For more than a decade, I’ve been using a series of HP and Compaq laptops and as a result, I had accumulated a pile of expired, apparently dead batteries composed of lithium-based cells. I decided to resuscitate a couple of the old laptops for a project in Campbell River, and needed a couple of working batteries. Rather than buy new ones, I decided to crack open a few of the old ones to see if they still had any working cells that I could re-use. (more…)
September 17, 2012
November 19, 2011
How to rejuvenate rechargeable NiCd batteries
NiCd battery pack
This post is about a method to restore (rejuvenate) NiCd (NiCad) battery packs that are failing to charge. I have 2 sets of cordless tools (drill, circular saw, reciprocating saw and more) that use rechargeable NiCd battery packs. Three of the battery packs were failing to charge. Having had some previous success with rejuvenating apparently expired NiCd cells, I decided to do some tinkering, and I was able to restore the packs such that they will now charge to a usable level. I’ve previously used the same procedure, at lower current, to rejuvenate NiCd cells for cordless phones.
These tool sets and battery packs are very common. Mine were MasterCraft brand purchased from Canadian Tire, but there are many similar ones on the market with other branding. I’d guess millions of similar cordless sets have been sold, so maybe someone else can benefit from this post and save a few $ on new batteries. Perhaps more significantly, maybe this will save some battery packs and even the tools themselves from adding to our garbage output; the Cd in the cells is very toxic, so the less of it we put into use and the less that goes into the waste stream, the better. (more…)
July 12, 2011
Reducing audio frequency electrical noise in a PC sound system
Kinter Amplifier in PC Case
I recently built a new PC that I use for multimedia and other purposes. It’s Intel “Sandybridge” 1155 -based, with a Gigabyte P67 series motherboard and Realtek onboard sound. Unfortunately, like so many other recent PC audio systems, it doesn’t have sufficient output power to drive unamplified speakers directly. I have some unpowerd bookshelf speakers that I wanted to keep using. So, I added a cheap audio power amplifier to the Realtek output. The resultant system had slightly annoying audio frequency noise, not 60Hz noise but various other noise from misc. stuff in the PC. Here are some details re the amp and what I did to fix the noise problem.
The audio amplifier is one I found on eBay from a Chinese manufacturer, with labeling “Kinter 500W”. Price was about $10 including shipping, cheaper than I could build one for myself. I knew what was in the amp from some googling: an LM-series audio amp IC and typical supporting parts, providing a few watts per channel. Not the claimed 500W :-), but adequate for what I wanted. I run the amp from the PC 12V supply, which is far enough beyond spec for the other stuff in the PC that it’s fine to power the amp with it too. I started with a generic 1/8″ stereo to RCA patch cord about 3ft. long to connect the amp to the PC audio output. (more…)
September 19, 2010
My Subaru Outback Head Gasket Repair
This could be your Subaru (parts).
I have a 1997 Subaru Outback with about 280,000km on it. It began showing the head gasket failure symptoms so typical of the Subaru boxer 2.5L engine of this series of cars: foaming/bubbling in the coolant (the reservoir actually looked like a boiling kettle when the engine was running), brief random apparent spikes of the temperature gauge, and coolant loss. Much has been written elsewhere about this issue, and there are a few references about the problem and some repair examples at the end of this blog. Known model years affected by this problem are at least 1996-2002, so be aware of it if you are looking at a used Subaru of that age. I decided to do the repair myself, being very inclined to tinkering, foolish enough to attempt it, and also being unwilling to spend about $2500+ for a shop mechanic to do the job.
Edit Oct. 2011: A few people have asked me about the “head gasket sealer in a can” products. There are a few on the market. I actually had tried one of these, Bar’s Leaks, before I did the real repair, with no success. What I’ve seen in other reports is that they simply don’t work on “internal” head gasket leaks such as what this series of Outbacks gets. Furthermore, given how severe the gasket damage tends to be, I don’t have much confidence in them. The gasket replacement job looks to be the only option, if you want to keep the engine. The good news, though, is that you don’t need to remove the engine from the car to do this repair.
Here are some details of the head gasket repair that I did, in case it helps anyone else trying to do the same thing. Note that this is a big job, (more…)
Amy, next steps in diagnosis might be using an ohmmeter to do some continuity checks from the relay pins outward,…