I absolutely love D.I.Y. repair! I have been taking things apart and putting them back together for as far back as I remember. You often hear people say they were good at taking things apart and not being able to put them back, or reassembling them and ending up with useless junk? That isn't/wasn't me. Today's repair of my uninterruptible power supply (UPS) was so successful it gave me a rush.
The Story before today...
Every August, myself and two others build and run a cyber cafe called Mystic Mail at the Pennsic War. It is very anachronistic to have such a business at this event, but after having run it succesfully for nine years (and still going strong) I can say honestly that it is needed there.
One of the hidden benefits is that we offer filtered power, via an Exide Electronics Powerware Prestige 1000VA UPS. This device was bequeathed to me while I was working for Exide as a programmer / internet administrator. What makes this kind of UPS special is that it is an on-line technology, meaning that it converts its power from AC to DC and back to AC all the time. It is less efficient than standard off-the-shelf UPS's but it is much more stable and reliable. At 1000VA it can support about 700 watts of our electrical needs, which isn't everything but it does cover a lot of the essentials.
This year, a mouse got into my storage unit and ate new holes in the roof of my canvas tent, which makes up Mystic Mail. The holes, unfortunately, were right over where the UPS was located. And as you can guess, it rained during the event and the UPS got wet one day. I wiped it dry and hoped for the best. It kept on running and I thought nothing of it. It lasted the entire event, thankfully. I packed it up, took it home, and plugged it in to return it to service on one of our servers. No go! Apparently the rain had done more damage than I thought.
I took it apart that day, saw that there was some corrosion but no remaining water. All my tests showed it was essentially brain dead. I had no idea how to fix it. The UPS got shelved, and I started scanning eBay auctions for a replacement. On eBay the same unit goes for about $250 without batteries. New on-line UPS models of the same wattage (modern day units) go for $500-600. I resigned myself to spending a lot of money someday soon to replace it.
Yesterday I had an epiphany out of the blue -- why not assume the water only damaged the PC board tracking and see if I could repair any that were totally eroded? The area of damage didn't look all that great. So this morning I took the UPS apart again and started testing traces with my meter. Beeep. Beeeeeep. Beep. Bep. Beeep. (silence). Beeeep.
After my poking around, I found only one trace so badly eroded that it needed to be hardwired. The operation took about 5 minutes. When I plugged in the UPS and it started working again, I was practically jumping for joy. Why not! I had just saved myself a good $300-500.
I celebrated by immediately spending $300 on cave diving gear I'd been waffling about buying. My little contribution to economic recovery.
Friday, November 6, 2009
Monday, November 2, 2009
NiMH followup
Thought I'd post a brief followup on my new Sunpak 2650 mAH batteries. They sorta suck.
I've been doing multiple charge/discharge cycles both manually (charge in the MSCAA fast charger, discharge in the Maha) and automatically (refresh cycle on the Lacrosse). The Lacrosse charger's refresh cycle is "smart" in that it will repeatedly charge and discharge the battery until it determines that the maximum discharge capacity has been achieved. I found this mode to be ideal for conditioning new batteries.
However... The Sunpak batteries are showing capacities notably lower than the Lenmar 2500 mAH batteries they are supposed to replace! Typically I am getting between 1500 and 1800 mAH on a Sunpak. Never more than 1900 mAH. Whereas the 2-year old Lenmar batteries are still showing 2000-2200 mAH per battery under the same test conditions!
Do the Sunpak batteries need more conditioning?
Do the Lenmar batteries work better only because they've endured regular use?
Do Sunpak 2650 batteries simply just suck?
I've been doing multiple charge/discharge cycles both manually (charge in the MSCAA fast charger, discharge in the Maha) and automatically (refresh cycle on the Lacrosse). The Lacrosse charger's refresh cycle is "smart" in that it will repeatedly charge and discharge the battery until it determines that the maximum discharge capacity has been achieved. I found this mode to be ideal for conditioning new batteries.
However... The Sunpak batteries are showing capacities notably lower than the Lenmar 2500 mAH batteries they are supposed to replace! Typically I am getting between 1500 and 1800 mAH on a Sunpak. Never more than 1900 mAH. Whereas the 2-year old Lenmar batteries are still showing 2000-2200 mAH per battery under the same test conditions!
