Part2 of the Hameg HM303-6 oscilloscope repair which had suffered transit damage due to insufficient packaging however it had a deflection fault which did not seem to be related to the transit damage. The fault was the traces were deflected off the screen in the vertical direction to the point where they could just be seen at the bottom if V-position was turned up to the top. The Y plate voltages were at 146V and 85V with the lowest varying depending on Y position control. The other remained at 146V which is the same as the supply voltage so it appeared that the final output amplifier transistor was not being switched on. All voltages were OK and the transistor measured OK when tested but appeared to fail open circuit when current was passed through it. After unsoldering it from the PCB it became faulty permanently with no connection to the collector. Replacing the transistor restored normal operation. Never seen a transistor fail open circuit like that. But at least it's now working. Part 1 of this repair - troubleshooting process and determining the faulty component https://youtu.be/Ko8XvbpFYdU ... https://www.youtube.com/watch?v=dC9k6eLt1pw

A look at the inside of a high end (for 2008) Cisco network switch/ firewall / router type thing. See my channel for more electronics and teardown videos. ... https://www.youtube.com/watch?v=Y1j2bqePP8Y

A 8 digit LED clock showing the time including seconds which synchronises with the NTP protocol on the hour for accurate time keeping. No RTC required and uses the ESP8266 NodeMCU to handle NTP requests and generate the bit patterns etc for the ICM7218A / ICM7228A LED driver IC. WiFi credentials are configured by a web browser and stored in EEPROM so there is no need to hard code the SSID and password in the code. Daylight saving time is handled by a button that toggles it on and off. This is based on a project I made a while ago which was a universal internet connected LED display which displayed YouTube channel statistics on it's 8 digit LED display. I made ten of them and managed to sell two and kept one for myself. One of the buyers just wanted it for the secondary clock function so I decided to make a version of the firmware which is simply just that; an LED clock. This turned out to be more successful in selling on eBay as I sold another two within a week so I decided to convert the remaining YouTube counters to LED clocks instead. I also have a limited supply of the blank unpopulated PCB's for sale if anyone is interested. This video is a quick demonstration but basically in a nutshell the project is powered by a Wi-Fi connected microcontroller which allows the unit to sync time with the global NTP server every hour. Connectivity is configured via a simple web interface so no need to edit and upload the firmware every time you need to change Wi-Fi networks. It just wasn't a good idea hard coding the SSID and passphrase into the code... Anyway, a full article on this can be found on my blog at https://www.adrian-smith31.co.uk/blog where you can find firmware and a link to the eBay listing where you can purchase one. I may make other versions with different colour LED displays in the future. Links to purchase one will be on my blog above. Video of the YouTube statistics counter version is here https://www.youtube.com/watch?v=ZtJfRzs-TSw #esp8266 #IOTprojects #diyelectronics ... https://www.youtube.com/watch?v=2e2seXHxOjs

A look at a Xiaolin LM324 electronic load kit that I got in a box of misc. electronics goodies bought from eBay. This came assembled but missing the 4.7K multiturn potentiometer for adjusting the output current. A heatsink was missing too but that isn't included in the original kit anyway. I convert the board to DC power as in the original design it is supposed to be powered from 12V AC and has onboard rectifier diodes. As a 12V DC wall wart is readily available I removed the diodes and connected the jack directly to the rectified output. I also fasten it to a good heatsink - this gets HOT at full load so a fan is also recommended (there are two fan headers on the board) and give it a test with a 20W and 60W load. I did buy a cheap dual panel meter for it but it didn't work so I had to return the meter to Amazon and used two multimeters instead which given the amount of times this will be used is sufficient. I might do a part 2 showing it working with one of these dual panel meters testing some batteries. This kit has been available since around 2018 and is getting harder to find now but it's quite a solid, well designed little unit. There's provision for several types of MOSFETS which is a nice touch. It's a useful addition to my test equipment anyway. Ideal for testing power supplies and batteries. ... https://www.youtube.com/watch?v=Gv9-I2wNcWc