sci.electronics.repair
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Today's topics:

* Magnetic door holders question - 11 messages, 7 authors
http://groups.google.com/group/sci.electronics.repair/t/21eb21515055e1fe?hl=en
* Trying to understand the current draw of a Samsung Galaxy S3 under GPS & low
battery - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/1dceb0f9a68c6f2d?hl=en
* Roland Cube 30 - 3 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/a23b78ce21495f68?hl=en
* JCM2000 DSL100 - 7 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/e1a795448919201c?hl=en
* Inverter Manufacturer With Charger In China - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/5ea22cb635c5548f?hl=en
* Do remote keypads sweat silcone oil? - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/c14d8e962b605e97?hl=en

==============================================================================
TOPIC: Magnetic door holders question
http://groups.google.com/group/sci.electronics.repair/t/21eb21515055e1fe?hl=en
==============================================================================

== 1 of 11 ==
Date: Mon, Feb 10 2014 10:16 am
From: Cydrome Leader


captainvideo462009@gmail.com wrote:
> I work on commercial fire alarm systems mostly in apartment houses. Many of these buildings in the common hallways employ electromagnetic units mounted on the walls and an iron disk on the back corner of the doors. When the doors are opened and the disks are mated with the electromagnet the doors are held open in place. These doors all have pneumatic closers on them as well which are always applying a force in the opposite direction to try to close the door.
>
> When the alarm is activated the 24VDC is removed from the coils and the doors are supposed to be automatically pulled closed by the force of the pneumatic unit. This doesn't always work because in spite of the opposing force applied by the pneumatic unit, in many cases the electromagnets seem to hold enough residual magnetism to keep disks from releasing and the doors from closing. It often becomes necessary to increase the opposing pneumatic force tremendously in order to overcome this.
>
> I have discussed this with various manufacturers of these electromagnetic units and in all but one instance have received the same bullshit answer that they've "never heard of this".
>
> The one exception was one tech who ventured that perhaps momentarily reversing polarity on alarm before DC drop out might work, however he had never tried it. Does anyone have any ideas about this? Thanks, Lenny

feed them less than 24 volts, or maybe put a layer of packing tape over
the plate to add some space, or get somebody to "accidentally" paint over
the mating surfaces, although this is likely to make them stick as well.






== 2 of 11 ==
Date: Mon, Feb 10 2014 11:06 am
From: "hrhofmann@sbcglobal.net"


On Monday, February 10, 2014 11:32:26 AM UTC-6, captainvi...@gmail.com wrote:
> I work on commercial fire alarm systems mostly in apartment houses. Many of these buildings in the common hallways employ electromagnetic units mounted on the walls and an iron disk on the back corner of the doors. When the doors are opened and the disks are mated with the electromagnet the doors are held open in place. These doors all have pneumatic closers on them as well which are always applying a force in the opposite direction to try to close the door. When the alarm is activated the 24VDC is removed from the coils and the doors are supposed to be automatically pulled closed by the force of the pneumatic unit. This doesn't always work because in spite of the opposing force applied by the pneumatic unit, in many cases the electromagnets seem to hold enough residual magnetism to keep disks from releasing and the doors from closing. It often becomes necessary to increase the opposing pneumatic force tremendously in order to overcome this. I have discussed this with various manufacturers of these electromagnetic units and in all but one instance have received the same bullshit answer that they've "never heard of this". The one exception was one tech who ventured that perhaps momentarily reversing polarity on alarm before DC drop out might work, however he had never tried it. Does anyone have any ideas about this? Thanks, Lenny

Ken and Cydrome's idea to put a thin spacer on the disc to make it easier to release sounds like a good idea. My experience has always been that the magnetism was not strong enough to hold the door open, not that it would not release.





== 3 of 11 ==
Date: Mon, Feb 10 2014 11:11 am
From: Tim R


On Monday, February 10, 2014 2:06:37 PM UTC-5, hrho...@sbcglobal.net wrote:
> Ken and Cydrome's idea to put a thin spacer on the disc to make it easier to >release sounds like a good idea. My experience has always been that the >magnetism was not strong enough to hold the door open, not that it would not >release.

I've never seen this and I have a fair amount of experience with these doors in hospitals.

It is more commonly hard to get them to stay open.

I would suspect a door closer problem first.





== 4 of 11 ==
Date: Mon, Feb 10 2014 12:39 pm
From: RobertMacy


On Mon, 10 Feb 2014 10:32:26 -0700, <captainvideo462009@gmail.com> wrote:

>> ...snip...
> The one exception was one tech who ventured that perhaps momentarily
> reversing polarity on alarm before DC drop out might work, however he
> had never tried it. Does anyone have any ideas about this? Thanks, Lenny


I've always found that having ferrous metal in a DC field touching each
other is not a good idea. Add a 3 mil layer of kapton tape between the
two. the extra distance will prevent the 'residual' magnetism from having
enough strength to hold and keep the doors open. More likely difficulty
keeping them open.




