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#8297 From: Homebrew_PCBs@yahoogroups.com
Date: Tue Mar 1, 2005 10:01 am
Subject: File - monthly.txt
Homebrew_PCBs@yahoogroups.com
Send Email Send Email
 
Monthly Reminder, please read:

Subject lines:
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thread. Please change the subject line if you are on digest, as "Digest 1044"
means nothing to anyone.
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Me" is bad subject line. "Bits for milling PCBs" is a good subject line.
    Subject lines affect whether or not people even read your message, and affect
people searching the archives for help at a later date.

Trim messages- especially if you are receiving messages in digest form. By the
same token, quote enough so we know what you are responding to. "Yeah, I agree"
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#8298 From: "Stefan Trethan" <stefan_trethan@...>
Date: Tue Mar 1, 2005 5:05 pm
Subject: lexmark m412 board results
stefan_trethan
Send Email Send Email
 
Hi,

tried the m412 for the first time today.
After printing the layout (at darkest setting) i was convinced the printer
is useless for TT because it was not opaque on paper against a light
source.

However, i was surprised to see the final result be flawless, only the
board outline didn't transfer fully but i'll figure that out somehow. The
only drawback is that the 1200dpi is a "fake" photo mode, i'd probably
have gone for a "true 1200" HP if i had known that. I fear i'll only get
600x600 real-life dpi but i sure hope it'll last me a few years.
The low amount of toner solves many problems with spreading and stuff, so
the gain in resolution is better than the pure DPI gain anyway.


Anyhow, the M412/412 from lexmark is definitely on the "this one works"
list (will list in database after next board). Also, don't get discouraged
if the printout doesn't seem fully opaque, it needn't mean it won't work.

ST

#8299 From: "William Raymond Maxwell" <wrmaxwell@...>
Date: Tue Mar 1, 2005 11:47 pm
Subject: Re: lexmark m412 board results
bill_maxwellau
Send Email Send Email
 
Thanks for that news Stefan.  Anybody using a Lexmark X215 and can report
results?  I have not long installed one here, now that I have retired.  I
expect that it will work well, as I expect that any of the contemporary
Lexmark lasers will most likely share common technology.

By the way, I visited Lexmark's headquarters in Lexington, Kentucky back in
July and have very good contacts with Lexmark here in Australia.  I suspect
that I should be able to source any technical advice we might require.

Cheers

Bill
-----Original Message-----
From: Stefan Trethan <stefan_trethan@...>
To: homebrew_pcbs@yahoogroups.com <homebrew_pcbs@yahoogroups.com>
Date: Wednesday, 2 March 2005 4:05
Subject: [Homebrew_PCBs] lexmark m412 board results


>
>Hi,
>
>tried the m412 for the first time today.
>After printing the layout (at darkest setting) i was convinced the printer
>is useless for TT because it was not opaque on paper against a light
>source.
>
>However, i was surprised to see the final result be flawless, only the
>board outline didn't transfer fully but i'll figure that out somehow. The
>only drawback is that the 1200dpi is a "fake" photo mode, i'd probably
>have gone for a "true 1200" HP if i had known that. I fear i'll only get
>600x600 real-life dpi but i sure hope it'll last me a few years.
>The low amount of toner solves many problems with spreading and stuff, so
>the gain in resolution is better than the pure DPI gain anyway.
>
>
>Anyhow, the M412/412 from lexmark is definitely on the "this one works"
>list (will list in database after next board). Also, don't get discouraged
>if the printout doesn't seem fully opaque, it needn't mean it won't work.
>
>ST
>
>
>
>Be sure to visit the group home and check for new Bookmarks and files:
>http://groups.yahoo.com/group/Homebrew_PCBs
>Yahoo! Groups Links
>
>
>
>
>
>
>

#8300 From: Naveed Alam <naveedguy2@...>
Date: Wed Mar 2, 2005 5:04 am
Subject: CuCl
naveedguy2
Send Email Send Email
 
I bought a copper board. The shop-keeper also gave
CuCl but that is in the solid form. Can anyone tell me
about the proportions of water and this solid used to
prepare solution for etching. Can I also use some
other chemical to improve the etching process or make
it faster. It's black in colour. Is it OK?



