printed on the back, or on
the PCB. Just check which are logarithmic[1] (probably the volumes)
and which are linear (probably the tone controls).

Tone pots don't usually see enough wear to wear out, so just cleaning
will nearly always sort them out. Volume is worth trying for cleaning,
but you might well need to replace them.

scratchy pots on old bass amp - diyable?
 

In article
,
jim wrote:
poss OT but it's DIY :-

I have an old but nice Yamaha bass amp combo which has had scratchy
pots since I bought it years ago - they are nearly all (volume, tone
etc) scratchy to a greater or lesser extent.

How feasible is a DIY repair? I am ok with a soldering iron and would
appreciate any help/pointers as to what to look for/check when finding/
buying new pots to replace the old and from where to buy them.

I'd first try using a cleaner/lubricant. This is my favourite - Maplin
may sell it too.

http://www.solotechnic.co.uk/super-1...nt-i23588.html

Just cleaning can be a short term fix but they really need a suitable
lubricant in the longer term.

It should be easy to get electrically similar replacements, but the
larger older types can be difficult to match mechanically.

Also note 'preferred' values may have changed - so you'll probably have
to use a 47kohm where the original was 50kohm, etc.

If the pots are just mounted on a panel and wired to the board, changing
to modern ones should be easy. More difficult if they're mounted on the
PCB.

If you have got to change to something different, I'd go for moulded
track ones - they last longer.

Somewhere like RS Components have a large range of generic types. But you
might find originals by Googling.

--
*I didn't fight my way to the top of the food chain to be a vegetarian.

Dave Plowman London SW
To e-mail, change noise into sound.

scratchy pots on old bass amp - diyable?
 

In article ,
The Medway Handyman wrote:
So, given that we don't know the exact ingredients, but have a rough
idea http://en.wikipedia.org/wiki/WD-40 what is it that makes WD40 so
evil & wicked?

Because like all that type of stuff it does many things after a fashion,
but non well. It's not a good lubricant. Not a good penetrating oil. Not a
long lasting rust proofer.

I love the stuff, use it all the time.

Works well enough to stop a garden gate squeaking. But not for long.

--
*How do they get the deer to cross at that yellow road sign?

Dave Plowman London SW
To e-mail, change noise into sound.

scratchy pots on old bass amp - diyable?
 

John Rumm writes:
[1] That reminds me, what is the lubricant usually used on
things like scanner runners - typically plastic bearings on
highly polished rails?

Often there is no lubricant, the friction between the plastic and metal
being very small.

I have a Nikon slide/film scanner that could really use relubricating
since it suffers stiction problems sometimes that prevent it working
correctly.

Have you tried cleaning the slide and bearings very thoroughly? Of
course, the other possibility is that enough of the plastic has worn
away that you're getting the toy-woodpecker-on-a-pole effect.

--
Jón Fairbairn
http://www.chaos.org.uk/~jf/Stuff-I-dont-want.html (updated 2009-01-31)

scratchy pots on old bass amp - diyable?
 

In article ,
John Rumm wrote:
[1] That reminds me, what is the lubricant usually used on things like
scanner runners - typically plastic bearings on highly polished rails?
I have a Nikon slide/film scanner that could really use relubricating
since it suffers stiction problems sometimes that prevent it working
correctly.

I got some spray silicone lubricant in Lidl. Sort of dries so it won't
come off on the finger etc or collect dust. Worked a treat on a slow
electric car window by lubricating the glass channel.

--
*If all the world is a stage, where is the audience sitting?

Dave Plowman London SW
To e-mail, change noise into sound.

scratchy pots on old bass amp - diyable?
 

John Rumm wrote:

[1] That reminds me, what is the lubricant usually used on things like
scanner runners - typically plastic bearings on highly polished rails?
I have a Nikon slide/film scanner that could really use relubricating
since it suffers stiction problems sometimes that prevent it working
correctly.



Its silicone grease spray on sort.

I had this issue with a big plotter. Man came to fix, diagnosed sticky
runners, and I had to tell him to remove the dried on gunk with I think
acetone, and then relube with his spray silicone.

scratchy pots on old bass amp - diyable?
 

