Got a Samsung Infuse when they first came out. So yeah, mine is now ‘old’. All of a sudden about a month ago, battery life went into the dumper. Charge to 100% before going to bed, then in the morning less than 50% remaining. Also noted that the Samsung Infuse case seemed warmer than expected. Not hot enough to really cause me concern, but generally warmer.

First thought was I’d installed something that was draining the battery. Has happened before. Some app leaves the GPS searching for a signal and wham, no battery life. So started uninstalling recent installs No difference.

Second thought, is the battery just ‘old’, ie no longer has the same mah capacity? LiPo, that happens. So a test, fully charge, shut off the phone, go to bed. In the morning, power up, check the battery, 50%. Yikes! even ‘turned off’ so beginning to suspect a LiPo whisker or something shorting inside the battery draining the life during the night (basically self discharging). But… you know ‘turned off’ really isn’t ‘off’ with these things. So….

Third thought, another test. same as before. fully charge, ‘turn off’ phone, but this time remove the battery. Now the Infuse is really off! Come morning, put the battery back in, power up, 98%. Wow! so apparently it’s not the battery, it’s something in the phone (even ‘turned off’) is massively draining the battery. Would certainly explain the ‘warmer than expected’ temp and the significantly reduced battery life. Except that once I set the phone down and a few minutes later try to unlock it, it’s completely dead. No Power, nothing. remove the battery, reinsert battery, nothing. no Samsung display, nothing, dead, dead, dead…

Now what to do… Start thinking some more about it and remember that the last time I went jogging, using the RunKeeper app, the phone seemed a little warm and that’s about the time things started going south. So now another theory emerges, that I got some sweat in the power switch and it’s preventing the Infuse from turning on. At this point figuring that the phone is dead anyway, rip it open and try to clean the power switch.

Found this Phone Doctors video on opening the Infuse. Seemed pretty easy, and what do I have to lose? And sure enough, the phone is pretty easy to open up. And then…. it becomes obvious what the problem is. It’s not the power switch. Appears a bit of sweat got on the back of the phone near the camera, leaked around the camera and on to the main board. There’s 3 or 4 caps and likely resistors covered with green salt corrosion. Yikes, that’s the problem. not the power switch…

At this point, wonder if it’s even salvageable, but again, nothing to lose, so scrape off the crud with a wooden tooth pick. Try to power up again. Nothing… I think what happened is that w/ the battery in, the short remained hot. removing the battery over night allowed everything to cool, reinserting the battery the short got hot again and the thermal cycle pulled loose a solder joint. sigh….

So, assuming bad solder joint, pull out the trusty soldering iron, crank it up fairly hot (assuming unleaded solder) and applied so heat to the components that were shorted. Crossed fingers, replaced the battery, hit the power switch and…. “Samsung” proudly displays on the Infuse screen! success One raised from the dead Samsung Infuse.

As you likely surmise the most expensive component of the Cat Faucet is the solenoid valve. So as my supply is getting low, started looking at other, less expensive resources. All these valves are really just made in China and imported, so I figured why not go straight to the source. Found a web site AliExpress which attempts to connect China resources with international purchasers. The even do a holding account thing where they middle man the funds until you accept delivery. It’s not by any means perfect. Search the web, there’s lots of complaints. Funds never returned, bad merchandise, all kinds of fun. But… the price can’t be beat.

I found one seller listing what appear to be the necessary valves, sold in units of 10 with free international shipping and a substantially lower price then I’d been finding here in the states. I figured with the low, low price and free shipping, what’s the risk? So I ordered 10 units, AliExpress charged my credit card, the seller said he got my order and off we went.

Free shipping was FedEx international, so I could track the shipment all the way from China to here in the states. Was wondering how it was going to come through customs, but not a hitch. Box (slightly beat up) was delivered at my door a little more than a week after the order was placed.

Upon inspection, the valves actually looked pretty good. No identifying marks on them other than the 12VDC stamp on the solenoid. The plastic looked to be molded ok. Applied power, go the normal “click”. Tried blowing through them, seemed to be working ok with power on, power off. Wow, what a deal. So I signed off and went about my business.