== 5 of 11 ==
Date: Mon, Feb 10 2014 12:47 pm
From: adrian@poppyrecords.invalid.invalid (Adrian Tuddenham)


<captainvideo462009@gmail.com> wrote:

> I work on commercial fire alarm systems mostly in apartment houses. Many
> of these buildings in the common hallways employ electromagnetic units
> mounted on the walls and an iron disk on the back corner of the doors.
> When the doors are opened and the disks are mated with the electromagnet
> the doors are held open in place. These doors all have pneumatic closers
> on them as well which are always applying a force in the opposite
> direction to try to close the door.
>
> When the alarm is activated the 24VDC is removed from the coils and the
> doors are supposed to be automatically pulled closed by the force of the
> pneumatic unit. This doesn't always work because in spite of the opposing
> force applied by the pneumatic unit, in many cases the electromagnets seem
> to hold enough residual magnetism to keep disks from releasing and the
> doors from closing. It often becomes necessary to increase the opposing
> pneumatic force tremendously in order to overcome this.
>
> I have discussed this with various manufacturers of these electromagnetic
> units and in all but one instance have received the same bullshit answer
> that they've "never heard of this".
>
> The one exception was one tech who ventured that perhaps momentarily
> reversing polarity on alarm before DC drop out might work, however he had
> never tried it. Does anyone have any ideas about this? Thanks, Lenny

That last idea is an elegant one which would probably work quite well;
however, it has one very big drawback:

The safety of the whole system depends on the doors closing if anything
goes wrong. If the wires were burned through, the control box would
lose contact with the magnets and could not demagnetise them. The
fail-safe aspect of the system would be lost.


The usual method is to insert a non-magnetic shim of some kind, but this
can wear down and fail after a few years. A more subtle way is to
abrade or machine down one of the pole faces so that it is not quite in
the same plane as the other. If these are 'pot' magnets, you could skim
a thou or so off the centre pole if you have access to a lathe.
Unfortunately this would destroy any anti-corrosion plating on the
metal, but that might not matter if the buildings are dry.

An alternative would be to 'dish' the armature plate so that the concave
side was towards the magnet. To do this you would need to take it off
the door and stand it outside on a solid foundation (or an anvil, if you
have one). A supporting ring to back up the outer edge can be
improvised from a piece of hard wood with a hole in it or a short offcut
of steel pipe. To dish it slightly you will need a steel bar or other
hard object with one end slightly rounded - and a sledge hammer to hit
it with. Try to do it in one hit, so as to avoid peening the surface.


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk




== 6 of 11 ==
Date: Mon, Feb 10 2014 5:51 pm
From: Cydrome Leader


Adrian Tuddenham <adrian@poppyrecords.invalid.invalid> wrote:
> <captainvideo462009@gmail.com> wrote:
>
>> I work on commercial fire alarm systems mostly in apartment houses. Many
>> of these buildings in the common hallways employ electromagnetic units
>> mounted on the walls and an iron disk on the back corner of the doors.
>> When the doors are opened and the disks are mated with the electromagnet
>> the doors are held open in place. These doors all have pneumatic closers
>> on them as well which are always applying a force in the opposite
>> direction to try to close the door.
>>
>> When the alarm is activated the 24VDC is removed from the coils and the
>> doors are supposed to be automatically pulled closed by the force of the
>> pneumatic unit. This doesn't always work because in spite of the opposing
>> force applied by the pneumatic unit, in many cases the electromagnets seem
>> to hold enough residual magnetism to keep disks from releasing and the
>> doors from closing. It often becomes necessary to increase the opposing
>> pneumatic force tremendously in order to overcome this.
>>
>> I have discussed this with various manufacturers of these electromagnetic
>> units and in all but one instance have received the same bullshit answer
>> that they've "never heard of this".
>>
>> The one exception was one tech who ventured that perhaps momentarily
>> reversing polarity on alarm before DC drop out might work, however he had
>> never tried it. Does anyone have any ideas about this? Thanks, Lenny
>
> That last idea is an elegant one which would probably work quite well;
> however, it has one very big drawback:
>
> The safety of the whole system depends on the doors closing if anything
> goes wrong. If the wires were burned through, the control box would
> lose contact with the magnets and could not demagnetise them. The
> fail-safe aspect of the system would be lost.
>
>
> The usual method is to insert a non-magnetic shim of some kind, but this
> can wear down and fail after a few years. A more subtle way is to
> abrade or machine down one of the pole faces so that it is not quite in
> the same plane as the other. If these are 'pot' magnets, you could skim
> a thou or so off the centre pole if you have access to a lathe.
> Unfortunately this would destroy any anti-corrosion plating on the
> metal, but that might not matter if the buildings are dry.
>
> An alternative would be to 'dish' the armature plate so that the concave
> side was towards the magnet. To do this you would need to take it off
> the door and stand it outside on a solid foundation (or an anvil, if you
> have one). A supporting ring to back up the outer edge can be
> improvised from a piece of hard wood with a hole in it or a short offcut
> of steel pipe. To dish it slightly you will need a steel bar or other
> hard object with one end slightly rounded - and a sledge hammer to hit
> it with. Try to do it in one hit, so as to avoid peening the surface.

The problem with the heavy handed methods is you're then deliberately
altering a safety device. A little tape here and there could have been
done by anybody who just didn't know better.

Granted, it's unlikely to cause the building to catch on fire, with the
doors stuck open killing everybody inside, but these are not really
devices to mess with. The door might just slam into somebody's face- you
never know.

