Favourite parts with off-label uses?

[Chris Jones]

On 11/04/2020 10:50, Phil Hobbs wrote:

On 2020-04-10 18:41, Jeff Liebermann wrote:
On Thu, 9 Apr 2020 21:21:19 +1000, Chris Jones
lugnut808@spam.yahoo.com> wrote:

On 09/04/2020 14:56, Jeff Liebermann wrote:
The P2055DN is not what I would consider a good printer.

What is the best old HP printer?

Sigh.  Whenever I get into a printer discussion, someone always ask
that question.

A nice refurb 2300DTN is the ticket.

Cheers

Phil Hobbs

Thanks Jeff and Phil.

 

[Don Kuenz]

Gerhard Hoffmann wrote:

Am 12.04.20 um 07:05 schrieb dagmargoodboat@yahoo.com:
Lasse Langwadt Christensen wrote:
(and others)

so much about problems and possible solutions that my mailer
would reject the post for excessive quoting..



The more I read here, the more I'm convinced to stay with the
photochemical priciple. The boards are cleaner than one could
ever hope to clean them oneself, surfaces lapped and covered
with photo resist and then protection foil.

All one needs is a UV source (face tanner in my case), NaOH
as developper and stripper, the etchant, Na- or Ammonium-
persulfate and two sheets of glass to enforce direct contact
between the film and the board during exposure.

I can easily produce anything my laser printer can print, easily
down to 4 mil / 4 mil feature size with offset film.
The process takes less than an hour from the time I've printed
the film and is absolutely reproducible.

I use their board material:

https://www.bungard.de/shop/index.php/de/fotobeschichtetes-basismaterial

but not their machines. There must be similar offers on other
continents.

And yes, I also use PCBway and others when there is time and
willingness to deal with DHL and our customs office
who question the price of the boards on a regular base.
That cheap, absolutely impossible! Fraud!

It works best for me to avoid Deutsche Post, DHL, and Customs whenever
possible because it takes an inordinate amount of time for my orders to
arrive in America. And shipping costs from Germany to America are
typically sky high.

Anyhow, this website shows how to print PCBs on glossy laser paper and
then transfer the pattern to plain old copper boards with an electric
clothing iron:

http://buildaudioamps.com/make-pcbs/

Although the website uses ferric chloride, it ought be relatively easy
to substitute in persulfate. The hard part is preparing the copper board
beforehand.

Thank you,

--
Don Kuenz KB7RPU
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.

 

[George Herold]

On Saturday, April 11, 2020 at 5:38:40 PM UTC-4, Joe Gwinn wrote:

On Tue, 7 Apr 2020 07:55:27 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-04-06 21:35, jlarkin@highlandsniptechnology.com wrote:
On Mon, 6 Apr 2020 17:43:46 -0400, Phil Hobbs
[snip]

I guess the seive would soak up humidity and reduce the pressure
inside, so a tiny flow through the seals would introduce a little more
humidity. Wouldn't that eventually get to zero humidity and zero
pressure differential?

I guess atmospheric changes would still pump the system slightly.

Simon's the seal expert at this point. A sufficiently stiff box, with
enough screws holding the lid on, and hermetic connectors, ought to be
able to stay sealed pretty well. The pressure changes are nontrivial
though--our box is about 3 x 5 inches, so a 7% pressure change amounts
to about 15 pounds over the surface of the lid. They're also fairly
slow, so it doesn't take much of a leak rate to equalize the pressure.

We're using a cable gland rather than a hermetic connector, primarily
for cost reasons. I suspect that enough air will flow inside the cable
to manage the vent job, but we'll probably have to measure that to find out.

A traditional alternative is a long thin tube whose volume is
sufficient to ensure that no inside air gets out or outside air gets
in, despite the +/- 7% variation in ambient air pressure. Invented by
Louis Pasteur in 1859.

.<https://en.wikipedia.org/wiki/Swan_neck_flask


Joe Gwinn

Nice, I was trying to express this idea, but I was more focused on
keeping the length of the tube long to limit diffusion of the H2O.

George H.

 

On Sat, 11 Apr 2020 22:05:17 -0700 (PDT), dagmargoodboat@yahoo.com
wrote:

On Saturday, April 11, 2020 at 1:29:23 PM UTC-4, Lasse Langwadt Christensen wrote:
lřrdag den 11. april 2020 kl. 19.16.51 UTC+2 skrev dagmarg...@yahoo.com:
On Saturday, April 11, 2020 at 3:21:43 AM UTC-4, Clifford Heath wrote:
On 11/4/20 4:10 pm, dagmargoodboat@yahoo.com wrote:
On Saturday, April 11, 2020 at 1:00:09 AM UTC-4, dagmarg...@yahoo.com wrote:
On Friday, April 10, 2020 at 8:19:13 PM UTC-4, Clifford Heath wrote:
On 9/4/20 9:39 am, dagmargoodboat@yahoo.com wrote:
I haven't been able to get toner transfer working since I changed
toner carts. But I've dabbled with two promising variations.

1) If you lacquer-coat the PCB *then* transfer the toner, the
lacquer fills in the toner's pores.
James,

What exactly is the stuff that Americans call lacquer? That's not a term
that has a single meaning here.