Several days later…..

Attempted to actually put a Cat Faucet together using these valves. Hmmmm…. can’t thread in the 1/4″ NPT connectors. Close, but just won’t got in. First thought, they sent metric rather than english or some crazy thing like that. So actually went through all 10 valves to check them out. More interesting. 3 of the 10 thread in, mostly; but the fit is pretty right. 7 however, no go. won’t even start. Almost looks like the whole is a tad too small, but the threads look about right.

Anyway, here’s my guess. These are end-run units. discards from the end of a run where the 1/4″ NPT tap had worn down a bit and so the holes are just not quite right. Close, but just not there. NPTis kind of weird as it’s a tapered hole. Would explain why those 3 are ‘mostly fitting but tight.

So decision point. Go argue with the guy that the product description says 1/4″ NPT and 1/4″ NPT won’t fit, or try to do something else. Figured even if I go the guy to accept them back it’s a gamble with the next box will contain. at least with these I think I know the problem. So, I’ll keep’em. Get a 1/4″ NPT tap and redress the holes myself. If my theory is right, this should yield 10 functional valves at a substantially reduced price. but… for future orders I’ve still got to find something else.

A few more days….

well… got a 1/4″ NPT tap. Certainly helps re-tapping the hole, but does not really fix the problem.

The root problem is that NPT is a tapered hole and on these small valves there is not enough length to get to a normal diameter (ie a ’standard’ 1/4″ NPT tap is too long, it bottoms out before it gets full width)

So, my thought for attempted fix is trim the bottom of the tap (make the tap shorter, and thus the wider part sooner). Question is, how hardened is the tap and can I really trim it?

And more….

Ended up having to slice about a 1/4″ or more off the end of the tap. However, I was then able to re-tap both inlet and outlet holes so the normal NPT fittings work. I’ve got one pressure testing right now, but it looks like it’s going to work ok.

And finally…..

Ran through that order of valves. Decision point, go back to the same guy or risk someone (and somewhere) totally new? Classic “devil you know…” decision. So shot the vendor an e-mail, explained that I needed more valves, would like to order from him, but had to have 1/4″ NPT threading and could he deliver. Said “yes”, so gave it a shot. Couple o weeks later, new valves in hand, look to be 1/4″ NPT. Still not 100% accurate (still suspect a worn tap) but certainly functional for Cat Faucet needs.

Looks like I’ve got another board with capacitor problems. This one I’ve caught before the ultimate failure. Here’s a shot overlayed with the temperatures of the various capacitors I took with an IR sensor. Note that the right most two caps are already showing a distended top and they’re also the hottest. Can you imagine 164 Deg F?? heck the CPU is only running at 115F so it’s not airflow from the CPU heat sink warming the caps, it’s internally generated heat Certainly soon to fail…

ok, so accidentally ripped off the USB plug from the USB cable on a Magellan Roadmate GPS. Figured I’d just stick on another Mini-B cut off another cable, connect the + and – (pin 1 and 4) and be done. No go, the GPS thinks that it’s plugged into a PC and won’t navigate. Some investigation later turns up the fact that the ‘X’ pin needs to be grounded to get the Magellan Roadmate GPS to work right. (mini-usb is pin 1,2,3,x,4) and… the problem with that is trying to find a pre-existing mini-B with attached cable with the ‘X’ pin wired is dang near impossible. Ended up replacing the end with a usb mini-b with a solder tail connection like a KMBX-BP-KIT-ST30. But note that it’s a tough soldering job getting the wires in the Magellan charger soldered into the jack, including shorting X to pin 4, without shorting the whole thing out, but it is doable.

Ok, this one was in the works for some time. Now called USB-GPIO (General Purpose IO). Adding simple digital IO capability back to a PC when there is no more parallel port to use.

check it out here

not really a project, but a tutorial on how I make rectangular holes for the sensor box on the cat faucet

Quick and dirty interval timer for Nikon. It’s about as dirt cheap as they come, but it works. check out the video at the end of the project page for a sample time-lapse movie

One thing keeping me from updating the RecLight page is had another motherboard fail. As this is the 2nd one in same number of months, thought I’d document some of the problems / solutions.

