Yamaha RX385 No HDMI Output - Page 1
Forum section: electronics / repair

author: zizebra
author_rank: Contributor
timestamp: May 25, 2025, 03:44:00 pm
content: Hi All,I'm seeking some assistance with a persistent issue I'm experiencing with my Yamaha AV receiver.Last week, my receiver suddenly stopped working. Upon attempting to power it on, I was met with a blinking red light and the device immediately shut off. I could hear the relay clicking when trying a reset (using the tone+control and power buttons), but after 4 or 5 attempts, the clicking would cease until power was removed. The receiver briefly displayed a PS1:PRT 164 error, with the "164" value fluctuating.After leaving the receiver unplugged for two days, I reconnected it today. The PRT 164 error reappeared briefly. I then opened the unit to inspect the internal components. After briefly disconnecting and then re-seating some of the internal boards, I accessed the diagnostic menu. To my surprise, a new error appeared: PS2:PRT 255. This time, however, the receiver did not switch off and remained powered on within the diagnostic menu.Assuming a loose connection, I re-seated all the connectors. Upon powering on the receiver again, it appeared to be fully functional. However, I've since discovered several new issues:No HDMI output: Neither the main HDMI out nor the monitor out ports are producing a signal.Radio not working: The receiver scans and finds stations, but there's no audio output.Remote control unresponsive.Despite these problems:All HDMI inputs are working, and I can hear audio from connected devices.eARC appears to be functional, as my TV can still switch the receiver off.I've searched online extensively but haven't found any definitive solutions for this specific combination of symptoms.Has anyone encountered a similar issue or have any insights into what might be causing the loss of HDMI output and radio functionality, especially after the receiver initially went into protection mode? Any ideas or troubleshooting steps would be greatly appreciated.

author: m k
author_rank: Super Contributor
timestamp: May 31, 2025, 03:58:56 pm
content: Is it close to RX-V385?That model has a service manual available.Since it originally had a fatal problem and now is missing functions one possibility is that one short connection is now a no connection.Since inputs are functioning more than outputs a missing voltage is a good guess.

author: zizebra
author_rank: Contributor
timestamp: July 26, 2025, 12:02:35 pm
content: apologies, yes this is RV-385. You are probably right that there was short somewhere which is now open. The interesting thing also picked up is that Remote also not working.

author: MathWizard
author_rank: Super Contributor
timestamp: July 26, 2025, 03:04:18 pm
content: I'm not familiar with Yamaha's, but just as an example of some things that can go wrong and have similar results....I bought a used stereo, and it has problems.One that happened this year, was in the overload protection circuits. There was a transistor circuit that monitored the outputs, the heatsink temps, and something else. And it had an electrolytic cap attached to it. And one of the solder pads broke loose, and it would cause the overload circuit to activate, and trip the power-in relay. So that was an easy fix, and me working on the stereo was probably what knocked it apart in the 1st place.The other serious issue is has, is with the main MCU/Microcontroller. Sometimes it doesn't send all the commands and data it normally does, like to the volume IC's, the digital IC's, etc. And iirc sometimes volume IC or SW IC had problems. The display still seems to always get the correct info. So I was working on some mods to get around it, using my own MCU's I programmed the hard way.But there's basically no external parts between most of these IC's and the MCU, so it's either waste more money on a used chip, from another whole unit, or get my MCU hacks to do the jobs the MCU can't do anymore.So I'm doing this more for fun and learning how it all works.

author: zizebra
author_rank: Contributor
timestamp: July 26, 2025, 03:34:07 pm
content: Today, i had some energy and did some troubleshooting. I was testing the voltage on the processors and other chips hoping to find a missing voltage. While all power rails on the cpu appeared. I noticed that whenever i disconnect power and reconnect, i get "usb overloaded" error. This error shows up even when all other boards and the usb board are disconnected. The radio module works and can tune radio stations manually on the receiver.It appears that the overload error is probably related to why the remote and hdmi not working. Overload is probably coming from short somewhere on the main board.Iam not sure on one finding, the power supply has a voltage of 5.6V on a 5.5v rail going to Digital_CB81. Is this too high?

author: m k
author_rank: Super Contributor
timestamp: July 26, 2025, 06:38:24 pm
content: RX-V385 has a source voltage of 5.5V for many low voltage things.If that is low it can affect 5V stuff, analog video and USB are some of those.

author: zizebra
author_rank: Contributor
timestamp: July 26, 2025, 07:47:29 pm
content: Thanks, the 5.5v rail is measuring 5.6V. I actually tried powering with external 1A 5v which is too low as you pointed out.

