[studiorat]

Hello,
I need to replace a few pots on my console. I'm just wondering if
anybody has any tips on the correct way to remove and replace these
pots. Particularly with regard to not removing the little rings that
seem to surround the holes on the PCB there the pots are connected!!!
I'm sure that can't be good.

Thanks in advance.
Dave.

[Chris Hornbeck]

On Thu, 04 Oct 2007 17:26:19 -0700, studiorat
wrote:

I need to replace a few pots on my console. I'm just wondering if
anybody has any tips on the correct way to remove and replace these
pots. Particularly with regard to not removing the little rings that
seem to surround the holes on the PCB there the pots are connected!!!
I'm sure that can't be good.

Some folks like Solder Wick to remove the solder, but I'm
a strong proponent of Solder Suckers. Different strokes.

Remove as much solder as possible; then wiggle the tip
of the control's terminal free from the remaining solder.

Do it all in *one* application of heat and you'll be fine.
Practice on a junker if you've never done it. But don't
worry; it's very do-able.

All good fortune,
Chris Hornbeck

[studiorat]

Well, just around one of the holes a little washer like silver circle
has come off the pcb. Is this important for the contact of the new
pot? Can I just buy a bunch of these things? Also there seems to be a
kind of a varnish over the old joints?
guess the iron was too hot, will use a croc clip as heat sink next
time.

[Jason]

In article . com,
says...

Well, just around one of the holes a little washer like silver circle
has come off the pcb. Is this important for the contact of the new
pot? Can I just buy a bunch of these things? Also there seems to be a
kind of a varnish over the old joints?
guess the iron was too hot, will use a croc clip as heat sink next
time.


Is the silver circle flat or did it extend into the hole in the PCB? Are
there traces to that spot on both sides of the board? Sometimes
manufacturers use a little grommet-like gizmo to simulate at "plated
through" hole that connects to traces on both sides of the board. If
there are traces on both sides, toss the silver thingee and carefully
apply solder on both sides and you should be fine.

Jason
--
reverse my name in email address

[Mike Rivers]

On Oct 4, 8:26 pm, studiorat wrote:

I need to replace a few pots on my console. I'm just wondering if
anybody has any tips on the correct way to remove and replace these
pots. Particularly with regard to not removing the little rings that
seem to surround the holes on the PCB there the pots are connected!!!

Use a good pair of wire cutters to cut the pot leads and remove the
pot from the board, leaving a little bit of lead soldered in. Sure,
this destroys the pot, but if it was still good, you wouldn't want to
replace it. Cutting off the leads assures that you won't try to use it
again.

Anyway, when you have just the little stub of lead sticking out from
the board, tin your soldering iron, head the corener where the lead
meets the pad, and when the solder flows, pull out the lead with
tweezers or long nose pliers. Then use Solder-Wick to clean out the
hole so you can get the leads for the new pot in.

[studiorat]

They seem to be flat. I'll have a closer look. There only seems to be
a circut on one side. On the one in question anyway.
D.

[Chris Hornbeck]

On Thu, 04 Oct 2007 18:26:52 -0700, studiorat
wrote:

Well, just around one of the holes a little washer like silver circle
has come off the pcb. Is this important for the contact of the new
pot? Can I just buy a bunch of these things? Also there seems to be a
kind of a varnish over the old joints?
guess the iron was too hot, will use a croc clip as heat sink next
time.

Sometimes processes, like cooking or ****ing, are best learned
from somebody experienced. Sometimes, that isn't possible. Usenet
is a poor substitute, but I'll help as best as I can (in the case
of soldering ONLY of course).

You might see two different kinds of PCB sleeves on boards you'd
be likely to tackle. There's a sleeve with a lip on the component side
and that's maybe still soldered to the removed control. This
little guy is intended to keep mechanical stresses (like you! Arf)
from wiggling the solder joint itself, in day-to-day use.

You might want to remove this little sleeve and re-use it. I've
never seen replacements for sale, but some kind soul might have
some and be willing to put a few in an envelope. Or you might
just forgo it and move on.

There's another kind of PCB sleeve used in double-sided boards
that carries an electrical connection between the sides of the
board. If that kind can't be salvaged, you'll have to be sure that
you've resoldered the new control to *both* sides of the board.

