Topics

Cleaning TM500 module pushbutton switches

W1PJE
 

Hi all,

Hopefully not way off topic:

I have some TM500 modules with sticky/intermittently responsive
pushbutton switches (the small square kind). What is the recommended
cleaning procedure - Deoxit from Caig, or something else?

Cheers, Phil

Andy Warner
 

I use standard DeOxit D5 and it has worked great for every one of my TM500
modules.

Depending on the module in question, I try and be careful not to
accidentally spray any variable caps in the vicinity.

On Thu, Jul 9, 2020 at 8:05 PM W1PJE <@W1PJE> wrote:

Hi all,

Hopefully not way off topic:

I have some TM500 modules with sticky/intermittently responsive
pushbutton switches (the small square kind). What is the recommended
cleaning procedure - Deoxit from Caig, or something else?

Cheers, Phil



--
Andy

 

Over the years, the best method I have found for the
TM500 pushbutton switches is to spray a small bit of de-oxit into the rear open end,
and let it flood down to the front shaft (very important). hold the unhit so the opne back is UP, and the
shaft is DOWN.

once it has penetrated, cycle the switch rapidly a few times, this will also *free up the switch **
**shaft, and locking mechanism,* as well as clean the contacts.  a second flush is usually NOT required, and
if solvent based, would make the *shaft bind at the front*. many problems are shaft friction related, and not bad contacts, so this method fixes both nicely.

almost all the the switches are silver plated, so de-oxit is really the magic answer for aged contacts.

this method has restored switches I thought were totally useless, so I really recommend it.
all the best,
walter

--
Walter Shawlee 2
Sphere Research Corp. 3394 Sunnyside Rd.
West Kelowna, BC, V1Z 2V4 CANADA
Phone: +1 (250-769-1834 -:- http://www.sphere.bc.ca
+We're all in one boat, no matter how it looks to you. (WS2)
+All you need is love. (John Lennon)
+But, that doesn't mean other things don't come in handy. (WS2)
+Nature is trying very hard to make us succeed, but nature does not depend on us.
We are not the only experiment. (R. Buckminster Fuller)

Nenad Filipovic
 

On Fri, Jul 10, 2020 at 3:05 AM W1PJE <@W1PJE> wrote:

I have multiple TM500 modules that have developed sticky / intermittent
pushbutton switches (the square small ones). Is there a recommended
cleaning procedure? I was going to do the standard use of Caig's DeOxit in
a sparing manner, but perhaps there is a better way.
In some cases hard patina forms on contact surfaces and DeOxit can be
ineffective or just a short term solution. Additionally, DeOxit cannot
restore the original grease which is likely fully decomposed and dry due to
age. In that case I use the following procedure to restore these without
any desoldering:

- Gain access, carefully uncouple and remove the pushbutton shaft.
- Remove the clamp next to the spring, carefully remove the tiny parts
(spring, tiny rocker bolt and its elastic support).
- Carefully pull out the switch shaft at the back of the switch body - care
must be taken to go slow and grip the two metal contacts (use tweezers)
before they fully come out (otherwise they may fly off and get lost). Note
(or take photo of) the orientation of contacts with respect to their slot
in the shaft (the bend in the middle should be oriented away from the
switch body).
- If the switch is radio button type it will contain a "clutch" sliding
plate that needs to be pushed to one side so the shaft could be released
and removed.
- Sometimes a PCB component may get in the way of shaft removal, I almost
always find it easier to remove the offending component rather than the
switch body.
- If switch parts are clogged by ancient dried up grease, clean/wash
everything (both plastic and metal parts) with a paintbrush in petroleum
benzine (pharmaceutical grade, in Europe we get it in regular pharmacies;
however most non-polar solvents which are not aggressive to plastic would
do). Do not let the plastic parts sit in benzine for too long, all this can
and should be done in just a few minutes. Let the clean parts dry.
- Using a soft brass brush (I get these at dentist supply shops) gently
scrub the patina off the active side of the metal contacts. Soft brass
brush should not damage the contact plating that needs to be preserved.
- Use cotton ear buds soaked first in petroleum benzine, then IPA to clean
the internals of the switch body. I spend at least two sticks per switch.
- Grease all sliding surfaces of parts sparingly (innards of the switch
body, shaft, contacts, rocker bolt pathway in the shaft) with plastic safe
light grease. The goal of contact greasing is protection from moisture and
oxygen that may re-deposit the patina again in time. Light grease won't
interfere with low current low voltage electrical contact properties.
- Re-assemble and exercise the switch.