While I may have done electrical work before, if it's conduit painted red
(at least here in Chicago this is common) or marked Life/Safety or L/S or
something similar, the rule is don't open it, don't touch it.







== 7 of 11 ==
Date: Mon, Feb 10 2014 8:46 pm
From: "Michael A. Terrell"



captainvideo462009@gmail.com wrote:
>
> I work on commercial fire alarm systems mostly in apartment houses. Many of these buildings in the common hallways employ electromagnetic units mounted on the walls and an iron disk on the back corner of the doors. When the doors are opened and the disks are mated with the electromagnet the doors are held open in place. These doors all have pneumatic closers on them as well which are always applying a force in the opposite direction to try to close the door.
>
> When the alarm is activated the 24VDC is removed from the coils and the doors are supposed to be automatically pulled closed by the force of the pneumatic unit. This doesn't always work because in spite of the opposing force applied by the pneumatic unit, in many cases the electromagnets seem to hold enough residual magnetism to keep disks from releasing and the doors from closing. It often becomes necessary to increase the opposing pneumatic force tremendously in order to overcome this.
>
> I have discussed this with various manufacturers of these electromagnetic units and in all but one instance have received the same bullshit answer that they've "never heard of this".
>
> The one exception was one tech who ventured that perhaps momentarily reversing polarity on alarm before DC drop out might work, however he had never tried it. Does anyone have any ideas about this? Thanks, Lenny


Shoot video of the failure, and send it to them. Tell them if they
can't fix the problem that you will post the video and details online,
in case of a fire. Put it some place like Youtube or Vimeo, where it is
sure to be seen by people and asked the OEM what it will do to their
reputation and their insurance costs.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.




== 8 of 11 ==
Date: Tues, Feb 11 2014 2:11 am
From: adrian@poppyrecords.invalid.invalid (Adrian Tuddenham)


Cydrome Leader <presence@MUNGEpanix.com> wrote:

> Adrian Tuddenham <adrian@poppyrecords.invalid.invalid> wrote:
> > <captainvideo462009@gmail.com> wrote:
> >
> >> I work on commercial fire alarm systems mostly in apartment houses. Many
> >> of these buildings in the common hallways employ electromagnetic units
> >> mounted on the walls and an iron disk on the back corner of the doors.
> >> When the doors are opened and the disks are mated with the electromagnet
> >> the doors are held open in place. These doors all have pneumatic closers
> >> on them as well which are always applying a force in the opposite
> >> direction to try to close the door.
> >>
> >> When the alarm is activated the 24VDC is removed from the coils and the
> >> doors are supposed to be automatically pulled closed by the force of the
> >> pneumatic unit. This doesn't always work because in spite of the opposing
> >> force applied by the pneumatic unit, in many cases the electromagnets seem
> >> to hold enough residual magnetism to keep disks from releasing and the
> >> doors from closing. It often becomes necessary to increase the opposing
> >> pneumatic force tremendously in order to overcome this.
> >>
> >> I have discussed this with various manufacturers of these electromagnetic
> >> units and in all but one instance have received the same bullshit answer
> >> that they've "never heard of this".
> >>
> >> The one exception was one tech who ventured that perhaps momentarily
> >> reversing polarity on alarm before DC drop out might work, however he had
> >> never tried it. Does anyone have any ideas about this? Thanks, Lenny
> >
> > That last idea is an elegant one which would probably work quite well;
> > however, it has one very big drawback:
> >
> > The safety of the whole system depends on the doors closing if anything
> > goes wrong. If the wires were burned through, the control box would
> > lose contact with the magnets and could not demagnetise them. The
> > fail-safe aspect of the system would be lost.
> >
> >
> > The usual method is to insert a non-magnetic shim of some kind, but this
> > can wear down and fail after a few years. A more subtle way is to
> > abrade or machine down one of the pole faces so that it is not quite in
> > the same plane as the other. If these are 'pot' magnets, you could skim
> > a thou or so off the centre pole if you have access to a lathe.
> > Unfortunately this would destroy any anti-corrosion plating on the
> > metal, but that might not matter if the buildings are dry.
> >
> > An alternative would be to 'dish' the armature plate so that the concave
> > side was towards the magnet. To do this you would need to take it off
> > the door and stand it outside on a solid foundation (or an anvil, if you
> > have one). A supporting ring to back up the outer edge can be
> > improvised from a piece of hard wood with a hole in it or a short offcut
> > of steel pipe. To dish it slightly you will need a steel bar or other
> > hard object with one end slightly rounded - and a sledge hammer to hit
> > it with. Try to do it in one hit, so as to avoid peening the surface.
>
> The problem with the heavy handed methods is you're then deliberately
> altering a safety device. A little tape here and there could have been
> done by anybody who just didn't know better.
>
> Granted, it's unlikely to cause the building to catch on fire, with the
> doors stuck open killing everybody inside, but these are not really
> devices to mess with. The door might just slam into somebody's face- you
> never know.
>
> While I may have done electrical work before, if it's conduit painted red
> (at least here in Chicago this is common) or marked Life/Safety or L/S or
> something similar, the rule is don't open it, don't touch it.

It is a sad situation where a safety device could be made more reliable
by a simple modification but this is prevented by the legislation which
is there to make things safer.