Do the Sunpak batteries need more conditioning?
Do the Lenmar batteries work better only because they've endured regular use?
Do Sunpak 2650 batteries simply just suck?
Friday, October 23, 2009
Nickel Metal Hydride (NiMH) Dilemma
I've been using Nickel Metal Hydride (NiMH) batteries for about eight years now, and have been saving oodles of $$cash$$ by not buying disposables. I've been so impressed by the performance of NiMH batteries that I've spent many hours reading about the chemistry and experimenting with many different brands of cells and chargers. I currently use three different chargers/analyzers:
Powerex Maha MH-C9000 (analyzer/charger)
Lenmar MSCAA (charger only)
Lacrosse Technology BC-9009 (analyzer/charger)
Between the two analyzers, the Maha is easier to use, but the Lacrosse is smaller and better for taking on trips.
Today I semi-retired a 20 pack of Lenmar 2500 mAH cells which I bought two years ago. They have been used in virtually every piece of equipment I own that take AA cells and have worked beautifully. Even after 2 years they still provide about 70% of rated capacity. It is important to note that their good performance is because they are regularly used and frequently charged. I am retiring them mostly because their plastic casing is shredding and I am concerned about short circuits between cells.
And Today, I received their replacement: a 20 pack of Sunpak 2650 cells. I'd first tried Sunpak batteries when they were loaned to me by Andrew D. for use in my tech flashlight. I was impressed at their capacity and their better than average self-discharge rate. I hoped these cells would do as well. They were purchased from Adorama at a cost of $32 including shipping. Just out of the box, however, they offered me a new disappointment. Two of the cells were DEAD. No voltage, could not be charged. I'd read reviews online when people wrote about Lenmar and other brands of batteries having DOA's but I'd never had it happen to me. Two out of twenty.
When you get a shorted Nickel Cadmium (NiCd) you take it to a power supply and zap the hell out of it, in order to break up a crystalline structure which has formed in the electrolyte. So I thought I'd try the same thing with these, seeing as how they were destined for the trash bin. Using an Agilent U8002A bench supply, I set voltage at 12v and current at 500 milliamps. The first one started taking a charge (from zero volts) very slowly, then when it hit about 200 millivolts it suddenly ZOOMED up to 1.4 volts. At that point I put it in my Lacrosse charger and as I write this, it is still charging. The second battery stayed dead. Zap, zap zap. At 500 milliamps it wasn't making a dent. So I thumbed the current first to 1A (zap zap zap, nothing) and then to 2A. On the second zap, the battery broke free and started slowly charging! (I was prepared to take the Agilent all the way up to its rated 5A. I'm glad that wasn't necessary.)
So... both "dead" cells are now charging and if my guess is correct, the discharge tests on the first run will suck, but then after the 3rd or 4th cycle they will be as good as the other 18 batteries.
If you don't have a bench power supply and want to see if you can un-short your NiMH batteries, here is something you can try. It is (mostly) harmless, so even if it doesn't work you shouldn't lose anything. Take your dead cell and a perfectly good fully charged one. They must both be NiMH. Put them in your palm parallel, so both (+) buttons face the same way. Take two quarters (or other large coinage) and put one each across the terminals at each end. Hold firmly for about 3-5 seconds -- but not longer than 5 seconds. You may or may not see a spark when you do this -- don't worry about it. Afterwards, put the "dead" cell into a charger and see if the charger now charges it. If not, repeat the procedure with the quarters, maybe using a different fully charged battery.
I guarantee this will work for some, but probably not all, DOA cells. It doesn't hurt to try, and if it works you've rescued your investment! Just remember that recovered DOA cells will need 3-4 charge/discharge cycles before they run at capacity.
And bear in mind: NiMH cells only hold effective charge for about two weeks. Charge your batteries just before using them if you want best performance. (This does not apply to those newer ultra-slow discharge batteries like Sanyo Eneloop. Charging these every 6-12 months probably adequate.)