HTH,
Best regards,
Nenad

Colin Herbert
 

Nenad,
You mention something you call "petroleum benzine". Though I am a retired research chemist living in Britain, I have no idea of what this is and others may not also. It _could_ be "petroleum ether", which I am familiar with, but that comes in various boiling-point ranges and you wouldn't want to use a high-boiling fraction; 60-40 is the most likely (boiling-range between 60 and 40 degrees Centigrade/Celsius). Be cautious, this solvent is very inflammable and not a little smelly. If you are actually thinking of "benzene" (note the "e", not "i"), then I doubt that anyone in an EU country would be able to buy that, as it is carcinogenic (causes cancer) and is therefore controlled. Perhaps you could clarify?
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Nenad Filipovic
Sent: 10 July 2020 15:42
To: TekScopes@groups.io
Subject: Re: [TekScopes] Cleaning TM500 module pushbutton switches

On Fri, Jul 10, 2020 at 3:05 AM W1PJE <@W1PJE> wrote:

I have multiple TM500 modules that have developed sticky / intermittent
pushbutton switches (the square small ones). Is there a recommended
cleaning procedure? I was going to do the standard use of Caig's DeOxit in
a sparing manner, but perhaps there is a better way.
In some cases hard patina forms on contact surfaces and DeOxit can be
ineffective or just a short term solution. Additionally, DeOxit cannot
restore the original grease which is likely fully decomposed and dry due to
age. In that case I use the following procedure to restore these without
any desoldering:

- Gain access, carefully uncouple and remove the pushbutton shaft.
- Remove the clamp next to the spring, carefully remove the tiny parts
(spring, tiny rocker bolt and its elastic support).
- Carefully pull out the switch shaft at the back of the switch body - care
must be taken to go slow and grip the two metal contacts (use tweezers)
before they fully come out (otherwise they may fly off and get lost). Note
(or take photo of) the orientation of contacts with respect to their slot
in the shaft (the bend in the middle should be oriented away from the
switch body).
- If the switch is radio button type it will contain a "clutch" sliding
plate that needs to be pushed to one side so the shaft could be released
and removed.
- Sometimes a PCB component may get in the way of shaft removal, I almost
always find it easier to remove the offending component rather than the
switch body.
- If switch parts are clogged by ancient dried up grease, clean/wash
everything (both plastic and metal parts) with a paintbrush in petroleum
benzine (pharmaceutical grade, in Europe we get it in regular pharmacies;
however most non-polar solvents which are not aggressive to plastic would
do). Do not let the plastic parts sit in benzine for too long, all this can
and should be done in just a few minutes. Let the clean parts dry.
- Using a soft brass brush (I get these at dentist supply shops) gently
scrub the patina off the active side of the metal contacts. Soft brass
brush should not damage the contact plating that needs to be preserved.
- Use cotton ear buds soaked first in petroleum benzine, then IPA to clean
the internals of the switch body. I spend at least two sticks per switch.
- Grease all sliding surfaces of parts sparingly (innards of the switch
body, shaft, contacts, rocker bolt pathway in the shaft) with plastic safe
light grease. The goal of contact greasing is protection from moisture and
oxygen that may re-deposit the patina again in time. Light grease won't
interfere with low current low voltage electrical contact properties.
- Re-assemble and exercise the switch.

HTH,
Best regards,
Nenad

Renée
 

I have the same issue only with the plastic on plastic ( the actuator for finger poking to the to the outside world) is causing the sticking. they were cleaned with soap and water ( yes disassembled) to remove dirt and then ipa without success. suggestions?
I have used WD40 to soften grease for easier removal. leave it sit for a day or two, sometimes multiple applications...I try not to make it too messy.
thanks for the procedure, some things I had not considered, very helpful!
Renée

On 7/10/20 7:42 AM, Nenad Filipovic wrote:
On Fri, Jul 10, 2020 at 3:05 AM W1PJE <@W1PJE> wrote:
I have multiple TM500 modules that have developed sticky / intermittent
pushbutton switches (the square small ones). Is there a recommended cleaning procedure? I was going to do the standard use of Caig's DeOxit in a sparing manner, but perhaps there is a better way.
In some cases hard patina forms on contact surfaces and DeOxit can be ineffective or just a short term solution. Additionally, DeOxit cannot restore the original grease which is likely fully decomposed and dry due to age. In that case I use the following procedure to restore these without any desoldering: - Gain access, carefully uncouple and remove the pushbutton shaft. - Remove the clamp next to the spring, carefully remove the tiny parts (spring, tiny rocker bolt and its elastic support). - Carefully pull out the switch shaft at the back of the switch body - care must be taken to go slow and grip the two metal contacts (use tweezers) before they fully come out (otherwise they may fly off and get lost). Note (or take photo of) the orientation of contacts with respect to their slot in the shaft (the bend in the middle should be oriented away from the switch body). - If the switch is radio button type it will contain a "clutch" sliding plate that needs to be pushed to one side so the shaft could be released and removed. - Sometimes a PCB component may get in the way of shaft removal, I almost always find it easier to remove the offending component rather than the switch body. - If switch parts are clogged by ancient dried up grease, clean/wash everything (both plastic and metal parts) with a paintbrush in petroleum benzine (pharmaceutical grade, in Europe we get it in regular pharmacies; however most non-polar solvents which are not aggressive to plastic would do). Do not let the plastic parts sit in benzine for too long, all this can and should be done in just a few minutes. Let the clean parts dry. - Using a soft brass brush (I get these at dentist supply shops) gently scrub the patina off the active side of the metal contacts. Soft brass brush should not damage the contact plating that needs to be preserved. - Use cotton ear buds soaked first in petroleum benzine, then IPA to clean the internals of the switch body. I spend at least two sticks per switch. - Grease all sliding surfaces of parts sparingly (innards of the switch body, shaft, contacts, rocker bolt pathway in the shaft) with plastic safe light grease. The goal of contact greasing is protection from moisture and oxygen that may re-deposit the patina again in time. Light grease won't interfere with low current low voltage electrical contact properties. - Re-assemble and exercise the switch. HTH, Best regards, Nenad .

scm@...
 