__________________________________
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#8301 From: "Stefan Trethan" <stefan_trethan@...>
Date: Wed Mar 2, 2005 9:28 am
Subject: Re: CuCl
stefan_trethan
Send Email Send Email
 
On Tue, 1 Mar 2005 21:04:21 -0800 (PST), Naveed Alam
<naveedguy2@...> wrote:

> I bought a copper board. The shop-keeper also gave
> CuCl but that is in the solid form. Can anyone tell me
> about the proportions of water and this solid used to
> prepare solution for etching. Can I also use some
> other chemical to improve the etching process or make
> it faster. It's black in colour. Is it OK?


If it is really CuCl you can use it, i think there is some text in the
links section about this black powder and how to prepare it.
My gut feeling is a flame should turn blue (maybe green) if you put a
small amount of powder in.

In any case, you need HCl (Hydrochloric acid), which provides the Cl for
forming more CuCl from the copper on the PCB.


Also, you need either a air bubbler, or H2O2 to regenerate the etchant
(The added oxygen makes the Cl free from the HCl by forming water i
think). I suggest a bubbler in any case because it is cheap (10eur
aquarium airpump) and it speeds up etching dramatically. I prefer H2O2 for
regenerating, because it isn't expensive and "instant" rather than tedious
bubbling.

ST

#8302 From: Adam Seychell <a_seychell@...>
Date: Wed Mar 2, 2005 9:37 am
Subject: Re: CuCl
a_seychell
Send Email Send Email
 
Naveed Alam wrote:
> I bought a copper board. The shop-keeper also gave
> CuCl but that is in the solid form. Can anyone tell me
> about the proportions of water and this solid used to
> prepare solution for etching. Can I also use some
> other chemical to improve the etching process or make
> it faster. It's black in colour. Is it OK?

Ask the the shop keeper. The molecular formula for CuCl is Cu2Cl2, and
is called cuprous chloride or copper(I) chloride, its a white powder,
unstable in water and oxygen and even decomposes in light. How do you
know its CuCl ?

Adam

#8303 From: "Leon Heller" <leon.heller@...>
Date: Wed Mar 2, 2005 9:44 am
Subject: Re: CuCl
leon_heller
Send Email Send Email
 
----- Original Message -----
From: "Adam Seychell" <a_seychell@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, March 02, 2005 9:37 AM
Subject: Re: [Homebrew_PCBs] CuCl


>
> Naveed Alam wrote:
>> I bought a copper board. The shop-keeper also gave
>> CuCl but that is in the solid form. Can anyone tell me
>> about the proportions of water and this solid used to
>> prepare solution for etching. Can I also use some
>> other chemical to improve the etching process or make
>> it faster. It's black in colour. Is it OK?
>
> Ask the the shop keeper. The molecular formula for CuCl is Cu2Cl2, and
> is called cuprous chloride or copper(I) chloride, its a white powder,
> unstable in water and oxygen and even decomposes in light. How do you
> know its CuCl ?

If it's black, it is probably anhydrous ferric chloride. I used to buy it
like that, many years ago.

Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller



--
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Version: 7.0.300 / Virus Database: 266.5.7 - Release Date: 01/03/2005

#8304 From: "Stefan Trethan" <stefan_trethan@...>
Date: Wed Mar 2, 2005 9:47 am
Subject: Re: lexmark m412 board results
stefan_trethan
Send Email Send Email
 
On Wed, 2 Mar 2005 10:47:27 +1100, William Raymond Maxwell
<wrmaxwell@...> wrote:

> I
> expect that it will work well, as I expect that any of the contemporary
> Lexmark lasers will most likely share common technology.
> By the way, I visited Lexmark's headquarters in Lexington, Kentucky back
> in
> July and have very good contacts with Lexmark here in Australia.  I
> suspect
> that I should be able to source any technical advice we might require.
> Cheers
> Bill


I expect too. What i wonder is if "fuser oil" is beeing a problem with
some printers.
The felt "wiper" on the upper fuser roller is applying fuser oil in some
models (silicone oil).

I guess that would thwart any attemt to transfer the toner.