I'm not completely sure. I believe it might be shellac, made from
actual shells of actual lac bugs? The important property here is
that it's alcohol-soluble. You might be able to vet local products
by checking the clean-up solvents spec'd.

This is what I tried & recommend --
https://www.homedepot.com/p/Rust-Oleum-Specialty-11-oz-Gloss-White-Lacquer-Spray-Paint-1904830/100163605

I recommend white, as contrasting brilliantly with the black toner.

It's easily removed with 90% isopropyl alcohol, leaving printer toner
completely unaffected. Toner scoffs at IPA.


Acrylic, thanks. I had no idea that IPA would attack it but not lift
toner. That's good to know, I'll give it a try. I'll have to find
suitable local products, as the ones you mention don't ship to Australia.

I think you missed a note in there -- they've changed the product.
The original (that worked) was shellac(?), but it has been changed
to a new formula that allegedly does not work as well.

Ammonia strips acrylic floor wax, so maybe it would strip an acrylic
undercoating, if acrylic is all we can get.

I don't know which Rust-Oleum formula I got. Whatever's in my
two-or-three-years-old can of the stuff works wonderfully. It wipes
off the open surfaces readily with 90% alcohol(*), but stays in the
toner's pores, sealing them.

(*) 50% IPA was unsatisfactory.

I could try shellac, I have some flakes here. It's intrinsically more
variable though, being a natural product; the water content and age are
factors in using it for French polish. And it doesn't come in a
convenient spray can.

The toner image is printed on the paper you peel off the back of
adhesive labels, or in my case, backing peeled off adhesive
shelf-liner paper from the one-dollar store.

I tried things like that but they were too slippery - bits of toner just
fell off before getting transferred. I'm using toner transfer paper
bought for the purpose.

I had that experience early on, years ago. But the current label-
backing type paper didn't have that problem. It's truly a godsend;
no more rubbing, soaking and peeling, hoping the toner sticks.

The paper I use has a significant starch (I think) content, and wets
really quickly - like 10 seconds before it comes off cleanly. The only
other relevant factor is how much it slows down the heat transfer in the
laminator; even after proper pre-warming I pass it through 2 or 3 times.

Transferring to a lacquer-coated board might be easier. The lacquer
is infinitely grabbier than even roughed up copper.

Good to know.


BACKING PAPER
This gent illustrates my joyous experience printing onto backing paper,
and the ease of transfer--the toner just comes right off, eliminating
a wet step. He uses the paper he peels off Arlon vinyl.
https://www.youtube.com/watch?v=haqP8xhsYas

These are the labels whose baking paper is salvaged and used by
the gentleman in the first of those YouTubes above--

Best PRINT half-sheet labels (1/2 page-sized labels)
https://www.amazon.com/Best-Print-200-Half-Sheet/dp/B0069RY9BY

The big lure of backing paper to me was eliminating the process
variations of thermally transferring toner to copper from paper.
The backing paper goes a long way toward accomplishing that. I
still have trouble getting adhesion to bare copper.


Overall, this ability to use two different resist coatings (toner and
lacquer) that dissolve in different solvents feels full of
promise & possibilities...

Well, after all, this is only for Saturday afternoon prototyping at RF.

Yes, exactly. I've designed a class-C HF QRP PA using CMOS gates
that might see first power this way. LTSpice says it's about 80%
efficient, ideally, from d.c. input power to 50-ohm load.

Other prototypes can be on assorted grid boards that don't provide a
ground plane, and anything more permanent can go through one of the many
quick-turn board houses.

A friend uses a modified record-player to spin photoresist onto boards,
and makes double-sided boards quite frequently, but the process took a
lot of work to perfect.

Yep. The dry photo resist film method looks easier than spincoating,
but I'd really like to _reduce_ the wet steps and process variables.
https://www.instructables.com/id/Photoresist-Dry-Film-a-New-Method-of-Applying-It-t/

There's something about knocking up a schematic in Kicad, laying it on a
board, and soldering it up an hour after you started. Sometimes the
magic flows and you want to try something *now*.

There sure is something magical about it and that's exactly why I do
it. It's liberating.

Frankly I'd still be using unmodified toner transfer if it hadn't
quit on me. Previously I was making 0.012" traces and spaces with ease.
I had no problems at all, worked every time without trouble, and I
wondered what everyone else was griping about. But once it quit,
no amount of fiddling has gotten it working again. Same papers,
same printer, same clothes iron, etc., but no joy.

My problem is getting the toner to adhere to the copper. I had the same
difficulty transferring thermally, and with the cold transfer (solvent)
methods that rely on making the toner sticky--the darn toner just won't
stick to the board. But I must say toner sticks very aggressively to a
sticky lacquered board, whether I use heat or solvents to soften the
lacquer and make it sticky.


tried a quick dip in etchant before the transfer?

a few seconds and the copper turns a more dull rough surface

Yes, thanks, I've tried a quick dip to roughen the copper surface,
but it didn't make any difference. It's mysterious.

When TT was working, I prepared the copper with fine steel wool,
then sometimes Comet (an abrasive kitchen cleaner with soap and bleach)
for de-greasing. I've the original method, rough sandpaper, fine
sandpaper, cross-hatching, and etching.

Cheers,
James Arthur

Soft Scrub is great, practically an optical grade abrasive. It makes
copper (or gold plated copper) all shiny without scratching.

