Question for the electrical engineers...

[glowstix]

I'm wondering if it's possible that perhaps there's a slight power fluctuation in the building wiring itself that these boxes are sensitive to...while no other electronic system in the salle is affected.

If it IS a power problem, would plugging the boxes into a power strip with a surge protector help?

Thanks

its the machine. if other clubs are using the same box with no problems then it's your box. this is more of a technician's problem than an engineer.

[SJCFU#2]

its the machine. if other clubs are using the same box with no problems then it's your box. this is more of a technician's problem than an engineer.

And both machines have the same problem?

Simple test - take one (or both) of the machines somewhere else and see how they behave. If the problem goes away then it is something at the club.

[blue_falcon]

I personally like penguin's solution of "percussive maintenance" (aka hitting the darned thing). It's quick, it's cost effective, and, while it may not solve the problem, it'll give you a solution (you hit it enough, it'll break and you'll have to replace it anyway). He must be one of these real-world engineers!

But seriously, SJCFU#2's proposal makes the most sense. Isolate the problem first, then look for solutions.

[RITFencing]

I personally like penguin's solution of "percussive maintenance" (aka hitting the darned thing). It's quick, it's cost effective, and, while it may not solve the problem, it'll give you a solution (you hit it enough, it'll break and you'll have to replace it anyway). He must be one of these real-world engineers!

Nah, a real world engineer would never have neglected the vital step of cursing at it and threatening to turn it into a voice activate toaster oven. Works pretty well on my computer.

[Purple Fencer]

I hadn't thgought ot check both boxes at the same time....they're mounted on opposite sides of hte pole, tho, so it'd be hard to see.

IU keep forgetting to say that we have tried different power supplies (external ones), but still had the same problem.

I'm goving the boxes to BSL to check...when they come back I'll try putting them on different outlets....

Thanks for all the ideas, guys.

[ThatReallyHurt]

Have you tried taking the reels off and watching them to see if they still reset? I don't mean switching reels, I mean removing them entirely... Larrison's idea about interference, the reels and their cords are basically two antennae, perhaps they're picking up someone's cell phone call.

[RITFencing]

Have you tried taking the reels off and watching them to see if they still reset? I don't mean switching reels, I mean removing them entirely... Larrison's idea about interference, the reels and their cords are basically two antennae, perhaps they're picking up someone's cell phone call.

Doubtful; the metal boxes around the coiled wires would act as a faraday's cage, shielding the stuff inside. Also, the inductance of the coiled wire will change as the number of coils does (ie during fencing) which will change the frequency the circuit will resonate the most. If they've changed power supplies before, it's most likely a problem with the box. There may have been a bad batch; it happens.

[ThatReallyHurt]

Doubtful; the metal boxes around the coiled wires would act as a faraday's cage, shielding the stuff inside. Also, the inductance of the coiled wire will change as the number of coils does (ie during fencing) which will change the frequency the circuit will resonate the most. If they've changed power supplies before, it's most likely a problem with the box. There may have been a bad batch; it happens.

Okay, but reducing the number of parts involved will help in troubleshooting...

[RITFencing]

Okay, but reducing the number of parts involved will help in troubleshooting...

It's true that eliminating the reels wouldn't hurt.

[Purple Fencer]

WHen I get the boxes back, I'll put them on the other pillar....that'll put them on a different set of reels AND a different power outlet.

[EricS]

The symptoms you describe sound like an ESD discharge. Since you probably don't leave the boxes turned on unless you're fencing, the discharge probably occurs from static buildup formed by the constant motion between the fencers shoes and the rubber floor. Try leaving the boxes turned on with nobody using them.

As an aside, surge protectors are not AC line filters. Take apart a surge protector sometime--you will find several small round objects, often with a blue coating. These are Metal Oxide Varistors (MOVs), which shunt high voltage spikes to prevent them from reaching the equipment connected on the other side. Smaller voltage spikes and voltage sags pass right through. Some power strips include a small inductor, but generally it's too small to do any good.

[SJCFU#2]

WHen I get the boxes back, I'll put them on the other pillar....that'll put them on a different set of reels AND a different power outlet.

Make sure that the "different power outlet" is connected to a different circuit breaker - otherwise you if the problem is in the wiring somewhere between the breaker box and the outlet then you will probably still be connected to it.