With new HP toner came a wiper once that seemed to contain the oil, so i
haven't changed it. The wiper in the Lexmark was new and seemed dry.
Fuser oil is one of the things i still wonder about.


By the way, while at printers, the quartz lamp in a fuser seems to be the
same as the "halogene lamp" in floodlights, true? would that be a cheap
replacement? Just wondering, 'cause they seem overly expensive at printer
spare parts shops...

ST

#8305 From: "Stefan Trethan" <stefan_trethan@...>
Date: Wed Mar 2, 2005 10:30 am
Subject: Re: CuCl
stefan_trethan
Send Email Send Email
 
On Wed, 2 Mar 2005 09:44:45 -0000, Leon Heller <leon.heller@...>
wrote:

>
> If it's black, it is probably anhydrous ferric chloride. I used to buy it
> like that, many years ago.
> Leon
> --
> Leon Heller, G1HSM
> http://www.geocities.com/leon_heller


There was mentioned some time back some form of copper powder is sold as
pigment in arts stores, it is black or brown i think.
Maybe it is that, but i wouldn't expect that is sold in a electronics
store, while FeCl is highly likely.
There was a document describing how to convert the "pigment" copper into
CuCl.

ST

#8306 From: "Stefan Trethan" <stefan_trethan@...>
Date: Wed Mar 2, 2005 10:41 am
Subject: CuCl disposal, "flip stick", burning
stefan_trethan
Send Email Send Email
 
Hi,

remember the "flip stick" source for CuCl?
It is simply thrown into the fire and burnt.

I wonder, would that be a appropriate way to dispose of excess CuCl?
If one neutralizes the HCl with NaOh or something else, then evaporates
the water, and then burns the crystals?

If flip sticks containing copper cloride are burnt it can't be bad???
Get rid of the "overgrowth" of CuCl and clean the oven at the same time.

Any thoughts welcome.


ST

#8307 From: "Leon Heller" <leon.heller@...>
Date: Wed Mar 2, 2005 11:26 am
Subject: Re: CuCl disposal, "flip stick", burning
leon_heller
Send Email Send Email
 
----- Original Message -----
From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, March 02, 2005 10:41 AM
Subject: [Homebrew_PCBs] CuCl disposal, "flip stick", burning


>
> Hi,
>
> remember the "flip stick" source for CuCl?
> It is simply thrown into the fire and burnt.
>
> I wonder, would that be a appropriate way to dispose of excess CuCl?
> If one neutralizes the HCl with NaOh or something else, then evaporates
> the water, and then burns the crystals?
>
> If flip sticks containing copper cloride are burnt it can't be bad???
> Get rid of the "overgrowth" of CuCl and clean the oven at the same time.
>
> Any thoughts welcome.

Extract the copper by electrolysis and sell it. 8-)

Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller


--
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.300 / Virus Database: 266.5.7 - Release Date: 01/03/2005

#8308 From: Adam Seychell <a_seychell@...>
Date: Wed Mar 2, 2005 11:40 am
Subject: Re: CuCl disposal, "flip stick", burning
a_seychell
Send Email Send Email
 
Stefan Trethan wrote:

> Hi,
>
> remember the "flip stick" source for CuCl?
> It is simply thrown into the fire and burnt.
>
> I wonder, would that be a appropriate way to dispose of excess CuCl?
> If one neutralizes the HCl with NaOh or something else, then evaporates
> the water, and then burns the crystals?
>
> If flip sticks containing copper cloride are burnt it can't be bad???
> Get rid of the "overgrowth" of CuCl and clean the oven at the same time.
>
> Any thoughts welcome.
>


Copper(II) oxide is black/brown powder. You'll get this if you heat
copper chloride pretty hot. All you do is make the copper insoluble so
its much less likely to leach in soil.

#8309 From: "Stefan Trethan" <stefan_trethan@...>
Date: Wed Mar 2, 2005 11:43 am
Subject: Re: CuCl disposal, "flip stick", burning
stefan_trethan
Send Email Send Email
 
On Wed, 2 Mar 2005 11:26:35 -0000, Leon Heller <leon.heller@...>
wrote:

>
> Extract the copper by electrolysis and sell it.
> Leon
> --
> Leon Heller, G1HSM
> http://www.geocities.com/leon_heller


That's not that easy 'cause it produces heaps of chlorine gas.