And there are much, much worse circuit boards; fortunately they're in
the punch-through-to-the-modern-world region of designed-last-week and
not-to-be-repaired-because-outdated-last-month.

All good fortune,

Chris Hornbeck

[Chris Hornbeck]

On Thu, 04 Oct 2007 19:22:55 -0700, studiorat
wrote:

They seem to be flat. I'll have a closer look. There only seems to be
a circut on one side. On the one in question anyway.

Oh, that's different. Sounds like the ring from the plated
PCB track has come off. This isn't a sleeve at all, as I'd assumed?
Just a flat "washer", very thin?

This is a part of the PCB that needs to connect to where it
usedta connect ta. You don't really need that little ring,
but you *do* need to make the original electrical connections.

Even if you go to the trouble of re-applying the ring, you'll
still need to scrape some paint off the connecting plated
"wires" and bridge across the broken connection with a little
piece of real wire. (Use a big enough piece to give you a
stable grip, then trim ends.) Do not trust a sloppy solder
bridge across the junction. Just ain't the Cowboy Way.

All good fortune,

Chris Hornbeck

[studiorat]

Little piece of wire to bridge the contact?
Gotcha!
Thanks.

[[email protected]]

The little 'washers' in question were on the opposite side to the
circut 'the back' they look like little circles of solder even, I had
a look again this morning. The contacts on the front will be fine with
a bit of a rub with soft wire wool. I'll turn down that soldering iron
though.
Thanks for all the help.
Dave

[Scott Dorsey]

Chris Hornbeck wrote:
On Thu, 04 Oct 2007 17:26:19 -0700, studiorat
wrote:

I need to replace a few pots on my console. I'm just wondering if
anybody has any tips on the correct way to remove and replace these
pots. Particularly with regard to not removing the little rings that
seem to surround the holes on the PCB there the pots are connected!!!
I'm sure that can't be good.

Some folks like Solder Wick to remove the solder, but I'm
a strong proponent of Solder Suckers. Different strokes.

You need both, for different parts.

Remove as much solder as possible; then wiggle the tip
of the control's terminal free from the remaining solder.

Do it all in *one* application of heat and you'll be fine.
Practice on a junker if you've never done it. But don't
worry; it's very do-able.

Get some junked PC motherboards and try those for an afternoon before
you touch something real. The key is that you need to ADD solder to
the joint to make it melt completely, then remove the solder after you
have done that. If you don't add solder, you can't remove it.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

studiorat wrote:

Well, just around one of the holes a little washer like silver circle
has come off the pcb. Is this important for the contact of the new
pot? Can I just buy a bunch of these things? Also there seems to be a
kind of a varnish over the old joints?

No, once you have lifted the trace it's gone. The worse news is that
in many cases they are part of through-hole connections.

guess the iron was too hot, will use a croc clip as heat sink next
time.

It is better to be too hot than too cold. You will be more apt to do
damage with too cold an iron because it will take too long to do the
job. You should be able to melt solder into the joint and then suck it
all up within about two seconds. The key is to work hot and work fast.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[g]

In article , (Scott Dorsey) wrote:
Chris Hornbeck wrote:
On Thu, 04 Oct 2007 17:26:19 -0700, studiorat
wrote:

I need to replace a few pots on my console. I'm just wondering if
anybody has any tips on the correct way to remove and replace these
pots. Particularly with regard to not removing the little rings that
seem to surround the holes on the PCB there the pots are connected!!!
I'm sure that can't be good.

Some folks like Solder Wick to remove the solder, but I'm
a strong proponent of Solder Suckers. Different strokes.

You need both, for different parts.

Remove as much solder as possible; then wiggle the tip
of the control's terminal free from the remaining solder.

Do it all in *one* application of heat and you'll be fine.
Practice on a junker if you've never done it. But don't
worry; it's very do-able.

Get some junked PC motherboards and try those for an afternoon before
you touch something real. The key is that you need to ADD solder to
the joint to make it melt completely, then remove the solder after you
have done that. If you don't add solder, you can't remove it.
--scott

They probably are not accessible, but anytime you can clip off the leads first
will make unsoldering much easier. Liquid flux is also a must. I like to
wet the wick first, especially older wick that gets funky.


greg