I sometimes use a Scotchbrite pad with Softscrub to deburr and polish
dremel'd boards, but that does scratch the beautiful gold a bit.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[amdx]

On 4/12/2020 10:58 AM, Don Kuenz wrote:

Gerhard Hoffmann wrote:
Am 12.04.20 um 07:05 schrieb dagmargoodboat@yahoo.com:
Lasse Langwadt Christensen wrote:
(and others)

so much about problems and possible solutions that my mailer
would reject the post for excessive quoting..



The more I read here, the more I'm convinced to stay with the
photochemical priciple. The boards are cleaner than one could
ever hope to clean them oneself, surfaces lapped and covered
with photo resist and then protection foil.

All one needs is a UV source (face tanner in my case), NaOH
as developper and stripper, the etchant, Na- or Ammonium-
persulfate and two sheets of glass to enforce direct contact
between the film and the board during exposure.

I can easily produce anything my laser printer can print, easily
down to 4 mil / 4 mil feature size with offset film.
The process takes less than an hour from the time I've printed
the film and is absolutely reproducible.

I use their board material:

https://www.bungard.de/shop/index.php/de/fotobeschichtetes-basismaterial

but not their machines. There must be similar offers on other
continents.

And yes, I also use PCBway and others when there is time and
willingness to deal with DHL and our customs office
who question the price of the boards on a regular base.
That cheap, absolutely impossible! Fraud!

It works best for me to avoid Deutsche Post, DHL, and Customs whenever
possible because it takes an inordinate amount of time for my orders to
arrive in America. And shipping costs from Germany to America are
typically sky high.

Anyhow, this website shows how to print PCBs on glossy laser paper and
then transfer the pattern to plain old copper boards with an electric
clothing iron:

http://buildaudioamps.com/make-pcbs/

Although the website uses ferric chloride, it ought be relatively easy
to substitute in persulfate. The hard part is preparing the copper board
beforehand.

Thank you,

I found a youtube that showed Hydrogen peroxide and muratic acid (swim
pool variety), it work very well for me.
> https://www.youtube.com/results?search_query=Hydrogen+peroxide+and+muratic+acid+etching

Mikek

 

[Rich S]

On Wednesday, April 8, 2020 at 7:39:11 PM UTC-4, dagmarg...@yahoo.com wrote:

On Wednesday, April 8, 2020 at 7:20:56 PM UTC-4, Clifford Heath wrote:
On 8/4/20 10:22 pm, Gerhard Hoffmann wrote:
Am 08.04.20 um 05:51 schrieb Clifford Heath:
On 8/4/20 12:39 pm, Gerhard Hoffmann wrote:
Getting closer to saturation
than 20 dB will damage the crest ratio / noise statistics.
Right. Not sure what that will do to the spectrum though?

No idea. But a customer of mine had some problems with the
autocorrelation of pseudo-noise for ranging purposes. The measured > S-curve did not look so triangle-like as it was supposed to be.

We'll see how the resistor noise looks. I'm just worried that much
amplification will show the noise of the first ERA3, or power supply or
ambient noise that I haven't filtered or screened out.

I'm using 0805 resistors but not series inductors, for now. Will that
affect flatness (rather than just lose some gain)?

Pure resistance from high VCC is probably easier for the beginning.
Use smaller R in series, it's a matter of C over the resistor vs. C from
resistor to GND. You get predictability and spend VCC.

I could easily put a tiny wire loop inductor in series after the R, at
risk of coupling to the next stage and singing. That should help at GHz..

I had quite good success with home etching, it helps during the lock-down.

I had excellent success with toner transfer, handling 0.6mm pin-pitch
parts easily, when I was using my ancient HP LJ6L. That finally died,
and the replacement HP2055DN produces a porous checker-plate that's
visible only under magnification. I haven't worked out how to stop it
doing that, but the etchant gets through the tiny gaps, even if I use
the toner transfer foil. Perhaps I'll have another go at it, I've only
tried etching once (printing many times, but only one seemed good enough
to etch.

I haven't been able to get toner transfer working since I changed
toner carts. But I've dabbled with two promising variations.

1) If you lacquer-coat the PCB *then* transfer the toner, the
lacquer fills in the toner's pores. The lacquer itself, meanwhile,
can be easily removed with alcohol, but the toner's pores seem to
stay filled.

The toner image is printed on the paper you peel off the back of
adhesive labels, or in my case, backing peeled off adhesive
shelf-liner paper from the one-dollar store.

2) A variation of the above is to spray the lacquer, then transfer
the toner almost immediately, before the lacquer dries. The lacquer
itself grabs the toner.
https://www.youtube.com/watch?v=0dpCi9kgpuw

3) A third method is to zap the toner with acetone/alcohol mix to
make the toner tacky, then stick it to the board. That always
smears the traces when I try it. "Cold Toner Transfer"
e.g. https://www.youtube.com/watch?v=cVhSCEPINpM

Cheers,
James Arthur

Some tips, re: toner transfer method for making PCBs. Consumer-type laser printers are generally focused on producing sharp text, not graphics (like PCB patterns). Only some will be best for that. Based on visual judgments of printed fine detail by my fellow experts, I'd take a look at these color lasers:
HP Color Laserjet Pro MFP M177fw (HP 130 toner set), American and EU markets
HP Color Laserjet Pro MFP M476dw (HP 312 toner set), American model
Canon i-Sensys MF8230Cn (Canon 731 toner set), EU model
HP Color Laserjet Pro M452NW (HP 410 toner set), EU model
HP Color Laserjet Pro M477FDW (HP 410 toner set), EU model

Mono lasers we've tested have not done as well as color lasers for graphics.. Not that mono's couldn't in theory - perhaps the manufacturers assume people only care about text quality on these lower-cost models. Also make sure the setting in the printer driver are optimal: (1) "toner saving" feature turned off (2) heavy or high-quality mode turned on.