ST

#8310 From: "Stefan Trethan" <stefan_trethan@...>
Date: Wed Mar 2, 2005 11:51 am
Subject: Re: CuCl disposal, "flip stick", burning
stefan_trethan
Send Email Send Email
 
On Wed, 02 Mar 2005 22:40:21 +1100, Adam Seychell
<a_seychell@...> wrote:

>
> Copper(II) oxide is black/brown powder. You'll get this if you heat
> copper chloride pretty hot. All you do is make the copper insoluble so
> its much less likely to leach in soil.


so how do flip-sticks work?
the copper oxide ends up in the ash and all they produce is chlorine? or
what?
why can't chemistry be as easy as electronics???

ST

#8311 From: "Stefan Trethan" <stefan_trethan@...>
Date: Wed Mar 2, 2005 5:39 pm
Subject: resolution test, pictures
stefan_trethan
Send Email Send Email
 
Hi,


made a pcb with lines:
1/1200" (0.833mil)
2/1200" (1.66mil)
4/1200" (3.33mil)
8/1200" (6.66mil)
16/1200" (13.3mil)
32/1200" (26.6mil)

printed at 600dpi resolution the first 2 are the same, and totally broken
up after transfer and etch.
3.33mil is partially broken up, 6.66 is consistent. didn't try 3 600dpi
dots, but it will be in between.


33mil high text is well readable in copper, 16mil text is bad already, i
think 25mil might be the limit.

i futher did a series of 13mil wide tracks spaced the listed above
distances, the smallest two result in no visible gap, the third just a
hairline. 6.66mil gap seems reliable, but i haven't rubbed the paper well
so it is not etched completely.

Groundplane worked fine.

You can see the results at
<http://www.trethan.at.tf/pub/img1/>
, the images pcb?.jpg.

There's also some other stuff for PCB making, note that the pivoting drill
press is prepared for mounting the optical projection viewfinder but there
wasn't time to actually implement it. The image will be taken by a lens
right under the pcb and mirrored back to a screen on the big frame you
see. Also i must make springs to balance the press (hold it up when idle)
and a better stop.

The fuser assy is a proof of concept that stayed that way, but it works
just fine.

The etchtank is almost perfect (for me, anyway), only thing i'd change is
rotate it 90 degrees (more high than wide) for various reasons. You can
see the one-hand-no-gloves-no-mess holder/lid.

Anyone wanting the resolution test layout is welcome, but i would make it
different the next time.
seems to me 6.66mil is pretty much all we get, i would like to know if a
1200dpi printer allows better results.

ST

#8312 From: "Tony Smith" <ajsmith@...>
Date: Wed Mar 2, 2005 6:21 pm
Subject: RE: Lamps, was lexmark m412 board results
dropcat2001
Send Email Send Email
 
>
> By the way, while at printers, the quartz lamp in a fuser seems
> to be the
> same as the "halogene lamp" in floodlights, true? would that be a cheap
> replacement? Just wondering, 'cause they seem overly expensive at
> printer
> spare parts shops...
>
> ST
>

Same thing, althought you might have trouble matching power rating & sizes.
The fuser section from a photocopier I have here to make a laminator out of
has a 850 watt lamp in it.  Old HP LaserJets are about 500 watt.

If you find one that is the right length & has the correct connectors, it
should work.  The lamp for those work lamps will probably be ok, although
they don't seem to have a very long life.  I can only recall one time I
replaced a printer lamp, and that was thru someone breaking it, not it
wearing out.  Might explain the cost!  Quality!

The 850 watt one I mention here has the wires permanently attached, and is
about 300mm long, to handle A3 paper.  The HP one would be about 200mm long.