My biggest worry would be how such a badly-designed "safety" system with
an easily-recognised fault came to be made by a manufacturer who
presumably specialises in that field. Add to that, the inspection and
checking processes which must all have failed to pick up the problem.
It isn't as though D.C. electromagnetism is a new and unknown field full
of unsuspected effects - this problem has been well-understood for over
100 years.

Perhaps the O/P should contact the manufacturer and suggest they stamp
their armatures slightly concave in future.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk




== 9 of 11 ==
Date: Tues, Feb 11 2014 2:55 am
From: Leif Neland


captainvideo462009@gmail.com:
> I work on commercial fire alarm systems mostly in apartment houses. Many of
> these buildings in the common hallways employ electromagnetic units mounted
> on the walls and an iron disk on the back corner of the doors. When the doors
> are opened and the disks are mated with the electromagnet the doors are held
> open in place. These doors all have pneumatic closers on them as well which
> are always applying a force in the opposite direction to try to close the
> door.
>
> When the alarm is activated the 24VDC is removed from the coils and the doors
> are supposed to be automatically pulled closed by the force of the pneumatic
> unit.

Would it be possible to feed the electromagnets with 24V AC?

That should prevent the doors to get permanently magnetized.
I don't know if that'll make the doors/magnets hum though.

Leif

--
Husk kørelys bagpå, hvis din bilfabrikant har taget den idiotiske
beslutning at undlade det.






== 10 of 11 ==
Date: Tues, Feb 11 2014 4:49 am
From: adrian@poppyrecords.invalid.invalid (Adrian Tuddenham)


Leif Neland <leif@neland.dk> wrote:

> captainvideo462009@gmail.com:
> > I work on commercial fire alarm systems mostly in apartment houses. Many
> > of these buildings in the common hallways employ electromagnetic units
> > mounted on the walls and an iron disk on the back corner of the doors.
> > When the doors are opened and the disks are mated with the electromagnet
> > the doors are held open in place. These doors all have pneumatic closers
> > on them as well which are always applying a force in the opposite
> > direction to try to close the door.
> >
> > When the alarm is activated the 24VDC is removed from the coils and the
> > doors are supposed to be automatically pulled closed by the force of the
> > pneumatic unit.
>
> Would it be possible to feed the electromagnets with 24V AC?
>
> That should prevent the doors to get permanently magnetized.
[...]

A.C. magnets can also get stuck because of residual magnetism, depending
on whereabouts in the cycle the current is broken.

I occasionally have to file down areas of the pole faces of A.C.
contactors that have become polished through frequent use and have
started randomly sticking in the "on" position (highly embarrassing if
they control motors).

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk




== 11 of 11 ==
Date: Tues, Feb 11 2014 9:21 am
From: Cydrome Leader


Adrian Tuddenham <adrian@poppyrecords.invalid.invalid> wrote:
> Cydrome Leader <presence@MUNGEpanix.com> wrote:
>
>> Adrian Tuddenham <adrian@poppyrecords.invalid.invalid> wrote:
>> > <captainvideo462009@gmail.com> wrote:
>> >
>> >> I work on commercial fire alarm systems mostly in apartment houses. Many
>> >> of these buildings in the common hallways employ electromagnetic units
>> >> mounted on the walls and an iron disk on the back corner of the doors.
>> >> When the doors are opened and the disks are mated with the electromagnet
>> >> the doors are held open in place. These doors all have pneumatic closers
>> >> on them as well which are always applying a force in the opposite
>> >> direction to try to close the door.
>> >>
>> >> When the alarm is activated the 24VDC is removed from the coils and the
>> >> doors are supposed to be automatically pulled closed by the force of the
>> >> pneumatic unit. This doesn't always work because in spite of the opposing
>> >> force applied by the pneumatic unit, in many cases the electromagnets seem
>> >> to hold enough residual magnetism to keep disks from releasing and the
>> >> doors from closing. It often becomes necessary to increase the opposing
>> >> pneumatic force tremendously in order to overcome this.
>> >>
>> >> I have discussed this with various manufacturers of these electromagnetic
>> >> units and in all but one instance have received the same bullshit answer
>> >> that they've "never heard of this".
>> >>
>> >> The one exception was one tech who ventured that perhaps momentarily
>> >> reversing polarity on alarm before DC drop out might work, however he had
>> >> never tried it. Does anyone have any ideas about this? Thanks, Lenny
>> >
>> > That last idea is an elegant one which would probably work quite well;
>> > however, it has one very big drawback:
>> >
>> > The safety of the whole system depends on the doors closing if anything
>> > goes wrong. If the wires were burned through, the control box would
>> > lose contact with the magnets and could not demagnetise them. The
>> > fail-safe aspect of the system would be lost.
>> >
>> >
>> > The usual method is to insert a non-magnetic shim of some kind, but this
>> > can wear down and fail after a few years. A more subtle way is to
>> > abrade or machine down one of the pole faces so that it is not quite in
>> > the same plane as the other. If these are 'pot' magnets, you could skim
>> > a thou or so off the centre pole if you have access to a lathe.
>> > Unfortunately this would destroy any anti-corrosion plating on the
>> > metal, but that might not matter if the buildings are dry.
>> >
>> > An alternative would be to 'dish' the armature plate so that the concave
>> > side was towards the magnet. To do this you would need to take it off
>> > the door and stand it outside on a solid foundation (or an anvil, if you
>> > have one). A supporting ring to back up the outer edge can be
>> > improvised from a piece of hard wood with a hole in it or a short offcut
>> > of steel pipe. To dish it slightly you will need a steel bar or other
>> > hard object with one end slightly rounded - and a sledge hammer to hit
>> > it with. Try to do it in one hit, so as to avoid peening the surface.
>>
>> The problem with the heavy handed methods is you're then deliberately
>> altering a safety device. A little tape here and there could have been
>> done by anybody who just didn't know better.
>>
>> Granted, it's unlikely to cause the building to catch on fire, with the
>> doors stuck open killing everybody inside, but these are not really
>> devices to mess with. The door might just slam into somebody's face- you
>> never know.
>>
>> While I may have done electrical work before, if it's conduit painted red
>> (at least here in Chicago this is common) or marked Life/Safety or L/S or
>> something similar, the rule is don't open it, don't touch it.
>
> It is a sad situation where a safety device could be made more reliable
> by a simple modification but this is prevented by the legislation which
> is there to make things safer.
>
> My biggest worry would be how such a badly-designed "safety" system with
> an easily-recognised fault came to be made by a manufacturer who
> presumably specialises in that field. Add to that, the inspection and
> checking processes which must all have failed to pick up the problem.
> It isn't as though D.C. electromagnetism is a new and unknown field full
> of unsuspected effects - this problem has been well-understood for over
> 100 years.
>
> Perhaps the O/P should contact the manufacturer and suggest they stamp
> their armatures slightly concave in future.