In the US, benzene is one of many aromatic hydrocarbons. Aromatic hydrocarbons
are incompatible with many plastics; it can soften, or even dissolve, them. I would be very cautious about using "petroleum benzine" without testing it first. Isopropyl alcohol is much safer from both environmentally and from a compatibility viewpoiont.

Nenad Filipovic
 

On Fri, Jul 10, 2020 at 4:53 PM Colin Herbert via groups.io <colingherbert=
blueyonder.co.uk@groups.io> wrote:

Nenad,
You mention something you call "petroleum benzine". Though I am a retired
research chemist living in Britain, I have no idea of what this is and
others may not also. It _could_ be "petroleum ether", which I am familiar
with, but that comes in various boiling-point ranges and you wouldn't want
to use a high-boiling fraction; 60-40 is the most likely (boiling-range
between 60 and 40 degrees Centigrade/Celsius). Be cautious, this solvent is
very inflammable and not a little smelly. If you are actually thinking of
"benzene" (note the "e", not "i"), then I doubt that anyone in an EU
country would be able to buy that, as it is carcinogenic (causes cancer)
and is therefore controlled. Perhaps you could clarify?
Colin.
Hi Colin,

Yes indeed, I suspected that "petroleum benzine" might cause confusion, and
I'd be glad if we could clear it. The issue is that these damn chemicals
have notorious local names, and something that is quite wide known in one
country can have a completely different name in another, or not be
available at all.

To be honest, I am also not sure about my "petroleum benzine" true content,
but I strongly believe it's just a kind of petroleum ether. It is sold in
pharmacies and has the following uses and properties:
- often called "Benzinum medicinale" and can be looked up by that name in
Europe
- used in medicine as a solvent to clean skin and surfaces off greasy or
similar non-polar contaminants (commonly used to remove traces of adhesive
from skin after patches and bandages are taken off)
- generally used to remove greasy contaminants (as a non-polar solvent),
especially by watchmakers and jewelers
- is "moderately" volatile (e.g. less than acetone)
- is smelly, but certainly not very smelly or outright unpleasant (e.g.
acetone is much more pungent)
- certainly does not smell like benzEne (C6H6), I remember benzene smell
from chemistry classes as much "heavier" and more "oily" than this

These are the only links I found related to its technical properties:
http://www.gram.co.rs/ser/benzin_za_odmascivanje.htm
and
https://www.pharmawiki.ch/wiki/index.php?wiki=Wundbenzin

Due to its pharmaceutical use (application on skin) I was inclined to
believe it is not an aggressive substance. Throughout years of various uses
I can confirm that assumption, I find it mild on rubber and plastic
surfaces. I often use it to clean my photographic lenses, it does an
excellent job on fingerprints and all greasy stuff, evaporates without a
trace, and also no trace/damage on the surrounding plastic parts.

Best regards,
Nenad

Glenn Little
 

Ensure that you remove all traces of the WD40.
WD40 is a water displacer.
It will leave a gummy mess.

Glenn

On 7/10/2020 11:30 AM, Renée wrote:
I have the same issue only with the plastic on plastic ( the actuator for finger poking to the to the outside world) is causing the sticking. they were cleaned with soap and water ( yes disassembled) to remove dirt and then ipa without success. suggestions?
I have used WD40 to soften grease for easier removal. leave it sit for a day or two, sometimes multiple applications...I try not to make it too messy.
thanks for the procedure, some things I had not considered, very helpful!
Renée