Tony

#8313 From: "Stefan Trethan" <stefan_trethan@...>
Date: Wed Mar 2, 2005 6:45 pm
Subject: Re: Lamps, was lexmark m412 board results
stefan_trethan
Send Email Send Email
 
On Thu, 3 Mar 2005 05:21:17 +1100, Tony Smith <ajsmith@...>
wrote:

>
> Same thing, althought you might have trouble matching power rating &
> sizes.
> The fuser section from a photocopier I have here to make a laminator out
> of
> has a 850 watt lamp in it.  Old HP LaserJets are about 500 watt.
> If you find one that is the right length & has the correct connectors, it
> should work.  The lamp for those work lamps will probably be ok, although
> they don't seem to have a very long life.  I can only recall one time I
> replaced a printer lamp, and that was thru someone breaking it, not it
> wearing out.  Might explain the cost!  Quality!
> The 850 watt one I mention here has the wires permanently attached, and
> is
> about 300mm long, to handle A3 paper.  The HP one would be about 200mm
> long.
> Tony
>


The lexmark printer has the same ceramic ends with brass contacts where a
spring contact presses against, no wires, exactly the same as in the
lamps. the power's another issue...

ST

#8314 From: Terry Mickelson <tmdslca@...>
Date: Wed Mar 2, 2005 7:27 pm
Subject: Question on printers for TT
trm1945
Send Email Send Email
 
I just bought an ESR kit that measures a capacitor's Equivalent Series
Resistance. That has nothing to do with this forum, however the manual
that came with this kit was printed on glossy paper and the toner is "B
L A C K" and shines. There are no visible pinholes nor is there any
tangible height to the toner. There is none of the edge fuzz that's
associated with ink jets and the pattern for grey areas is a set of
black dots in a one to one size-wise relationship with the white
background. What type of printer does this because it looks like a good
candidate for toner transfer printing.
Terry M

#8315 From: "Tony Smith" <ajsmith@...>
Date: Wed Mar 2, 2005 7:32 pm
Subject: RE: Lamps, was lexmark m412 board results
dropcat2001
Send Email Send Email
 
> -----Original Message-----
> From: Stefan Trethan [mailto:stefan_trethan@...]
> Sent: Thursday, 3 March 2005 5:45 AM
> To: Homebrew_PCBs@yahoogroups.com
> Subject: Re: [Homebrew_PCBs] Lamps, was lexmark m412 board results
>
>
>
> On Thu, 3 Mar 2005 05:21:17 +1100, Tony Smith <ajsmith@...>
> wrote:
>
> >
> > Same thing, althought you might have trouble matching power rating &
> > sizes.
> > The fuser section from a photocopier I have here to make a
> laminator out
> > of
> > has a 850 watt lamp in it.  Old HP LaserJets are about 500 watt.
> > If you find one that is the right length & has the correct
> connectors, it
> > should work.  The lamp for those work lamps will probably be
> ok, although
> > they don't seem to have a very long life.  I can only recall one time I
> > replaced a printer lamp, and that was thru someone breaking it, not it
> > wearing out.  Might explain the cost!  Quality!
> > The 850 watt one I mention here has the wires permanently
> attached, and
> > is
> > about 300mm long, to handle A3 paper.  The HP one would be about 200mm
> > long.
> > Tony
> >
>
>
> The lexmark printer has the same ceramic ends with brass contacts
> where a
> spring contact presses against, no wires, exactly the same as in the
> lamps. the power's another issue...
>
> ST

HP lamps are like that too, from what I remember.  The one with the wire
attached was from a Canon photocopier.  I think they did this to reduce
manufacturing costs, it had a lot of 'let's do it as cheap as possible
features' in it.  Not one of their better efforts.

In theory, you could replace the lamp with strands of nichrome wire.  The
fact that everyone uses halogen lamps probably means it's more hassle than
it's worth.  (The wire would burn out, stretch, insulation problems, etc)

Tony

#8316 From: "Stefan Trethan" <stefan_trethan@...>
Date: Wed Mar 2, 2005 7:52 pm
Subject: Re: Question on printers for TT
stefan_trethan
Send Email Send Email
 
On Wed, 2 Mar 2005 11:27:51 -0800, Terry Mickelson <tmdslca@...>
wrote:

> I just bought an ESR kit that measures a capacitor's Equivalent Series
> Resistance. That has nothing to do with this forum, however the manual
> that came with this kit was printed on glossy paper and the toner is "B
> L A C K" and shines. There are no visible pinholes nor is there any
> tangible height to the toner. There is none of the edge fuzz that's
> associated with ink jets and the pattern for grey areas is a set of
> black dots in a one to one size-wise relationship with the white
> background. What type of printer does this because it looks like a good
> candidate for toner transfer printing.
> Terry M


Ask the supplier?