 

On Sat, 4 Apr 2020 17:49:18 -0700 (PDT), pcdhobbs@gmail.com wrote:

Following up on blocher's sterling work,(*)

Many of us use parts off-label, often very successfully. A few examples:

SAV-551+ pHEMTs make very good wideband bootstraps. Their f_max is around 12 GHz, but they're amazingly stable.

74HC4352s make good flying-capacitor diff amp front ends.

TMUX1511s make very nice analogue lock-ins--their Coff*Ron FOM is almost in a class with relays, but 1E5 times faster.

Zero-ohm jumpers have about the right resistance to stabilize LDO regulators with ceramic output caps. (It's good to be able to disconnect the supplies during bring-up, and putting the jumper between the reg and the output cap has this additional benefit.

Your faves?

Cheers

Phil Hobbs
(*) who may be bulegoge's good twin, given the similarity of their emails

An old TV HV rectifier tube, a 1B3 or whatever, makes a good
high-voltage capacitor.

It makes a good HV amplifier too, with the input being the filament
voltage. A little slow maybe. When I was a kid, I used to charge HV
oil caps from a neon sign transformer. A 1B3 was the controlled
rectifier to set the voltage, with a flashlight battery and a rheostat
(with a long insulated shaft and a knob) for the filament supply.

NE2 type neon lamps make good transient supressors, relaxation
oscillators, and noise sources.

PMTs have been used as random pulse sources, for example in radar
jammers.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[Ricky C]

On Sunday, April 12, 2020 at 6:03:01 PM UTC-4, Jasen Betts wrote:

On 2020-04-12, George Herold <ggherold@gmail.com> wrote:
On Saturday, April 11, 2020 at 5:38:40 PM UTC-4, Joe Gwinn wrote:
On Tue, 7 Apr 2020 07:55:27 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-04-06 21:35, jlarkin@highlandsniptechnology.com wrote:
On Mon, 6 Apr 2020 17:43:46 -0400, Phil Hobbs
[snip]

I guess the seive would soak up humidity and reduce the pressure
inside, so a tiny flow through the seals would introduce a little more
humidity. Wouldn't that eventually get to zero humidity and zero
pressure differential?

I guess atmospheric changes would still pump the system slightly.

Simon's the seal expert at this point. A sufficiently stiff box, with
enough screws holding the lid on, and hermetic connectors, ought to be
able to stay sealed pretty well. The pressure changes are nontrivial
though--our box is about 3 x 5 inches, so a 7% pressure change amounts
to about 15 pounds over the surface of the lid. They're also fairly
slow, so it doesn't take much of a leak rate to equalize the pressure..

We're using a cable gland rather than a hermetic connector, primarily
for cost reasons. I suspect that enough air will flow inside the cable
to manage the vent job, but we'll probably have to measure that to find out.

A traditional alternative is a long thin tube whose volume is
sufficient to ensure that no inside air gets out or outside air gets
in, despite the +/- 7% variation in ambient air pressure. Invented by
Louis Pasteur in 1859.

.<https://en.wikipedia.org/wiki/Swan_neck_flask


Joe Gwinn

Nice, I was trying to express this idea, but I was more focused on
keeping the length of the tube long to limit diffusion of the H2O.

George H.


With minimally vented or imperfectly sealed enclosure you have the
problem that if it gets splashed with cold water on a hot day it
cools rapdily and the air inside contracts and sucks surface water
in.

Using the cable to vent the enclosure seems like a good scheme,
assuming that air flows freely enough and it terminates in a dry
location.

Talking with hams it seems they never trust sealing to keep an enclosure free of moisture. After reading about a defect in a auto brake pressure switch impacting something else at the other end of the car I realized why. The pressure switch was sealed, but the switch itself developed a leak, not to the outside, but to the also enclosed space with the wire which wicked it into the spaces between the strands. The brake fluid was carried to the other end of the vehicle where it came in contact with something that it then messed up.

So if you have any insulated wires exiting a sealed enclosure, in the long term it is not sealed. I guess that's why they use those through the bulkhead solid pins to pass signals in and out of a sealed box.

--

Rick C.

-+- Get 1,000 miles of free Supercharging
-+- Tesla referral code - https://ts.la/richard11209

 

[Jasen Betts]

On 2020-04-12, George Herold <ggherold@gmail.com> wrote:

On Saturday, April 11, 2020 at 5:38:40 PM UTC-4, Joe Gwinn wrote:
On Tue, 7 Apr 2020 07:55:27 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-04-06 21:35, jlarkin@highlandsniptechnology.com wrote:
On Mon, 6 Apr 2020 17:43:46 -0400, Phil Hobbs
[snip]

I guess the seive would soak up humidity and reduce the pressure
inside, so a tiny flow through the seals would introduce a little more
humidity. Wouldn't that eventually get to zero humidity and zero
pressure differential?