On 7/10/20 7:42 AM, Nenad Filipovic wrote:
On Fri, Jul 10, 2020 at 3:05 AM W1PJE <@W1PJE> wrote:
I have multiple TM500 modules that have developed sticky / intermittent
pushbutton switches (the square small ones). Is there a recommended cleaning procedure? I was going to do the standard use of Caig's DeOxit in a sparing manner, but perhaps there is a better way.
In some cases hard patina forms on contact surfaces and DeOxit can be ineffective or just a short term solution. Additionally, DeOxit cannot restore the original grease which is likely fully decomposed and dry due to age. In that case I use the following procedure to restore these without any desoldering: - Gain access, carefully uncouple and remove the pushbutton shaft. - Remove the clamp next to the spring, carefully remove the tiny parts (spring, tiny rocker bolt and its elastic support). - Carefully pull out the switch shaft at the back of the switch body - care must be taken to go slow and grip the two metal contacts (use tweezers) before they fully come out (otherwise they may fly off and get lost). Note (or take photo of) the orientation of contacts with respect to their slot in the shaft (the bend in the middle should be oriented away from the switch body). - If the switch is radio button type it will contain a "clutch" sliding plate that needs to be pushed to one side so the shaft could be released and removed. - Sometimes a PCB component may get in the way of shaft removal, I almost always find it easier to remove the offending component rather than the switch body. - If switch parts are clogged by ancient dried up grease, clean/wash everything (both plastic and metal parts) with a paintbrush in petroleum benzine (pharmaceutical grade, in Europe we get it in regular pharmacies; however most non-polar solvents which are not aggressive to plastic would do). Do not let the plastic parts sit in benzine for too long, all this can and should be done in just a few minutes. Let the clean parts dry. - Using a soft brass brush (I get these at dentist supply shops) gently scrub the patina off the active side of the metal contacts. Soft brass brush should not damage the contact plating that needs to be preserved. - Use cotton ear buds soaked first in petroleum benzine, then IPA to clean the internals of the switch body. I spend at least two sticks per switch. - Grease all sliding surfaces of parts sparingly (innards of the switch body, shaft, contacts, rocker bolt pathway in the shaft) with plastic safe light grease. The goal of contact greasing is protection from moisture and oxygen that may re-deposit the patina again in time. Light grease won't interfere with low current low voltage electrical contact properties. - Re-assemble and exercise the switch. HTH, Best regards, Nenad  .

--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"

Ray
 

It might be close to what is called white gas or camping gas, used to fuel portable camping stoves.Colman is one of the brands.It is essential gasoline without any aditives.73Sent from my T-Mobile 4G LTE device------ Original message------From: Nenad FilipovicDate: Fri, Jul 10, 2020 11:04To: TekScopes@groups.io;Cc: Subject:Re: [TekScopes] Cleaning TM500 module pushbutton switchesOn Fri, Jul 10, 2020 at 4:53 PM Colin Herbert via groups.io wrote:

Nenad,
You mention something you call "petroleum benzine". Though I am a retired
research chemist living in Britain, I have no idea of what this is and
others may not also. It _could_ be "petroleum ether", which I am familiar
with, but that comes in various boiling-point ranges and you wouldn't want
to use a high-boiling fraction; 60-40 is the most likely (boiling-range
between 60 and 40 degrees Centigrade/Celsius). Be cautious, this solvent is
very inflammable and not a little smelly. If you are actually thinking of
"benzene" (note the "e", not "i"), then I doubt that anyone in an EU
country would be able to buy that, as it is carcinogenic (causes cancer)
and is therefore controlled. Perhaps you could clarify?
Colin.
Hi Colin,

Yes indeed, I suspected that "petroleum benzine" might cause confusion, and
I'd be glad if we could clear it. The issue is that these damn chemicals
have notorious local names, and something that is quite wide known in one
country can have a completely different name in another, or not be
available at all.

To be honest, I am also not sure about my "petroleum benzine" true content,
but I strongly believe it's just a kind of petroleum ether. It is sold in
pharmacies and has the following uses and properties:
- often called "Benzinum medicinale" and can be looked up by that name in
Europe
- used in medicine as a solvent to clean skin and surfaces off greasy or
similar non-polar contaminants (commonly used to remove traces of adhesive
from skin after patches and bandages are taken off)
- generally used to remove greasy contaminants (as a non-polar solvent),
especially by watchmakers and jewelers
- is "moderately" volatile (e.g. less than acetone)
- is smelly, but certainly not very smelly or outright unpleasant (e.g.
acetone is much more pungent)
- certainly does not smell like benzEne (C6H6), I remember benzene smell
from chemistry classes as much "heavier" and more "oily" than this

These are the only links I found related to its technical properties:
http://www.gram.co.rs/ser/benzin_za_odmascivanje.htm
and
https://www.pharmawiki.ch/wiki/index.php?wiki=Wundbenzin

Due to its pharmaceutical use (application on skin) I was inclined to
believe it is not an aggressive substance. Throughout years of various uses
I can confirm that assumption, I find it mild on rubber and plastic
surfaces. I often use it to clean my photographic lenses, it does an
excellent job on fingerprints and all greasy stuff, evaporates without a
trace, and also no trace/damage on the surrounding plastic parts.

Best regards,
Nenad

 

I do not recommend using WD40 anywhere near the TM500 switches.
as I explained earlier, using de-oxit (which is slightly lubricating), and letting it fall right
to the front plastic shaft solves ALL seizing problems in the switch assembly, as well as fixing the contacts.
let it drain down to the shaft from the open back, work the mechanism rapidly at least a dozen times, and
you should have good results. I have also had good success with nu-trol, used in the same way from the
 open back of the switch.

