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Roland RD-300S trouble

Roland RD-300S trouble

2006-01-26 by Antoine Deschênes

Hi,

Someone asked me to fix a Roland RD-300S(7 notes not working). I managed 
to open it and remove the keys. Now, the only problem is that there is 
some rust on the solders, but the contact looks OK(After cleanup). I'll 
re-work the solder points tomorrow, but I'd like to know the diode type 
in case that one of them is dead.

--
Antoine

Re: [vintagesynthrepair] Roland RD-300S trouble

2006-01-26 by grantbt@jps.net

I don't know this unit, but I think they are probably
just common signal diodes like 1n4148 or 1n914.
If it's not the wiring/solder/diodes, it could be the
chip that is either driving the keyboard scan lines
or the chip that is reading them.  You'll have to 
follow the traces to find the offender...

-----Original Message-----
Show quoted textHide quoted text
>From: Antoine Deschênes <antdes45@...>
>Sent: Jan 26, 2006 7:20 AM
>To: vintagesynthrepair@yahoogroups.com
>Subject: [vintagesynthrepair] Roland RD-300S trouble
>
>Hi,
>
>Someone asked me to fix a Roland RD-300S(7 notes not working). I managed 
>to open it and remove the keys. Now, the only problem is that there is 
>some rust on the solders, but the contact looks OK(After cleanup). I'll 
>re-work the solder points tomorrow, but I'd like to know the diode type 
>in case that one of them is dead.
>
>--
>Antoine

Re: [vintagesynthrepair] Roland RD-300S trouble

2006-01-26 by Antoine Deschênes

Well I'm sure that the problem is on the PCB because there is some rust 
on the diode solder points that connect to the 7 notes with 
problems.(They are all one next to the other)

Does it matter if I use an other kind of diodes?

grantbt@... a \ufffdcrit :
Show quoted textHide quoted text
> I don't know this unit, but I think they are probably
> just common signal diodes like 1n4148 or 1n914.
> If it's not the wiring/solder/diodes, it could be the
> chip that is either driving the keyboard scan lines
> or the chip that is reading them.  You'll have to
> follow the traces to find the offender...
>
> -----Original Message-----
> >From: Antoine Desch\ufffdnes <antdes45@...>
> >Sent: Jan 26, 2006 7:20 AM
> >To: vintagesynthrepair@yahoogroups.com
> >Subject: [vintagesynthrepair] Roland RD-300S trouble
> >
> >Hi,
> >
> >Someone asked me to fix a Roland RD-300S(7 notes not working). I managed
> >to open it and remove the keys. Now, the only problem is that there is
> >some rust on the solders, but the contact looks OK(After cleanup). I'll
> >re-work the solder points tomorrow, but I'd like to know the diode type
> >in case that one of them is dead.
> >
> >--
> >Antoine

RE: [vintagesynthrepair] Roland RD-300S trouble

2006-01-26 by Brian Davies

I\u2019m a bit puzzled and no one else seems to have picked up on this, solder cannot rust it has no iron in it! So just what do you mean by the solder has rust on it? Note also that the PCB tracks are made of copper and they are either tin plated of solder plated or varnished so again they do not contain iron ergo they also cannot rust.

Regards

Brian Davies G3OYU

www.g3oyu.co.uk

From: vintagesynthrepair@yahoogroups.com [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of Antoine Deschênes
Sent: Thursday, 26 January 2006 19:51
To: vintagesynthrepair@yahoogroups.com
Subject: Re: [vintagesynthrepair] Roland RD-300S trouble

Well I'm sure that the problem is on the PCB because there is some rust
on the diode solder points that connect to the 7 notes with
problems.(They are all one next to the other)

Does it matter if I use an other kind of diodes?

grantbt@... a écrit :
> I don't know this unit, but I think they are probably
> just common signal diodes like 1n4148 or 1n914.
> If it's not the wiring/solder/diodes, it could be the
> chip that is either driving the keyboard scan lines
> or the chip that is reading them. You'll have to
> follow the traces to find the offender...
>
> -----Original Message-----
> >From: Antoine Deschênes
> >Sent: Jan 26, 2006 7:20 AM
> >To: vintagesynthrepair@yahoogroups.com
> >Subject: [vintagesynthrepair] Roland RD-300S trouble
> >
> >Hi,
> >
> >Someone asked me to fix a Roland RD-300S(7 notes not working). I managed
> >to open it and remove the keys. Now, the only problem is that there is
> >some rust on the solders, but the contact looks OK(After cleanup). I'll
> >re-work the solder points tomorrow, but I'd like to know the diode type
> >in case that one of them is dead.
> >
> >--
> >Antoine


Re: [vintagesynthrepair] Roland RD-300S trouble

2006-01-26 by Antoine Deschênes

Well, maybe oxydation. There were brown traces on the solder, but they 
went off by using rubbing alcohol. Also, it went under the varnish and 
made some oxydation on the cooper. I finally found the -real- problem, 
it's that next to the solder points, there is no more cooper under the 
varnish on one thin trace that is passing next to them. The traces going 
to the solder points are OK, strange... I scraped the varnish at two 
places and will put a jumper wire to fix the problem.

