# Audiomobile SA1600 blows pico fuses



## caraudionovice (Dec 13, 2014)

I hope this unit qualifies as "Old School"! My SA1600 was built in May 1984 & I have owned it and the vehicle it came in since March 1986. Years ago I had problems with the two right channel pico fuses blowing, but did not have to do any internal amp repairs to solve the problem. It has been setting for years and recently I hooked it up and it blew all four (L & R channel) 5 amp pico fuses immediately when power was applied. The speakers are not shorted & the four subs have been replaced. I tried it with a new head unit, and with and without the front speakers & fader connected, similar to a SA1200 hook up. I have removed the system from the vehicle to replace all the carpeting, but it is connected on a work bench. What next?
I have a few additional questions, Is it worth fixing? Does it have any value? What would be a basic budget unit that I could hook up to all the existing speakers with the new head? 
Any opinions and suggestions welcome.


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## ween (Mar 12, 2009)

If it blows fuses with no speaker wiring connected, then it is internal. There are four diodes, (D5, D6, D12, D13) after each picofuse. They are connected across the power input to each amplifier section. If power to the amp was connected reversed, the diodes will short, blowing the picofuses. This hopefully protects the amp from reverse polarity. I'll take the amp off your hands, but I'd fix it  The amp is stable to 1 ohm (each channel) with the correct picofuse. It's rated at 40W x 4 @ 2 ohms..if you were looking for something similar. If it was running four 2 ohm subs, those channels would be 80W each.


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## caraudionovice (Dec 13, 2014)

ween said:


> If it blows fuses with no speaker wiring connected, then it is internal. There are four diodes, (D5, D6, D12, D13) after each picofuse. They are connected across the power input to each amplifier section. If power to the amp was connected reversed, the diodes will short, blowing the picofuses. This hopefully protects the amp from reverse polarity. I'll take the amp off your hands, but I'd fix it  The amp is stable to 1 ohm (each channel) with the correct picofuse. It's rated at 40W x 4 @ 2 ohms..if you were looking for something similar. If it was running four 2 ohm subs, those channels would be 80W each.


Thanks ween. I'll have to check it with no speakers connected to see if the picofuses blow. Please clarify, You say "stable to 1 ohm with correct picofuse", does the picofuse add something to the circuit besides a 5 amp level of protection?? 
In the mean time, I've started to look for a replacement amp. I checked with one of the Crutchfield tech advisors, he said that the SA1600 was 160 watts RMS X 4 @ 4 ohms and suggested several Alpine amps at $749 & $799. 
I'm not ready to spend any where close to that much $$$. So I've been checking out a couple of Boss Phantom 4 & 5 channel units, a PH4.600 or a PV3700, they both received good reviews, but are probably overkill for what I need, but would leave room for expansion. At $100 and $125 @ Amazon, that's more what I'm willing to spend. I really do not understand the specs of the amps enough to make a good decision. If you have the time I'd be interested in your opinion of the two amps I mentioned above. 
I'll keep you in mind, & PM you if I decide to just go with a new amp. What part of the country are in? Thanks again!


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## ween (Mar 12, 2009)

Here's some info: http://www.diymobileaudio.com/forum/1355894-post3772.html ...read the article. 5A at 12V...60W assuming 100% efficient, which it isn't. The article states it did 40W @t 2 ohms. Ohm's law I^2*R=P, solve for I...approx 4.5A. So there's the 5A picofuse. 80W @ 1 ohm...approx 8.8A. There's the larger picofuse value needed. There's no power supply (dc/dc converter) in the amplifier, it'll do a 1 ohm load. The 1600 is 160 total watts, 40w x 4 @ 2 ohms. The 1200 didn't have rear speakers so 120W, 40w x 2 @ 2 plus 20w x 2 @ 4. Are your replacement subs 2 or 4 ohm?


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## caraudionovice (Dec 13, 2014)

Thanks for pointing out that article, that explains it better. Quite a system for the time! The system has a total of 12 speakers. 6 sets, Each set of 2 speakers = 4 ohm except for the subs which = 2.5 ohm.


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## ween (Mar 12, 2009)

If the picofuses blow with speaker wiring connected, and don't without, inspect the speaker wiring for shorting to the vehicle chassis/body.


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## caraudionovice (Dec 13, 2014)

ween said:


> If the picofuses blow with speaker wiring connected, and don't without, inspect the speaker wiring for shorting to the vehicle chassis/body.


Ween, I disconnected all inputs & outputs to the amp & momentarily connected power, all four internal fuses blew out.


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## ween (Mar 12, 2009)

Definitely something internal. As worth fixing hard to say. If it's just the diodes that are bad, plus the picofuses, of course, that less than $10 in parts. You'd need to determine if that is the extent of the damage. Then labor to repair, probably 1/2 hour. Don't know what shops are charging though. What head unit are you using...you stated it's new.


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## caraudionovice (Dec 13, 2014)

ween said:


> Definitely something internal. As worth fixing hard to say. If it's just the diodes that are bad, plus the picofuses, of course, that less than $10 in parts. You'd need to determine if that is the extent of the damage. Then labor to repair, probably 1/2 hour. Don't know what shops are charging though. What head unit are you using...you stated it's new.


Ween, Internal, that's what I thought. I'm not going to dig into the SA1600, or pay to have it fixed. The cost of many of the new amps is so reasonable. So I'm just going to order a new one. The head unit, I bought before I realized the amp was toast, is a cheap Pyle PLR-27MPBU ($28 @ Amazon). I'm also looking at the Boss Audio PV3700, ($125 @ Amazon) it's a 5 channel amp with plenty of power. Thanks for your help.


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## ween (Mar 12, 2009)

The amp looks as if will suit your needs fine. Has four channels input, remote bass level, built-in crossovers, ample power. If you'd like to part with the blown up SA1600, I'd like to purchase it, recover some money spent on the new amp.


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## caraudionovice (Dec 13, 2014)

ween said:


> The amp looks as if will suit your needs fine. Has four channels input, remote bass level, built-in crossovers, ample power. If you'd like to part with the blown up SA1600, I'd like to purchase it, recover some money spent on the new amp.


PM Sent!


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