Emory's Electronic Emporium

Emory's Electronic Emporium All things electronic and scientific.

My Bad Barbie Collection🙀
04/29/2023

My Bad Barbie Collection🙀

Here's the ESR tester working in the simulator:1. Scope setup.2. Scope running.3. Circuit setup.4. Circuit running.The r...
03/19/2023

Here's the ESR tester working in the simulator:
1. Scope setup.
2. Scope running.
3. Circuit setup.
4. Circuit running.
The readings from the simulator are nearly identical to the real thing on the bench. The "DUT" is a cap with an actual .68 Ohm resistor in series.
You'd be surprised how ugly the waveforms are on old high-ESR capacitors running in a SMPS. Nasty, jaggy noise riding on a funky 200 Hz sawtooth from the PWM chip trying to correct the mess.

03/19/2023

Can anybody see this? Is this thing on?
If you can't see this, let me know.
If you see it and don't want to, call schmuckerborg.
Or bill gates. Or one of the clones at Apple. Or Pornhub.
They've gone to great trouble to make this unpleasant, user-vicious, and non-fun.
Computers used to be fun when it was just unix and CP/M.

03/19/2023

With the successful repair of the PC PSU a couple of weeks ago, I've been looking into a DIY ESR measuring device. It's on the bench as we type and two of the caps from that PSU read very different from brand new, known good caps. More in the next few days.
:
-btw, most modern ATX PSUs use MAGAMPS to produce all that power in such a small space. Haven't messed with those things since the NAVY!

I have a bunch of LCD computer monitors gathering dust. Most of them start up and then shut off. The usual problem is ag...
03/25/2019

I have a bunch of LCD computer monitors gathering dust. Most of them start up and then shut off. The usual problem is aging capacitors going shorted. I COULD replace the caps and wait for other components to fail
or...

I could turn the monitors into TVs with VGA inputs! For ~$21.00, you can get LCD control boards with HDMI, Component, VGA, and USB inputs. IR remote, inverter, and control panel included. Just add a 12V/3A PSU and you're rockin'!

Here, we have a modern-day data terminal.(And you thought serial was dead!). It's not!Almost all electronic devices have...
03/15/2019

Here, we have a modern-day data terminal.
(And you thought serial was dead!). It's not!
Almost all electronic devices have hidden serial ports for debugging. Not the DB25 or DB9 ports one would expect but three or four pins for TxD, RxD, and GND at TTL levels instead of RS232s +/- 12V levels.

The little contraption at right is an Orange Pi running minicom as a terminal emulator. On top is a "Hat" I made for power, I/O, level translation, etc. (The Pi community calls them Hats.)

In addition to the TTL level ports, the little blue module on top of the Hat is a Max3232 TTL/RS232 level shifter/inverter so I can do regular RS232. Baud rates from 75 to 115,200 as well as all the usual serial handshaking signals are operative. That big VGA cable will be replaced with a 6" barebones "cable" with RGB, GND, HSync & VSync.

I am making an enclosure that will attach to the 7" monitor to house the Pi, power supply and all connections. At present, I am using a USB keyboard and USB trackpad from a dead laptop for HID. I intend to get Bluetooth working so I can use my BT kbd/trackpad.
It has ethernet and WiFi if needed.

My problem is that P*s use frame buffers instead of ordinary video circuitry.
Frame buffers do not have cursors. A bad thing! :(
Fortunately, minicom is open source and I have the source code. Hopefully, I can simulate a hardware cursor by putting a chr(0x5f) underscore wherever the hardware cursor would be.
Wish me luck.

Hantek app running on the A10s.At rear is a NiMh 9.6V/4200 mAH battery with 5V/3A regulator for USB power connected thro...
03/15/2019

Hantek app running on the A10s.
At rear is a NiMh 9.6V/4200 mAH battery with 5V/3A regulator for USB power connected through a USB > PowerPlug for the scope module. I'll put a female PowerPlug on the regulator as soon as the order arrives.
The scope draws ~180mA so it can run all day if needed.

This is no substitute for my Philips PM3335 scope but it can go anywhere, anytime. I got the Auto(mobile) module for the Hantek app for poking around CAN bus, sensors, ignition, etc.

DIYHakko 9xx Soldering Controller.Using the on-board +/- 8V powered by a 12V transformer for the OPAMPand a 19V/4A lapto...
03/14/2019

DIYHakko 9xx Soldering Controller.
Using the on-board +/- 8V powered by a 12V transformer for the OPAMP
and a 19V/4A laptop PSU to power the heating element in the iron.
A IRF9540A MOSFET ($1.60) turns the power to the iron off and on.

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