Andy Dingley wrote:
On 30 Aug, 19:56, Owain wrote:

Open up. Identify pots. Values should be printed on the back, or on
the PCB. Just check which are logarithmic[1] (probably the volumes)
and which are linear (probably the tone controls).

Tone pots don't usually see enough wear to wear out, so just cleaning
will nearly always sort them out. Volume is worth trying for cleaning,
but you might well need to replace them.
Or hard wire the lot to '11' ;-)

scratchy pots on old bass amp - diyable?
 

On Tue, 01 Sep 2009 07:21:39 +0000, The Medway Handyman wrote:
So, given that we don't know the exact ingredients, but have a rough idea
http://en.wikipedia.org/wiki/WD-40 what is it that makes WD40 so evil &
wicked?

I've always been told that it evaporates quickly, leaving a residue behind
- which then attracts dust and other debris, making it useless as a
lubricant, and potentially worse than not having used anything at all.

It seems reasonable - but not great - as a penetrating fluid, so long as
the parts are thoroughly cleaned afterwards and then treated as
appropriate; other products designed to just be a penetrating fluid will
likely do a much better job, ditto with rust proofers.

I love the stuff, use it all the time.

As Dave says, it's a quick fix - just not a long-term solution to any
problem.

That's probably why it's so popular, because lots of people either use it
in situations where they don't get to see the long-term problems (e.g.
such as tradesfolk who come in, do a job, then leave again) - or because
when the problem reoccurs they don't put it down to being a failing of
WD40 (and realise that doing the job using something else would have fixed
the issue for much longer).

cheers

Jules

scratchy pots on old bass amp - diyable?
 

"Ian White" wrote in message
...
Arfa Daily wrote:
It's just that WD40 is nasty stuff when it comes to electronic equipment,
and I would rather that DIYers don't get the idea that it is ok to use it
*anywhere* in such items of equipment. It's not just that there are
"better" chemicals for the job. It's more a case of there being correct
ones, and unsuitable ones, and WD40 is a singularly unsuitable one. It's
not even a good lubricant when it comes to plastic, and many pots have
plastic component parts.

Sorry to harp on about this, and it's not particularly a dig at you John.
You've been more than helpful to me over the years, on questions that I
have asked here. It's just that I have seen so much irrepairable damage
done to equipment by people that believe WD40 to be a magic cure-all, that
I always get upset when I see anyone recommending it for tasks such as
this.

Yes, we can see that...

The point about "correct" solvents for electronics work is that they have
been specifically formulated not to attack the large majority of
components. That is the main reason for using those particular solvents.

There are still no guarantees, but with any other solvents you're
completely on your own.


Arfa, I hesitate to ask this... but please could you be more specific
about the kinds of damage that WD40 can do?



--
Ian White

It wrecks the frictional properties of rubber (neoprene ?) drive components
such as belts, idlers, pinch rollers, clutches etc. Once it has found its
way into / onto these items, there is no removing it no matter what you use.
Replacement of the afflicted items is the only possible way forward. This is
often either impractical or not cost effective, if the individual parts are
even available. The stuff clings, and creeps by its very nature, so as fast
as you think that you've cleaned it off any affected surface, ten minutes
later, it's back ...

I have also seen a lot of CD and DVD mechs over the years, which have been
treated to a dose of WD40 to try to cure things like trays that don't come
out properly. Often, trays are designed to run 'dry' - that is with no
grease - relying on the fact that the sliding and bearing surfaces are very
smooth 'oily' plastic. WD40 can completely wreck this delicate situation,
such that one or other side of the tray sticks, particularly if the drive
scheme is asymmetric, or the whole opening / closing sequence becomes
'stuttery'. Once a tray has been affected in this way, I've never managed to
totally successfully restore it. Sometimes a repolish with jeweller's rouge
will get it 'good enough', and sometimes some silicone based furniture
polish will help, but they are never quite the same again. And the chances
are, all that was needed was a new belt, in the first place ...

Arfa

scratchy pots on old bass amp - diyable?
 

"John Rumm" wrote in message
o.uk...



[1] That reminds me, what is the lubricant usually used on things like
scanner runners - typically plastic bearings on highly polished rails? I
have a Nikon slide/film scanner that could really use relubricating since
it suffers stiction problems sometimes that prevent it working correctly.


--
Cheers,

John.


