Author Topic: Rx-v675 ACPWR_DET Low  (Read 341 times)

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Offline mjk52Topic starter

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Rx-v675 ACPWR_DET Low
« on: December 30, 2024, 12:45:15 am »
Hi,

I've been puzzling with this receiver for a while now. Is there a specific IC I should be looking at that generates this acpwr_det voltage?
My receiver is showing this voltage as 3.0V instead of 3.3V.
After searching here I saw that the 3.3M is not generated from the OP(3) board. Is it the same for ACPWR_DET?

Receiver works perfectly fine when I am able to switch it on, but cuts off after a bit of running. I sometimes get a PS3 fault, but not all the time.

Thanks in advance.

Edit.
The voltage readings on the onboard sensors all show within range, the PS1 is not constant, it reads from 114-118
PS2 is constant at 120
PS3 is constant at 154

However on the protect faults. PS3 has an entry showing 95. So it would have been low.
After going into no protect to check the voltages and faults, the receiver switches on perfectly fine and runs perfectly fine for a while, then switches off with usually the PS3 fault. I haven't seen anything physically wrong with any of the caps, and have even replaced the usual yamaha caps just in case.

The 3.3M voltage is perfect all the time. It's just the acpwr_det that is low.

« Last Edit: December 30, 2024, 05:56:06 am by mjk52 »
 

Offline mjk52Topic starter

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  • Country: za
Re: Rx-v675 ACPWR_DET Low
« Reply #1 on: January 03, 2025, 08:14:29 am »
Hi, I've checked ic84, 85 both those regulators are working fine. Outputs are normal, 3.3V.

IC83 main processor, pin12 is showing 2.99/3v same as all the other obviously marked acpwr_det points.

There's nothing in the schematic that I can see that shows what is generating that acpwr_det voltage. If anybody else has an idea please let me know.

The other thing that is now not working is the standby LED. I see no voltage going to it, so I'm not sure if that is also part of yamahas protection.

« Last Edit: January 03, 2025, 01:31:34 pm by mjk52 »
 

Offline m k

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Re: Rx-v675 ACPWR_DET Low
« Reply #2 on: January 13, 2025, 10:17:02 am »
3.3M is a power source for standby LED and it's generated by IC85.

So if IC85 is fine somewhere must be a contact problem.
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