sci.electronics.repair
http://groups.google.com/group/sci.electronics.repair?hl=en

sci.electronics.repair@googlegroups.com

Today's topics:

* JCM2000 DSL100 - 18 messages, 5 authors
http://groups.google.com/group/sci.electronics.repair/t/e1a795448919201c?hl=en
* Magnetic door holders question - 4 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/21eb21515055e1fe?hl=en
* Identifying buck-boost transformer windings? - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/401048ec1c4ab948?hl=en
* Magnastat soldering iron bits users in the UK , here? - 3 messages, 2
authors
http://groups.google.com/group/sci.electronics.repair/t/f2ca2d42217d01e2?hl=en

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

== 1 of 18 ==
Date: Wed, Feb 12 2014 4:57 am
From: "Gareth Magennis"


As a matter of interest, how old is this amplifier?

It'll be part of the serial number.



Gareth.






== 2 of 18 ==
Date: Wed, Feb 12 2014 5:29 am
From: "Gareth Magennis"



"N_Cook" <diverse@tcp.co.uk> wrote in message
news:ldflvg$5tj$1@dont-email.me...
> On 12/02/2014 10:20, Gareth Magennis wrote:
>> http://imageshack.com/a/img845/570/o62e.jpg
>>
>>
>> The old PCB is the top one.
>>
>> Note Con15 below the bridge rectifier, it is connected to + and - of
>> rectifier.
>> Con 16 is below Con 8 and is just wired in paralell with it.
>>
>> The old PCB has an LDR, the new one a relay.
>>
>>
>> There may be more differences, I haven't bothered to check thoroughly.
>>
>>
>>
>> Gareth.
>>
>>
>
> It would be nice to nail down exactly what the problem was with the pcb
> manufacture. As China made, probably affects other makes, which at lower
> voltages perhaps would take longer to emerge as a problem. I posited NaCl
> salt contamination to the filler material as it seems to give the right
> sort of temperature / conduction graph. The problem does not require the
> amps to be stored in sheds or garages, ie dampish, to induce the fault
> condition.


In this case the problem may have been exacerbated by incorrect value and
possibly temperature co-efficient type of resistors fitted, if Phil's link
is to be believed, so possibly a combination of problems, not a single one.

It would be unwise, IMHO, to assume ALL PCBs in the faulty batches ended up
suffering from this problem. Any contamination/faults may have been quite
clumpy in distribution, and/or down to a single individual during their
shift.

Who knows.




Cheers,


Gareth.






== 3 of 18 ==
Date: Wed, Feb 12 2014 6:24 am
From: "Phil Allison"



"Gareth Magennis"
> "Phil Allison"
>>
>>> I found this page that details the many problems techs have found with
>>> these Marshalls.
>>>
>>> http://www.lynx.net/~jc/TSL122.html
>>>
>>> Quote from Malcolm:
>>>
>>> " I have just been visiting your web site and had a look at your
>>> attempts
>>> to deal with one of the most diabolical amps ever to see the light of
>>> day.
>>>
>>> My advice to anyone given one of these thing to fix - drop it like a
>>> hot
>>> potato and run in the opposite direction. These things were doomed the
>>> moment they left the factory " .
>>>
>>> Says it all really.
>>>
>>
>>>
>>> Well, what it says is what we already know, that a batch of faulty
>>> circuit boards were manufactured.
>>
>>
>> ** Wot - a single batch ??
>>
>> 1. How about 20 or 30 batches over a period of 5 or 6 years ?
>>
>> 2. How about publishing schems AND making many thousands of PCBs with
>> 5.6k grid suppressors substituted for 220k ?
>>
>> 3. Have about never informing any of their overseas agents about it ?
>>
>> 4. How about 10s of thousands of EL34s ( and OTs) destroyed by the
>> stupid problem ?
>>
>> 5. How about the hefty repair bills paid by Marshall owners and
>> consequent bad will generated against hard working amp techs who were
>> deliberately NOT informed of the REAL problem by the culprits - ie
>> Marshall.
>>
>>
>>> Marshall have since redesigned it and the replacement seems to have
>>> sorted the problem out.
>>
>> ** You ARE fucking joking !!!!
>>
>> You must be sucking those cunt's cocks so hard.
>>
>>
>>> Of course you could argue that Marshall should be offering a free
>>> exchange replacement on such boards, but that is a different debate.
>>
>> ** No it fucking is not.
>>
>> It is nothing short of gross consumer fraud.
>>
>
> I'm not going to respond to that, it is disingenous on far too many
> levels.
>

** It is all simple fact, you lying pommy cunt.

Points 1,2 & 3 are detailed in the link I posted - which I seriously
doubt you bothered to read.