I guess atmospheric changes would still pump the system slightly.

Simon's the seal expert at this point. A sufficiently stiff box, with
enough screws holding the lid on, and hermetic connectors, ought to be
able to stay sealed pretty well. The pressure changes are nontrivial
though--our box is about 3 x 5 inches, so a 7% pressure change amounts
to about 15 pounds over the surface of the lid. They're also fairly
slow, so it doesn't take much of a leak rate to equalize the pressure.

We're using a cable gland rather than a hermetic connector, primarily
for cost reasons. I suspect that enough air will flow inside the cable
to manage the vent job, but we'll probably have to measure that to find out.

A traditional alternative is a long thin tube whose volume is
sufficient to ensure that no inside air gets out or outside air gets
in, despite the +/- 7% variation in ambient air pressure. Invented by
Louis Pasteur in 1859.

.<https://en.wikipedia.org/wiki/Swan_neck_flask


Joe Gwinn

Nice, I was trying to express this idea, but I was more focused on
keeping the length of the tube long to limit diffusion of the H2O.

George H.

With minimally vented or imperfectly sealed enclosure you have the
problem that if it gets splashed with cold water on a hot day it
cools rapdily and the air inside contracts and sucks surface water
in.

Using the cable to vent the enclosure seems like a good scheme,
assuming that air flows freely enough and it terminates in a dry
location.

--
Jasen.

 

[Clifford Heath]

On 13/4/20 1:58 am, Don Kuenz wrote:

Gerhard Hoffmann wrote:
Am 12.04.20 um 07:05 schrieb dagmargoodboat@yahoo.com:
Lasse Langwadt Christensen wrote:
(and others)

so much about problems and possible solutions that my mailer
would reject the post for excessive quoting..



The more I read here, the more I'm convinced to stay with the
photochemical priciple. The boards are cleaner than one could
ever hope to clean them oneself, surfaces lapped and covered
with photo resist and then protection foil.

All one needs is a UV source (face tanner in my case), NaOH
as developper and stripper, the etchant, Na- or Ammonium-
persulfate and two sheets of glass to enforce direct contact
between the film and the board during exposure.

I can easily produce anything my laser printer can print, easily
down to 4 mil / 4 mil feature size with offset film.
The process takes less than an hour from the time I've printed
the film and is absolutely reproducible.

I use their board material:

https://www.bungard.de/shop/index.php/de/fotobeschichtetes-basismaterial

but not their machines. There must be similar offers on other
continents.

And yes, I also use PCBway and others when there is time and
willingness to deal with DHL and our customs office
who question the price of the boards on a regular base.
That cheap, absolutely impossible! Fraud!

It works best for me to avoid Deutsche Post, DHL, and Customs whenever
possible because it takes an inordinate amount of time for my orders to
arrive in America. And shipping costs from Germany to America are
typically sky high.

Anyhow, this website shows how to print PCBs on glossy laser paper and
then transfer the pattern to plain old copper boards with an electric
clothing iron:

http://buildaudioamps.com/make-pcbs/

Whoosh! Right back to just before where (this part of) the thread began.

It doesn't work if you don't get solid blacks from your laser printer.
It doesn't work the same for apparently equivalent papers - it takes a
lot of experiment to find one that works for you. There is paper that is
specified and sold for this specific purpose, and it works well.

There are many other things that have to go just right too. A clothes
iron is plagued with problems which is why I (and many others) use a
modified laminator. Much more controllable.

CH

 

On Sunday, April 12, 2020 at 3:58:04 PM UTC-4, Rich S wrote:

Some tips, re: toner transfer method for making PCBs. Consumer-type laser printers are generally focused on producing sharp text, not graphics (like PCB patterns). Only some will be best for that. Based on visual judgments of printed fine detail by my fellow experts, I'd take a look at these color lasers:
HP Color Laserjet Pro MFP M177fw (HP 130 toner set), American and EU markets
HP Color Laserjet Pro MFP M476dw (HP 312 toner set), American model
Canon i-Sensys MF8230Cn (Canon 731 toner set), EU model
HP Color Laserjet Pro M452NW (HP 410 toner set), EU model
HP Color Laserjet Pro M477FDW (HP 410 toner set), EU model

Mono lasers we've tested have not done as well as color lasers for graphics. Not that mono's couldn't in theory - perhaps the manufacturers assume people only care about text quality on these lower-cost models. Also make sure the setting in the printer driver are optimal: (1) "toner saving" feature turned off (2) heavy or high-quality mode turned on.

Thanks Rich.

My frustration was that I had a working setup, reliable, used for
a few years, that suddenly completely quit working for no apparent
reason. Other than moving all the equipment to a new location, I
was still using the same equipment, technique, and supplies.

So, I don't think it's the printer, though I experimented by changing
cartridges, nor the paper -- I'm using the same paper from the same
original pack -- and so forth.

Gerhard's probably right, the dry photoresist method is probably
best, but I've had poor luck, historically, with photo methods.

A list of good laser printers that make dense prints is a handy
thing for all these processes, thanks.