Between the two analyzers, the Maha is easier to use, but the Lacrosse is smaller and better for taking on trips.
Today I semi-retired a 20 pack of Lenmar 2500 mAH cells which I bought two years ago. They have been used in virtually every piece of equipment I own that take AA cells and have worked beautifully. Even after 2 years they still provide about 70% of rated capacity. It is important to note that their good performance is because they are regularly used and frequently charged. I am retiring them mostly because their plastic casing is shredding and I am concerned about short circuits between cells.
And Today, I received their replacement: a 20 pack of Sunpak 2650 cells. I'd first tried Sunpak batteries when they were loaned to me by Andrew D. for use in my tech flashlight. I was impressed at their capacity and their better than average self-discharge rate. I hoped these cells would do as well. They were purchased from Adorama at a cost of $32 including shipping. Just out of the box, however, they offered me a new disappointment. Two of the cells were DEAD. No voltage, could not be charged. I'd read reviews online when people wrote about Lenmar and other brands of batteries having DOA's but I'd never had it happen to me. Two out of twenty.
When you get a shorted Nickel Cadmium (NiCd) you take it to a power supply and zap the hell out of it, in order to break up a crystalline structure which has formed in the electrolyte. So I thought I'd try the same thing with these, seeing as how they were destined for the trash bin. Using an Agilent U8002A bench supply, I set voltage at 12v and current at 500 milliamps. The first one started taking a charge (from zero volts) very slowly, then when it hit about 200 millivolts it suddenly ZOOMED up to 1.4 volts. At that point I put it in my Lacrosse charger and as I write this, it is still charging. The second battery stayed dead. Zap, zap zap. At 500 milliamps it wasn't making a dent. So I thumbed the current first to 1A (zap zap zap, nothing) and then to 2A. On the second zap, the battery broke free and started slowly charging! (I was prepared to take the Agilent all the way up to its rated 5A. I'm glad that wasn't necessary.)
So... both "dead" cells are now charging and if my guess is correct, the discharge tests on the first run will suck, but then after the 3rd or 4th cycle they will be as good as the other 18 batteries.
If you don't have a bench power supply and want to see if you can un-short your NiMH batteries, here is something you can try. It is (mostly) harmless, so even if it doesn't work you shouldn't lose anything. Take your dead cell and a perfectly good fully charged one. They must both be NiMH. Put them in your palm parallel, so both (+) buttons face the same way. Take two quarters (or other large coinage) and put one each across the terminals at each end. Hold firmly for about 3-5 seconds -- but not longer than 5 seconds. You may or may not see a spark when you do this -- don't worry about it. Afterwards, put the "dead" cell into a charger and see if the charger now charges it. If not, repeat the procedure with the quarters, maybe using a different fully charged battery.
I guarantee this will work for some, but probably not all, DOA cells. It doesn't hurt to try, and if it works you've rescued your investment! Just remember that recovered DOA cells will need 3-4 charge/discharge cycles before they run at capacity.
And bear in mind: NiMH cells only hold effective charge for about two weeks. Charge your batteries just before using them if you want best performance. (This does not apply to those newer ultra-slow discharge batteries like Sanyo Eneloop. Charging these every 6-12 months probably adequate.)
Sunday, October 18, 2009
Printer Ink Karma
If you haven't guessed, I am a *BIG* fan of D.I.Y. I've been repairing minor and major appliances, lawn mowers, cars, stereos, motherboards, ... just about anything and everything that comes with a sticker that says "No User Serviceable Parts Inside." And my success ratio is pretty darn good. I usually can get the car back together after major surgery and have only 2 or 3 screws left over. Just kidding.
One of the big money saving DIY efforts of our generation is refilling ink cartridges. Overall, one full refill of all 5 tanks on my Canon MP600 saves about $50. Since there are two such printers in the house, that means that $hundreds have been saved over the years. There is one tool that makes this possible: the German-made Canon cartridge chip resetter. I got one when they first came out and it cost me a fortune: $68. But the ink savings have well justified it.