Points 4 & 5 are the unavoidable consequential outcomes.

You have no response because you have been caught lying.

Again.

Fuck you.




.... Phil









== 4 of 18 ==
Date: Wed, Feb 12 2014 6:30 am
From: "Phil Allison"



"Gareth Magennis = Liar"
>
> In this case the problem may have been exacerbated by incorrect value and
> possibly temperature co-efficient type of resistors fitted,


** Regular carbon film types were fitted to early examples and later metal
film - neither were the culprits.

The first and worst case I saw ( a TSL 122 ) used metal film types.

FYI, fuckwit:

NTC resistors in the bias feed would have HELPED the problem.


... Phil









== 5 of 18 ==
Date: Wed, Feb 12 2014 6:30 am
From: dave


On 02/11/2014 05:40 PM, Phil Allison wrote:
> "Gareth Magennis"
>> "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 ?
>>>
>>
>> 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.
>>
>
> ** Thanks again.
>
> I found this page that details the many problems techs have found with these
> Marshalls.
>
> http://www.lynx.net/~jc/TSL122.html
>
> Quote from Malcolm:
>
> " I have just been visiting your web site and had a look at your attempts
> to deal with one of the most diabolical amps ever to see the light of day.
>
> My advice to anyone given one of these thing to fix - drop it like a hot
> potato and run in the opposite direction. These things were doomed the
> moment they left the factory " .
>
> Says it all really.
>
>
>
> .... Phil
Or read the article you showed us, which doesn't really say to give up,
after all.





== 6 of 18 ==
Date: Wed, Feb 12 2014 6:33 am
From: dave


On 02/12/2014 05:29 AM, Gareth Magennis wrote:
> "N_Cook" <diverse@tcp.co.uk> wrote in message
> news:ldflvg$5tj$1@dont-email.me...
>> On 12/02/2014 10:20, Gareth Magennis wrote:
>>> http://imageshack.com/a/img845/570/o62e.jpg
>>>
>>>
>>> The old PCB is the top one.
>>>
>>> Note Con15 below the bridge rectifier, it is connected to + and - of
>>> rectifier.
>>> Con 16 is below Con 8 and is just wired in paralell with it.
>>>
>>> The old PCB has an LDR, the new one a relay.
>>>
>>>
>>> There may be more differences, I haven't bothered to check thoroughly.
>>>
>>>
>>>
>>> Gareth.
>>>
>>>
>>
>> It would be nice to nail down exactly what the problem was with the pcb
>> manufacture. As China made, probably affects other makes, which at lower
>> voltages perhaps would take longer to emerge as a problem. I posited NaCl
>> salt contamination to the filler material as it seems to give the right
>> sort of temperature / conduction graph. The problem does not require the
>> amps to be stored in sheds or garages, ie dampish, to induce the fault
>> condition.
>
>
> In this case the problem may have been exacerbated by incorrect value and
> possibly temperature co-efficient type of resistors fitted, if Phil's link
> is to be believed, so possibly a combination of problems, not a single one.
>
> It would be unwise, IMHO, to assume ALL PCBs in the faulty batches ended up
> suffering from this problem. Any contamination/faults may have been quite
> clumpy in distribution, and/or down to a single individual during their
> shift.
>
> Who knows.
Read the last 2 letters on Phil's link. The bias problem is on the
Overdrive board.





== 7 of 18 ==
Date: Wed, Feb 12 2014 6:35 am
From: "Phil Allison"



"dave the stinking cunt"


>> I found this page that details the many problems techs have found with
>> these
>> Marshalls.
>>
>> http://www.lynx.net/~jc/TSL122.html
>>
>> Quote from Malcolm:
>>
>> " I have just been visiting your web site and had a look at your
>> attempts
>> to deal with one of the most diabolical amps ever to see the light of
>> day.
>>
>> My advice to anyone given one of these thing to fix - drop it like a hot
>> potato and run in the opposite direction. These things were doomed the
>> moment they left the factory " .
>>
>> Says it all really.
>>
> Or read the article you showed us, which doesn't really say to give up,


** Malcolm does not say that either, you stinking trolling moron.





.... Phil








== 8 of 18 ==
Date: Wed, Feb 12 2014 6:38 am
From: "Phil Allison"



"dave the trolling cunt "


> Read the last 2 letters on Phil's link.

