I had a great time doing some interesting repairs at the Repair Cafe event in Campbell River yesterday. One of the most interesting and challenging repairs was that of a Food Saver plastic bag vacuum sealer, for which the heat sealing wasn’t functioning, but the vacuum function was apparently OK. In this case, the problem was not apparently common heat strip failure, but rather a failed vacuum activated switch. Here’s what I did to diagnose and repair it.
February 21, 2016
Repair of a Food Saver model V845
November 14, 2015
Repair of a Traynor YGL3 Mark 3 Guitar Amplifier and Accusonic Reverb Tank
This post is about a fun, relatively easy repair/restoration project on a classic piece of electric guitar/music gear: a Traynor YGL3 Mark 3 amplifier. The YGL3 is a vacuum tube -based piece of rock/music history. This project grew out of the Repair Cafe event in the Campbell River Sportsplex last month that I was a volunteer repair person for. A new friend, Joedy W, had brought this amp in to the Repair Cafe, but I didn’t have the time or the parts during that busy day to do the full repair. After I got back from some travels, we were able to re-connect yesterday and I could get to work on the amp. The whole repair/restore operation had four distinct elements to it. This was a pretty interesting project for me because I had never worked on a musical instrument amp before (that I can recall), but the repairs needed were fairly easy, requiring diagnosis mainly by observation with ears and eyes and ultimately just one test instrument, an ohmmeter.
August 25, 2014
Granularity of Repair: fixing the volume control potentiometer in a Pioneer VSX-3800 receiver
For several months, the primary audio system in Gimli’s media room (well, the couch is Gimli’s) has had the annoying problem of an intermittent left channel due to a problematic volume control element, one part in a triple-ganged, motorized potentiometer in an otherwise great Pioneer VSX-3800 receiver . I’d tried the usual fixes such as a couple of “control cleaner” sprays, a few times, with only temporary success at best. So, based on previous similar experiences, this electronics doctor decided that it was time to operate on the patient. This time, I had no replacement part on hand, and it was looking impossible to get one shipped to me quickly. Here’s the procedure:
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September 17, 2012
Harvesting and Re-using Lithium Cells from Laptop Batteries
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…)
December 16, 2011
In Praise Of Programmable Thermostats
About 2 years ago, I installed programmable thermostats throughout our house, which has electric baseboard heaters. Now I have enough data to see the savings from that effort. Overall, I’ve been able to cut our electric usage by 30% to 50% during the cold months of the year in Vancouver (the larger number in the coldest months, November-February essentially). Compare the usage shown in the graph before and after fall 2009 when the programmable units were installed to see this. (Thanks BC Hydro for the graph!)
November 19, 2011
How to rejuvenate rechargeable NiCd batteries
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
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…)
Amy, next steps in diagnosis might be using an ohmmeter to do some continuity checks from the relay pins outward,…