That sort of white synthetic 'buttery' grease that you always used to find
on slide rails in CD mechs, cassette mechs etc, was called "Floil" - at
least the one that Sony supplied was. I had a tube of it for years as only a
tiny amount is used. Sadly, it finally ran out last year. I've no idea
whether you can still readily get it. I don't find that there's a lot of
call for it now, as not many CD lasers are still changed, and many DVD
lasers are replaced as a pre-aligned and greased deck, or sub chassis. Where
I do need to lube slide rods these days, I use a light synthetic machine oil
called "CMO" (Clear Machine Oil) from Electrolube. Very good lubricant, with
excellent long term 'cling' properties to very shiny items, like chrome
plated slide rods.

Arfa

scratchy pots on old bass amp - diyable?
 

"The Medway Handyman" wrote in message
om...
Arfa Daily wrote:
Please please don't recommend that
DIYers bring WD40 anywhere near electronic equipment. It is not
designed as a switch cleaner / lubricant chemical, and whilst in some
very few instances it may be effective in providing an apparent cure
to some electronic ill, in the vast majority of places that owners
try it - for cleaning and lubricating CD drives, tape decks etc - it
spells instant and irreversible death. I have lost count over the
many years that I have been involved in electronic service, of how
many owners' pride and joy items have been wrecked by use of WD40. My
heart sinks every time one appears on my bench with that
characteristic smell wafting up from it ...

So, given that we don't know the exact ingredients, but have a rough idea
http://en.wikipedia.org/wiki/WD-40 what is it that makes WD40 so evil &
wicked?

I love the stuff, use it all the time.


--
Dave - WD40 Liberation Front.


See my reply to Ian, Dave. Don't misunderstand me though. I'm not anti WD40
at all - honest! In fact I have a can right now in my garage, but that's
where I feel it belongs. It is an excellent product for the purposes that
the manufacturers advocate, and I use it as my preferred product for wiping
on tool blades, releasing stubborn bolts, penetrating rust, driving off
water etc.

It's just that IM (electronically experienced) O it shouldn't be brought
within 10 feet of anything electronic ... :-)

Arfa

scratchy pots on old bass amp - diyable?
 

On Tue, 01 Sep 2009 20:07:50 +0100, Arfa Daily wrote:

It is an excellent product for the purposes that
the manufacturers advocate

Except that the manufacturers claim it to be a lubricant - in much the
same way that snot is, I suppose.

I find it's useful for times where I don't want to be carting more
specialised products around, but for something like shed / workshop / home
there are all sorts of better things around.

scratchy pots on old bass amp - diyable?
 

In message , Arfa Daily
writes

"John Rumm" wrote in message
news:V5mdnQyoPqisjgHXnZ2dnUVZ8npi4p2d@brightview. co.uk...
Arfa Daily wrote:

Normally John, I would hang on every word that you would have to say on
this group, but not this time. Please please don't recommend that DIYers
bring WD40 anywhere near electronic equipment. It is not designed as a
switch

I have already said its not the best thing for the job, what more do you
want, blood? ;-)


OK, fair enough, but I actually posted that reply before you said that there
were better products. The order that posts appear depend on how quickly they
arrive at the servers.



cleaner / lubricant chemical, and whilst in some very few instances it
may be effective in providing an apparent cure to some electronic ill, in
the vast majority of places that owners try it - for cleaning and
lubricating CD drives, tape decks etc - it spells instant and
irreversible death. I have lost count over the many years that I have
been involved in electronic service, of how many owners' pride and joy
items have been wrecked by use of WD40. My heart sinks every time one
appears on my bench with that characteristic smell wafting up from it ...

Indeed, and I would not suggest it for that application either. However
the one case of a wiping contact as in a pot - I have had some success
with.


I don't doubt it. It's just that WD40 is nasty stuff when it comes to
electronic equipment, and I would rather that DIYers don't get the idea that
it is ok to use it *anywhere* in such items of equipment. It's not just that
there are "better" chemicals for the job. It's more a case of there being
correct ones, and unsuitable ones, and WD40 is a singularly unsuitable one.
It's not even a good lubricant when it comes to plastic, and many pots have
plastic component parts.

