Recent Posts

1

Repair / Tektronix 2225 vertical display problem

« Last post by AndrewEp17 on Today at 06:19:27 am »

Hello, this is my first post. I bought a broken Tektronix 2225 to fix it for fun and the tube works and it has a trace but when I input a signal to either channel it displays a wave form but its barely there. I replaced pretty much every capacitor in it other than a few in the power supply. I checked the voltages and they seem to be correct. But i have to check them again. I think it might be a bad IC or transistor in the vertical amplifier or something and I was wondering if anybody here has any idea of what part would cause this. I included some pictures of channel 1 with and without a 1khz square wave. It doesn't look any better no matter what i change.

2

Buy/Sell/Wanted / FS [worldwide] 2x Yokogawa 701943 500MHz 1:10 passive voltage probe

« Last post by Kirkhaan on Today at 06:18:38 am »

Anyone interested in these 2 Yokogawa probes? Asking price is €100 both together.

They are in excellent condition and working properly.
What you see on the pictures is what you get.

I am based in Germany and willing to ship worldwide. PM me in case you are intersted.

Payment via Paypal. Buyer protection is possible if buyer pays the ~4% uplift.

3

Test Equipment / Re: SDS800X HD - Issue disscusions - is it me, or the scope?

« Last post by eTobey on Today at 06:17:15 am »

I have indeed not used the mask editor at all yet. Could you describe what seems to be wrong? Ideally in a simple step-by-step sequence which we can try and reproduce.

- create a mask
- save the mask
- load the mask
- observe how the steps above have changed vertial scale, vertical position, and

I can not reproduce this issue as yesterday, but it had changed vertial scale, vertical position and i belive the trigger level.


But instead i can deliver another issue (never mind as it might be fixed in the next version):
I have setup a qualified trigger that triggers just fine with 200mv/div, but changing to 100mv/div it freezes. I start wondering if my scope hase some issues itself, but then many of those were confirmed by others...

4

Beginners / Re: Mystery relic Microchip SOT style chip identify please? Looked everywhere

« Last post by TnF on Today at 06:16:49 am »

Not Microchip, but Mitsumi.

PST600DM in MMP-3A package.

Thanks a lot! You are godsend ;p
I saw this brand while looking, searched for the logo too but didn't do a good job it seems;p To be fair they look identical 
I wonder though, where/how did you actually find it?

5

General Technical Chat / Re: Russia and China to Build a Nuclear Plant on the Moon.

« Last post by Artz on Today at 06:16:19 am »

When China figures out how to land something on the moon in a few decades, russian scientists will just let the reactor core overheat and irradiate half the moon.

6

Repair / Re: Rigol DP712 Output Shorted; Fuse? / I Screwed Up

« Last post by Harry_22 on Today at 06:08:43 am »

Dear Zanfar, don't worry this is normal situation if you work with batteries.
Just open the cover find powerful diode near output and put it out.

7

General Technical Chat / Re: Do you think an LED is a resistor?

« Last post by Simon on Today at 06:02:01 am »

Dave, I locked the thread and this guy is taking the piss. PM from him:

Hi, have you had a breach in the system?
In the poll "do you think an LED is a resistor?" You wrote that the question was changed.

I just checked and the question is as I first formulated it. Has it been changed by someone else and then reverted back to its original form?

8

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

« Last post by Shell Albert on Today at 05:45:10 am »

great job!  your first PCB project is much more beautiful than mine, couples of years ago. More PCB layout you do, more better it will be. I sincerely accept other experts suggestions, but I insist on reducing complex, like if there's no GND connecting terminals, I would solder two wires together, it won't be a problem.

9

RF, Microwave, Ham Radio / Re: RF 2.4GHZ through Via

« Last post by 24602 on Today at 05:35:05 am »

What would the best next step, any recommendations for RF simulators?

10

Projects, Designs, and Technical Stuff / Re: Coulomb counter IC for coin cell products.

« Last post by Berni on Today at 05:32:20 am »

It doesn't make sense to use a fuel gauge IC for this.

Those chips are just MCUs that keep measuring the battery current and voltage using an ADC and then plugging that into some fancy algorithm to come up with a SOC in %

Whatever you are powering has to make extensive use of sleep modes to last this long, so just build the coulomb counting into that MCU that runs the show. They consume a pretty predictable amount of current when running and they can time themselves with a timer, multiply the two together and you got the energy used. If you have extra loads being run by the battery you could use the MCUs own ADC to measure the current, but only doing it while you are actually running. When in sleep assume the consumption is 0 by making your sleep mode consume <1uA

Once you get into the last 1/8th of the battery life you can switch to using voltage as a battery indicator (since even fully accurate counting wont be precisely accurate for SOC because not all coin cells are made equal and differ slightly in capacity)