Brian Davies a \ufffdcrit :
Show quoted textHide quoted text
>
> I\ufffdm a bit puzzled and no one else seems to have picked up on this, 
> solder cannot rust it has no iron in it! So just what do you mean by 
> the solder has rust on it? Note also that the PCB tracks are made of 
> copper and they are either tin plated of solder plated or varnished so 
> again they do not contain iron ergo they also cannot rust.
>
> Regards
>
> Brian Davies G3OYU
>
> www.g3oyu.co.uk <http://www.g3oyu.co.uk>
>
> ------------------------------------------------------------------------
>
> *From:* vintagesynthrepair@yahoogroups.com 
> [mailto:vintagesynthrepair@yahoogroups.com] *On Behalf Of *Antoine 
> Desch\ufffdnes
> *Sent:* Thursday, 26 January 2006 19:51
> *To:* vintagesynthrepair@yahoogroups.com
> *Subject:* Re: [vintagesynthrepair] Roland RD-300S trouble
>
> Well I'm sure that the problem is on the PCB because there is some rust
> on the diode solder points that connect to the 7 notes with
> problems.(They are all one next to the other)
>
> Does it matter if I use an other kind of diodes?
>
> grantbt@... a \ufffdcrit :
> > I don't know this unit, but I think they are probably
> > just common signal diodes like 1n4148 or 1n914.
> > If it's not the wiring/solder/diodes, it could be the
> > chip that is either driving the keyboard scan lines
> > or the chip that is reading them. You'll have to
> > follow the traces to find the offender...
> >
> > -----Original Message-----
> > >From: Antoine Desch\ufffdnes <antdes45@...>
> > >Sent: Jan 26, 2006 7:20 AM
> > >To: vintagesynthrepair@yahoogroups.com
> > >Subject: [vintagesynthrepair] Roland RD-300S trouble
> > >
> > >Hi,
> > >
> > >Someone asked me to fix a Roland RD-300S(7 notes not working). I managed
> > >to open it and remove the keys. Now, the only problem is that there is
> > >some rust on the solders, but the contact looks OK(After cleanup). I'll
> > >re-work the solder points tomorrow, but I'd like to know the diode type
> > >in case that one of them is dead.
> > >
> > >--
> > >Antoine
>

Re: [vintagesynthrepair] Roland RD-300S trouble

2006-01-27 by John Brewer

Hi Brian,
I think rust was a generic term intended to mean corrosion. However, just for an exercise, take a magnet and a selection of transistors and diodes and you will find you can actually pick some of these devices up. I discovered this when I found a diode hanging off of my magnetic screw driver.
Over the years, salts in the tinning used on these leads will leach out and react with the wire and solder causing corrosion and failed joints. A joint can look perfectly OK but you can put your Ohmmeter on the wire of a diode and get an open circuit at the next connection point on the card.
This leaching can also spread and destroy thin circuit tracks,reducing them to the texture of lace curtains and causing a high resistance or open circuit. I hope this helps.
JohnB
Show quoted textHide quoted text
----- Original Message -----
Sent: Thursday, January 26, 2006 9:46 PM
Subject: RE: [vintagesynthrepair] Roland RD-300S trouble

I’m a bit puzzled and no one else seems to have picked up on this, solder cannot rust it has no iron in it! So just what do you mean by the solder has rust on it? Note also that the PCB tracks are made of copper and they are either tin plated of solder plated or varnished so again they do not contain iron ergo they also cannot rust.

Regards

Brian Davies G3OYU

www.g3oyu.co.uk

RE: [vintagesynthrepair] Roland RD-300S trouble

2006-01-27 by Brian Davies

Hi John

Yes I take your point, semiconductor leads generally are made of some sort
of ferrous material, most probably steel and sure this can rust.  However
these are mostly plated in order that they take solder without trouble.  The
plating could be anyone of several metals, tin, silver, or even solder
itself.  I have to say that in 50 years as a test and servicing engineer I
have never come across the effect you mention.  That is not to say that the
problem doesn't occur only that I've never seen it.  Such corrosion problems
can occur in tropical climates but normally where equipment is known to
going into such climates the manufacturer would coat the board with a
tropical varnish.

 

What I have found, on many occasions, are problems associated with
components plated with nickel.  Nickel seems to deteriorate with time and
soldering nickel plated components can be impossible.  I have in stock a
quantity of nickel plated solder tags, in order to use these today - they
are at least 40 years old - I have to scrape off the plating down to bare
metal and then tin them with cored solder prior to using them. 

 

I had occasion to have to sort out an intermittent fault on a Kawai keyboard
only four days.  The reported fault was intermittent switching on.  Even
when the piano did come alive it rarely stayed on for more than a few
minutes.  I traced this to a dodgy solder joint on the power input jack
socket, the pins of which had clearly been nickel plated.  I ended up
re-soldering several joints around this component and this cured the fault.
However there was no visible sign of any corrosion.