Sorry to harp on about this, and it's not particularly a dig at you John.
You've been more than helpful to me over the years, on questions that I have
asked here. It's just that I have seen so much irrepairable damage



Irrepairable damage ?

by which you mean that the equipment cannot be repaired because someone
squirted a bit of WD40 in

because that is what you are implying. I wouldn't use it because my pcb
lab is suitably equipped with the right stuff. I don't see what a
smidjen of WD40 delicatelyly (new word) sprayed onto a pot track is
going to do that is going to do "irrepairable damage"


go on, I'm listening



--
geoff

scratchy pots on old bass amp - diyable?
 

In message , Arfa Daily
writes

"Ian White" wrote in message
...
Arfa Daily wrote:
It's just that WD40 is nasty stuff when it comes to electronic equipment,
and I would rather that DIYers don't get the idea that it is ok to use it
*anywhere* in such items of equipment. It's not just that there are
"better" chemicals for the job. It's more a case of there being correct
ones, and unsuitable ones, and WD40 is a singularly unsuitable one. It's
not even a good lubricant when it comes to plastic, and many pots have
plastic component parts.

Sorry to harp on about this, and it's not particularly a dig at you John.
You've been more than helpful to me over the years, on questions that I
have asked here. It's just that I have seen so much irrepairable damage
done to equipment by people that believe WD40 to be a magic cure-all, that
I always get upset when I see anyone recommending it for tasks such as
this.

Yes, we can see that...

The point about "correct" solvents for electronics work is that they have
been specifically formulated not to attack the large majority of
components. That is the main reason for using those particular solvents.

There are still no guarantees, but with any other solvents you're
completely on your own.


Arfa, I hesitate to ask this... but please could you be more specific
about the kinds of damage that WD40 can do?



--
Ian White

It wrecks the frictional properties of rubber (neoprene ?) drive components
such as belts, idlers, pinch rollers, clutches etc. Once it has found its
way into / onto these items, there is no removing it no matter what you use.
Replacement of the afflicted items is the only possible way forward. This is
often either impractical or not cost effective, if the individual parts are
even available. The stuff clings, and creeps by its very nature, so as fast
as you think that you've cleaned it off any affected surface, ten minutes
later, it's back ...

I have also seen a lot of CD and DVD mechs over the years, which have been
treated to a dose of WD40 to try to cure things like trays that don't come
out properly. Often, trays are designed to run 'dry' - that is with no
grease - relying on the fact that the sliding and bearing surfaces are very
smooth 'oily' plastic. WD40 can completely wreck this delicate situation,
such that one or other side of the tray sticks, particularly if the drive
scheme is asymmetric, or the whole opening / closing sequence becomes
'stuttery'. Once a tray has been affected in this way, I've never managed to
totally successfully restore it. Sometimes a repolish with jeweller's rouge
will get it 'good enough', and sometimes some silicone based furniture
polish will help, but they are never quite the same again. And the chances
are, all that was needed was a new belt, in the first place ...

So, your rant is concerned with mechanical assemblies NOT electronics

The OP specifically asked about pots on an old guitar amp and John
Rumm's reply was in the same vein

WD40 - magic stuff - I sprayed some onto a Suprima pcb last week, not
only did it completely redesign the circuit, but it got it CE certified
too ...


--
geoff

scratchy pots on old bass amp - diyable?
 

In message , "Dave Plowman (News)"
writes
In article
,
jim wrote:
poss OT but it's DIY :-

I have an old but nice Yamaha bass amp combo which has had scratchy
pots since I bought it years ago - they are nearly all (volume, tone
etc) scratchy to a greater or lesser extent.

How feasible is a DIY repair? I am ok with a soldering iron and would
appreciate any help/pointers as to what to look for/check when finding/
buying new pots to replace the old and from where to buy them.

I'd first try using a cleaner/lubricant. This is my favourite - Maplin
may sell it too.

http://www.solotechnic.co.uk/super-1...nt-i23588.html

Just cleaning can be a short term fix but they really need a suitable
lubricant in the longer term.

It should be easy to get electrically similar replacements, but the
larger older types can be difficult to match mechanically.

Also note 'preferred' values may have changed - so you'll probably have
to use a 47kohm where the original was 50kohm, etc.

47k x 11 is almost 50k

--
geoff

scratchy pots on old bass amp - diyable?
 