Today I went to refill a cyan cartridge. I always(?) reset the chip first, as it is less messy to use the resetter on an empty cartridge than a full one. This time, the unit was DEAD. No lights, no activity. I first suspected a bad cartridge. Nope, a yellow cartridge didn't work on it either. Next I guessed that after 2 years maybe the lithium battery had gone dead. So I popped it open and tested the voltage. Still good. Just for kicks I replaced the battery anyway. Still no go.
I poked around the PC board, looking for short circuits, dirt, bad connections, anything. Nothing. Basic DVM tests showed power going to the microcontroller and that it seemed to be otherwise mechanically and electrically sound. Finally after 30 minutes of playing with the thing, I gave up.
So... back onto Ebay I go, and the current day cost on a similar unit is $17.30. I go ahead and buy it. I kid you not, TEN seconds after I pressed the "Confirm Payment" button I had a thought: What about the "hit it when it don't work" philosophy? Nah, it's such a tiny circuit board with almost nothing on it. It'll never work. Twenty seconds after I had pressed the "Confirm Payment" button, and I dropped the unit on my desk from a height of about 5 inches. Klunk! it went.
And guess what! IT WORKS again!
Is this a fluke, or are the gods of Consumer Electronics karma frowning on me today?
I sense that Murphy is smirking at me from the next room.
One of the big money saving DIY efforts of our generation is refilling ink cartridges. Overall, one full refill of all 5 tanks on my Canon MP600 saves about $50. Since there are two such printers in the house, that means that $hundreds have been saved over the years. There is one tool that makes this possible: the German-made Canon cartridge chip resetter. I got one when they first came out and it cost me a fortune: $68. But the ink savings have well justified it.
Today I went to refill a cyan cartridge. I always(?) reset the chip first, as it is less messy to use the resetter on an empty cartridge than a full one. This time, the unit was DEAD. No lights, no activity. I first suspected a bad cartridge. Nope, a yellow cartridge didn't work on it either. Next I guessed that after 2 years maybe the lithium battery had gone dead. So I popped it open and tested the voltage. Still good. Just for kicks I replaced the battery anyway. Still no go.
I poked around the PC board, looking for short circuits, dirt, bad connections, anything. Nothing. Basic DVM tests showed power going to the microcontroller and that it seemed to be otherwise mechanically and electrically sound. Finally after 30 minutes of playing with the thing, I gave up.
So... back onto Ebay I go, and the current day cost on a similar unit is $17.30. I go ahead and buy it. I kid you not, TEN seconds after I pressed the "Confirm Payment" button I had a thought: What about the "hit it when it don't work" philosophy? Nah, it's such a tiny circuit board with almost nothing on it. It'll never work. Twenty seconds after I had pressed the "Confirm Payment" button, and I dropped the unit on my desk from a height of about 5 inches. Klunk! it went.
And guess what! IT WORKS again!
Is this a fluke, or are the gods of Consumer Electronics karma frowning on me today?
I sense that Murphy is smirking at me from the next room.
Wednesday, June 24, 2009
Random Acts of Kindness.... revisited?
I will never forget what Dervila said to me years ago about "random acts of kindness" - it puts new meaning to life, sometimes where I least expect it. I try to practice it whenever I can... often it is the little things that make the most difference!
The D.C. area where I live is a big melting pot of cultural groups and political agendas. It is often so competitive that people take out their daily frustrations in all aspects of their lives, especially driving. People here are also rather standoff-ish. Possibly because they subconsciously believe that if they help someone else, even a stranger, they give that someone an advantage over themselves. It's a very "I, Me" type of climate here.
So it was with great surprise that I had not one but TWO random acts of kindness granted to me today, in rapid succession. And here in D.C. nonetheless!! Today I visited one of my clients at a 6-story office complex. I was walking with three stacked boxes, with lots of papers and wires sticking out of the top box. A woman graciously rushed in front of me and opened not just the outer door, but then opened the inner door for me as well! I thanked her kindly and she walked back the other way. (Wow! She went out of her own way to help me!)
Then as I approached the elevator, I found a gentleman holding the elevator door for me. He didn't see me walk in, but must have heard me thanking the woman at the door and then generously assumed I was going to use the elevator next. Double wow!
