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Topic: Adapter for my Fender Amp Can |
Jim Cohen
From:
Philadelphia, PA
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Posted 10 Jun 2004 3:13 pm |
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OK, so I lost the adapter for my Fender AmpCan, and I can't recharge it without one. It's rated at 15vDC and 400mAmp. Went to Radio Shack and they only have one that's 15vDC and "up to 1000 mA". Is there any reason that that one shouldn't work ok?
I ask because I bought it and plugged it in and after several hours, it still has not recharged the amp at all...
Thanks,
jc |
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Jon Light
From:
Saugerties, NY
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Posted 10 Jun 2004 3:32 pm
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| Ought to work, Jim. Can you confirm that the polarity of the plug is correct? Tip negative (or positive, depending on the amp's specs)? |
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Blake Hawkins
From:
Florida
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Posted 10 Jun 2004 3:58 pm
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Jim,
According to the Fender Service Diagram for the Ampcan. Their "15 volt" power supply actually puts out 20 volts.
They run that into a 15 volt regulator which then charges the battery and operates the amp.
In order for the regulator to work properly, you need to hit it with at least 18 volts.
It is possible that your Radio Shack Power Supply puts out only 15 volts, which would be insufficient to charge the battery in the Ampcan.
Blake |
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Jim Cohen
From:
Philadelphia, PA
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Posted 10 Jun 2004 4:22 pm
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| Wow, thanks guys. Jon, yes the polarity is correct (tip positive). Blake, I had no idea. I don't think Radio Shack had one rated any higher than 15v. Anybody know where I can get one of those? Also, is it possible that if I buy, say a 20v one, it will damage the Ampcan? |
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Blake Hawkins
From:
Florida
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Posted 11 Jun 2004 7:48 am
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Jim, Here's probably more than you want to know about the Ampcan power supply.
To answer your question. You can put 20 to 24 volts into it with out hurting anything.
The power goes through a 1N4003 diode, which
protects the amp if you get the polarity wrong.
Then it goes to a 7815 voltage regulator.
The 7815 will typically run on about 23 volts input and will stand up to 35 volts before it blows.
Fender's power supply gives out 20 volts
which operates everything OK.
There is also a fuse in series with the battery. If the fuse is blown, the amp will not operate on the battery and the battery will not charge no matter which power supply you use. Also,with the fuse blown, the amp itself will probably work with the charger connected.
If you have access to a voltmeter, it would be worthwhile to measure the actual output of your Radio Shack Power Supply.
The best bet is to obtain another Fender power supply for it.
Blake[This message was edited by Blake Hawkins on 11 June 2004 at 08:53 AM.] |
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Jim Cohen
From:
Philadelphia, PA
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Posted 13 Jun 2004 12:11 pm
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| Great information, guys. Thank you all very much. |
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Jim Cohen
From:
Philadelphia, PA
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Posted 16 Jul 2004 2:21 pm
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Latest update: I finally got a replacement adaptor/charger from Fender for the amp can. Plugged it in and charged it up: No sound! Not when charged, and not when plugged in, even.
Is it possible that my earlier attempt with a non-Fender adaptor ruined the amp?
What to do now?
It says not to open it up ("No User-Serviceable Parts", etc.) and that to do so could lead to fire or injury (well, it does have a full charge of electricity stored in it now...) Yet, if I have a professional try to repair it, it'll probably cost too much, given the original cost of the amp is maybe around $175.
Ideas?
Thx,
jc |
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Blake Hawkins
From:
Florida
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Posted 17 Jul 2004 5:25 am
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Jim,
I don't think you could have hurt it with the RS adapter, the amp has protection built into it.
Does the green "charge" light come on when you plug the adapter in?
Actually, there are two lights. A green one that only comes on when the adapter is plugged in and a red/green one that indicates the battery condition.
With the adapter plugged in and the power switch on, you should have two green lights.
With the adapter unplugged, when you turn the power on you should get a green light unless the battery is low, then the light would be red. If the light does not come on, then probably the internal fuse is blown.
If you plug the adaper in will the amp run?
The internal fuse is in series with the battery. If it is blown, the battery will not charge.
If you can open the amp , the fuse should be easy to find.
You can check it with an ohm meter.
Note: The way the "charge" light is wired it only tells you that the adapter is plugged in. If the internal battery fuse is blown,
the "charge"light will still come on, making you think it is charging the battery, when in fact, it is not.
Sorry I'm not closer to you. I'd be glad to fix it for you at no charge.
Blake[This message was edited by Blake Hawkins on 17 July 2004 at 06:36 AM.] [This message was edited by Blake Hawkins on 17 July 2004 at 08:34 AM.] |
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Jim Cohen
From:
Philadelphia, PA
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Posted 17 Jul 2004 1:32 pm
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| Thanks, Blake. Yes, the green light comes on when I plug in the charger. The OTHER green light comes on when I turn the power switch on, even if it is NOT plugged into the wall outlet. So... it "appears" to be holding a charge but I still get no sound out of it. If I can't figure this out and you'd be willing to look at it, I'd be willing to pay the round-trip shipping. Otherwise it's gonna sit here a long time! |
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Blake Hawkins
From:
Florida
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Posted 18 Jul 2004 6:23 am
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Jim,
Since both lights come on, that means your power system is OK.
I'll be glad to look at it for you.
Check your e mail for my address.
Blake |
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