In article ,
geoff wrote:
Also note 'preferred' values may have changed - so you'll probably have
to use a 47kohm where the original was 50kohm, etc.

47k x 11 is almost 50k

That needs explaining.

--
*If at first you do succeed, try not to look too astonished.

Dave Plowman London SW
To e-mail, change noise into sound.

scratchy pots on old bass amp - diyable?
 

geoff wrote:

first place ...
So, your rant is concerned with mechanical assemblies NOT electronics

The OP specifically asked about pots on an old guitar amp and John
Rumm's reply was in the same vein

WD40 - magic stuff - I sprayed some onto a Suprima pcb last week, not
only did it completely redesign the circuit, but it got it CE
certified too ...

Come the revolution, you are safe comrade.


--
Dave - WD40 Liberation Front.

scratchy pots on old bass amp - diyable?
 

In message , "Dave Plowman (News)"
writes
In article ,
geoff wrote:
Also note 'preferred' values may have changed - so you'll probably have
to use a 47kohm where the original was 50kohm, etc.

47k x 11 is almost 50k

That needs explaining.

FFS - Spinal Tapesque ...

--
geoff

scratchy pots on old bass amp - diyable?
 

"geoff" wrote in message
...
In message , Arfa Daily
writes

"Ian White" wrote in message
...
Arfa Daily wrote:
It's just that WD40 is nasty stuff when it comes to electronic
equipment,
and I would rather that DIYers don't get the idea that it is ok to use
it
*anywhere* in such items of equipment. It's not just that there are
"better" chemicals for the job. It's more a case of there being correct
ones, and unsuitable ones, and WD40 is a singularly unsuitable one. It's
not even a good lubricant when it comes to plastic, and many pots have
plastic component parts.

Sorry to harp on about this, and it's not particularly a dig at you
John.
You've been more than helpful to me over the years, on questions that I
have asked here. It's just that I have seen so much irrepairable damage
done to equipment by people that believe WD40 to be a magic cure-all,
that
I always get upset when I see anyone recommending it for tasks such as
this.

Yes, we can see that...

The point about "correct" solvents for electronics work is that they
have
been specifically formulated not to attack the large majority of
components. That is the main reason for using those particular solvents.

There are still no guarantees, but with any other solvents you're
completely on your own.


Arfa, I hesitate to ask this... but please could you be more specific
about the kinds of damage that WD40 can do?



--
Ian White

It wrecks the frictional properties of rubber (neoprene ?) drive
components
such as belts, idlers, pinch rollers, clutches etc. Once it has found its
way into / onto these items, there is no removing it no matter what you
use.
Replacement of the afflicted items is the only possible way forward. This
is
often either impractical or not cost effective, if the individual parts
are
even available. The stuff clings, and creeps by its very nature, so as
fast
as you think that you've cleaned it off any affected surface, ten minutes
later, it's back ...

I have also seen a lot of CD and DVD mechs over the years, which have been
treated to a dose of WD40 to try to cure things like trays that don't come
out properly. Often, trays are designed to run 'dry' - that is with no
grease - relying on the fact that the sliding and bearing surfaces are
very
smooth 'oily' plastic. WD40 can completely wreck this delicate situation,
such that one or other side of the tray sticks, particularly if the drive
scheme is asymmetric, or the whole opening / closing sequence becomes
'stuttery'. Once a tray has been affected in this way, I've never managed
to
totally successfully restore it. Sometimes a repolish with jeweller's
rouge
will get it 'good enough', and sometimes some silicone based furniture
polish will help, but they are never quite the same again. And the chances
are, all that was needed was a new belt, in the first place ...

So, your rant is concerned with mechanical assemblies NOT electronics

The OP specifically asked about pots on an old guitar amp and John Rumm's
reply was in the same vein

Some people just *have* to be obtuse don't they ? There's one on every
group, and looky here, he's just popped up ... Are you totally incapable of
understanding bigger pictures ?



WD40 - magic stuff - I sprayed some onto a Suprima pcb last week, not only
did it completely redesign the circuit, but it got it CE certified too ...


--
geoff

Prat ...

Arfa

scratchy pots on old bass amp - diyable?
 