ST

#8317 From: Jason Giglio <jgiglio@...>
Date: Wed Mar 2, 2005 11:18 pm
Subject: Re: Question on printers for TT
jgiglio@...
Send Email Send Email
 
Terry Mickelson wrote:
> I just bought an ESR kit that measures a capacitor's Equivalent Series
> Resistance. That has nothing to do with this forum, however the manual
> that came with this kit was printed on glossy paper and the toner is "B
> L A C K" and shines. There are no visible pinholes nor is there any
> tangible height to the toner.

Have you considered it might have been printed on a normal lithographic
printing press?

#8318 From: "Dave" <wa4qal@...>
Date: Thu Mar 3, 2005 3:48 pm
Subject: Re: CuCl disposal, "flip stick", burning
wa4qal
Send Email Send Email
 
--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:
> On Wed, 2 Mar 2005 11:26:35 -0000, Leon Heller <leon.heller@d...>
> wrote:
>
> >
> > Extract the copper by electrolysis and sell it.
> > Leon
> > --
> > Leon Heller, G1HSM
> > http://www.geocities.com/leon_heller
>
>
> That's not that easy 'cause it produces heaps of chlorine gas.
>
> ST

Not if the Chlorine reacts with the positive electrode material.
I've had some success with a very limited trial of extracting
Copper using an Iron electrode with electrolysis.

Dave

#8319 From: "bill_at_pearl" <custserv@...>
Date: Thu Mar 3, 2005 4:04 pm
Subject: ESR Measurement Kit, was: Question on printers for TT
bill_at_pearl
Send Email Send Email
 
Terry Mickelson wrote:
> I just bought an ESR kit that measures a capacitor's Equivalent
Series Resistance.

[snip]

> Terry M

Hi:
From whom did you buy the abovementioned kit ? ?

Thx

#8320 From: "Bill P @ PEARL" <custserv@...>
Date: Thu Mar 3, 2005 4:13 pm
Subject: Providers of CNC routed "Printed" Circuits ? ?
bill_at_pearl
Send Email Send Email
 
Hi All:
     I'm looking for a privateer or a company who can provide CNC-routed,
rather than etched, PCBs.
     I have to make up several one-off extender boards for doing repairs and
calibration on gear that uses motherboard back planes on card cages.
     So, in other words, I need boards that are complete no-brainers but
which can run, say, 15" long and I do need them cut to shape.
     Thanks . . .

     Bill

#8321 From: "Stefan Trethan" <stefan_trethan@...>
Date: Thu Mar 3, 2005 4:41 pm
Subject: Re: ESR Measurement Kit, was: Question on printers for TT
stefan_trethan
Send Email Send Email
 
On Thu, 03 Mar 2005 16:04:42 -0000, bill_at_pearl
<custserv@...> wrote:

>
>
>
> Terry Mickelson wrote:
>> I just bought an ESR kit that measures a capacitor's Equivalent
> Series Resistance.
>
> [snip]
>
>> Terry M
>
> Hi:
> From whom did you buy the abovementioned kit ? ?
>
> Thx
>

Not a kit, but a schematic for a very easy to build one:

<http://www.albany.net/~gwoods/esr_meter/esr_meter_index.html>

I've made it and it works really great. Has singlehandedly repaired
several appliances already.

Planning to offer a pcb for it for ages, still haven't had time to rework
it.

ESR meter is a must have i think...


ST

#8322 From: Lez <lez.briddon@...>
Date: Thu Mar 3, 2005 4:53 pm
Subject: Re: ESR Measurement Kit, was: Question on printers for TT
lez_briddon
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Am I missing something here, does it measure it resistance when in
circuit and running?

Do you the plug/connect the cap into the box and it 'performs a test' on
it and tells you its resistance? if so do you need to remove one side of
it from the circuit its in?

