how hot is that chip...
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| Author | Content |
|---|---|
| cr Jan 06, 2011 12:46 PM EDT |
...when you go into your bare-to-the-world routine? If it's nasty-hot to a fingertip, its problem might be a lack of ventilation. In which case, you can't very well put new holes in the case, but maybe you can glue on a thin heatsink to give it a better share of whatever cooling is available within. |
| Steven_Rosenber Jan 06, 2011 2:02 PM EDT |
That's a good idea. It's the wired interface that's giving me trouble. I'll have to look for it when I crack the case the next time. |
| cr Jan 06, 2011 2:45 PM EDT |
Check out allelectronics.com to see what they might have available for glue-on heatsinks. All-Electronics is in Van Nuys, so they're local to you; they're an electronics/electromechanical surplus house. I've bought a bunch of stuff from them. I'm sure they're in business; other places I bought parts from when I lived in SFV&Simi ('80-'93) might not be. Sandy's Electronics is probably still in business, but they sell only new stuff and they're pricey (I mainly bought tools and prototyping parts from them). Still, if you can't find what you need at All, give 'em a try. |
| Steven_Rosenber Jan 06, 2011 4:00 PM EDT |
I've been to All-Electronics many times. That's definitely the place to go for smallish heatsinks. |
| hkwint Jan 06, 2011 4:40 PM EDT |
No no no, please don't do that, don't buy a glue-on heatsink! Last time I did this, the glue couldn't stand the temperature, heatsink fell of and southbridge 'burned', which meant farewell to my mobo. Even though I bought an official pre-glued fan! Which of course ought to stick until at least 60C I'd say, but it didn't. Please reconsider twice! |
| Steven_Rosenber Jan 06, 2011 5:19 PM EDT |
I don't think my problem is heat-related. I think it's an intermittent short. |
| cr Jan 06, 2011 8:29 PM EDT |
Quoting: I don't think my problem is heat-related. I think it's an intermittent short. Or an intermittent open, more likely, but it might still be heat-related (the way you originally described it sounds like it to me). I recently had my older son come to me with wall-wart power adapter in hand, saying that the connector had to be plugged into his synthesizer (a consumer-grade Yamaha) just-so to get power into the thing. Suspicious, I pulled out meter and resistor box and clipleads, held the plug end of the cord in a bench vise and wiggled it all around, but even on the 'scope there was no glitch, no outage. I had him bring the keyboard down, and opened up the case for a good look around. Bingo -- the hot lead of the coaxial power jack had worked free of the solder, which looked like your typical crappy crusty wave-solder job where they get as many boards through as possible before reloading the tank, counting on the touchup person not missing anything. The joint itself looked like it started out weak, then, once fractured, cooked itself to failure. One joint-resoldering later with good-quality solder and the keyboard was stone-reliable again. Cr@ppy solder isn't uncommon in consumer goods, especially from the cheaper corners of Asia, and yes, you can get thermal intermittents, such as when a marginal solder-joint on a gull-wing SM lead comes free under thermal load and the lead plays thermostat, just kissing the pad when cold; you can use up a lot of Freez-Mist chasing such a fault. Touching up that kind of solder job (surface-mount with fine lead-pitch on zap-prone packages) is a job for a tech with experience, good eyesight and the right equipment. Even when I could see and solder the leads of a QFP44 package unaided (twenty years ago) I did so only under duress, and I had spares waiting to be programmed and installed if I screwed up the first one. Fortunately, the pins of jacks are suspect right off, because they're subject to a lot of physical force just from inserting and removing the mating connector, never mind the torque a plug can deliver when cable and machine move in different directions. Trying flexing the ethernet cable while running saturation pings (ping -f; best if it's a crossover cable between two machines) to see if you can provoke some dropout; if so, check where that jack is mounted first. If the fault's there, and you can get to it with a good iron and thin solder, you can touch it up yourself if you're brave. Of course, if saturation pings reliably cause the chip to stop working, without any flexing whatsoever, the chip might need a heatsink after all. |
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