Recent Posts

1

Beginners / Re: First PCB - how does it look?

« Last post by ataradov on Today at 11:47:45 pm »

There is no ground pour. All your components are just hanging in the air. EDIT: I see your comment about the ground. Well, the ground is basically the most important part with voltage regulators and similar power-related devices.
 
Instead of those pointlessly thick traces, move capacitors as close to the IC pins as possible.

The datasheet has recommended PCB layout. Yours is not even close.

2

General Technical Chat / Re: new propellantless drive company

« Last post by m98 on Today at 11:45:33 pm »

The physics sound whacky, and I can say that nobody in the EP community is taking any of this seriously. That said, I'm looking forward to Martin Tajmar getting bored again and trying this out.

3

Test Equipment / HP 16700 PSU in 230V region woes

« Last post by FrodeM on Today at 11:45:06 pm »

Have anyone here experienced problems with the power-supply of the HP 16700 logic analyzer blowing up when running in 230V regions? I am in particular thinking of the Celestica 7000 variety, which does claim to handle 230V just fine but I have had two blow on me so far.

The first time it was the switcher for the standby power source. An all-in-one TOP227Y switch mode regulator in a single TO-220 package. This blew quite violently, taking out a whole trace on the PCB, some resistors in its path, as well as D7.

For the second one , it was a small 8-pin chip, probably part of the main regulator. Fortunately, not as violently and this far I only found D7 as the only other part that has blown.

Is it just me, or does this PSU have really slim margins?

Some notes on the design. I plan to fix the second one with parts from the first one, and I'm in the process of drawing up a schematics as a consequence. I now see that the main board of the PSU uses a charge-pump type of design, instead of switching a transformer. That explains why D7 is very prone to damage: it's the main boost converter diode. All current driving the unit passes through it, and with 230V mains it is natural that the flyback suges it needs to pass will peak harder.

Does anyone else have similar experience with these supplies?

4

Projects, Designs, and Technical Stuff / Re: Nichicon UPJ for switching power supplies - what's so special about these caps?

« Last post by wraper on Today at 11:43:35 pm »

Then there's "audio grade"...

Ideally suited for first class audio equipment where qualitative and quantitative
comfortableness is required.

https://www.mouser.com/datasheet/2/293/e_ukz-1513448.pdf

Stupid tax grade.

5

Projects, Designs, and Technical Stuff / Re: Nichicon UPJ for switching power supplies - what's so special about these caps?

« Last post by bdunham7 on Today at 11:38:31 pm »

Or "automotive" grade is another one, it meets automotive spec (wide temperatures, reliable, etc.) but you can freely use it for other designs.

Then there's "audio grade"...

Ideally suited for first class audio equipment where qualitative and quantitative
comfortableness is required.

https://www.mouser.com/datasheet/2/293/e_ukz-1513448.pdf

So many people love Nichicon for whatever reason, but they had capacitor failures in the plague times just like the cheap brands.  And they have a high degree of market wankery.  They're not my go-to brand at all.

6

Manufacturing & Assembly / Re: LPKF Protomat S42: Machine "shock absorber"/"stroke limiter" tuning

« Last post by DiodeDipShit on Today at 11:30:49 pm »

The bumpers are there to prevent shock to the drive motors in case of over limit travel.  The machine should never get to close the the bumpers. It seems that Your tool bit may be the wrong length. Try holding the a tool slightly further out of the collet/holder then tighten. Be cautious as You could drive right through Your work and into the table. Make sure the 'Z' start is above Your work and the 'z' feed is reasonable, 5-10 inches per minute.  Protomat may have proprietary bits and You are coming up short. Contact them for new tooling or look in McMaster-Carr for equivalent length carbide bits and adjust Your 'Z' depth accordingly in the program. The machine should never get to close the the bumpers. There are parameters in the bios that set travel limits. These are hard to find in the general program. If in doubt, read the Program manual thoroughly. Then read it again. Also second hand generic software is OK, but can leave out many options.
This is the link for the software for the machine: https://app.lpkfusa.com/products/pcb_prototyping/software/circuitpro_pm/

7

Manufacturing & Assembly / Re: Source for small "potting boxes"??.....

« Last post by Smokey on Today at 11:29:40 pm »

https://www.polycase.com/potting-box
https://www.budind.com/series/general-use-boxes/potting-box-style-b-series-2/#group=series-products&external_dimensions_group=0&internal_dimensions=0
https://www.ionnic.com/electrical/wiring-accessories/enclosures-1118/potting-box.html

https://www.alibaba.com/product-detail/Case-for-Negative-Ion-Generator-Module_1601044423197.html
https://www.alibaba.com/product-detail/Negative-ion-Generator-Modules-Plastic-Housing_1601044289977.html

Winner!  Obviously they are listed as "Negative Ion Generator Modules"!  How the hell did you find that?

8

Projects, Designs, and Technical Stuff / Re: Nichicon UPJ for switching power supplies - what's so special about these caps?

« Last post by thm_w on Today at 11:27:15 pm »

I was curious if there was a specific characteristic of the UPJ that made it particularly suitable for switching power supplies, and whether that would imply a tradeoff to using the same caps in other applications. It sounds like it may be just marketing. Would love to hear from someone at Nichicon regarding this but they have ignored my request.

Its reasonably well explained at the top of the datasheet: https://www.nichicon.co.jp/english/series_items/catalog_pdf/e-upj.pdf
- Low impedance and high reliability withstanding 5000 hours load life at +105˚C (3000 hours for smaller case sizes as specified below).
- Ideally suited for use of switching power supplies.

But yes, these topline quotes are generally marketing focused. If you see an opamp that says "for oscilloscopes" that doesn't mean you can't use it elsewhere, just means it has some properties that are useful in that specific scenario. Or "automotive" grade is another one, it meets automotive spec (wide temperatures, reliable, etc.) but you can freely use it for other designs.

9

General Technical Chat / Re: $20,000 dollars of software or licences on a thumbdrive ?

« Last post by abeyer on Today at 11:26:28 pm »

If you are carrying around $20k on a single drive, with no backup image copy, on at least 2 other media, you are not doing it correctly.

... or you're doing it so right that $20k isn't worth your time to be bothered over.

10

Projects, Designs, and Technical Stuff / Re: Small and inexpensive direct thermal printer to print labels

« Last post by abeyer on Today at 11:23:38 pm »

I don't know of anything intended to be integrated into another product... though would be interested to see if you find something. Also, I think you can do labels in many of the "receipt" printers if you find label rolls the right size, and that narrow width works for what you need.

If you go with an off the shelf product and just do the integration, Zebra as mentioned, or Brother would be where I'd look.