It might be worth looking into the power source for those devices. Too
much voltage will likely cause them to be too strong.







==============================================================================
TOPIC: Trying to understand the current draw of a Samsung Galaxy S3 under GPS &
low battery
http://groups.google.com/group/sci.electronics.repair/t/1dceb0f9a68c6f2d?hl=en
==============================================================================

== 1 of 2 ==
Date: Mon, Feb 10 2014 12:12 pm
From: artleknock


Going back to original query.
Ignoring all of the technical jargon, it could be that the GPS is
using power faster than it can be replaced.
According to the battery utility app on my Samsung Note 10.1 it takes
a very low battery in excess of 2.5hrs to charge on a mains charger,
but with a full battery the GPS will only function for 1hr and
39minutes. So the GPS is using power faster than even a mains
connection can replace it, it would be even faster with a USB
connection.




== 2 of 2 ==
Date: Mon, Feb 10 2014 12:24 pm
From: Juan Wei


Danny D. has written on 2/1/2014 10:45 PM:
> On Sat, 01 Feb 2014 05:17:38 -0600, Capt Rick wrote:
>
>> No need to sacrifice a USB cable.
>> Measure the current going into the
>> cigarette lighter adapter.
>
> Now why hadn't I thought of that!
>
> I can just hook an ammeter across the fuse
> for the cigarette lighter socket, which
> will give me the current being consumed
> with, and without the phone being charged!

(If you hook it across the fuse, you won't get the current you want.
Remove the fuse and connect the ammeter to the fuse terminals.)





==============================================================================
TOPIC: Roland Cube 30
http://groups.google.com/group/sci.electronics.repair/t/a23b78ce21495f68?hl=en
==============================================================================

== 1 of 3 ==
Date: Mon, Feb 10 2014 1:04 pm
From: "Gareth Magennis"




"N_Cook" wrote in message news:ldaps1$9s$1@dont-email.me...

before consigning to the mule park , investigated the JAPN IC a bit
5 pin,
p1&2 gnd, 3 N/C unless hidden in an interlayer,4 to large Boss R03015201
p21, p5 absent, p6 3.3V
Power-on reset IC?




The schematic designates the output of this chip to be Reset0, and becomes
Reset1 after R19.

Reset0 goes to logic chip IC1, Reset1 goes to CN U2 pin6, CN U2 being
designated Not Utilised.


I can't see any direct connections of these reset lines to the main CPU.



Gareth.





== 2 of 3 ==
Date: Mon, Feb 10 2014 1:15 pm
From: "Gareth Magennis"




"Gareth Magennis" wrote in message news:d9bKu.854$VO6.809@fx32.am4...



"N_Cook" wrote in message news:ldaps1$9s$1@dont-email.me...

before consigning to the mule park , investigated the JAPN IC a bit
5 pin,
p1&2 gnd, 3 N/C unless hidden in an interlayer,4 to large Boss R03015201
p21, p5 absent, p6 3.3V
Power-on reset IC?




The schematic designates the output of this chip to be Reset0, and becomes
Reset1 after R19.

Reset0 goes to logic chip IC1, Reset1 goes to CN U2 pin6, CN U2 being
designated Not Utilised.


I can't see any direct connections of these reset lines to the main CPU.







Oops, that's bollocks. Reset0 goes to pin 81 on the main CPU. My eyesight
is getting worse.

But Reset0 does indeed also go to some logic at IC1, thence into IC2.


Gareth.