** Don't waste your time.

> The bias problem is on the Overdrive board.


** Like hell it is.



... Phil








== 9 of 18 ==
Date: Wed, Feb 12 2014 6:41 am
From: "Gareth Magennis"



"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:bm1es4Ft85pU1@mid.individual.net...
>
> "Gareth Magennis = Liar"
>>
>> In this case the problem may have been exacerbated by incorrect value and
>> possibly temperature co-efficient type of resistors fitted,
>
>
> ** Regular carbon film types were fitted to early examples and later metal
> film - neither were the culprits.
>
> The first and worst case I saw ( a TSL 122 ) used metal film types.
>
> FYI, fuckwit:
>
> NTC resistors in the bias feed would have HELPED the problem.
>
>
> ... Phil
>



Oh I see what you did there Phil, you changed this:

In this case the problem may have been exacerbated by incorrect value and
possibly temperature co-efficient type of resistors fitted, if Phil's link
is to be believed, so possibly a combination of problems, not a single one.



To this:

>> In this case the problem may have been exacerbated by incorrect value and
>> possibly temperature co-efficient type of resistors fitted,



For one who is always complaining about snipping and changing the context,
that takes the biscuit.

You lying snipping changing the context Marsupial's dirty unwiped arse.



Cheers,


Gareth.






== 10 of 18 ==
Date: Wed, Feb 12 2014 6:44 am
From: "Gareth Magennis"



"Gareth Magennis" <sound.service@btconnect.com> wrote in message
news:gIqdndJVuamLFWbPnZ2dnUVZ8sudnZ2d@bt.com...
>
> "Phil Allison" <phil_a@tpg.com.au> wrote in message
> news:bm1es4Ft85pU1@mid.individual.net...
>>
>> "Gareth Magennis = Liar"
>>>
>>> In this case the problem may have been exacerbated by incorrect value
>>> and possibly temperature co-efficient type of resistors fitted,
>>
>>
>> ** Regular carbon film types were fitted to early examples and later
>> metal film - neither were the culprits.
>>
>> The first and worst case I saw ( a TSL 122 ) used metal film types.
>>
>> FYI, fuckwit:
>>
>> NTC resistors in the bias feed would have HELPED the problem.
>>
>>
>> ... Phil
>>
>
>
>
> Oh I see what you did there Phil, you changed this:
>
> In this case the problem may have been exacerbated by incorrect value and
> possibly temperature co-efficient type of resistors fitted, if Phil's link
> is to be believed, so possibly a combination of problems, not a single
> one.
>
>
>
> To this:
>
>>> In this case the problem may have been exacerbated by incorrect value
>>> and possibly temperature co-efficient type of resistors fitted,
>
>
>
> For one who is always complaining about snipping and changing the context,
> that takes the biscuit.
>
> You lying snipping changing the context Marsupial's dirty unwiped arse.
>
>
>
> Cheers,
>
>
> Gareth.
>


Which kind of proves "Malcolm" is talking a load of bollocks then.



Gareth.






== 11 of 18 ==
Date: Wed, Feb 12 2014 6:52 am
From: "Phil Allison"


"Gareth Magennis = Stinking Liar"

>>
>>> In this case the problem may have been exacerbated by incorrect value
>>> and possibly temperature co-efficient type of resistors fitted,
>>
>>
>> ** Regular carbon film types were fitted to early examples and later
>> metal film - neither were the culprits.
>>
>> The first and worst case I saw ( a TSL 122 ) used metal film types.
>>
>> FYI, fuckwit:
>>
>> NTC resistors in the bias feed would have HELPED the problem.

>
> In this case the problem may have been exacerbated by incorrect value and
> possibly temperature co-efficient type of resistors fitted, if Phil's link
> is to be believed,

** Utter crap.

Some people who posted in that link HAVE worked out the real problem, ie
the PCB itself - but others ( having never seen anything like it before)
fell for red herrings.

Such a weird fault is bound to cause confusion among valve amp techs - most
of whom are not very bright .

Like you.