I have done hundreds of these switches both in the TM500 and 7K /5K series. I am 100% confident
that the process I described will work IF ANYTHING CAN WORK (in other words if there's any good
contact surface left in the switch). I strongly advise against anything like solvents, WD40, oils or
other highly active chemicals, and I have NOT found that disassembly and manual cleaning works
any better than the process I described, although disassembly can be useful when the sliding
contact has to be replaced. to be candid, if it's at that point, the switch itself has to go.

we used a variant of this same switch (the origin of which goes WAY back to itt-schadow in europe) for many
years in avionics systems as well, but paid to have the contacts gold plated from E-switch, and had almost no failures over decades of use.

just my $0.02 worth on this topic.
all the best,
walter

--
Walter Shawlee 2
Sphere Research Corp. 3394 Sunnyside Rd.
West Kelowna, BC, V1Z 2V4 CANADA
Phone: +1 (250-769-1834 -:- http://www.sphere.bc.ca
+We're all in one boat, no matter how it looks to you. (WS2)
+All you need is love. (John Lennon)
+But, that doesn't mean other things don't come in handy. (WS2)
+Nature is trying very hard to make us succeed, but nature does not depend on us.
We are not the only experiment. (R. Buckminster Fuller)

Chuck Harris
 

Petroleum benzine is a redundant redundancy for white gasoline.

White gasoline is an additive free (typically) mixture of heptane
and hexane and their isomers. It is also called stove gas. And
a more pure form also exists as a rubber cement solvent.

-Chuck Harris

Colin Herbert via groups.io wrote:

Nenad,
You mention something you call "petroleum benzine". Though I am a retired research chemist living in Britain, I have no idea of what this is and others may not also. It _could_ be "petroleum ether", which I am familiar with, but that comes in various boiling-point ranges and you wouldn't want to use a high-boiling fraction; 60-40 is the most likely (boiling-range between 60 and 40 degrees Centigrade/Celsius). Be cautious, this solvent is very inflammable and not a little smelly. If you are actually thinking of "benzene" (note the "e", not "i"), then I doubt that anyone in an EU country would be able to buy that, as it is carcinogenic (causes cancer) and is therefore controlled. Perhaps you could clarify?
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Nenad Filipovic
Sent: 10 July 2020 15:42
To: TekScopes@groups.io
Subject: Re: [TekScopes] Cleaning TM500 module pushbutton switches

On Fri, Jul 10, 2020 at 3:05 AM W1PJE <@W1PJE> wrote:

I have multiple TM500 modules that have developed sticky / intermittent
pushbutton switches (the square small ones). Is there a recommended
cleaning procedure? I was going to do the standard use of Caig's DeOxit in
a sparing manner, but perhaps there is a better way.
In some cases hard patina forms on contact surfaces and DeOxit can be
ineffective or just a short term solution. Additionally, DeOxit cannot
restore the original grease which is likely fully decomposed and dry due to
age. In that case I use the following procedure to restore these without
any desoldering:

- Gain access, carefully uncouple and remove the pushbutton shaft.
- Remove the clamp next to the spring, carefully remove the tiny parts
(spring, tiny rocker bolt and its elastic support).
- Carefully pull out the switch shaft at the back of the switch body - care
must be taken to go slow and grip the two metal contacts (use tweezers)
before they fully come out (otherwise they may fly off and get lost). Note
(or take photo of) the orientation of contacts with respect to their slot
in the shaft (the bend in the middle should be oriented away from the
switch body).
- If the switch is radio button type it will contain a "clutch" sliding
plate that needs to be pushed to one side so the shaft could be released
and removed.
- Sometimes a PCB component may get in the way of shaft removal, I almost
always find it easier to remove the offending component rather than the
switch body.
- If switch parts are clogged by ancient dried up grease, clean/wash
everything (both plastic and metal parts) with a paintbrush in petroleum
benzine (pharmaceutical grade, in Europe we get it in regular pharmacies;
however most non-polar solvents which are not aggressive to plastic would
do). Do not let the plastic parts sit in benzine for too long, all this can
and should be done in just a few minutes. Let the clean parts dry.
- Using a soft brass brush (I get these at dentist supply shops) gently
scrub the patina off the active side of the metal contacts. Soft brass
brush should not damage the contact plating that needs to be preserved.
- Use cotton ear buds soaked first in petroleum benzine, then IPA to clean
the internals of the switch body. I spend at least two sticks per switch.
- Grease all sliding surfaces of parts sparingly (innards of the switch
body, shaft, contacts, rocker bolt pathway in the shaft) with plastic safe
light grease. The goal of contact greasing is protection from moisture and
oxygen that may re-deposit the patina again in time. Light grease won't
interfere with low current low voltage electrical contact properties.
- Re-assemble and exercise the switch.

HTH,
Best regards,
Nenad







n4buq
 

Does lighter fluid such as Ronsonal, etc., fall into that same category?

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Chuck Harris" <cfharris@...>
To: TekScopes@groups.io
Sent: Friday, July 10, 2020 1:18:44 PM
Subject: Re: [TekScopes] Cleaning TM500 module pushbutton switches

Petroleum benzine is a redundant redundancy for white gasoline.

White gasoline is an additive free (typically) mixture of heptane
and hexane and their isomers. It is also called stove gas. And
a more pure form also exists as a rubber cement solvent.

