Planet Audio ZR300.4

[o. l. t.]

We posted at the same time, none of those TL494 will work I linked above? I should use the 594 you posted?

[Perry Babin]

I would use the part I suggested. The ICs (494/594) are essentially identical.

[o. l. t.]

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.

[o. l. t.]

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?

[o. l. t.]

Here's the chip up close. Looks like we have a match 494

[Perry Babin]

It's the same IC.

[o. l. t.]

I got a power light!!!!!!!!!!!!!

(I'm happy)

Thanks Perry

[o. l. t.]

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?

[o. l. t.]

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.

[o. l. t.]

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.