BTW:

Try learning Ohms Law you stinking pommy LIAR !!!!




... Phil









== 12 of 18 ==
Date: Wed, Feb 12 2014 6:57 am
From: "Phil Allison"



"Nutcase Kook the Fuckwit Pommy Nut Case "

>
> Knowing how precious some guitarists are, I'd rather mechanically adapt
> the original board rather than swap out to what may or may not be a
> sound-wise eqivalent replacement board.


** Why were you not aborted ?









== 13 of 18 ==
Date: Wed, Feb 12 2014 7:02 am
From: "Gareth Magennis"



"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:bm1g4nFtgjuU1@mid.individual.net...
> "Gareth Magennis = Stinking Liar"
>
>>>
>>>> In this case the problem may have been exacerbated by incorrect value
>>>> and possibly temperature co-efficient type of resistors fitted,
>>>
>>>
>>> ** Regular carbon film types were fitted to early examples and later
>>> metal film - neither were the culprits.
>>>
>>> The first and worst case I saw ( a TSL 122 ) used metal film types.
>>>
>>> FYI, fuckwit:
>>>
>>> NTC resistors in the bias feed would have HELPED the problem.
>
>>
>> In this case the problem may have been exacerbated by incorrect value and
>> possibly temperature co-efficient type of resistors fitted, if Phil's
>> link
>> is to be believed,
>
> ** Utter crap.
>
> Some people who posted in that link HAVE worked out the real problem, ie
> the PCB itself - but others ( having never seen anything like it before)
> fell for red herrings.
>
> Such a weird fault is bound to cause confusion among valve amp techs -
> most of whom are not very bright .
>
> Like you.
>
> BTW:
>
> Try learning Ohms Law you stinking pommy LIAR !!!!
>
>
>
>
> ... Phil
>
>


I learnt that once before and its a bit boring. Murphys law is a little
more interesting.

And by the way I see you have just repeated the snipped and contex changed
post of mine above.
That's not very sporting, now is it?


You stinking half dried up pool of Wallaby vomit.



Cheers,


Gareth.






== 14 of 18 ==
Date: Wed, Feb 12 2014 7:10 am
From: "Phil Allison"


"Gareth Magennis = Stinking Liar"

>>
>>> In this case the problem may have been exacerbated by incorrect value
>>> and possibly temperature co-efficient type of resistors fitted,
>>
>>
>> ** Regular carbon film types were fitted to early examples and later
>> metal film - neither were the culprits.
>>
>> The first and worst case I saw ( a TSL 122 ) used metal film types.
>>
>> FYI, fuckwit:
>>
>>NTC resistors in the bias feed would have HELPED the problem.
>> --------------------------------------------------------------------------



>
> In this case the problem may have been exacerbated by incorrect value and
> possibly temperature co-efficient type of resistors fitted, if Phil's link
> is to be believed,

** Utter crap.

Some people who posted in that link HAVE worked out the real problem, ie
the PCB itself - but others ( having never seen anything like it before)
fell for red herrings.

Such a weird fault is bound to cause confusion among valve amp techs - most
of whom are not very bright .

While other are complete fuckwits - like you.

BTW:

Try learning Ohms Law you stinking pommy LIAR !!!!

NTC resistors in the bias feed would have HELPED the problem.


BTW2:

You drunk ?

You sure sound like you are.



... Phil










== 15 of 18 ==
Date: Wed, Feb 12 2014 7:23 am
From: "Gareth Magennis"



"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:bm1h61FtnbbU1@mid.individual.net...
> "Gareth Magennis = Stinking Liar"
>
>>>
>>>> In this case the problem may have been exacerbated by incorrect value
>>>> and possibly temperature co-efficient type of resistors fitted,
>>>
>>>
>>> ** Regular carbon film types were fitted to early examples and later
>>> metal film - neither were the culprits.
>>>
>>> The first and worst case I saw ( a TSL 122 ) used metal film types.
>>>
>>> FYI, fuckwit:
>>>
>>>NTC resistors in the bias feed would have HELPED the problem.
>>> --------------------------------------------------------------------------
>
>
>
>>
>> In this case the problem may have been exacerbated by incorrect value and
>> possibly temperature co-efficient type of resistors fitted, if Phil's
>> link
>> is to be believed,
>
> ** Utter crap.
>
> Some people who posted in that link HAVE worked out the real problem, ie
> the PCB itself - but others ( having never seen anything like it before)
> fell for red herrings.
>
> Such a weird fault is bound to cause confusion among valve amp techs -
> most
> of whom are not very bright .
>
> While other are complete fuckwits - like you.
>
> BTW:
>
> Try learning Ohms Law you stinking pommy LIAR !!!!
>
> NTC resistors in the bias feed would have HELPED the problem.
>
>
> BTW2:
>
> You drunk ?
>
> You sure sound like you are.
>
>
>
> ... Phil
>



No Phil, I don't drink during the day at work, you can do as you please.