 

Regards

Brian Davies G3OYU

www.g3oyu.co.uk

 

  _____
Show quoted textHide quoted text
From: vintagesynthrepair@yahoogroups.com
[mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of John Brewer
Sent: Friday, 27 January 2006 14:16
To: vintagesynthrepair@yahoogroups.com
Subject: Re: [vintagesynthrepair] Roland RD-300S trouble

 

Hi Brian, 

I think rust was a generic term intended to mean corrosion. However, just
for an exercise, take a magnet and a selection of transistors and diodes and
you will find you can actually pick some of these devices up.  I discovered
this when I found a diode hanging off of my magnetic screw driver.

Over the years, salts in the tinning used on these leads will leach out and
react with the wire and solder causing corrosion and failed joints.  A joint
can look perfectly OK but you can put your Ohmmeter on the wire of a diode
and get an open circuit at the next connection point on the card.

This leaching can also spread and destroy thin circuit tracks,reducing them
to the texture of lace curtains and causing a high resistance or open
circuit.  I hope this helps.

JohnB

----- Original Message ----- 

From: Brian <mailto:briang3oyu@...>  Davies 

To: vintagesynthrepair@yahoogroups.com 

Sent: Thursday, January 26, 2006 9:46 PM

Subject: RE: [vintagesynthrepair] Roland RD-300S trouble

 

I'm a bit puzzled and no one else seems to have picked up on this, solder
cannot rust it has no iron in it!  So just what do you mean by the solder
has rust on it?  Note also that the PCB tracks are made of copper and they
are either tin plated of solder plated or varnished so again they do not
contain iron ergo they also cannot rust.

 

Regards

Brian Davies G3OYU

 <http://www.g3oyu.co.uk> www.g3oyu.co.uk

 

 

 

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YAHOO! GROUPS LINKS 

 

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<http://groups.yahoo.com/group/vintagesynthrepair> " on the web.
  
*	 To unsubscribe from this group, send an email to:
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  _____

RE : RE: [vintagesynthrepair] Roland RD-300S trouble

2006-01-28 by Antoine Deschênes

OK well, now, the synth is repaired and the owner has it now. The corrosion split a trace next to some solder points, but not the ones going to the solders themselves.

Brian Davies a \ufffdcrit :
Hi John
Yes I take your point, semiconductor leads generally are made of some sort of ferrous material, most probably steel and sure this can rust. However these are mostly plated in order that they take solder without trouble. The plating could be anyone of several metals, tin, silver, or even solder itself. I have to say that in 50 years as a test and servicing engineer I have never come across the effect you mention. That is not to say that the problem doesn\ufffdt occur only that I\ufffdve never seen it. Such corrosion problems can occur in tropical climates but normally where equipment is known to going into such climates the manufacturer would coat the board with a tropical varnish.
What I have found, on many occasions, are problems associated with components plated with nickel. Nickel seems to deteriorate with time and soldering nickel plated components can be impossible. I have in stock a quantity of nickel plated solder tags, in order to use these today \ufffd they are at least 40 years old \ufffd I have to scrape off the plating down to bare metal and then tin them with cored solder prior to using them.
I had occasion to have to sort out an intermittent fault on a Kawai keyboard only four days. The reported fault was intermittent switching on. Even when the piano did come alive it rarely stayed on for more than a few minutes. I traced this to a dodgy solder joint on the power input jack socket, the pins of which had clearly been nickel plated. I ended up re-soldering several joints around this component and this cured the fault. However there was no visible sign of any corrosion.
Regards
Brian Davies G3OYU
www.g3oyu.co.uk
From: vintagesynthrepair@yahoogroups.com [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of John Brewer
Sent: Friday, 27 January 2006 14:16
To: vintagesynthrepair@yahoogroups.com
Subject: Re: [vintagesynthrepair] Roland RD-300S trouble
Hi Brian,
I think rust was a generic term intended to mean corrosion. However, just for an exercise, take a magnet and a selection of transistors and diodes and you will find you can actually pick some of these devices up. I discovered this when I found a diode hanging off of my magnetic screw driver.
Over the years, salts in the tinning used on these leads will leach out and react with the wire and solder causing corrosion and failed joints. A joint can look perfectly OK but you can put your Ohmmeter on the wire of a diode and get an open circuit at the next connection point on the card.
This leaching can also spread and destroy thin circuit tracks,reducing them to the texture of lace curtains and causing a high resistance or open circuit. I hope this helps.
JohnB
----- Original Message -----
From: Brian Davies
Sent: Thursday, January 26, 2006 9:46 PM
Subject: RE: [vintagesynthrepair] Roland RD-300S trouble
I\ufffdm a bit puzzled and no one else seems to have picked up on this, solder cannot rust it has no iron in it! So just what do you mean by the solder has rust on it? Note also that the PCB tracks are made of copper and they are either tin plated of solder plated or varnished so again they do not contain iron ergo they also cannot rust.
Regards
Brian Davies G3OYU
www.g3oyu.co.uk



Antoine Desch\ufffdnes

L\ufffdche-vitrine ou l\ufffdche-\ufffdcran ? Yahoo! Magasinage.

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