-Chuck Harris

Colin Herbert via groups.io wrote:
Nenad,
You mention something you call "petroleum benzine". Though I am a retired
research chemist living in Britain, I have no idea of what this is and
others may not also. It _could_ be "petroleum ether", which I am familiar
with, but that comes in various boiling-point ranges and you wouldn't want
to use a high-boiling fraction; 60-40 is the most likely (boiling-range
between 60 and 40 degrees Centigrade/Celsius). Be cautious, this solvent
is very inflammable and not a little smelly. If you are actually thinking
of "benzene" (note the "e", not "i"), then I doubt that anyone in an EU
country would be able to buy that, as it is carcinogenic (causes cancer)
and is therefore controlled. Perhaps you could clarify?
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Nenad
Filipovic
Sent: 10 July 2020 15:42
To: TekScopes@groups.io
Subject: Re: [TekScopes] Cleaning TM500 module pushbutton switches

On Fri, Jul 10, 2020 at 3:05 AM W1PJE <@W1PJE> wrote:

I have multiple TM500 modules that have developed sticky / intermittent
pushbutton switches (the square small ones). Is there a recommended
cleaning procedure? I was going to do the standard use of Caig's DeOxit in
a sparing manner, but perhaps there is a better way.
In some cases hard patina forms on contact surfaces and DeOxit can be
ineffective or just a short term solution. Additionally, DeOxit cannot
restore the original grease which is likely fully decomposed and dry due to
age. In that case I use the following procedure to restore these without
any desoldering:

- Gain access, carefully uncouple and remove the pushbutton shaft.
- Remove the clamp next to the spring, carefully remove the tiny parts
(spring, tiny rocker bolt and its elastic support).
- Carefully pull out the switch shaft at the back of the switch body - care
must be taken to go slow and grip the two metal contacts (use tweezers)
before they fully come out (otherwise they may fly off and get lost). Note
(or take photo of) the orientation of contacts with respect to their slot
in the shaft (the bend in the middle should be oriented away from the
switch body).
- If the switch is radio button type it will contain a "clutch" sliding
plate that needs to be pushed to one side so the shaft could be released
and removed.
- Sometimes a PCB component may get in the way of shaft removal, I almost
always find it easier to remove the offending component rather than the
switch body.
- If switch parts are clogged by ancient dried up grease, clean/wash
everything (both plastic and metal parts) with a paintbrush in petroleum
benzine (pharmaceutical grade, in Europe we get it in regular pharmacies;
however most non-polar solvents which are not aggressive to plastic would
do). Do not let the plastic parts sit in benzine for too long, all this can
and should be done in just a few minutes. Let the clean parts dry.
- Using a soft brass brush (I get these at dentist supply shops) gently
scrub the patina off the active side of the metal contacts. Soft brass
brush should not damage the contact plating that needs to be preserved.
- Use cotton ear buds soaked first in petroleum benzine, then IPA to clean
the internals of the switch body. I spend at least two sticks per switch.
- Grease all sliding surfaces of parts sparingly (innards of the switch
body, shaft, contacts, rocker bolt pathway in the shaft) with plastic safe
light grease. The goal of contact greasing is protection from moisture and
oxygen that may re-deposit the patina again in time. Light grease won't
interfere with low current low voltage electrical contact properties.
- Re-assemble and exercise the switch.

HTH,
Best regards,
Nenad









Roy Thistle
 

On Fri, Jul 10, 2020 at 09:03 AM, Nenad Filipovic wrote:


"petroleum benzine" might cause confusion
Petroleum benzine is "benzene" in the same way as Silk Almondmilk is milk (unless ur silky cow happens to be named Almond... and then, technically it's Almond's milk... and it is milk.)
The very same thing, petroleum benzine... and labeled as such, under BP, or USP... used to be sold, at drugstores, here in the colonies... in little bottles, among the witch hazel, flowers of sulphur, and saltpetre... and no... I never found any witches, flowers, or salted peters, in the lot.
I always thought petroleum benzene was highly refined (desulfanated, and hydrogenated) hexanes. But, I suppose it could have octanes et.al in it too.
As to what's in your particular petroleum benzene... mileage may very... see your local chromatograph.
As for what's not in it (or not very much at all)... that would be benzene.
By the way... in the BP... there are a number of petroleum medicinals, such as "light"... and "jellied"... and so your pharmacist comes by the name petroleum benzine legitimately.
There are a number of names for similar petroleum based non-polar (or mostly so) solvents... naptha, white gasoline, varsol, mineral spirits, petroleum spirits, lighter fluid, paint thinner (no not water)... and so on.
Call it what you will... you should know what it is still... if you want to use it safely.

Chuck Harris
 

Naphtha is a very ambiguous term.

I don't know exactly what the "naphtha" in Ronsonol is, but it is
definitely not the same "naphtha" from which is derived white gas.

I think the important feature needed to be called naphtha today is
for the liquid to have 5 to 7 carbons arranged in straight or
cyclic groupings... That covers everything from Ronsonol to Coleman
fuel to benzene... And they are not even close to all being equivalent.

The structure makes all the difference in the world as to how the
substance called naptha behaves.

I switched from Ronsonol to VM&P Naphtha, available in pints and
gallons in hardware stores, as Varnish Makers and Painters Naphtha.