author: David_AVD
author_rank: Super Contributor
timestamp: July 26, 2025, 08:30:05 pm
content: Test / replace all of the power sense resistors as they sometimes go high in value causing PS1 and PS2 protection errors. These are the resistors that feed from the various power rails to a common sense point to derive the PS1 and PS2 figures you see in the diagnostic display. They are usually 0603 SMD resistors. The resistors going bad is more common than the actual power rails going bad.That all said, they won't affect HDMI output. That will be a different issue, possibly just dirty HDMI sockets.

author: zizebra
author_rank: Contributor
timestamp: July 26, 2025, 08:43:03 pm
content: thank you. i will try that. On the HDMI point, not sure if you missed another related issue where the IR remote is not working, would this be seperate from the HDMI.

author: David_AVD
author_rank: Super Contributor
timestamp: July 27, 2025, 01:36:13 am
content: Maybe double check all of the voltage rails and interconnects.Also, does the top board (with DSP, HDMI and CPU) have any corrosion on it? I've seen plenty of weird faults that were due to corroded traces and / or corroded vias. The top board is the most susceptible as it collects all the dust through the vents, then high humidity wicks into the dust and corrodes things. Ingress of insects / lizards that leave deposits or water stills are also seen on occasions.

author: zizebra
author_rank: Contributor
timestamp: July 27, 2025, 08:53:54 am
content: No it looks very new. No corrision or rust seen.

author: m k
author_rank: Super Contributor
timestamp: July 27, 2025, 04:42:35 pm
content: Since you have a less trusted situation you must measure from the end.Manual page 103/133 has USB power, left of rightmost OPE(7).There you have a feedback voltage of 5.2V, if USB module is missing there's no feedback and error happens.3.3V for actual USB chip is different.Page 80/133 has that source voltage is 5.4 - 5.5V, so 5.6V can be too much, but that's not the cause.It would mean that the voltage varies with the load and now load is less than expected.Bottom right of page 104/133 has a video part.If you can't measure close to chip itself, add an extra wire.It's important that you measure the voltage from the final destination.Page 97/133 has HDMI stuff, seems that 5V is only for HDMI Out.

author: zizebra
author_rank: Contributor
timestamp: July 29, 2025, 04:41:43 pm
content: Quote from: m k on July 27, 2025, 04:42:35 pmThanks, I haven’t worked on the unit since last Sunday, but I wanted to follow up on some of the suggestions that were made.About the USB issue: the overload message first appeared when power was applied while the USB module was still connected. I disconnected the USB unit to isolate the problem, but the error message persisted even with it removed, which seemed odd.Also, I noticed that the power supply board outputs 5.6V, even when it's not linked to any other boards. The manual lists the voltage as 5.5V, so I’m wondering whether this discrepancy might be contributing to the problems—could the higher voltage be causing HDMI video out, the remote control interface, and USB functions to fail?The manual indicates that a USB overload can shut down the power supply. But it’s unclear which supply is impacted—is it just the USB’s own power line, or does it trigger a broader shutdown involving CPU and associated circuits? If, as you pointed out, 5.6V is indeed too high and causes some kind of protection cutoff, it might explain the behavior.

author: m k
author_rank: Super Contributor
timestamp: July 29, 2025, 07:11:54 pm
content: 5.6V itself is not likely a problem, it's too close to correct value.But it's possible that somewhere is an over zealous overvoltage detector.Though that would most likely shutdown much more parts, like HDMI inputs and other 3.3V stuff.Page 98/133 MCU pin 101, through a resistor, is the final destination of half (p.102 right) of that USB 5.2V feedback.If it is never present then error is, always.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: July 30, 2025, 08:27:24 am
content: There is a known issue with what I think was these units where the main IC dies and requires replacement... search for Nicks Electronic Repair on YouTube as he has done videos on them.

author: David_AVD
author_rank: Super Contributor
timestamp: July 30, 2025, 11:02:26 am
content: The DSP IC can be an issue, but that's audio not video.

author: m k
author_rank: Super Contributor
timestamp: August 01, 2025, 01:22:09 pm
content: Don't forget the error, low left of page 104/133 has the source.Somewhere was that 255 is 3.3V, so 164 should be ~2V.

author: zizebra
author_rank: Contributor
timestamp: October 08, 2025, 05:23:30 pm
content: Apologies for the long absence. I revisited the earlier advice regarding the resistors suggested by MK, but I didn’t get a chance to test them—strangely, the device powered up without issue this time. It worked fine for about a week, then suddenly stopped producing sound.Here’s the odd part: when I press “Direct,” the radio plays with full audio. But when switching to HDMI, the front left and right channels go silent. The center and surround speakers initially had sound, but that eventually faded too. Unlike the units Nick showed, where the DSP appears to be missing, mine seems to have DSP active across all channels—just no output.