Random Projects

I bought an Astron RS-20 on the cheap at the local hamfest for my radio. Only problem was the supply was lacking some basic features such as a panel meter for the load current and a banana jack on the front to make the supply output accessible. No problem, with a 200mV digital panel meter laying around, I knew exactly what I wanted to do...  read more »

Peavey JSX Mini This amp came to me with a very low output problem from a music store. All the power supply voltages were fine, but the output was low and it seemed like the amp was loaded down because the output transformer was fine. Since the amp was a "Power Soak" feature, I disconnect that to see it it was the issue. It was not. Upon futher disassembling the amp, it was apparent that the output wire from the output transformer was pinched. The power soak PCB was pinching the wire against the chassis. It was probably fine at the factory, but over a period of time and jostling around, it ended up a partial short. A little heat shrink tubing and re-routing the wire fixed things right away.

Then I went on to some mods...  read more »

Univox U65RN Front: No speaker, scratchy pots, intermittent jack.

Made in Japan, this is actually a decent sounding solid state amp with decent reverb. The reverb tank is pretty small and it's located inside the chassis, so you won't see it from the outside. Amp didn't need much besides a good cleaning and a "new" speaker. I put an old Stromberg Carlson ceramic speaker (similar to a Jensen C12R) in there and that did the job nicely. The input jack was corroded and the connection to the chassis wasn't solid.  read more »

Orange Crush 20B Amp Front: Loose speaker connection.

This is a cheap bass amp. The original owner said there was no sound. Easy enough, once disassembled, it was obvious that the speaker connection came off the PCB. These quick connects are often loose and a quick clamp with a wrench can tighten them down. These quick connects are used in the Valve Juniors and Champs too.

I wanted to be able to fall asleep listening to my stereo playing the radio, but I did not have a sleep timer fuction on my receiver, so I built this device to add sleep timer functionality to the stereo. The timer can be configured to run in two ranges: 99..1 seconds or 99..1 minutes.  read more »

This digital thermometer remembers the 12-hours high and low temperatures. This design uses a PIC microcontroller with a built in A/D converter. All the parts are tolerant to temperatures from -40 to 100 degrees Fahrenheit, so you can keep the device outside.  read more »

I built a cheap laser pattern generator from stuff I found lying around my house and a few store bought items, I think I spent <$10. Here I am including the plans for the circuit and pictures of the finished project. Once upon a time I also took pictures of the patterns using a digital camera, but the shutter speed was too fast, so only part of the pattern was viewable.  read more »