"geoff" wrote in message
...
In message , Arfa Daily
writes

"John Rumm" wrote in message
news:V5mdnQyoPqisjgHXnZ2dnUVZ8npi4p2d@brightview .co.uk...
Arfa Daily wrote:

Normally John, I would hang on every word that you would have to say on
this group, but not this time. Please please don't recommend that
DIYers
bring WD40 anywhere near electronic equipment. It is not designed as a
switch

I have already said its not the best thing for the job, what more do you
want, blood? ;-)


OK, fair enough, but I actually posted that reply before you said that
there
were better products. The order that posts appear depend on how quickly
they
arrive at the servers.



cleaner / lubricant chemical, and whilst in some very few instances it
may be effective in providing an apparent cure to some electronic ill,
in
the vast majority of places that owners try it - for cleaning and
lubricating CD drives, tape decks etc - it spells instant and
irreversible death. I have lost count over the many years that I have
been involved in electronic service, of how many owners' pride and joy
items have been wrecked by use of WD40. My heart sinks every time one
appears on my bench with that characteristic smell wafting up from it
...

Indeed, and I would not suggest it for that application either. However
the one case of a wiping contact as in a pot - I have had some success
with.


I don't doubt it. It's just that WD40 is nasty stuff when it comes to
electronic equipment, and I would rather that DIYers don't get the idea
that
it is ok to use it *anywhere* in such items of equipment. It's not just
that
there are "better" chemicals for the job. It's more a case of there being
correct ones, and unsuitable ones, and WD40 is a singularly unsuitable
one.
It's not even a good lubricant when it comes to plastic, and many pots
have
plastic component parts.

Sorry to harp on about this, and it's not particularly a dig at you John.
You've been more than helpful to me over the years, on questions that I
have
asked here. It's just that I have seen so much irrepairable damage



Irrepairable damage ?

by which you mean that the equipment cannot be repaired because someone
squirted a bit of WD40 in

because that is what you are implying. I wouldn't use it because my pcb
lab is suitably equipped with the right stuff. I don't see what a smidjen
of WD40 delicatelyly (new word) sprayed onto a pot track is going to do
that is going to do "irrepairable damage"


go on, I'm listening

--
geoff


I didn't ever say that it wasn't going to provide a cure to a scratchy pot.
In fact, if you took the trouble to read the thread properly, instead of
just running off at the mouth, I accepted what John said, and actually said
that I "didn't doubt" that he had had success cleaning pots with it. The
point that I have been labouring to make, and that you seem singularly
unable to see, is that once Joe Punter gets a whiff of success stopping his
pot being scratchy, by squirting in this unsuitable chemical, the 'Magic
WD40!' mentality will often kick in, and when the tray on his CD player
stops going in and out, or his cassette deck starts squeaking, or his
turntable starts running slow, out will come his can of WD40, and a wrecked
piece of kit will likely result.

Your "pcb lab" is presumably not a repair workshop for domestic equipment?
An item is irrepairable if the parts are not available, which is very often
the case. An item becomes irrepairable, or more correctly BER, if the cost
of the labour exceeds the value of the equipment, which is often the case
with ****s who squirt a water dispersant into their equipment, in the fond
hope that it's going to stop it from crackling.

Do you think I am making this up just for something to say ? I have been
professionally involved in repair of domestic and industrial electronic
equipment for nearly 40 years, so believe me when I tell you that WD40 and
electronic equipment don't mix. Or actually, don't even. Be a smart-arse and
use the stuff where you like. Recommend it to all your friends. I don't
really care any more to be honest. I make a genuine attempt to use my
considerable experience in the field to perhaps save other readers from
future grief, and then along comes someone like you trying to score 'clever
points', by disputing everything I say.

My can of WD40 will stay in the garage where it belongs, for use on my
lawnmower or garden shears ...

Arfa

scratchy pots on old bass amp - diyable?
 

"Jules" wrote in message
ail.com...
On Tue, 01 Sep 2009 20:07:50 +0100, Arfa Daily wrote:

It is an excellent product for the purposes that
the manufacturers advocate

Except that the manufacturers claim it to be a lubricant - in much the
same way that snot is, I suppose.

I find it's useful for times where I don't want to be carting more
specialised products around, but for something like shed / workshop / home
there are all sorts of better things around.



Quite.

Arfa