Recent Posts

1

Repair / Re: Commodore 1901 monitor repair

« Last post by scroeffie on Today at 05:46:01 am »

i have 3 of these ,first i would replace all purple caps they leak and most are out of spec .did you replace the front rifa cap they wil explode
also chek the voltage regulator .these monitors also have allot of cold solder joints reflow everything .remove all old glue
chek front switch sometimes they are dirty
i just done the scart rgb mod works perfect 

2

Projects, Designs, and Technical Stuff / Re: Practically smallest SMD size for assembly run of 1 to 100 pieces by PCBWay etc

« Last post by charliehorse55 on Today at 05:44:28 am »

How small does it need to be? I use 0402 as standard for passives, never had a problem with it. I just ordered a board from them with ~600 components per board, had 3x3mm 9-pin QFN,  SOT-23, and a few different ICs with 0.5mm pin spacing.

They have x-ray inspection available for BGA and other high pin count devices, but normally they rely on optical inspection. It works quite well.

3

EEVblog Specific / Re: EEVblog 1612 - Siglent SDS1000X HD 12 bit Oscilloscope Teardown

« Last post by EEVblog on Today at 05:43:14 am »

4

Repair / Re: HP54600B with spike problem with and without signal

« Last post by sacha on Today at 05:41:05 am »

Hi  fmashockie,Thanks, I'll try to ask.

5

Test Equipment / Re: Choosing between entry-level 12-bit DSOs

« Last post by DaneLaw on Today at 05:31:15 am »

Can the TSA do amplitude modulation?
Put in some AM at about 10% of the frequency.

It only supports a limited number of amplitude levels (I think 8 or so) for the the modulating signal, so it's a "stair step sine wave".
And the modulating signal is limited to 10 kHz.

EDIT: See also Erik's video: https://youtu.be/U2cw0bmuSLM?t=239

The TinySA supports 8-point interpolation, while the Ultra can muster up to around 128 points depending on modulaton frequency.

6

Test Equipment / Re: Siglent SDS3000X HD and upgraded SDS1000X HD

« Last post by ebastler on Today at 05:31:00 am »

I would rather enjoy the fact that there has never been so much “scope” for the money as there is now, instead of brooding about it.
Not so long ago, the 12-bit ADCs used were cited as one of the reasons why the 2000X HD was twice as expensive as the 2000X plus.
Now you can get them in a 500€ model.

Who's brooding? I am just curious why certain design decisions were made and what they imply. Maybe there is something to be learned?

Let's face it, most of our threads here are about "scopology" rather than about using the scopes in practice. (Which is fine by me, there are Project setions etc. which discuss the latter.) No doubt that we get excellent affordable scopes today, which most of the time we won't even use at their full potential. But what's wrong with also being curious about how they work, how they were designed and why? The Test Equipment section would be pretty quiet otherwise.

7

Projects, Designs, and Technical Stuff / Re: role of optocoupler for biasing drain of amplifiers

« Last post by john23 on Today at 05:19:07 am »

Hello XVR, You said i should put a zenner diode .
did you meen in parralel to the power supply? becuase i had negative power supplyand it solved the problem :-)

Regarding what you said for pulse and heat.In the datashet there is a plot  figure 11 attached.
suppuse i have 1sec period and 50% duty cycle.
t1=0.5sec so r(t) is 0.5
R_JA=110 C/W *0.5 =55C/W
What is Tj-TA in the plot? how do i know what temperature rise the mosfet can handle?

https://www.mouser.com/datasheet/2/308/1/NDT3055L_D-2317585.pdf

8

Power/Renewable Energy/EV's / Re: DIY Battery Bank from Recycled 18650

« Last post by ledtester on Today at 05:17:22 am »

What are those things in a glass package? Fuses?

9

RF, Microwave, Ham Radio / Re: Cascade RF Frontend 2.4GHz possible?

« Last post by Flunze on Today at 05:09:08 am »

Please see attachments for Front, back side and the circuit I want to use.

10

General Technical Chat / Re: Is LinkedIn worth keeping?

« Last post by Bud on Today at 04:40:57 am »

LinkedIn web site is the text version of TikTok and a model of a garbage useless web site.