The problem presented itself as the PC just randomly rebooting. the dreaded “Machine Check” error 25. Sometimes it would run for a couple of hours, then just bang like someone hit the reset button all of a sudden rebooting. Checked the usual things, the temps were OK, no disk errors, voltages, nothing installed recently, etc.

Finally took a good visual look at the motherboard. Guess what capacitors with bulging tops.

In fact all the 6.3V caps had distended tops. So I determined that was the likely culprit. bad 6.3V caps means bad 5V power on the motherboard. Now I’ve been running MotherBoardMonitor and it’s been reporting ‘normal’ voltages the whole time, so you think how could the board have bad power? The problem is the ripple, the A/C component on top of the normal 5VDC supply. The capacitors are meant to smooth that out. Bad caps, more ripple on what should be a DC power level. No way MBM samples the voltages fast enough to detect that ripple.

So, it’s on to “let’s replace the dead capacitors on the motherboard”. How to go about that? first, size’em and count’em. On this board, there are 5, 6.3V 3300uF caps (all bulging). Go buy some new ones, that’s the first step ’cause if you can’t find replacements, why bother taking the old ones out?

Couple of things to keep in mind when buying replacement caps

• of course make sure the ratings match. Note that most motherboard caps have a “high temperature” rating (ie 105 degrees)
• watch the physical size. You may find that physically it’s a tight fit. The replacement capacitors I found were slightly larger.

Once you’ve got replacement parts, now you’ve got to get the old one’s out without damaging the motherboard. This will likely be the hardest part. A good soldering iron is essential as well as a good quantity of solder-wick (braided copper).

One thing you’re likely up against is that the solder on the motherboard is lead-free, which means to you, it melts at a higher temperature than leaded solder. Worse, the power supply capacitors will likely have their negative (-) lead soldered into the ground-plane on the motherboard. Why’s this bad? well the ground-plane amounts to a (relatively) large amount of copper, which unfortunately here, is a very good head conductor. So not only do you have to get enough heat on the lead to melt the lead-free solder, you’re fighting the ground-plane which is sucking all the heat away from the lead.

On my soldering iron, I had to keep the temperature control turned all the way up and to have patience to allow the ground-plane to warm up too. You do NOT want to get antsy and try pulling the capacitor out of the holes. You’ll likely just rip off a trace and ruin the motherboard.

Some tips I can suggest

• Keep the soldering iron hot Hot HOT. The high heat will try to oxidize the tip, so make sure to keep it well tinned
• Use the solder-wick to remove as much of the lead-free solder that you can
• As crazy as it sounds, try re-soldering the capacitor lead, but use leaded solder
• You may want to repeat the wick, re-solder step a couple of times. Eventually you can get most of the high-temp lead free solder in the joint replaced with lower-temp leaded solder
• Then… apply a small dab of solder to the soldering iron and heat the lead/board joint well, let it soak up the heat a bit, then quickly apply the solder wick. The goal is to get all the solder out at one go because as soon as the top surface of solder is gone, you’ve lost your main path of heat transfer into the joint
• You’ll find that only the neg(-) lead on the capacitor will cause you grief. the pos(+) side has much less copper directly connected to it and so not the severe heat capacity issue.

Repeat the process for each dead cap and then replace with the appropriately sized replacements. For me, this gave the motherboard new life. Hopefully you’ll find similar luck!

slow on posts… Too many other irons in the fire, but am working on converting the RecLight to USB from Parallel port. Looks like it actually work on USB now, both 32 and 64 bit o/s! Need to update the RecLight page and start this moving forward again,

My article on constructing a Bluetooth interface for my car got published in the July issue of Circuit Cellar.   Page 36; “Wireless Data Exchange, Build a 2,700-lb. Bluetooth Headset”.  Give it a read when you get the chance.