By the way, read my post again. You know, the one you snipped. It says:

>> In this case the problem may have been exacerbated by incorrect value and
>> possibly temperature co-efficient type of resistors fitted, if Phil's
>> link
>> is to be believed,


I never mentioned NTC resistors at all. I quickly read that page before
going to work this morning and merely re-iterated that Malcolm seemed to
think the wrong type had been fitted.

Which is exactly what I said.


You lying content changing Fuckwit.



Cheers,


Gareth.







== 16 of 18 ==
Date: Wed, Feb 12 2014 1:17 pm
From: dave


On 02/12/2014 06:35 AM, Phil Allison wrote:
> "dave the stinking cunt"
>
>
>>> I found this page that details the many problems techs have found with
>>> these
>>> Marshalls.
>>>
>>> http://www.lynx.net/~jc/TSL122.html
>>>
>>> Quote from Malcolm:
>>>
>>> " I have just been visiting your web site and had a look at your
>>> attempts
>>> to deal with one of the most diabolical amps ever to see the light of
>>> day.
>>>
>>> My advice to anyone given one of these thing to fix - drop it like a hot
>>> potato and run in the opposite direction. These things were doomed the
>>> moment they left the factory " .
>>>
>>> Says it all really.
>>>
>> Or read the article you showed us, which doesn't really say to give up,
>
>
> ** Malcolm does not say that either, you stinking trolling moron.
>
>
>
>
>
> .... Phil
>
>
>
>
I don't know Malcolm. The last couple letters are from someone else I
think. Or maybe not. It's not important. I've only had a couple of those
on my bench and aside from the general cheapness certainly no worse than
many other amps. Now I am in an arid climate 25.6 miles from the sea, so
that may be why I haven't noticed any 500 VDC HV peter tracks.




== 17 of 18 ==
Date: Wed, Feb 12 2014 3:55 pm
From: "Gareth Magennis"




"dave" wrote in message
news:wLCdneJfmd9-eWbPnZ2dnUVZ_sidnZ2d@earthlink.com...

On 02/12/2014 06:35 AM, Phil Allison wrote:
> "dave the stinking cunt"
>
>
>>> I found this page that details the many problems techs have found with
>>> these
>>> Marshalls.
>>>
>>> http://www.lynx.net/~jc/TSL122.html
>>>
>>> Quote from Malcolm:
>>>
>>> " I have just been visiting your web site and had a look at your
>>> attempts
>>> to deal with one of the most diabolical amps ever to see the light of
>>> day.
>>>
>>> My advice to anyone given one of these thing to fix - drop it like a
>>> hot
>>> potato and run in the opposite direction. These things were doomed the
>>> moment they left the factory " .
>>>
>>> Says it all really.
>>>
>> Or read the article you showed us, which doesn't really say to give up,
>
>
> ** Malcolm does not say that either, you stinking trolling moron.
>
>
>
>
>
> .... Phil
>
>
>
>
I don't know Malcolm. The last couple letters are from someone else I
think. Or maybe not. It's not important. I've only had a couple of those
on my bench and aside from the general cheapness certainly no worse than
many other amps. Now I am in an arid climate 25.6 miles from the sea, so
that may be why I haven't noticed any 500 VDC HV peter tracks.





I've had a little bit more time to look at that web page now.

Seems to me about a lot of so called Engineers blowing their own trumpets
and becoming Superheroes for sorting it out.
But actually not really.


The first time I came across this problem, I was totally confused. What I
was seeing could not logically be happening.
I changed everything in the Output stage, but still the same symptoms.
Eventually I phoned Marshall, and spoke to one of their techs, who informed
me that yes, there was a problem with the PCB's, and yes, I should replace
it with a re-designed one.

All admitted by Marshall up front, job done, sorted.



