And what did we buy today?

Got a Craftsman chainsaw in exceptional condition at a yard sale for $30. Finally found something to put the extra 18" chain on that I bought for the electric Craftsman that I burned up. With that, cuts like a knife through butter. Wife said "if the best you can get is $100, why dont we just keep it?" Nice! It's got a little Sta-Bil in the tank and fuel I ran through it. Hope that's good enough til next time...

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Got a Craftsman electric leaf vacuum for $25 at Goodwill. Used it today under a couple of trees, before the rain just beginning wets the leaves making them that much harder to deal with. (3/4 still up on the trees; they wait here until it rains continuously to ensure these things clog up better and that nice new bag get all saturated with wet goo to ensure a good moldering!)

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...Anyway, I've always been fascinated by why circuit designers do things they way they do...
These things can be entertaining sometimes. Many years ago, I bought a pretty cool Craig R551 car stereo line-level EQ. It had a number of features which were fairly innovative at the time, but also a couple of head-scratchers.

One was the input stage, an inverting op-amp w/ adjustable gain. This adjustment was made by a DPDT switch, one pole for each channel. Each throw of the switch would connect different resistors in the feedback path to set the gain. But this also meant that whenever the switch wasn't making contact for some reason - whether oxidized contacts, or even just throwing the switch with power applied - the gain stage would go open-loop and become a COMPARATOR. Talk about turning it up to eleven!! :oops: Even as a young noob, I was able to see this on paper* before anything Really Bad happened, and rearranged the circuit to a single-throw arrangement with a switched parallel resistance, so at least an open switch would only result in the hi-gain mode. Sheesh...

Another (potentially) cool feature of this unit was something called an Ambience Expander. It used a BBD to create a short audio delay in a sidechain, which could then be remixed into the main audio. But the input to this circuit was a simple mono mix (L+R), which hobbled the effect significantly. I put a unity-gain inverter on a piece of perfboard to make a L-R feed for the delay circuit, which although program-dependent, was a lot more interesting! I'd planned to bring out the output of this circuit on separate jacks to feed its own speakers on the rear deck, but the damn thing got stolen out of my car before I could get to that mod. :mad:

*Remember when manufacturers used to actually put schematics in the back of the owners manuals? Ah the good old days...
 

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Amazon FIRE 7, 9gen, $16.50 "Used, acceptable".

Well it won't remember who it is registered to (random deregistration), hangs-up a lot, insists I feed it a kid for KIDS mode.... something real wrong in there. Smells like bad DRAM. Gotta go to the UPS store because getting it picked-up is almost more than it cost me.
 
Hmmm, a few things recently. A 120V photocell to make a dusk-to-dawn controller for Halloween lights. Some 3.3V SOT regulators to convert Halloween battery lights to line powered. A 12V blower fan to repair our big Santa blowup. An adapter to stick an M.2 SSD in a PCIe slot. A 27" 16oz softball bat ($10 score!) for my 9yr old daughter to use for indoor softball training.
 
Just ordered a bunch of IC sockets, headers, & other sundries to fill a bare PC board that took me about 4 months to get (from Japan), which will replace the CPU/digital board that's missing from the classic Kawai SX-210 polyphonic synthesizer that's been languishing in my attic for about 20 years!! Starting to get a little excited about this project, heh.
 
Rooting a Kindle involved inserting a memory card with the then current Cyanogen version, and forcing the unit to boot from the card instead of the internal memory. The idea was to replace the Kindle OS with the Cyanogen OS.

Did not work properly, but some of the Kindle locks disappeared, and the friend's daughter was able to do things which were not possible earlier, so she was satisfied.

Cyanogen was a modified version of Android, there was a weekly release and so on, open source stuff.
The business has gone corporate, maybe the founder has left, it is now slowly becoming obscure, as Android gradually improved and added many functions offered by Cyanogen.

If you feel like, try to replace the OS in this way.
Use a version from about the manufacturing date, newer ones may need lots more memory and processor power.
 
My new Yamaha SLG 130 I suspect eats 9V batteries for lunch (especially when the on-board reverb is used), so I purchased a set of 4 https://www.ebay.com/itm/275206338185 rechargeable Lith-ion 9V.

The way these work is they have a switcher inside that kicks the voltage up to 9 - Doh! I've heard they have emi issues that can effect audio applications - like my guitar, stomp boxes, etc. Some have said a treatment for this is needed, such as a ferrite core in one of the connector leads. We shall see. If they dont work out and cant be "fixed", I got a couple of AC powered fire alarms that annoyingly use a 9V too, a DMM - I'm sure they'll all get used in something.
 
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My new Yamaha SLG 130 I suspect eats 9V batteries for lunch (especially when the on-board reverb is used), so I purchased a set of 4 https://www.ebay.com/itm/275206338185 rechargeable Lith-ion 9V.

The way these work is they have a switcher inside that kicks the voltage up to 9 - Doh! I've heard they have emi issues that can effect audio applications - like my guitar, stomp boxes, etc. Some have said a treatment for this is needed, such as a ferrite core in one of the connector leads. We shall see. If they dont work out and cant be "fixed", I got a couple of AC powered fire alarms that annoyingly use a 9V too, a DMM - I'm sure they'll all get used in something.
Do you use it with headphones only? If it were me I would probably replace the TS jack with a TRS jack and run 9VDC externally to it over the extra conductor, because I HATE batteries, but I know that's just mostly how I think.