Amp is not getting remote power. This amp was playing just fine and suddenly cut off. It does nothing, dead as a doornail. No amp draw, nothing. I get power all the way up to the chip on the remote input side and no further.
Ideas welcome.
Ideas welcome.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
It may simply be a broken connection on a component or jumper. The layout is shown on the top of the board. Follow the voltage from the remote terminal towards the 494 to see where you lose voltage.
Right there. Input pin 1 I suppose of the chip is where the remote power stops. It was once suggested a capacitor may be to blame since these chips rarely fail, but the idea went no further.
Post the voltage on all 16 pins.
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 15:
Pin 16:
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 15:
Pin 16:
Hilarious, all I have is paint on this computer. Pathetic looking ain't it?
The one pin that shows 1 volt rises from zero to 1 volt over the first 30 seconds the amp is on, the others are dead except where it is marked 12 volts.
The one pin that shows 1 volt rises from zero to 1 volt over the first 30 seconds the amp is on, the others are dead except where it is marked 12 volts.
An externally hosted image should be here but it was not working when we last tested it.
I posted the list so you could copy and paste and fill in the blanks. If you don't know the pin numbering scheme, see attached.
It appears that the IC is defective or something is dragging the 5v regulated output to ground. Pin 14 is the regulated output and should have 5v on it.
As a side note... If you need a better program for drawing, download Open Office (free) and use the 'Draw' application. It's not great but it's MUCH better than paint.
It appears that the IC is defective or something is dragging the 5v regulated output to ground. Pin 14 is the regulated output and should have 5v on it.
As a side note... If you need a better program for drawing, download Open Office (free) and use the 'Draw' application. It's not great but it's MUCH better than paint.
Attachments
Pin 3 has 1 volt on it, but must rise from zero over 30 seconds to get there.
Pins 8, 12, 11 all have 12 volts on them.
What part number readily available would replace that chip? That one is a booger to find.
Pins 8, 12, 11 all have 12 volts on them.
What part number readily available would replace that chip? That one is a booger to find.
We posted at the same time, none of those TL494 will work I linked above? I should use the 594 you posted?
Thank you Perry, I'll update when it gets here. 🙂 I'll order monday, and in the meantime go out to the shed to see if the Ample Audio A226 I have blown has a spare one in it. 🙂
Hmmmm looks like I can steal IC16 by the power supply torrid in my A226
Ample Audio A226 - Amp Guts
Yeah? I wanted to fix my ample but the torrid is burned and I've accepted it's death. Might as well use parts if I can. Whadda ya think?
Ample Audio A226 - Amp Guts
Yeah? I wanted to fix my ample but the torrid is burned and I've accepted it's death. Might as well use parts if I can. Whadda ya think?
Here's the chip up close. Looks like we have a match 494 🙂
An externally hosted image should be here but it was not working when we last tested it.
Well that was.......fun. It turned on and lasted a total of about 4 minutes then started killing fuses. I put two more fuses in it thinking I had blown them since I was up pretty decently in volume and the amp (*which has protection, but will not go into protection) turns the green light on like it is supposed to, shows the green light for about 5 seconds, then something starts screaming in the amp and it kills the fuses.
I think it might be the transistor marked IFRZ48B in the power supply, but they all checked good on pins 2 and 3 for diode check.
Any other ideas what it might be?
I think it might be the transistor marked IFRZ48B in the power supply, but they all checked good on pins 2 and 3 for diode check.
Any other ideas what it might be?
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Ok, I have removed every single transistor off the walls of this amp, all of them. Power supply and audio side, everything. All of it checks out good.
The amp will power up with a green light for a second or two and start sucking amps in a dead short. It does not go into protect. IT will do it with no load or input at all, just the amp at idle on power supply voltage.
I also checked the large rectifier on the power input. Everything I have checked is good.
What next? It started this after a high volume song that was only on for about 10 seconds, just a rock song turned up reasonably loud.
The amp will power up with a green light for a second or two and start sucking amps in a dead short. It does not go into protect. IT will do it with no load or input at all, just the amp at idle on power supply voltage.
I also checked the large rectifier on the power input. Everything I have checked is good.
What next? It started this after a high volume song that was only on for about 10 seconds, just a rock song turned up reasonably loud.
An externally hosted image should be here but it was not working when we last tested it.
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Ok well it's back working. I resoldered every single place on the mobo and it fired up (sounds like the PPI 600 problem, doesn't it?). Looks like when I was hammering on it out there in the car testing it I found it's Achilles heel.
Well, I'm running this one to the pawn shop before something else goes wrong. Trade it in on a good weed eater or something. 😀
Well, I'm running this one to the pawn shop before something else goes wrong. Trade it in on a good weed eater or something. 😀
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