Recent Posts

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Projects, Designs, and Technical Stuff / PC74hct4046ap Replacement

« Last post by dj_holmes on Today at 10:56:13 pm »

Hi,

first I'm way over my expertise when it comes to this. I've read a few posts from here and I knew the clever members have a much better understand that I ever will and I would appreciate some advice.

I have this Digital to analogue converter with this Philips PC74hct4046ap, everyone says its rubbish and even one member talked about modern equivelants. I'm looking for less jitter or something to tray to reduce it as its directly affecting the sound quality. I've attached a schematic of where it goes.

Thank you in advance

2

General Technical Chat / Re: A serious (as in not troll) requestfor help w/ultrasonic transducer

« Last post by watchmaker on Today at 10:55:25 pm »

i will look him up.

The workers who made parts were not considered craftsmen.  They worked in their homes and in the UK and in that period interior lighting was highly dependent on the sun, and daylight hours are more limited than in most of the USA.  This fact even draws into question many battle accounts, especially in Scotland which is even further north.

A lot of work (such as making fusee chains; 1/100th scale bicycle chains) was poor house work.

In chronometers, a "maker" such as Mercer would make the rounds and collect screws, detents, pinions, jewels wetc from people who had no idea what the parts they made were to be used in.  Then the parts would be assembled and finished into a working chronometer.  The "art" was all in the balance assembly and balance spring.  It could take a year before it was ready for trials at Kew.

Early on, jewel making was a national secret.  I think it held for 25 years or so.

3

Repair / Re: JBC SL-2300

« Last post by fzabkar on Today at 10:54:40 pm »

According to the exploded diagram on page 12 of the user manual, it would appear that this station has no stepdown transformer. Therefore, the heating element must be controlled via a TRIAC. I would think that you would need to measure the heater voltage with an RMS voltmeter.

Page 13 identifies the part numbers of the individual components of the handpiece.

https://www.jbctools.com/pdf/manual_SL2300.pdf

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Projects, Designs, and Technical Stuff / Re: Rigol DHO804 Stand alone remoting application

« Last post by moffy on Today at 10:54:08 pm »

Thanks for the application.

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Projects, Designs, and Technical Stuff / Re: Arduino Stand Alone Programmer

« Last post by PCB.Wiz on Today at 10:52:43 pm »

I have been looking to see if it's possible to program Arduino boards without the use of a computer. Just wondered if anyone has tried that or if it is just not feasible

MCU vendors do offer off-line programmers.
STC and Nuvoton are two examples, and these typically have Serial Flash that is loaded with your binary, and then a PGM button can update MCUs without 
needing PC connections.
Field use and production line programming are common uses.

If your code is only small (uses < 75% of the ardunio), you could use any ardunio to copy a block of its own memory to a programming port.
If you want to pgm 100% of code area, you will need some external flash/eprom/etc memory to copy from.

6

Beginners / Re: Convert US standard 115V to International 230V

« Last post by IanB on Today at 10:42:07 pm »

I'm afraid that such approach is not acceptable for safety critical devices development because it don't guarantee that device will never consume more power under some specific conditions.

Undefined/unspecified behavior of device is not acceptable because it is unpredictable and can make harm to the patient. This is uncontrolled potentially life threatening risks for the patient and it's presence shows serious issue in validation/verification process and broken quality management system. 

The above two statements are in contradiction with each other. Either you can specify the designed behavior, or you cannot. If you specify the behavior, then you cannot also say, "but this is unacceptable, because it may behave in ways other than those specified".

7

Manufacturing & Assembly / Re: Vacuum Pick-Up Tool for Rework (Includes video of my own design)

« Last post by Doctorandus_P on Today at 10:34:39 pm »

Has anyone come across any decent pick-up tool for components?

Use the magic words "luer lock". This is the fitting used between needles and syringes. It's very popular in hospitals, but also used for dispensing solder paste, glues, and all sorts of other liquids. You can buy both straight or bent needles for very little money, and the rest can easily be made from parts lying around. (Except for the vacuum pump).

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Power/Renewable Energy/EV's / Re: Output Capacitor Selection for Buck Converter

« Last post by uer166 on Today at 10:33:50 pm »

, and fired me ....

Are you 10000% sure it was because of that issue, and that issue only?

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Manufacturing & Assembly / Re: AXI (xray inspection) licencing / regulatory requirments in Australia

« Last post by loki42 on Today at 10:31:40 pm »

Hah,  yeah the whole x ray part of it sounds a bit hectic. Lucky the machine had all the shielding etc.  Though I'm much less nervous about buying used optical gear! 

The fault finding capabilities does look very impressive compared to 3d AOI but I'd be keen to hear actual user opinions instead of marketing.  I chatted to Oritech (local support) and they also told me new prices...

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Projects, Designs, and Technical Stuff / Re: How is a motor run capacitor sized?

« Last post by bdunham7 on Today at 10:26:37 pm »

electrolytic.

That certainly looks like an NP electro to me.  They probably used a 150V one to get a high enough current rating.

https://www.cde.com/resources/catalogs/BPA.pdf