== 3 of 3 ==
Date: Tues, Feb 11 2014 12:46 am
From: N_Cook


On 10/02/2014 16:38, Gareth Magennis wrote:
> "N_Cook" <diverse@tcp.co.uk> wrote in message
> news:ldaps1$9s$1@dont-email.me...
>> before consigning to the mule park , investigated the JAPN IC a bit
>> 5 pin,
>> p1&2 gnd, 3 N/C unless hidden in an interlayer,4 to large Boss R03015201
>> p21, p5 absent, p6 3.3V
>> Power-on reset IC?
>
>
>
>
> That IC is S80130ANMC. Voltage supervisor with built in delay.
>
>
>
> Gareth.
>
>

I've never seen such long timed power-up reset/delay IC before.
I suppose one dot is the index mark and the other dot Seiko logo.
Another SMD topcode out there now.





==============================================================================
TOPIC: JCM2000 DSL100
http://groups.google.com/group/sci.electronics.repair/t/e1a795448919201c?hl=en
==============================================================================

== 1 of 7 ==
Date: Mon, Feb 10 2014 10:24 pm
From: "Phil Allison"


Hi,

just put a Marshall JCM2000, DSL100 on the bench.

Looks nice .....

3 output valves installed, 6CA7EH ( Electro-Harmonix, 02/12), only one of
which works.

Two, large mirror burn marks on the glass of one of the dead ones, but the
OT and rest of amp seem OK.

Pulled all the 6CA7s and checked the bias voltage on pin 5 of all 4 sockets
= -43V at max setting.

Played hot air onto the PCB near the octal sockets for about 20 seconds and
re-checked.

Pin 5 voltages had dropped to between 28V & 14 V.

Oh shit !!!!!

How did this amp ever survive for this long with such massive PCB leakage
???

The grid feed resistors are all 220kohms too !!!!

Do Marshall actually have spare PCBs for this god awful POS any more ??

What sort of cost delivered to Sydney Australia ?


.... Phil






== 2 of 7 ==
Date: Tues, Feb 11 2014 2:04 am
From: "Gareth Magennis"



"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:bltu0uF63k6U1@mid.individual.net...
> Hi,
>
> just put a Marshall JCM2000, DSL100 on the bench.
>
> Looks nice .....
>
> 3 output valves installed, 6CA7EH ( Electro-Harmonix, 02/12), only one of
> which works.
>
> Two, large mirror burn marks on the glass of one of the dead ones, but the
> OT and rest of amp seem OK.
>
> Pulled all the 6CA7s and checked the bias voltage on pin 5 of all 4
> sockets = -43V at max setting.
>
> Played hot air onto the PCB near the octal sockets for about 20 seconds
> and re-checked.
>
> Pin 5 voltages had dropped to between 28V & 14 V.
>
> Oh shit !!!!!
>
> How did this amp ever survive for this long with such massive PCB leakage
> ???
>
> The grid feed resistors are all 220kohms too !!!!
>
> Do Marshall actually have spare PCBs for this god awful POS any more ??
>
> What sort of cost delivered to Sydney Australia ?
>
>
> .... Phil
>
>


There is no reason why Marshall would not have these PCB's for sale.
The last one I bought cost me just short of £50 including VAT and carriage.

I guess if you could persuade them to ship to Sydney, the VAT would be
deducted and you would pay VAT/import duty in Australia instead.

They did have a policy of only selling things that might kill people to bone
fide engineers who wouldn't kill themselves or others with High Voltage, so
you might also have to prove you are not a numpty.


If you're really stuck I have one here I could ship you, but with carriage
and import taxes and already paid VAT @20% now, its going to end up bloody
expensive.



Cheers,


Gareth.






== 3 of 7 ==
Date: Tues, Feb 11 2014 2:14 am
From: N_Cook


On 11/02/2014 10:04, Gareth Magennis wrote:
> "Phil Allison" <phil_a@tpg.com.au> wrote in message
> news:bltu0uF63k6U1@mid.individual.net...
>> Hi,
>>
>> just put a Marshall JCM2000, DSL100 on the bench.
>>
>> Looks nice .....
>>
>> 3 output valves installed, 6CA7EH ( Electro-Harmonix, 02/12), only one of
>> which works.
>>
>> Two, large mirror burn marks on the glass of one of the dead ones, but the
>> OT and rest of amp seem OK.
>>
>> Pulled all the 6CA7s and checked the bias voltage on pin 5 of all 4
>> sockets = -43V at max setting.
>>
>> Played hot air onto the PCB near the octal sockets for about 20 seconds
>> and re-checked.
>>
>> Pin 5 voltages had dropped to between 28V & 14 V.
>>
>> Oh shit !!!!!
>>
>> How did this amp ever survive for this long with such massive PCB leakage
>> ???
>>
>> The grid feed resistors are all 220kohms too !!!!
>>
>> Do Marshall actually have spare PCBs for this god awful POS any more ??
>>
>> What sort of cost delivered to Sydney Australia ?
>>
>>
>> .... Phil
>>
>>
>
>
> There is no reason why Marshall would not have these PCB's for sale.
> The last one I bought cost me just short of £50 including VAT and carriage.
>
> I guess if you could persuade them to ship to Sydney, the VAT would be
> deducted and you would pay VAT/import duty in Australia instead.
>
> They did have a policy of only selling things that might kill people to bone
> fide engineers who wouldn't kill themselves or others with High Voltage, so
> you might also have to prove you are not a numpty.
>
>
> If you're really stuck I have one here I could ship you, but with carriage
> and import taxes and already paid VAT @20% now, its going to end up bloody
> expensive.
>
>
>
> Cheers,
>
>
> Gareth.
>
>