Cheers,
James Arthur

 

[Clifford Heath]

On 8/4/20 12:39 pm, Gerhard Hoffmann wrote:

Am 08.04.20 um 03:05 schrieb Clifford Heath:
On 7/4/20 11:03 pm, George Herold wrote:
On Monday, April 6, 2020 at 7:32:00 PM UTC-4, Clifford Heath wrote:
George, I'm trying to understand this. What do you need 20 zeners for?

FWIW, I'm currently making a broadband noise source for testing filters
up to 1.5GHz. Still scratching around for the best source to put before
a string of ERA-3 MMIC amplifiers.

The BFR93A data sheet says abs max Vbe is 2V, but it doesn't zener at
5V. Although avalanche zeners produce much more noise, I'd rather not
boost my 5V supply (though I might need to). I wonder how much reverse
current a microwave Shottky diodes (say HSMS-286) would survive. Abs
max
peak reverse voltage is 4V, so it might withstand 5V anyway...

Any better suggestions for a device I might have in the drawer already?

Clifford Heath.

Arghh!  typo. sorry a 20V zener!  Run near the knee you get these big
avalanche spikes, with ~1us rise/ fall times.

1 GHz noise sounds hard.

It doesn't look hard, a lot of people have done it. I've built the
amplifier, I just need a noise diode that will give me me 20db ENR or
better to feed into it. The only zeners I can easily get are 1W and
above, so have big capacitance, only good for audio. I need a
physically small device that will have low capacitance. That's why I
started with a GHz transistor.

I've thought about trying an HSMS286 series microwave Schottky, which
break down at about 4V (if the data sheet is to be believed). The
literature says that devices with a sharp breakdown curve last longer
- a soft curve indicates partial breakdown at the edge of the die,
which leads to early failure. So I'll need to evaluate the sharpness
of the breakdown to see if it's likely to last a while.

But first I'm going to crank the Vbe on this BFR93A to see where it
really breaks down. If I can get it to zener on w 12v supply, that'll
probably do.

I'd prefer not to need a higher supply voltage, but I might have to
compromise on that. Pure zener noise (low voltage) is much lower
amplitude than higher-voltage devices which have avalanche
multiplication.

I have done that thing with the BFR93A many years ago...

Today I would not use a "Zener" source. If you have them, spend
2 more ERAs and amplify the noise of a 50 Ohm resistor. Yes, they
have a noise figure of a few dB but you know it and it's flat.
More flat than a BFR93A breakdown, and much better than any
Z-diode with its huge capacitance. 1K may produce more voltage noise,
but @ 50 Ohms you know that the ERAs will behave.

Well I've done quite a bit of mucking around with 4 ERA-3's (96dB gain!)
and nothing I've tried will stop it from oscillating. Because I used
33nF coupling caps, with the 50R matched impedance it oscillates about
200-300kHz.

During the few occasions where it was well-behaved I got really nice
looking noise from the resistor source, with most of the density within
20mV of the origin, and a scope trace that barely changed in appearance
between 10ms/div right up to 5ns/div.

It was all looking pretty ok for a while actually, until I noticed some
noise spikes from the fan in my PSU getting to the output, so in
addition to the 220nF decoupling caps on each stage, I added a 10uF
aluminium electrolytic - and since I added that it takes off like a
rocket at any bias level above 15mA.

I had to reduce the bias current below the recommended 40mA, because the
maximum input level (13dBm) is just below the maximum output level
(13.6dBm), and when it oscillates at full power that was enough to blow
up MMIC 3&4 in the chain. Reduced current stopped them expiring, but
doesn't stop the oscillation.

I tried a small can over the first stage but suspect the feedback path
is on the board. An inductor in series with the first stage bias might help?

Pictures here (the noise is with the zener source):

<https://www.dropbox.com/sh/v9h6p7ajtvyllng/AAD9Y69UpRU1o1yMQgUuxMpxa?dl=0>

You can see I used generic grid-punch prototyping PCB, with adhesive
copper foil to make a ground plane on the back.

I think I'll just drop back to the zener source, two stages, and call it
done... unless someone else has a better idea?

Clifford Heath.

 

[Chris Jones]

On 13/04/2020 08:12, Ricky C wrote:

On Sunday, April 12, 2020 at 6:03:01 PM UTC-4, Jasen Betts wrote:
On 2020-04-12, George Herold <ggherold@gmail.com> wrote:
On Saturday, April 11, 2020 at 5:38:40 PM UTC-4, Joe Gwinn wrote:
On Tue, 7 Apr 2020 07:55:27 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-04-06 21:35, jlarkin@highlandsniptechnology.com wrote:
On Mon, 6 Apr 2020 17:43:46 -0400, Phil Hobbs
[snip]

I guess the seive would soak up humidity and reduce the pressure
inside, so a tiny flow through the seals would introduce a little more
humidity. Wouldn't that eventually get to zero humidity and zero
pressure differential?

I guess atmospheric changes would still pump the system slightly.

Simon's the seal expert at this point. A sufficiently stiff box, with
enough screws holding the lid on, and hermetic connectors, ought to be
able to stay sealed pretty well. The pressure changes are nontrivial
though--our box is about 3 x 5 inches, so a 7% pressure change amounts
to about 15 pounds over the surface of the lid. They're also fairly
slow, so it doesn't take much of a leak rate to equalize the pressure.