Maybe today's absolutely beautiful summer weather had something to do with people's moods. But I'd like to believe that in these financially turbulent times, people are making the effort to open up to add more hope and joy to others' lives.
The D.C. area where I live is a big melting pot of cultural groups and political agendas. It is often so competitive that people take out their daily frustrations in all aspects of their lives, especially driving. People here are also rather standoff-ish. Possibly because they subconsciously believe that if they help someone else, even a stranger, they give that someone an advantage over themselves. It's a very "I, Me" type of climate here.
So it was with great surprise that I had not one but TWO random acts of kindness granted to me today, in rapid succession. And here in D.C. nonetheless!! Today I visited one of my clients at a 6-story office complex. I was walking with three stacked boxes, with lots of papers and wires sticking out of the top box. A woman graciously rushed in front of me and opened not just the outer door, but then opened the inner door for me as well! I thanked her kindly and she walked back the other way. (Wow! She went out of her own way to help me!)
Then as I approached the elevator, I found a gentleman holding the elevator door for me. He didn't see me walk in, but must have heard me thanking the woman at the door and then generously assumed I was going to use the elevator next. Double wow!
Maybe today's absolutely beautiful summer weather had something to do with people's moods. But I'd like to believe that in these financially turbulent times, people are making the effort to open up to add more hope and joy to others' lives.
Friday, June 19, 2009
Climbing to Greater Heights
Some of you already know that I started a new hobby last fall. Rock climbing! I got pretty serious into it pretty quickly, and rapidly moved up the difficulty scale. I started doing 5.6 and 5.7 routes (beginner) and am currently at about a 5.10 (intermediate) difficulty level. I expect it will be a year before I get to 5.11, but that's okay because 5.10 has four sub-grades labelled "a" "b" "c" and "d". Right now I can do a 5.10b with some difficulty. Haven't tried a 5.10c yet.
But tonight, I advanced in this sport in another way.... I am now LEAD CERTIFIED! This is the next major step forward in the hobby and adds another dimension of difficulty to the climbs I am already doing. The difference is this: the safest and easiest sport climbing is done by a system called "Top Rope" climbing, where the person scaling a cliff is secured by a rope that runs from him/herself to the top of the cliff, then back down to a safety partner called a Belayer. It's pretty safe in that if you fall, you're already roped to the top of the climb so you don't fall very far.
Lead rope climbing is much more dangerous. Your partner still belays, but you take the rope with you and clip it in to carabiners on the way up. As you climb, you go higher than the last place you clipped so the distance you fall can be much greater. There's also added dangers of: tangling in the rope as you climb it (called backstepping), putting the rope in the wrong side of the carabiner (called back clipping) or pulling up the wrong side of a rope from the previous carabiner (called Z-clipping). The techniques done by both the climber and the belayer are more technical and practiced in lead climbing.
So. I had taken a class on lead climbing in late March. Since then, half the time I've been to the gym I've practiced both lead climbing and lead belaying, as partner interests allowed. When I went to the gym tonite I wasn't thinking at all about the test. But as I got there, I found the gym only half crowded and some of the staff had time to administer the test. I did it pretty much spontaneously!
The lead belay part went well. That part never concerned me as it is pretty straight-forward. For the lead climbing, however, the instructor chooses a route (a 5.9, the first level of intermediate difficulty). He chose a route I had never tried before, on a wall I don't usually climb. Turns out it went very well! I controlled any nervousness and just focused on the task at hand. My clipping was perfect. I didn't fall or need to take a break. The holds were generous and the route, though it traversed a bit (it was one of Skella's routes) I found clips when and where I needed them.
Success! Achievement! I am now Lead Climb and Lead Belay certified.
But tonight, I advanced in this sport in another way.... I am now LEAD CERTIFIED! This is the next major step forward in the hobby and adds another dimension of difficulty to the climbs I am already doing. The difference is this: the safest and easiest sport climbing is done by a system called "Top Rope" climbing, where the person scaling a cliff is secured by a rope that runs from him/herself to the top of the cliff, then back down to a safety partner called a Belayer. It's pretty safe in that if you fall, you're already roped to the top of the climb so you don't fall very far.
