Recent Posts

1

Test Equipment / Re: Recommendations on Logic Analyser for embedded debugging

« Last post by pcprogrammer on Today at 01:33:28 pm »

OP mentions Aliexpress, so here is a cheap one: https://nl.aliexpress.com/item/1005006375064581.html

Plenty of these to be found there from different stores for around 5 bucks. Works with sigrok or when you don't mind pirating the saleae software.

Not sure if they can be used in parallel. Only have one of them so can't try it. Should not be a problem USB wise, but the software has to support it.

For looking at old computers 32 channels would be the best for scoping all the signals, but 16 is probably the minimum to be any useful. (8 data, 16 address, leaving 8 for control signals)

2

General Technical Chat / Re: What is this 8-knobbed IBM human interface device in a 1980's Boeing photo?

« Last post by Alex Eisenhut on Today at 01:33:28 pm »

I don't know if youtube checks google searches and it somehow knew to queue up this in my recommendations ...
https://youtu.be/J_Q-wjRxAYs?t=589

3

Projects, Designs, and Technical Stuff / Re: Homebrew Lock-In Amplifier

« Last post by Picuino on Today at 01:29:26 pm »

The measures shows lower noise:

Code: [Select]

MEASURE_TIME = 0.99
SAMPLES_PER_LEVEL = 40
LEVELS_PER_MEASURE = 222
21.09 mOhm
21.10 mOhm
21.06 mOhm
20.98 mOhm
20.99 mOhm
20.98 mOhm
21.11 mOhm
21.00 mOhm
21.01 mOhm
21.00 mOhm
21.03 mOhm
21.04 mOhm
21.06 mOhm
20.99 mOhm
21.04 mOhm
20.98 mOhm
21.00 mOhm
21.11 mOhm
21.06 mOhm
21.04 mOhm
20.99 mOhm
21.02 mOhm
21.06 mOhm
21.07 mOhm
21.04 mOhm
21.10 mOhm
21.08 mOhm
21.10 mOhm
20.98 mOhm
21.12 mOhm
21.02 mOhm
21.08 mOhm

EDIT:
Conclusion: the position of the gain resistor R1 is critical. Keep the resistor as close as possible to the integrated and free of noise.

4

Test Equipment / Re: Siglent SDS2000X HD, 12bit, 2GSa/s high definition oscilloscope serie.

« Last post by 2N3055 on Today at 01:27:38 pm »

Dear Forum,

I wondering if is there any way to display in the bode plot the frequecy axis logarithmic, i saw pictures on the internet with other siglent scopes and it was logarithmic. I it in this scope only like this ?

Not at the moment on last 1.2.2.5 FW

5

Altium Designer / Re: Altium questions

« Last post by PlainName on Today at 01:25:18 pm »

A screenshot might explain the issue many, many times more succinctly than how you've tried to describe it.

6

Vintage Computing / Looking for a Driver for S**Di** e270

« Last post by simon christo on Today at 01:25:00 pm »

Does anybody have the Windows Driver for this 6GB USB Stick -with screen ??

It's the one, with a up to 2GB SD card slot.

Tah, Simon.

7

Beginners / Re: Should I throw away CRT TV's PCB which has damaged soldering point?

« Last post by Gyro on Today at 01:23:48 pm »

All of the threads that you have started on the forum have been related to repairing this TV. From reading through them, I have the feeling that, although you are trying to learn and do things properly, you are out of your depth. I am worried about your safety.

Regarding the PCB, as CaptDon says, the STR-S6707 PSU IC is probably blown and maybe other parts too, but I think you expected this. To be able to replace it in the PCB, you need to determine whether you can safely remove all of the evaporated metal from the large spark that has now been deposited on the surface. After ensuring that ALL capacitors are safely discharged, you need to use cotton buds and Isoropyl Alcohol (IPA) to scrub the surface of the PCB to try to remove it. If you can restore it to the point of shiny green solder resist then it is probably safe to re-use. If there is any material burnt into the surface, then not.

Please be more careful.

8

Projects, Designs, and Technical Stuff / Re: Homebrew Lock-In Amplifier

« Last post by Picuino on Today at 01:23:07 pm »

I have changed the position of the gain resistor so that it is as close to the circuit as possible.
Now the noise has decreased quite a bit.


Instrumentation amplifier output = 2200 uVAC   (Gain = 1050)

9

Repair / Re: Brother MFC-8860DN repair attempt: "paper tray not detected"

« Last post by PA0PBZ on Today at 01:21:12 pm »

Sorry that this didn't help. Can you set the machine in Maintenance 32 on the "C1P1C2P2....." line and see if the sensors actually work or not? For instance remove the paper and see if "P1" changes. You also mentioned that before total failure you could make it work by pressing the tray, could it be that for some mechanical reason the tray just doesn't go in far enough? Also, inspect the tray for any clues where there might me some tab that is used by the sensor, and take a flashlight to inspect the inside of the printer where the tray is supposed to go.

10

Test Equipment / Re: New Hantek DSO2X1X models?

« Last post by Aldo22 on Today at 01:18:38 pm »

As of today, a new firmware version is officially available on the Hantek website.
https://www.hantek.com/download?key=fjzl&sid=3&pid=17182&word=