fuses
- Thread starter james m
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a 1 amp fuse is basically a 1 amp fuse. It blows when the current exceeds 1 amp. There doesn't really need to be any voltage component to the fuse you are looking to replace in your cassette deck. Most standard glass fuses do have a 250 volt rating.
But I would check it out before power up, in that cassette decks very seldom blow fuses unless there is a short in the power supply or elsewhere.
But I would check it out before power up, in that cassette decks very seldom blow fuses unless there is a short in the power supply or elsewhere.
james m
Active Member
i know there was a short. i caused it when i was changing belts and got a switch in the wrong place. thanks for the info.
I found this post by accident after I changed the belts on my CT-F2121. I promptly blew three fuses. Be careful when mounting the underside of the mechanism plate - the play switch may short. Pay attention to the position of the metal actuator - it must touch the plastic side of the leaf switch. For some reason it really wants to go back the wrong way.
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Fuses go by amperes of current glass auto fuses r fine. number is amps.
not true. auto fuses may have a maximum voltage of 32v i think.
you want 125/250v fuses of the proper amperage for home products.
Right, that's typical. One thing it means is that the fuse is not guaranteed to interrupt a circuit that bears more than 32 volts, regardless of how many amps flow through the fuse.
Is it likely that a 32V automotive fuse would simply arc over, and never interrupt the circuit, if the circuit is bearing a higher voltage (like you would find in many home hi-fi circuits)? Nah, not likely. But it's not designed to not do that.
As a thought experiment, imagine what an insurance adjuster would do if a fire was caused by a piece of home hi-fi gear that had a 32V fuse installed. Again, not a very likely scenario. But the potential downside is life-changing enough that it just might be worth a few pennies and some inconvenience to get the correct part.
Cheers,
You friendly neighborhood Fuse Fusilier
This is kind of OT. Truth is, I can't honestly recall ever encountering an arc-over situation caused by an under-rated fuse. But I have seen what it can do to an under-rated speaker protection relay. Spoiler alert: the speakers were not protected. I don't think any humans were physically harmed in this episode, but I think the teenage son who had the party might have been dis-inherited.
The moral of this story is that arc-over is definitely A Thing.
(Oh - and please consider arc suppression magnets for your next high-power audio amp design.)
The moral of this story is that arc-over is definitely A Thing.
(Oh - and please consider arc suppression magnets for your next high-power audio amp design.)
Go with a fuse of rated voltage capability. What happens after the fuse opens is important. A low open voltage rated fuse (such as an automotive one) could form a plasma after blowing in a high voltage setting and possibly cause s fire. Be safe in your fuse choice.
Just finished one of these and ran into an odd fault that I thought I'd share. When reassembling the deck after changing the belts & tires and cleaning/lubing, I installed the control assembly board (RWG-049) with the factory bodge 0.22uF capacitor (green arrow) so that the top of the cap was touching one of the terminals of the play switch.
This caused one of the 800mA fuses - F3 - to blow as soon as FF/REW/Play was engaged. Turns out the the case of that cap was connected to ground so it shorted out the power rail when the play switch was activated. Bad decision by the factory to put that cap so close to the switch terminal. It was one of those dreaded solid aluminum caps and had an ESR of ~100 ohms so it needed to be replaced anyway. I put a film cap in and we're back to playing well. One more thing to watch for on this deck . . . .
This caused one of the 800mA fuses - F3 - to blow as soon as FF/REW/Play was engaged. Turns out the the case of that cap was connected to ground so it shorted out the power rail when the play switch was activated. Bad decision by the factory to put that cap so close to the switch terminal. It was one of those dreaded solid aluminum caps and had an ESR of ~100 ohms so it needed to be replaced anyway. I put a film cap in and we're back to playing well. One more thing to watch for on this deck . . . .
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I would go with only a 125V fuse and not an automotive one of same amperage rating. Fuses have voltage ratings because if that rating is exceeded and the fuse opens, the vaporized metal and any air in the fuse could ionize and continue to conduct current, enough to start a fire, especially true the fuse is in a completely enclosed fuse holder and is used at AC line voltage levels. Fuses are tested to be sure that when they open, they stay that way when tested within their specified voltage ratings. I did time-to-blow vs. amount of overcurrent testing of a company's fuse products to be sure that this ionization problem did not happen. We would also place white cheese cloth around a fuse and then blow the fuse during UL or CE validation testing. That cheese cloth could have no burn mark or brown spots on it after the fuse blew in order to pass the validation testing. There could also be no blown apart fuse pieces, either. So, use only a 125V rated fuse in your cassette player. DO NOT use an automotive one, regardless of amperage rating. In general use only the fuse specified by the equipment manufacturer for any fused equipment you may have.