#8323 From: "Stefan Trethan" <stefan_trethan@...>
Date: Thu Mar 3, 2005 5:14 pm
Subject: Re: ESR Measurement Kit, was: Question on printers for TT
stefan_trethan
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On Thu, 03 Mar 2005 16:53:28 +0000, Lez <lez.briddon@...> wrote:

>
> Am I missing something here, does it measure it resistance when in
> circuit and running?
> Do you the plug/connect the cap into the box and it 'performs a test' on
> it and tells you its resistance? if so do you need to remove one side of
> it from the circuit its in?


in circuit, you don't need to desolder anything.

You should power off the unit, because AC signals on the cap can influence
the result, but you don't need to discharge the cap, the DC does no harm.

Of course if there are low resistance parts parallel you measure them too,
but so far that never happened to me.
(the only situation to desolder i can imagine is when you want to find a
faulty cap in a series of several parallel ones.)

The meter works by applying a small AC voltage of 50kHz across the cap and
measuring the resistance for this AC current. The voltage is small enough
not to trigger diodes.
I use the meter to check all caps in a faulty circuit, which takes maybe
one minute and you needn't replace old electrolytics "upon sight" as many
suggest. You can also use old stock with less risk if you test them before.


What i found most amazing is that the meter i linked to uses 3V single
supply voltage with a LM324 and actually works. (I use 2 nicad cells)

ST

#8324 From: Terry Mickelson <tmdslca@...>
Date: Thu Mar 3, 2005 6:50 pm
Subject: Re: ESR Measurement Kit
trm1945
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I bought the Australian designed kit for the "Dick Smith ESR meter"
locally from a distributer close to me for $80 Canadian.
The meter measures low ohms from .01 to 99 on a two digit display using
AC (actually it's pulses) instead of DC. It will measure capacitors in
circuit or out but they must be discharged first.
I've found that my standard (used) electrolytic caps are usually good
but some of the (used) Tantalums were highly variable and in one small
batch, three of them got thrown out. The meter measures caps from 1 uF
up to 10,000 uF. It doesn't measure accurately below 1uF. Caps below
1uF aren't usually electrolytics in any case.
The meter will also measure resistors from .01 to 99 ohms. My regular
ohmmeter doesn't do well below an ohm. As for the power supply, they
supply two battery holders for 6 triple A's. I went with a plug in AC
brick that supplies the 9 VDC. It's a switcher type that I found in a
thrift store for 25 cents.
The kit has been well thought out and is easy to assemble but I had to
measure the resistors first before installation because their color
codes on a blue background are hard to read. After assembly, there was
no need to calibrate as the readings were accurate as is.
Terry M

#8325 From: "Stefan Trethan" <stefan_trethan@...>
Date: Thu Mar 3, 2005 7:07 pm
Subject: Re: ESR Measurement Kit
stefan_trethan
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On Thu, 3 Mar 2005 10:50:01 -0800, Terry Mickelson <tmdslca@...>
wrote:

> I bought the Australian designed kit for the "Dick Smith ESR meter"
> locally from a distributer close to me for $80 Canadian.


I considered that one before i built mine, it is pretty nice, but was too
expensive as i had all the parts for the other meter at hand.
I have a milliohm meter already, so i don't miss that (and it would be
useless for motor-resistance anyway because of the ac signal, which is
what i need milliohm measured most often).
ESR is only "good" or "bad", so i find the analog meter has plenty of
resolution and allows quick reading.

I guess both do a similar job.

ST

#8326 From: "crankorgan" <john@...>
Date: Thu Mar 3, 2005 8:41 pm
Subject: Re: Providers of CNC routed "Printed" Circuits ? ?
crankorgan
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http://www.pcbmilling.com/



--- In Homebrew_PCBs@yahoogroups.com, "Bill P @ PEARL" <custserv@p...>
wrote:
>
>     Hi All:
>     I'm looking for a privateer or a company who can provide CNC-routed,
> rather than etched, PCBs.
>     I have to make up several one-off extender boards for doing
repairs and
> calibration on gear that uses motherboard back planes on card cages.
>     So, in other words, I need boards that are complete no-brainers but
> which can run, say, 15" long and I do need them cut to shape.
>     Thanks . . .
>
>     Bill

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