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ampeg BA-112 Fuse Rating and Type

Discussion in 'Amps [BG]' started by thehangingmist, Dec 9, 2013.


  1. thehangingmist

    thehangingmist

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    So the combo suddenly wont turn on and turns out the fuse is blown (checked with a multimeter)
    so it says "replace with fuse with same type and rating" how hard was it to just put the details right there?

    help me out with this please! i need to find out the right type and rating for this amp!
    on the original fuse it says 250v 800mAH in fine print! is that what am looking for? there is a bunch of stuff written on the PCB where i got the fuse out from but i think those numbers are for other stuff right there!?:confused:
     
  2. ArtechnikA

    ArtechnikA I endorsed a check once... Gold Supporting Member

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    Since it varies with the local power, and they don't know where you'll be using it when they made it - pretty hard...

    At first I was going to refer you to the manual, which is online, but the information is not in the manual! So I agree it oughtta be there, at minimum...

    800 mA I could believe.
    Yes - those sound like plausible ratings.
    Now you just have to find a fuse with those ratings in the exact same shape and size.
     
  3. thehangingmist

    thehangingmist

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    nothing in the manual. this amp was made in china. lets not start a debate about MIC now shall we :)
    anyway here in India the voltage ranges from 220-240v but again just to be sure, does the 800mA part sound ok to you?
     
  4. RustyAxe

    RustyAxe Supporting Member

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    According the schematic it's a 240V .8 amp slo blo fuse (IEC 127). The 250V would be fine, too.
     
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  6. ArtechnikA

    ArtechnikA I endorsed a check once... Gold Supporting Member

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    Since Rusty has a schematic to refer to, definitely go with that. However, we're all saying the same thing: 800mA (0.8A) at 250V.

    I already noted it wasn't in the manual, and IMO should be.

    I have no debate over where it's made, other than to note with some irony that the last page of the manual (http://www.ampeg.com/manuals/BA-112.PDF) proclaims "Ampeg is proudly Made in America." So two strikes on the manual ;-)
     
  7. thehangingmist

    thehangingmist

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    I could only find 1A fuses in the market! Word of advice?
     
  8. thehangingmist

    thehangingmist

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    Need to get it working pronto!
    A local tech here says 1A fuse would be OK he would put one in the amp as u cannot find 800mA here anyway and its a tiny difference. Is tiny enough to go with it?
     
  9. ArtechnikA

    ArtechnikA I endorsed a check once... Gold Supporting Member

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    Look, no one is going to tell you 1A is fine and go do it.

    BUT - I can tell you that some people would do it.
    I might even take it on my personal responsibility to do it, and watch (and listen, and smell...) really carefully.

    There's risks you are willing to take on your own, and there's risky behaviour you recommend to someone else. So I can't recommend you do it. But I'll just observe that I probably would in my own amp (never for a customer).

    Especially if you can find a 1A that is -not- a slo-blo. (But buy a few, just in case the startup surge takes it over the edge, in which case, slo-blo it is...)

    Keep that 800mA fuse on your shopping list and replace it when you can. Be very, very aware of any signs of overheating or stress if you do this which, I remind, I am not recommending ;-)
     
  10. thehangingmist

    thehangingmist

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    thanks a lot! i got a couple of 1A fuses i dont think they are slo blo! the guys behind the counter dont know what slo blo is, ill have to find another local term for it i guess! anyway so i have 1A fast blow fuse. it says "F1A" am gonna go looking for slo blo again tomorrow just to see if i can find any!
    ill try putting in the 1A fuse i do have because the tech i was going to to take it to said he would put the same 1A fuse in if i took it over to him and he is the only "Tech" i know who just fixes amps for a living so hmm ok "ill try it" ;) ?
     
  11. B-string

    B-string Gold Supporting Member

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    Slo-Blo is also known as "time delay". I might use a 1 amp personally for testing if I "had" to, but would not return it to a customer with the over-rated fuse. That is 200ma over the protection spec. (20% overrated).
     
  12. ArtechnikA

    ArtechnikA I endorsed a check once... Gold Supporting Member

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    25% actually, if the original spec is 800 mA.

    I'd never even have suggested it if the original fuse had blown.
    Putting an over-rated fuse into a product that has already blown one is (as I know you know) a really bad idea.

    But since the original failure was mechanical, not electrical, I think 'do it but be careful' might be a personal choice. I expect it'd void the waranty as well...

    DigiKey lists 194 800mA 250V slo-blo fuses. I expect many are inappropriate form factors but this is all I have to go on, having never seen the amp in question. I have no idea what's available in New Dehli...
     
  13. B-string

    B-string Gold Supporting Member

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    Yes 25%, multitasking :). I was just reaffirming this would be a test and carefully look/listen/smell and not a permanent use.

    To the OP a 1 amp fuse is 1000ma.
     
  14. RustyAxe

    RustyAxe Supporting Member

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  15. thehangingmist

    thehangingmist

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    Still haven't been able to find one! Should have just looked up on ebay or something a week back!
    A tube amp maker from another city said he has 1A slo blo fuses. I can order those now this is not fun :|
     
  16. ArtechnikA

    ArtechnikA I endorsed a check once... Gold Supporting Member

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    I would not use a 1A slo-blo unless it's absolutely all you can get.
    You have already over-rated the fuse by 25% just using the 1A.
    If the 1A will withstand the turn-on inrush surge, call it good.
    800 mA slo-blo is really what you need...
     
  17. BassmanPaul

    BassmanPaul Gold Supporting Member

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    nBack in the day in the UK these were known as Surge Resistant or Anti Surge. I am concerned about the fact that the fuse blew in the first place. It could well be that the amp has a problem.
     
  18. ArtechnikA

    ArtechnikA I endorsed a check once... Gold Supporting Member

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    For some reason, I was convinced that the OP had reported that the fuse was _broken_ i.e. mechanical failure. But in fact, upon review, he just says "blown."

    So - yeah - I agree...

    Uprating the fuse 'because it blew' is very bad, and a 25% uprate and slo-blow besides especially bad...
     
  19. Woodstockz

    Woodstockz

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    Often a blown fuse is indicative of some other problem, like a blown power amp or power supply. If it blows again, that's probably what is happening.
     
  20. thehangingmist

    thehangingmist

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    Ok so its been a while. Ive been practicing on a loaner combo but it needs to go back now. All i do have is a bunch of 1A slo blo and regular fast fuses. I haven't tried any yet! I really hope it just works fine once i put a fuse in it. Should i go all the way and find 800mA on ebay? Ill first check if the amp is otherwise ok for not with these fuses that i have i guess. Damn#
     
  21. B-string

    B-string Gold Supporting Member

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