Yamaha RX-V373 not powering up

[Rupsenkind]

Hi all,

I've a Yamaha RX-V373 which does not power up, only main relay clicks and then falls back, already checked the following:
- DIAG or Advanced menu does not work
- All relevant sub voltages are available (5-7-12V)
- According to the SM,IC's 268-262 and 261 should give 1.3V, 1.2V and 3.3V but at all I measure around 7V at pin 1 (so output voltage is equal to input voltage 7V)
- As a try I swapped IC-262 for a new one but still measuring 7V output.
- As these 1.3,1.2 and 3.3V voltages are feeding processors (a.o. uP and DSP) I assume this is the reason why the unit doesn't start up due to the voltage errors. For now I'm stuck where to look further and am hoping that someone had the same issue and can provide some tips/guidelines. Any help is welcome.

[R_J]

Re: Yamaha RX-V373 not powering up

I suspect you are using the wrong ground to check the voltage, use the DG digital ground for these voltages. I suspect the unit is going into protection due to a faulty audio output ic.

[Rupsenkind]

Re: Yamaha RX-V373 not powering up

Hi RJ, ok I've measured between pins 1(+) and 4(ground) of the IC's but still have around 6V in stead of the 1.2V and 1.3V what it should be....
To your suspicion of faulty output IC:
1) I've disconnected the AC connections from the transformator to the board that feeds the driver amps, so based on that at least it should start up with display but it doesn't
2) In case one of the driver amps is bad I still should be able to get into the DIAG menu which then would give me the DC-PRT xxx message. Or do you have an experience with a faulty driver IC that caused the amp to be dead completely? Appreciate your feedback!

[lotas]

Re: Yamaha RX-V373 not powering up

Hi RJ, ok I've measured between pins 1(+) and 4(ground) of the IC's but still have around 6V in stead of the 1.2V and 1.3V what it should be....
To your suspicion of faulty output IC:
1) I've disconnected the AC connections from the transformator to the board that feeds the driver amps, so based on that at least it should start up with display but it doesn't
2) In case one of the driver amps is bad I still should be able to get into the DIAG menu which then would give me the DC-PRT xxx message. Or do you have an experience with a faulty driver IC that caused the amp to be dead completely? Appreciate your feedback!

What are you measuring? You need to measure not between 1 and 4 pins, but between 3 and 4 pins.

[Rupsenkind]

Re: Yamaha RX-V373 not powering up

Tnx, see the mistake I made, measuring between 3-4 of the IC's provides the correct voltages. Also on the UPc IC voltages are correct so it may be assumed that the start up circuit works ok. Will check if UPc sents out start PWR RY 3.2V.

Also checked the 0.22 ohm protection resistors of the driver ic's but they all measure ok, so any reason to assume that the issue could be one of the IC's? Again I would expect in case of faulty end stage that at least unit would power up and then shuts of due to protection and you still would be able to enter DIAG menu, which is not the case. Display doesn't light up in any circumstance..tnx again for your support.

[lotas]

Re: Yamaha RX-V373 not powering up

Try this - connect to the network (220v) hold down the "TONE CONTROL" and "STRAGHT" buttons and press "POWER"

[lotas]

Re: Yamaha RX-V373 not powering up

More - Unplug the receiver

Hold down the "TONE CONTROL" and "INFO" buttons

Then connect the receiver to the network

And then press the "Power" button and hold all 3 buttons for at least 3 seconds.

[Rupsenkind]

Re: Yamaha RX-V373 not powering up

Hi lotas, that's what I tried already > getting in DIAG menu (tone control + straight + power) or Advanced Setup Menu (tone control + info and connect to power outlet). In both cases receiver does not start, only main power relais comes up and falls back again, so it doesn't look that protection circuit is activated, unit simply doesn't power up.
I checked the 3.2V PWR RY at CB151 once power button has been pushed and that's there but should be as the main relais is being activated shortly......

[tibimakai]

Re: Yamaha RX-V373 not powering up

In cases like this, I suspect amp shortage and I just start measuring the final transistors for shorts. Maybe unplug the amp section?!

[Rupsenkind]

Re: Yamaha RX-V373 not powering up

Hi Tibimakai, as mentioned earlier in the thread I disconnected the AC connection from transformer that feeds end stage but no result but anyway I'm one step futher: allthough nothing pointed at the driver stage based on measurements I decided to swap the STK433-330 and now the unit starts, at least I hear the driver stage relais coming up and I can switch off the unit again. But the display doesn't light up at all so I guess there was a double failure in the unit: both STK IC and display have an issue. Will now measure the display section to see where it goes wrong. Again many thanks for all ideas and tips! Cheers, Rob

[Rupsenkind]

Re: Yamaha RX-V373 not powering up

Update: voltages around display all ok, funny thing: display was set to -3 so nothing to see.. put it back to 0 and voila... only things still missing now: 1) sound, nothing coming through all inputs nor USB 2) Advanced Setup Menu: when entering the advanced setup menu the display only shows trash, nothing readable, strange enough the DIAG menu works fine. Already looked for latest firmware for this unit but it seems that Yamaha never has released another FW version than implemented during manufacturing....to be continued...

[lotas]

Re: Yamaha RX-V373 not powering up

Do you need firmware?

[Rupsenkind]

Re: Yamaha RX-V373 not powering up

Hi Iotas, if you would have FW for this one I would certainly try this. Just let me know how you want to sent it to me. Tnx!

[lotas]

Re: Yamaha RX-V373 not powering up

Hi Iotas, if you would have FW for this one I would certainly try this. Just let me know how you want to sent it to me. Tnx!

See private messages.

[Rupsenkind]

Re: Yamaha RX-V373 not powering up

Tnx Iotas for the FW,I think the issue with the failing sound and seems to be the flatcable between frontpanel and HDMI board, it looks damaged and when I move it, sound is there, now need to find an AWM 20798 17 pin but they look hard to find. Maybe I've a donor receiver in stock, need to check. Will keep you guys updated...

[lr.brasilino]

Re: Yamaha RX-V373 not powering up

Do you need firmware?

Good afternoon,
I saw your post mentioning that you would have Firmware for the Yamaha Receiver RX-V373 device. Mine is not transmitting 4k because I don't have hdcp 2.2. I would try to update the firmware to solve this problem. Would you help me? Thanks.

[Rupsenkind]

Hi all,

it's already quite a while ago but recently I picked up this issue again with the RX-V373 and managed to resolve it at 4 receivers: I did change the STK-433-33 but units still didn't start, also not in DIAG mode. Now the trick: for this units entering the DIAG mode is not to use Tone control & Info buttons but Tone control & Straight buttons. The the units started and I could remove the error message which prevented the units to start, even with a new STK module soldered in. Once done all units worked properly a they should.
Simple but I hope this will help fellow forum members. Cheers.

[R_J]

Actually the manual for this model says for Starting Self-Diagnostic Function, While pressing the “TONE CONTROL” and “STRAIGHT”
keys, press the “ ” (Power) key to turn on the power, and
release those 2 keys.

[Rupsenkind]

Hi R_J, correct and you suggetsed earlier as well but I kept Iotas'message in mind and used tone control/info (which is used on majority of Yama devices), my bad and typical case of RTFM..... My actual point is that even with new STK's the unit stays in protection mode unless you clear the messages. I haven't seen that on other series of Yamma. Tnx for all support!

Cheers..