We're using a cable gland rather than a hermetic connector, primarily
for cost reasons. I suspect that enough air will flow inside the cable
to manage the vent job, but we'll probably have to measure that to find out.

A traditional alternative is a long thin tube whose volume is
sufficient to ensure that no inside air gets out or outside air gets
in, despite the +/- 7% variation in ambient air pressure. Invented by
Louis Pasteur in 1859.

.<https://en.wikipedia.org/wiki/Swan_neck_flask


Joe Gwinn

Nice, I was trying to express this idea, but I was more focused on
keeping the length of the tube long to limit diffusion of the H2O.

George H.


With minimally vented or imperfectly sealed enclosure you have the
problem that if it gets splashed with cold water on a hot day it
cools rapdily and the air inside contracts and sucks surface water
in.

Using the cable to vent the enclosure seems like a good scheme,
assuming that air flows freely enough and it terminates in a dry
location.

Talking with hams it seems they never trust sealing to keep an enclosure free of moisture. After reading about a defect in a auto brake pressure switch impacting something else at the other end of the car I realized why. The pressure switch was sealed, but the switch itself developed a leak, not to the outside, but to the also enclosed space with the wire which wicked it into the spaces between the strands. The brake fluid was carried to the other end of the vehicle where it came in contact with something that it then messed up.

So if you have any insulated wires exiting a sealed enclosure, in the long term it is not sealed. I guess that's why they use those through the bulkhead solid pins to pass signals in and out of a sealed box.

You can get cable with all of the spaces between the strands etc. filled
not with air, but with some sort of gel. Very messy but probably
worthwhile if you need a cable to be buried and want it to stay free of
liquid water.

 

[Phil Hobbs]

On 2020-04-04 20:49, pcdhobbs@gmail.com wrote:

Following up on blocher's sterling work,(*)

Many of us use parts off-label, often very successfully. A few examples:

SAV-551+ pHEMTs make very good wideband bootstraps. Their f_max is around 12 GHz, but they're amazingly stable.

74HC4352s make good flying-capacitor diff amp front ends.

TMUX1511s make very nice analogue lock-ins--their Coff*Ron FOM is almost in a class with relays, but 1E5 times faster.

Zero-ohm jumpers have about the right resistance to stabilize LDO regulators with ceramic output caps. (It's good to be able to disconnect the supplies during bring-up, and putting the jumper between the reg and the output cap has this additional benefit.

Your faves?

Back when there were more analogue RF building-block chips available, I
used to get about 40X speedup by cascoding their RSSI current outputs.

I made an interesting lidar-style 3D scanner that way, using
current-tuning of a diode laser plus a diffraction-grating gizmo to
provide both a fast fine scan (20 pixels worth) and a triangle-wave FM
waveform.
The tri wave lets you measure both time-of-flight and Doppler, because
their frequency offsets add on one slope and subtract on the other.

In lots of situations you can get excellent results by connecting a
photodiode directly to the input of an MMIC amp with no coupling cap.
The input is usually within a factor of 2 of 50 ohms, and the noise
temperature may be as low as 100K.

Cascoding a solar cell can get you up to about 100 kHz bandwidth with
unbeatable detection area and good linearity at high current.

Gate drivers are good for running small Cockroft-Walton generators for
PMTs or APDs.

Some depletion pHEMTs will self-bias with the gate below the source, so
you can use them with no bias resistors. For the lowest-noise
applications, that saves some input capacitance, which helps. (You
can't get them anymore, unfortunately.)

The monitor photodiode of a diode laser can be used as a temperature
sensor--it's brazed to the same header as the laser, so it's super fast.

A quadrant photodiode will give a nice beam position indicator that's
independent of the laser power if you just add and subtract diagonally
opposite pairs of open circuit voltages.

1 | 2
-----
3 | 4

X = (1-4) - (2-3)
Y = (1-4) + (2-3)


Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

On Mon, 13 Apr 2020 11:34:41 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-04-04 20:49, pcdhobbs@gmail.com wrote:
Following up on blocher's sterling work,(*)

Many of us use parts off-label, often very successfully. A few examples:

SAV-551+ pHEMTs make very good wideband bootstraps. Their f_max is around 12 GHz, but they're amazingly stable.

74HC4352s make good flying-capacitor diff amp front ends.

TMUX1511s make very nice analogue lock-ins--their Coff*Ron FOM is almost in a class with relays, but 1E5 times faster.

Zero-ohm jumpers have about the right resistance to stabilize LDO regulators with ceramic output caps. (It's good to be able to disconnect the supplies during bring-up, and putting the jumper between the reg and the output cap has this additional benefit.

Your faves?

Back when there were more analogue RF building-block chips available, I
used to get about 40X speedup by cascoding their RSSI current outputs.

I made an interesting lidar-style 3D scanner that way, using
current-tuning of a diode laser plus a diffraction-grating gizmo to
provide both a fast fine scan (20 pixels worth) and a triangle-wave FM
waveform.
The tri wave lets you measure both time-of-flight and Doppler, because
their frequency offsets add on one slope and subtract on the other.

WWII vintage bomber radio altimeters worked that way. Send a CW
carrier that's triangle FM modulated, and mix the transmit and ground
echo signals. The beat frequency is proportional to altitude.

