B&F Enterprises "Digital Clock" flakes out
7 years 10 months ago #4821
by Dr. Optigan
My website: www.electronixandmore.com/adam/index.html
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Replied by Dr. Optigan on topic Re: B&F Enterprises "Digital Clock" flakes out
Yeah, whoever built this thing did a ham-fisted job of soldering it together. Appropriate, because I found it at a ham radio-related flea market...
I'll have to try cleaning the old flux off and check the joints when I go in there to re-seat the ICs. I'm not entirely convinced that the issues with the board are entirely due to the builder; my friend (who's an engineer) was cursing the size of the holes in the board, as well as the fragile condition of the wires connecting the switches and such to the board. I'll take some pictures of the component side of the board when I next remove it from its stand-offs.
The most annoying part of this clock's issues is that it seems entirely random; it'll run hours without a glitch, or it'll glitch up within a minute or so of being plugged in, and then run glitch-free for several hours. Also, there's no consistency to what it does during the glitch; it'll skip ahead several hours, or just a couple of minutes. In addition, tapping on the casing doesn't have any noticeable effect on how the clock works.
All in all, it definitely looks like I inherited someone else's problem.
I can't help but wonder if this glitching issue is what a previous repairman was trying to fix by replacing most of the ICs. As they say, you get what you pay for, and considering that I paid only $5 for this thing... 
-Adam
I'll have to try cleaning the old flux off and check the joints when I go in there to re-seat the ICs. I'm not entirely convinced that the issues with the board are entirely due to the builder; my friend (who's an engineer) was cursing the size of the holes in the board, as well as the fragile condition of the wires connecting the switches and such to the board. I'll take some pictures of the component side of the board when I next remove it from its stand-offs.
The most annoying part of this clock's issues is that it seems entirely random; it'll run hours without a glitch, or it'll glitch up within a minute or so of being plugged in, and then run glitch-free for several hours. Also, there's no consistency to what it does during the glitch; it'll skip ahead several hours, or just a couple of minutes. In addition, tapping on the casing doesn't have any noticeable effect on how the clock works.
All in all, it definitely looks like I inherited someone else's problem.
I can't help but wonder if this glitching issue is what a previous repairman was trying to fix by replacing most of the ICs. As they say, you get what you pay for, and considering that I paid only $5 for this thing... -Adam
My website: www.electronixandmore.com/adam/index.html
Goofy music:
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7 years 10 months ago #4824
by Ty_Eeberfest
Seriously, the intermittent nature of the problem(s?) is why I won't even guess at a specific part as a cause. It's also why I bothered to comment about flux and crappy assembly. I wasn't just punting; experience has taught me that poorly soldered dirty boards will often appear to be working fine when in reality signals are weak or noisy and the whole mess is just waiting for a cosmic ray or a change in room temperature or a stray freakin' neutrino to put it over the edge.
If you can get ahold of 1,1,1-trichloroethane it would be reasonable to soak the entire board in it.
Something else to worry about: if the board itself is as cheaply made as it sounds, you could have cut traces that are only cut at certain temperatures (or ???) and just a little bit resistive at other temperatures.
Giving the board itself sharp whacks with a wood dowel (or something) while the clock is operating wouldn't hurt anything and if you're real lucky it might help localize the problem.
Look into it later when the dust is clearing off the crater.
Replied by Ty_Eeberfest on topic Re: B&F Enterprises "Digital Clock" flakes out
But of course... if it was a repeatable problem you could find it, fix it and move on to the next project... but where's the fun in that??Dr. Optigan wrote: The most annoying part of this clock's issues is that it seems entirely random;
Seriously, the intermittent nature of the problem(s?) is why I won't even guess at a specific part as a cause. It's also why I bothered to comment about flux and crappy assembly. I wasn't just punting; experience has taught me that poorly soldered dirty boards will often appear to be working fine when in reality signals are weak or noisy and the whole mess is just waiting for a cosmic ray or a change in room temperature or a stray freakin' neutrino to put it over the edge.
If you can get ahold of 1,1,1-trichloroethane it would be reasonable to soak the entire board in it.
Something else to worry about: if the board itself is as cheaply made as it sounds, you could have cut traces that are only cut at certain temperatures (or ???) and just a little bit resistive at other temperatures.
Giving the board itself sharp whacks with a wood dowel (or something) while the clock is operating wouldn't hurt anything and if you're real lucky it might help localize the problem.
Look into it later when the dust is clearing off the crater.
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