It smells the same, and works the same as Ronsonol... even in a
Zippo lighter. Coleman fuel works in Zippo lighters too, but gets
pretty exciting with its bright billowing flame. Gasoline also
works in Zippo lighters, but I wouldn't do it.

Rononol is the standard fair for "fire-eaters". If they were to do
their tricks with Coleman Fuel, they would end up in the burn ward.

As to Tam's suggestion on cleaning TM500 module pushbutton switches,
VM&P Naphtha, or Ronsonol would work very well.

But, you would need some lubrication, as they both would wash all the
light oils away.

-Chuck Harris

n4buq wrote:

Does lighter fluid such as Ronsonal, etc., fall into that same category?

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Chuck Harris" <cfharris@...>
To: TekScopes@groups.io
Sent: Friday, July 10, 2020 1:18:44 PM
Subject: Re: [TekScopes] Cleaning TM500 module pushbutton switches

Petroleum benzine is a redundant redundancy for white gasoline.

White gasoline is an additive free (typically) mixture of heptane
and hexane and their isomers. It is also called stove gas. And
a more pure form also exists as a rubber cement solvent.

-Chuck Harris

Colin Herbert via groups.io wrote:
Nenad,
You mention something you call "petroleum benzine". Though I am a retired
research chemist living in Britain, I have no idea of what this is and
others may not also. It _could_ be "petroleum ether", which I am familiar
with, but that comes in various boiling-point ranges and you wouldn't want
to use a high-boiling fraction; 60-40 is the most likely (boiling-range
between 60 and 40 degrees Centigrade/Celsius). Be cautious, this solvent
is very inflammable and not a little smelly. If you are actually thinking
of "benzene" (note the "e", not "i"), then I doubt that anyone in an EU
country would be able to buy that, as it is carcinogenic (causes cancer)
and is therefore controlled. Perhaps you could clarify?
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Nenad
Filipovic
Sent: 10 July 2020 15:42
To: TekScopes@groups.io
Subject: Re: [TekScopes] Cleaning TM500 module pushbutton switches

On Fri, Jul 10, 2020 at 3:05 AM W1PJE <@W1PJE> wrote:

I have multiple TM500 modules that have developed sticky / intermittent
pushbutton switches (the square small ones). Is there a recommended
cleaning procedure? I was going to do the standard use of Caig's DeOxit in
a sparing manner, but perhaps there is a better way.
In some cases hard patina forms on contact surfaces and DeOxit can be
ineffective or just a short term solution. Additionally, DeOxit cannot
restore the original grease which is likely fully decomposed and dry due to
age. In that case I use the following procedure to restore these without
any desoldering:

- Gain access, carefully uncouple and remove the pushbutton shaft.
- Remove the clamp next to the spring, carefully remove the tiny parts
(spring, tiny rocker bolt and its elastic support).
- Carefully pull out the switch shaft at the back of the switch body - care
must be taken to go slow and grip the two metal contacts (use tweezers)
before they fully come out (otherwise they may fly off and get lost). Note
(or take photo of) the orientation of contacts with respect to their slot
in the shaft (the bend in the middle should be oriented away from the
switch body).
- If the switch is radio button type it will contain a "clutch" sliding
plate that needs to be pushed to one side so the shaft could be released
and removed.
- Sometimes a PCB component may get in the way of shaft removal, I almost
always find it easier to remove the offending component rather than the
switch body.
- If switch parts are clogged by ancient dried up grease, clean/wash
everything (both plastic and metal parts) with a paintbrush in petroleum
benzine (pharmaceutical grade, in Europe we get it in regular pharmacies;
however most non-polar solvents which are not aggressive to plastic would
do). Do not let the plastic parts sit in benzine for too long, all this can
and should be done in just a few minutes. Let the clean parts dry.
- Using a soft brass brush (I get these at dentist supply shops) gently
scrub the patina off the active side of the metal contacts. Soft brass
brush should not damage the contact plating that needs to be preserved.
- Use cotton ear buds soaked first in petroleum benzine, then IPA to clean
the internals of the switch body. I spend at least two sticks per switch.
- Grease all sliding surfaces of parts sparingly (innards of the switch
body, shaft, contacts, rocker bolt pathway in the shaft) with plastic safe
light grease. The goal of contact greasing is protection from moisture and
oxygen that may re-deposit the patina again in time. Light grease won't
interfere with low current low voltage electrical contact properties.
- Re-assemble and exercise the switch.

HTH,
Best regards,
Nenad











Roy Thistle
 

On Thu, Jul 9, 2020 at 08:06 PM, walter shawlee wrote:


de-oxit is really the magic answer
Hi Walter:
I'm not a fan of that libation... as my wankometer goes full double tilt at the mention... but, seeing as you've recommended it (and I know you've worked on a ton of TM500 stuff) my mind is somewhat changed.
And yes, I have noticed the stuff has magical properties too... at least when it comes to anti-gravity: my wallet always feels so much lighter after I buy it. Inexplicable really.
Best regards and wishes.
Roy

Bill Perkins
 

Walter:
Looking eBay:

https://tinyurl.com/y9s93ean

I see about 27 different offerings, what's your recommendation ?