In lots of situations you can get excellent results by connecting a
photodiode directly to the input of an MMIC amp with no coupling cap.
The input is usually within a factor of 2 of 50 ohms, and the noise
temperature may be as low as 100K.

I just did that in my new GHz o/e converter. The DC behavior of the
MMIC is dreadful, so I have a separate low-frequency gain path to get
clean DC-coupled step response.

MMICs have a lot of personality. You've got to test them to find out
what. And hope MiniCircuits doesn't switch fabs.





--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[Clifford Heath]

On 13/4/20 4:25 pm, Clifford Heath wrote:

On 8/4/20 12:39 pm, Gerhard Hoffmann wrote:
Am 08.04.20 um 03:05 schrieb Clifford Heath:
On 7/4/20 11:03 pm, George Herold wrote:
On Monday, April 6, 2020 at 7:32:00 PM UTC-4, Clifford Heath wrote:
George, I'm trying to understand this. What do you need 20 zeners for?

FWIW, I'm currently making a broadband noise source for testing
filters
up to 1.5GHz. Still scratching around for the best source to put
before
a string of ERA-3 MMIC amplifiers.

The BFR93A data sheet says abs max Vbe is 2V, but it doesn't zener at
5V. Although avalanche zeners produce much more noise, I'd rather not
boost my 5V supply (though I might need to). I wonder how much reverse
current a microwave Shottky diodes (say HSMS-286) would survive.
Abs max
peak reverse voltage is 4V, so it might withstand 5V anyway...

Any better suggestions for a device I might have in the drawer
already?

Clifford Heath.

Arghh!  typo. sorry a 20V zener!  Run near the knee you get these big
avalanche spikes, with ~1us rise/ fall times.

1 GHz noise sounds hard.

It doesn't look hard, a lot of people have done it. I've built the
amplifier, I just need a noise diode that will give me me 20db ENR or
better to feed into it. The only zeners I can easily get are 1W and
above, so have big capacitance, only good for audio. I need a
physically small device that will have low capacitance. That's why I
started with a GHz transistor.

I've thought about trying an HSMS286 series microwave Schottky, which
break down at about 4V (if the data sheet is to be believed). The
literature says that devices with a sharp breakdown curve last longer
- a soft curve indicates partial breakdown at the edge of the die,
which leads to early failure. So I'll need to evaluate the sharpness
of the breakdown to see if it's likely to last a while.

But first I'm going to crank the Vbe on this BFR93A to see where it
really breaks down. If I can get it to zener on w 12v supply, that'll
probably do.

I'd prefer not to need a higher supply voltage, but I might have to
compromise on that. Pure zener noise (low voltage) is much lower
amplitude than higher-voltage devices which have avalanche
multiplication.

I have done that thing with the BFR93A many years ago...

Today I would not use a "Zener" source. If you have them, spend
2 more ERAs and amplify the noise of a 50 Ohm resistor. Yes, they
have a noise figure of a few dB but you know it and it's flat.
More flat than a BFR93A breakdown, and much better than any
Z-diode with its huge capacitance. 1K may produce more voltage noise,
but @ 50 Ohms you know that the ERAs will behave.

Well I've done quite a bit of mucking around with 4 ERA-3's (96dB gain!)
and nothing I've tried will stop it from oscillating.

Oh never mind. It just needed (much) better supply decoupling at the
sensitive end. Working a treat now. Spectrum analysis next.

Clifford Heath.

 

[Phil Allison]

jla...@highlandsniptechnology.com wrote:

---------------------------------------

WWII vintage bomber radio altimeters worked that way.

** Few WW2 bombers ever had them.

Only useful at low altitudes as a blind landing aid.

Also for deck landings, which did not involve bombers.



..... Phil

 

понедельник, 13 апреля 2020 г., 18:34:49 UTC+3 пользователь Phil Hobbs написал:

A quadrant photodiode will give a nice beam position indicator that's
independent of the laser power if you just add and subtract diagonally
opposite pairs of open circuit voltages.

1 | 2
-----
3 | 4

X = (1-4) - (2-3)
Y = (1-4) + (2-3)

Erratum ?

INA330 with current output in simple PID controlled TEC (TO-8)
http://ixbt.photo/?id=photo:1337088


Internal gate-source zener FDV301N in zerocross detector 100Hz
http://ixbt.photo/?id=photo:1097722
http://ixbt.photo/?id=photo:748178

 

[Tauno Voipio]

On 13.4.20 18:58, jlarkin@highlandsniptechnology.com wrote:

WWII vintage bomber radio altimeters worked that way. Send a CW
carrier that's triangle FM modulated, and mix the transmit and ground
echo signals. The beat frequency is proportional to altitude.

That is how the airliner radio altimeters still work.

--

-TV

 

Tauno Voipio <tauno.voipio@notused.fi.invalid> wrote in
news:r7505i$5on$1@dont-email.me:

On 13.4.20 18:58, jlarkin@highlandsniptechnology.com wrote:

WWII vintage bomber radio altimeters worked that way. Send a CW
carrier that's triangle FM modulated, and mix the transmit and
ground echo signals. The beat frequency is proportional to
altitude.


That is how the airliner radio altimeters still work.

Marker beacons are similar but very nearly outmoded by GPS.

<https://en.wikipedia.org/wiki/Marker_beacon>

They have a sound of each indicator. Pretty cool.