Recent Posts

1

Test Equipment / Re: LCR Tweezer Fnirsi ST1 vs. Zoyi MD1

« Last post by Aldo22 on Today at 10:35:41 pm »

The first two look okay based on Figure 4, but the MD1 looks high looking at Figure 3. 60µA looks like it should be 475mV...but whether that's off because the MD1 isn't great, or because of ambient temperature is another question. Was it -25C while testing? 😉

I don't know that. It could be that the hand warms it up.
But maybe I measured it wrong.
The MD1 uses sine waves to measure diodes.
I'll have another look tomorrow.

2

Metrology / Re: 3458a and usage of guarding and the guard switch

« Last post by julian1 on Today at 10:34:04 pm »

Good eyesight. 

p57 suggests W1(1) is floating, to create an Open switch position
Probably GRD_LO is 'guard common' coming from the input terminal mux switch.

But what is the purpose of CR003 - a 6.2V diode (zener?) to ground.
How does the diode make sense when the max input voltage limits are much higher?

Perhaps to rectify CM voltages, so they are always positive wrt gnd/PE ?. 

3

Repair / Re: GW Instek MSO-2204EA Backlight Bleed - Solution request.

« Last post by wraper on Today at 10:33:11 pm »

IMHO either don't bother with it, or order a new display. Should be some off the shelf display that is likely available on aliexpress. If you decide to take the display apart, be ready it may be destroyed in the process. At least ensure that you can buy a replacement before doing anything with it.

4

Projects, Designs, and Technical Stuff / Re: Edge Detection

« Last post by Someone on Today at 10:27:05 pm »

Yes with MCU I can do it right away, but I can not use Microcontroler for this project only digital IC.

555 is analog, potentiometer is analog... only digital is very hard in comparison.

5

Projects, Designs, and Technical Stuff / Suggestions and guidelines for DIY test fixture for high densidty PCB

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

Hi,
I am designing a high density PCB (to the point of using 0402) and will also be designing and building a DIY test fixture (don't yet know the mechanical architecture yet - any suggestions also welcome!!) for it to use during development and also initial production testing and programming.

I am wondering about the following (any suggestions/tips) considering the test fixture will be DIY:
- smallest test pads size that still allows to use not too expensive probes
- preferred grid spacing to allow a relatively decent density while also make it not too difficult to assemble by hand (never done it before)
- any suggestions on the probes types (round tip, cone tip, different bodies perhaps) and a preferred or common brand/UK-distributor

Thank you

6

Projects, Designs, and Technical Stuff / Re: UK broadband... 3 of 5 copper wires cut resulted in decreased bandwidth...?

« Last post by Postal2 on Today at 10:23:40 pm »

... while the two for the comms are stranded.

If only one pair is twisted - of course it is broadband. I was mistaken, thinking that the Internet is delivered to you and your neighbor, and the router is hidden somewhere.

7

Repair / Re: GW Instek MSO-2204EA Backlight Bleed - Solution request.

« Last post by nctnico on Today at 10:18:40 pm »

Is the protective film still on the screen? TFT displays always have a protective film and many manufacturers leave it up to the user to remove it.

8

Projects, Designs, and Technical Stuff / Re: UK broadband... 3 of 5 copper wires cut resulted in decreased bandwidth...?

« Last post by ricko_uk on Today at 10:16:42 pm »

Thank you, I will try to do that.

What I also noticed is that the other 3 wires are all solid steel (someone might have mentioned it here too and it makes sense if they are for structural strength), while the two for the comms are stranded.

9

Test Equipment / Re: NEW Fluke 87-VI Multimeter

« Last post by BeBuLamar on Today at 10:15:30 pm »

Price of 87V today is also cretinously high.

Big corporation and government contract pricing. 

They simply aren't worth it if you can get hold of a Brymen.

Even the famous warranty doesn't mean much when you can buy three Brymens for the price of one Fluke.

I had the original 87 bought in 1988. It had bad display and so I had them fixed it in the mid 90's under warranty. Until 2004 it once again had bad display and I sent it in they don't fix it any more. So the lifetime warranty doesn't cover their or my lifetime.

10

Beginners / Amscope trinocular microscope and Eakins camera issues

« Last post by newtekuser on Today at 10:12:28 pm »

I recently purchased an Eakins camera for my Amscope trinocular off Aliexpress, it's the one with the IMX386 sensor. The problem I have with it is that the image it gives is only usable when the DUT is really close up to the scope lens (I have a Barlow lens attached). This is not optimal:

1. I can't do any work on the DUT when it's so up close
2. The image is very zoomed and can't see a lot of the work area
3. I need to raise the DUT very close to the microscope lens with a stand (using a cardboard box for now)

Do I need to add a reduction lens to the camera? https://www.amazon.com/OMAX-0-5X-Reduction-Microscope-Camera/dp/B00FG89IZO/ref=sr_1_21?crid=2R6GJZXLJS69T&dib=eyJ2IjoiMSJ9.vH-2BvgIXdTkk2uvtRxQdRlPfTdieko7tqxMNvvDtX3GjHj071QN20LucGBJIEps.UP4so_2F2kYCXlaKndWxOMxxUgN6DlPXEuYjgKit4RE&dib_tag=se&keywords=microscope+camera+lens&qid=1726784119&sprefix=microscope+camera+len%2Caps%2C193&sr=8-21