Thx,
Bill

I do not recommend using WD40 anywhere near the TM500 switches.
as I explained earlier, using de-oxit (which is slightly lubricating),
and letting it fall right
to the front plastic shaft solves ALL seizing problems in the switch
assembly, as well as fixing the contacts.
let it drain down to the shaft from the open back, work the mechanism
rapidly at least a dozen times, and
you should have good results. I have also had good success with nu-trol,
used in the same way from the
 open back of the switch.
I have done hundreds of these switches both in the TM500 and 7K /5K
series. I am 100% confident
that the process I described will work IF ANYTHING CAN WORK (in other
words if there's any good
contact surface left in the switch). I strongly advise against anything
like solvents, WD40, oils or
other highly active chemicals, and I have NOT found that disassembly and
manual cleaning works
any better than the process I described, although disassembly can be
useful when the sliding
contact has to be replaced. to be candid, if it's at that point, the
switch itself has to go.
we used a variant of this same switch (the origin of which goes WAY back
to itt-schadow in europe) for many
years in avionics systems as well, but paid to have the contacts gold
plated from E-switch, and had almost no failures over decades of use.
just my $0.02 worth on this topic.
all the best,
walter

Roy Thistle
 

On Fri, Jul 10, 2020 at 12:20 PM, Chuck Harris wrote:


I don't know exactly what the "naphtha" in Ronsonol is
Hydrocarbons, aliphatic hydrocarbons, C7-C9, n-alkanes, isoalkanes, cyclics.... so ya... we don't really know... but the guys at Ronson do... but, what matters to Ronson is the refinery tank cars them the "good stuff"... that is the stuff that meets Ronson's physio-chemical properties. I'm sure Ronson tests for that data, and they may use chromatography, et. al. to see what's really in the latest conforming batch too.

Greg Muir
 

I keep constantly preaching to people that WD40 is not intended for application to electrical items such as switches. It is basically a heavy oil that is thinned by a lighter more solvent-style carrier. Over time the lighter carrier will evaporate leaving behind the heavier, sticky oil that then starts to gum things up and collects dirt and dust.

in addition, WD40 has no properties to clean switch contacts short of initially carrying away any loose dirt that may be present on them. Use of electronic grade contact lubricants/cleaners is the recommended practice.

The Caig Laboratories line of contact cleaners and lubricants has gained wide acceptance as a reliable product for switches. But I have also found that MG Chemicals produces a very similar product under the name “Super Contact Cleaner” which is much cheaper in larger quantities. I have had no reliability issues using it cleaning & lubricating switches of all types, some found in very dirty and corroded conditions. And use of either product does not leave behind any sticky liquids that can attract dirt in the future.

I do understand that Caig has developed a high reputation and their prices show it. I try to save money if I can locate a similar product that functions the same way. (And I am not affiliated with either manufacturer).

Greg

Renée
 

Somehow this has moved in the wrong direction...however, Greg is correct!.
WD40 is only good for the shafts ( Think rotary switch shaft, stuck and the proper stuff for electrical equipment is not working btw Kroil etc...falls in the same category of bad for electrical items) in loosening/softening the hardened grease/rust etc....god forbid one gets it on electrical switch contacts or especially the insulating material.  It is not a lube in any way shape or form. Once the original shaft is loose and the assembly moves, I am able to completely disassemble the mechanical portion and I mean FULLY disassemble. Then fully clean removing the WD40 and the old grease lube, rust, debris etc . then if necessary lightly polish the shaft put in the proper lube and reassemble.
I work on some pretty rough poorly stored stuff...like stored in a barn for years with "stuff" sprayed on it by animals etc....

Every product has a proper usage. BTW I have been using Craig and MG chem stuff for years...they work great.

I am sorry I mentioned WD40 earlier. Never again will I mention it or like material.
Renée

On 7/10/20 2:37 PM, Greg Muir via groups.io wrote:
I keep constantly preaching to people that WD40 is not intended for application to electrical items such as switches. It is basically a heavy oil that is thinned by a lighter more solvent-style carrier. Over time the lighter carrier will evaporate leaving behind the heavier, sticky oil that then starts to gum things up and collects dirt and dust.

in addition, WD40 has no properties to clean switch contacts short of initially carrying away any loose dirt that may be present on them. Use of electronic grade contact lubricants/cleaners is the recommended practice.

The Caig Laboratories line of contact cleaners and lubricants has gained wide acceptance as a reliable product for switches. But I have also found that MG Chemicals produces a very similar product under the name “Super Contact Cleaner” which is much cheaper in larger quantities. I have had no reliability issues using it cleaning & lubricating switches of all types, some found in very dirty and corroded conditions. And use of either product does not leave behind any sticky liquids that can attract dirt in the future.

I do understand that Caig has developed a high reputation and their prices show it. I try to save money if I can locate a similar product that functions the same way. (And I am not affiliated with either manufacturer).

Greg