Or you could get sculpting on what you have. Possible with small conical
cintride/diamond bits but I now have a set of cintride tile-hole cutters
for a quick neat job.
Explained on a couple of M, on my file
http://www.divdev.fsnet.co.uk/repair2l.htm
IIRC one was thermally-kicked-off conductive pcb problem at a preamp
valve and the other for output valves. Neither have bounced back to me
and one of the owners I'm in regular contact with.
You have to wonder if the replacement M boards are old stock from the
original salt? contaminated board production run




== 4 of 7 ==
Date: Tues, Feb 11 2014 2:43 am
From: "Gareth Magennis"



"N_Cook" <diverse@tcp.co.uk> wrote in message
news:ldct6l$no1$1@dont-email.me...
> On 11/02/2014 10:04, Gareth Magennis wrote:
>> "Phil Allison" <phil_a@tpg.com.au> wrote in message
>> news:bltu0uF63k6U1@mid.individual.net...
>>> Hi,
>>>
>>> just put a Marshall JCM2000, DSL100 on the bench.
>>>
>>> Looks nice .....
>>>
>>> 3 output valves installed, 6CA7EH ( Electro-Harmonix, 02/12), only one
>>> of
>>> which works.
>>>
>>> Two, large mirror burn marks on the glass of one of the dead ones, but
>>> the
>>> OT and rest of amp seem OK.
>>>
>>> Pulled all the 6CA7s and checked the bias voltage on pin 5 of all 4
>>> sockets = -43V at max setting.
>>>
>>> Played hot air onto the PCB near the octal sockets for about 20 seconds
>>> and re-checked.
>>>
>>> Pin 5 voltages had dropped to between 28V & 14 V.
>>>
>>> Oh shit !!!!!
>>>
>>> How did this amp ever survive for this long with such massive PCB
>>> leakage
>>> ???
>>>
>>> The grid feed resistors are all 220kohms too !!!!
>>>
>>> Do Marshall actually have spare PCBs for this god awful POS any more ??
>>>
>>> What sort of cost delivered to Sydney Australia ?
>>>
>>>
>>> .... Phil
>>>
>>>
>>
>>
>> There is no reason why Marshall would not have these PCB's for sale.
>> The last one I bought cost me just short of £50 including VAT and
>> carriage.
>>
>> I guess if you could persuade them to ship to Sydney, the VAT would be
>> deducted and you would pay VAT/import duty in Australia instead.
>>
>> They did have a policy of only selling things that might kill people to
>> bone
>> fide engineers who wouldn't kill themselves or others with High Voltage,
>> so
>> you might also have to prove you are not a numpty.
>>
>>
>> If you're really stuck I have one here I could ship you, but with
>> carriage
>> and import taxes and already paid VAT @20% now, its going to end up
>> bloody
>> expensive.
>>
>>
>>
>> Cheers,
>>
>>
>> Gareth.
>>
>>
>
> Or you could get sculpting on what you have. Possible with small conical
> cintride/diamond bits but I now have a set of cintride tile-hole cutters
> for a quick neat job.
> Explained on a couple of M, on my file
> http://www.divdev.fsnet.co.uk/repair2l.htm
> IIRC one was thermally-kicked-off conductive pcb problem at a preamp valve
> and the other for output valves. Neither have bounced back to me and one
> of the owners I'm in regular contact with.
> You have to wonder if the replacement M boards are old stock from the
> original salt? contaminated board production run



No they are new boards, different colour, different screen printing.
Nobody in their right mind would comtemplate such a thing. Surely.



Gareth.






== 5 of 7 ==
Date: Tues, Feb 11 2014 3:53 am
From: "Phil Allison"



"Gareth Magennis"

> No they are new boards, different colour, different screen printing.


** I absolutely hope that IS the case.


> Nobody in their right mind would comtemplate such a thing. Surely.


** Right mind ?? "Nutcase Kook" ??

Surely you jest ...........

FYI:

Years ago, I established beyond all doubt that the PCB leakage problem with
these models extends waaaay beyond the octal vales back into the phase
splitter and earlier stages. PCB modifications and/or the use of fans are a
dodge at best and I will never try them again.

In this case, I'm gonna make the OWNER buy the new PCB and supply it to
me.

Soooo, if it turns out to be the wrong one OR has any kind of other
problem - I can just hand it back.

There are for too many *complete idiots* involved in the chain from
Marshall in the UK to me.

Just like the smug pommy bullshitter in these videos:

https://www.youtube.com/watch?v=WeerxAO3oRU

https://www.youtube.com/watch?v=rhe7qXP08qw


Fair makes my skin crawl .......




.... Phil







== 6 of 7 ==
Date: Tues, Feb 11 2014 4:02 am
From: "Phil Allison"



"Gareth Magennis"

>
> There is no reason why Marshall would not have these PCB's for sale.


** Double negatives like that are mind numbing.


> The last one I bought cost me just short of £50 including VAT and
> carriage.