Seems this problem is more about Ego's, than simply looking at the problem,
finding the solution, and implementing it at the least possible cost.



The best post on the site I found was this one, which kind of sums up what I
have experienced perfectly.

http://imageshack.com/a/img545/362/4pvn.jpg


Most everything else is all Me Me Me.
















== 18 of 18 ==
Date: Wed, Feb 12 2014 4:21 pm
From: "William Sommerwerck"


Do you realize that when you so viciously attack people who disagree with you
(whether they're right or wrong), you destroy the atmosphere needed for an
intelligent conversation?






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

== 1 of 4 ==
Date: Wed, Feb 12 2014 7:39 am
From: bud--


On 2/11/2014 4:08 PM, captainvideo462009@gmail.com wrote:
>
> I do like Michael's idea of video taping the failure and sending it to the manufacturer. Perhaps that will get them off their asses to come up with a solution. Lenny
>

The panel and other components are likely UL listed. I would set a video
to UL. May not help your immediate problem but could prevent similar
problems elsewhere in new installs.





== 2 of 4 ==
Date: Wed, Feb 12 2014 10:42 am
From: "Michael A. Terrell"



Adrian Tuddenham wrote:
>
> Cydrome Leader <presence@MUNGEpanix.com> wrote:
>
> > 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.
>
> It's the residual magnetism that is causing the problem; if the main
> magnetisation is above a certain minimum level, the residual is not much
> affected by any extra energisation. The limit to the power source is
> more likely to be the temperature rise of the energising coils.
>
> I don't know how the O/P's system is arranged, but I think the UK ones
> have the magnets in series around the building, so that the circuit can
> be broken near any doorway and all the doors on that circuit will shut.
> In that case the PSU would either be constant-current or would have a
> transformer with adjustable tappings which can be set according to how
> many magnets are in circuit.


All I've seen in use, use AC to prevent this problem.

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




== 3 of 4 ==
Date: Wed, Feb 12 2014 10:48 am
From: adrian@poppyrecords.invalid.invalid (Adrian Tuddenham)


Michael A. Terrell <mike.terrell@earthlink.net> wrote:

> Adrian Tuddenham wrote:
> >
> > Cydrome Leader <presence@MUNGEpanix.com> wrote:
> >
> > > 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.
> >
> > It's the residual magnetism that is causing the problem; if the main
> > magnetisation is above a certain minimum level, the residual is not much
> > affected by any extra energisation. The limit to the power source is
> > more likely to be the temperature rise of the energising coils.
> >
> > I don't know how the O/P's system is arranged, but I think the UK ones
> > have the magnets in series around the building, so that the circuit can
> > be broken near any doorway and all the doors on that circuit will shut.
> > In that case the PSU would either be constant-current or would have a
> > transformer with adjustable tappings which can be set according to how
> > many magnets are in circuit.
>
>
> All I've seen in use, use AC to prevent this problem.

...except that A.C. doesn't prevent it. I've seen enough stuck
contactors with A.C. coils to be quite certain of that.


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




== 4 of 4 ==
Date: Wed, Feb 12 2014 4:36 pm
From: "Michael A. Terrell"



Adrian Tuddenham wrote:
>
> Michael A. Terrell wrote:
> >
> >
> > All I've seen in use, use AC to prevent this problem.
>
> ...except that A.C. doesn't prevent it. I've seen enough stuck
> contactors with A.C. coils to be quite certain of that.


They are not contactors. Some hold the door open for years between
operations. Contactors get beat to death by repeatedly slamming the pole
piece into the metal on the moving contacts.


You're comparing apples to water melons.

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





==============================================================================
TOPIC: Identifying buck-boost transformer windings?
http://groups.google.com/group/sci.electronics.repair/t/401048ec1c4ab948?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Feb 12 2014 9:15 am
From: etpm@whidbey.com


On Tue, 11 Feb 2014 14:44:18 -0800, DaveC <invalid@invalid.net> wrote:

>> I have the wiring diagrams in .pdf for Square D buck/boost xmfrs. The
>> X wires are the heavy wires and the H wires the thin wires. X1 and X2
>> are the ends of one winding. X2 and X3 the ends of another winding.
>> The other windings are similar. Anyway, if you send me an email I'll
>> send you the .pdf of the wiring manual. Then you will be able to
>> figure out how to wire the thing. It should be easy enough, just
>> measure the output in one random configuration and you will be able to
>> tell what's what by looking at the manual.
>> Eric
>
>Have a wiring diag:
>
>http://oi59.tinypic.com/v3fuog.jpg
>
>How to wire it isn't the question. Which wires are H1, H2, X1, X2, etc. is
>the question.
>
>Series light bulb or Variac (will use 120 mains for testing as that is the
>only Variac I have...) seems the answer.
>
>Remaining question: are H1/2 and H3/4 primary windings interchangeable? X1/2
>and X3/4 windings interchangeable?
>
>Thanks.
Dave,
In my first post I mentioned which wire were which. To reiterate, on
my xmfr, the heavy wires are the X wires, the thin wires are the H
wires. The difference in size is about 4 to 1. Now, these wires are
the ones that show coming out of the potting compound. I cannot see
the actual coils because the whole xmfr is potted. I looked at the
picture in the link you sent me. If this is all the info you have then
you don't have enough. I checked my email and I didn't see one from
you. The email address with my posts is a real one. Send me an email
and I'll send you the manual which will explain the whole thing. The
manual has many wiring diagrams which will help you get it right the
first time. Or just search online for a buck/boost wiring manual.
That's how I found mine. I'm no electrician or electronics guy and it
took me less than 15 minutes to figure out the wiring of the xmfrs for
my 3 phase machine.
Eric

---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com






==============================================================================
TOPIC: Magnastat soldering iron bits users in the UK , here?
http://groups.google.com/group/sci.electronics.repair/t/f2ca2d42217d01e2?hl=en
==============================================================================

== 1 of 3 ==
Date: Wed, Feb 12 2014 11:21 am
From: N_Cook


I cannot find any major suppliers of these bits anymore in the UK,
despite the likes of RS selling magnastat irons.
I have a few hundred NOS , plated copper long cone bits, not Weller or
Cooper AFAIK, that take about 10 minutes to convert to magnastat ,
assuming you have the curie temp magnastat end caps from old bits
hanging around, easily removed when you know how.
If any interest I'll post more details, I'll not be around long enough
to have used up a few hundred




== 2 of 3 ==
Date: Wed, Feb 12 2014 12:57 pm
From: adrian@poppyrecords.invalid.invalid (Adrian Tuddenham)


N_Cook <diverse@tcp.co.uk> wrote:

> I cannot find any major suppliers of these bits anymore in the UK,
> despite the likes of RS selling magnastat irons.

Have the bits been removed from the RS catalogue recently? I bought
some about a year ago and they had a good selection listed then.

A lot of good stuff has dissapeared from RS in the last few years, but
most of it is still available from Farnell and their prices are
comparable. (e.g. A lot of the transistors from the ZTX range, good
quality 4mm plugs and sockets, plug-in DIL chips etc.)


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




== 3 of 3 ==
Date: Wed, Feb 12 2014 1:17 pm
From: N_Cook


On 12/02/2014 20:57, Adrian Tuddenham wrote:
> N_Cook <diverse@tcp.co.uk> wrote:
>
>> I cannot find any major suppliers of these bits anymore in the UK,
>> despite the likes of RS selling magnastat irons.
>
> Have the bits been removed from the RS catalogue recently? I bought
> some about a year ago and they had a good selection listed then.
>
> A lot of good stuff has dissapeared from RS in the last few years, but
> most of it is still available from Farnell and their prices are
> comparable. (e.g. A lot of the transistors from the ZTX range, good
> quality 4mm plugs and sockets, plug-in DIL chips etc.)
>
>

It was about a year ago I checked on wwwRS and they carried the bits
then and also 24V heaters which I was actually checking for as the
heater on mine is perhaps 20 years old. Who wants to use 240V magnastat
irons in post_CMOS days, especially without stocking replacement bits,
they do stock those though.




==============================================================================

You received this message because you are subscribed to the Google Groups "sci.electronics.repair"
group.

To post to this group, visit http://groups.google.com/group/sci.electronics.repair?hl=en

To unsubscribe from this group, send email to sci.electronics.repair+unsubscribe@googlegroups.com

To change the way you get mail from this group, visit:
http://groups.google.com/group/sci.electronics.repair/subscribe?hl=en

To report abuse, send email explaining the problem to abuse@googlegroups.com

==============================================================================
Google Groups: http://groups.google.com/?hl=en