Lead rope climbing is much more dangerous. Your partner still belays, but you take the rope with you and clip it in to carabiners on the way up. As you climb, you go higher than the last place you clipped so the distance you fall can be much greater. There's also added dangers of: tangling in the rope as you climb it (called backstepping), putting the rope in the wrong side of the carabiner (called back clipping) or pulling up the wrong side of a rope from the previous carabiner (called Z-clipping). The techniques done by both the climber and the belayer are more technical and practiced in lead climbing.
So. I had taken a class on lead climbing in late March. Since then, half the time I've been to the gym I've practiced both lead climbing and lead belaying, as partner interests allowed. When I went to the gym tonite I wasn't thinking at all about the test. But as I got there, I found the gym only half crowded and some of the staff had time to administer the test. I did it pretty much spontaneously!
The lead belay part went well. That part never concerned me as it is pretty straight-forward. For the lead climbing, however, the instructor chooses a route (a 5.9, the first level of intermediate difficulty). He chose a route I had never tried before, on a wall I don't usually climb. Turns out it went very well! I controlled any nervousness and just focused on the task at hand. My clipping was perfect. I didn't fall or need to take a break. The holds were generous and the route, though it traversed a bit (it was one of Skella's routes) I found clips when and where I needed them.
Success! Achievement! I am now Lead Climb and Lead Belay certified.
Monday, April 27, 2009
The Perfect Tempest
Tempest: The Perfect Video Arcade Game. Released in 1980 as the first of a handful of Atari Color Vector Graphics machines, this is reported to be one of the most popular collectors items among video arcade game enthusiasts. Keeping a 29+ year old piece of technology running is... challenging.
My machine is actually the 2nd Tempest I've owned. The first one I bought for $50, fixed it up, kept it for about 5 years during my college days and then sold for a reasonable profit. It took a few years before I really missed it. Fortunately opportunity knocked at the right time and I got the 2nd one about twelve years ago for $75.
This second unit was in poorer cosmetic condition than the first but the electronics still worked. Ironically, the X-Y deflection transistors (which are usually the first to blow) are still the originals! They look a bit rusty, but since I installed the LV2000 upgrade kit I have no worries about them burning up. (My 1st machine went through several sets of expensive transistors. Wish the LV2000 was available then!)
The only nagging problem I've had in the past few years is the spinner. The thing was very well designed, except Atari made it with cheap nylon bushings. Once they wear, even a little, the spinner knob will make the characteristic Tempest "Buzzzzz" when you try to spin it fast and the wheel quickly drags to a stop. And if you've ever played Tempest, you will know how important it is to spin fast and accurate. I tried applying heavy grease, but it didn't help one bit.
Last month I pulled the spinner unit out of the console and it sat on my desk for weeks. I wanted to install ball bearings but time constraints prevented me from going to the machine shop and fabricating pillow blocks for them. Every day, though, I'd stare at it, play with it when speaking on the phone, and envision ways to retrofit the bearings.
Then one day (about a week ago now) I grabbed a baggie of assorted ball bearings I had bought on eBay. I had several of the right size: 1/4" inside diameter for the shaft. But looky there! My baggie had a wonderful surprise for me. Bearings with flanged ends! I had no idea such things existed in this small a bearing.
It then took me only a few moments to devise a quick fix for the spinner, which entailed redrilling the 1/4" shaft holes in the frame to fit the 5/8" outside diameter of the bearing. In less than 60 minutes I disassembled the unit, bored holes using a 4-flute 5/8" end mill, cleaned off the oil and reassembled everything.
Best of all, the enlarged holes were the only modification for the retrofit. No changes were necessary to the flywheel, shaft or encoder itself. The flange on the bearing was maybe thrice the thickness of the original nylon bushings but there is still plenty of space between the E-clips on the shaft. Everything fit comfortably.
And the end result? Sweet gameplay control! No Buzzzz noise anymore, and the wheel is so slick it spins for several seconds before coming to a gentle stop. I had to change my gameplay strategy a bit because the spinner was so slippery, but that's all to the better.
Flanged bearings like the ones I used can be bought at McMaster Carr for about $7 each. Try part # 57155K324.
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