** Was that long ago ?



> They did have a policy of only selling things that might kill people to
> bone fide engineers who wouldn't kill themselves or others with High
> Voltage, so you might also have to prove you are not a numpty.


** Now, that is funny.

So * I * have to prove to Marshall that * I * know what I am doing ?????

They have SFA chance of ever proving the reverse.



> If you're really stuck I have one here I could ship you, but with carriage
> and import taxes and already paid VAT @20% now, its going to end up bloody
> expensive.

** Thanks for the offer.

Is there anything special about ordering such a PCB ?

Or is the amp model number and serial number enough ?



... Phil









== 7 of 7 ==
Date: Tues, Feb 11 2014 8:34 am
From: "Gareth Magennis"



"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:bluhqbFa5vuU1@mid.individual.net...
>
> "Gareth Magennis"
>
>>
>> There is no reason why Marshall would not have these PCB's for sale.
>
>
> ** Double negatives like that are mind numbing.
>
>
>> The last one I bought cost me just short of £50 including VAT and
>> carriage.
>
> ** Was that long ago ?
>
>
>
>> They did have a policy of only selling things that might kill people to
>> bone fide engineers who wouldn't kill themselves or others with High
>> Voltage, so you might also have to prove you are not a numpty.
>
>
> ** Now, that is funny.
>
> So * I * have to prove to Marshall that * I * know what I am doing
> ?????
>
> They have SFA chance of ever proving the reverse.
>
>
>
>> If you're really stuck I have one here I could ship you, but with
>> carriage and import taxes and already paid VAT @20% now, its going to end
>> up bloody expensive.
>
> ** Thanks for the offer.
>
> Is there anything special about ordering such a PCB ?
>
> Or is the amp model number and serial number enough ?
>
>
>
> ... Phil
>
>


Nothing special, just ask for a DSL 100 board.

Just for confirmation, both are marked JCM2-60-00.
The new board has two extra connectors, Con 15 and Con16, as well as a relay
which the old board does not. (Also Con 4 is not in the same orientation)
This is probably so it can be used in the TSL 100 as well, the 3 channel
version.
Definitely not the same PCB at all.

I think the DSL 50 also uses the same PCB, but with only 2 output valve
sockets populated, but don't quote me on that cos my memory is a bit shit
when it comes to things like that.


Cheers,


Gareth.







==============================================================================
TOPIC: Inverter Manufacturer With Charger In China
http://groups.google.com/group/sci.electronics.repair/t/5ea22cb635c5548f?hl=en
==============================================================================

== 1 of 1 ==
Date: Tues, Feb 11 2014 3:24 am
From: Albert Hou


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Website:http://www.powerinverterscn.com/





==============================================================================
TOPIC: Do remote keypads sweat silcone oil?
http://groups.google.com/group/sci.electronics.repair/t/c14d8e962b605e97?hl=en
==============================================================================

== 1 of 2 ==
Date: Tues, Feb 11 2014 4:18 am
From: dawend@gmail.com


On Saturday, December 9, 2000 3:40:23 AM UTC-5, Michael Shell wrote:
> Asimov wrote:
>
> >
> > The answer is that the plastic breaks down when in contact with vinyl.
> > I've experienced this problem a number of times when leaving guitar
> > patch cords on top of plastic equipment for a length of time.
>
> This is a real, and very serious, problem with lots of products.
> Vinyl seems to emit a gas which will react with and destroy many substances.
> A good example is those vinyl book covers which have turned the outside of
> many a book into eternal sticky mush.
>
> I thought that it may be a possibility that the keypad is reacting to the
> green
> protective PCB coating. The problem with that theory is:
>
> 1. The green coating is not degraded in any way.
> 2. Silicone rubber (and oil) is extremely inert. You have to work to
> find something that will pick a fight with it. ;)
>
> It seems from the URL I cited, that silicone oil is trapped in the polymer
> matrix during the manufacturing process. If steps are not taken to expel it,
> it will leach out years later. Pressure points, which are highest at the
> contact areas, tend to squeeze it out. Heat accelerates the process too.
> Also, gravity
> will tend to work the oil downward. Note that the idea that a soft rubber is
> carrying a liquid within it is, in my opinion, creepy.
>
> See a new thread: "my list of most hated design choices"
>
>
> Mike

Very interesting about Silicone and Vinyl.
Though I find myself cleaning my Bravia remote every few months and this is after putting up with sketchy behavior for a month. The area that is affected the most on any of my present or past remotes seems to only be the Volume and Mute buttons which are used more than any of the others. Don't like listening to the overly load commercials. So maybe there is the rubbing of silicone against vinyl that is in play here. ???




== 2 of 2 ==
Date: Tues, Feb 11 2014 5:49 am
From: "William Sommerwerck"


> Vinyl seems to emit a gas which will react with and destroy many
> substances. A good example is those vinyl book covers which have
> turned the outside of many a book into eternal sticky mush.

It's not a gas, it's the plasticizer that keeps the vinyl flexible. I had the
same trouble with textbooks that had a kind "plastic-coated-board" covers. And
I've seen the plasticizer in patch cords attack plastic surfaces.

I am no aware of any plasticizer in the rubbery contacts of remote controls.

I've taken apart the keypad for my Ford. There is a silicone goo in it, which
I assume is there to prevent rust or corrosion.





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