Anthem MRX500 - no sound. R2A15218FP issue??

[benspawn02]

Anthem MRX500 - no sound

Dear Electronics Experts:

I have the following problem I am trying to troubleshoot. Unfortunately, I have contacted Anthem themselves and even a local distributer but I am not having much luck. Also, I have scoured the internet and unable to obtain a service manual. The Anthem service rep has also replied that he is unable to provide me with any service documentation. I have performed numerous searches on the internet and cross-referenced a few other AV receiver makers (Denon, Marantz, Onkyo) and found certain similarities to block diagram routing, IC components, etc. Most other Anthem MRX users mention a bad HDMI board or the Pre-Amp board to be the issue.

The issue/symptom:
- No sound from the speakers or pre-out regardless of source mode. When I turn the receiver all the way to max +10dB, I hear just hissing air from the speakers. The voltmeter probe going into the Pre-Out RCA on AC Voltage mode, returns 0. Also checked Hz and % duty cycle, also 0.

My troubleshooting thus far:
- I believe the FM Tuner runs direct into a R2A15218FP audio controller switch although I am not 100% certain if the signal further goes to the DSP chips first and then comes back to this controller to be output to the Pre-Amp circuitry and ultimately the Amplifier circuitry.
- I isolated and removed the HDMI board and Multi-Media board (which houses an components to an Anthem Dock, USB hub, and Ethernet module). The AV receiver still turns on without these two boards. However, there may be some logic circuit missing as I am unable to enter the SETUP mode on the AVR to configure the AVR without these boards present.
- I also desoldered a couple of coupling capacitors on the FR circuitry on the Pre-Amp board. I measured these caps with my meter and they were within spec. Additionally, I also soldered on two good caps onto this FR circuit and tested the AVR but still the no-sound issue persisted. I returned the Pre-Amp board to its original state by returning the original caps back onto the FR circuit.
- The main DSP/MCU board contains the R2A15218FP audio controller, along with two DSP chips TMS320D788E001BFRP (these chips are not included in the defective list of TI chips causing the no sound problem plaguing other Denon, Marantz, and Onkyo receivers), as well as an ARM STM32F103ZE MCU. This main DSP/MCU board houses the FM tuner, and also all the analog inputs, REC OUT output, and Optical and Coaxial Input and Output.

Many of the various other threads had mentioned or questioned the durability of the R2A controller chip going bad but these posts seem to drop off and go silent before any definitive conclusion can be made.

- I am getting +7V and -6.8V respectively for ADCC and ADEE for the R2A chip.
- I am also getting the ADCL and ADCR signal when I feed in via the Analog inputs (probing Pin 54 and Pin 55). However, I am unable to further trace on this main DSP/MCU board if the ADCL and ADCR from the R2A chip goes any further. I suspect it has to based on other block diagram designs that I have read.
- I don't have an O-scope, so I tested via AC Voltage reading mode and switching to measure also Frequency and Duty Cycle on a ExTech EX520 meter.
- I tried probing the DATA and CLOCK pin on the R2A but I am unable to get any reading. This could possibly be that the meter is not picking up the signal. Based on numerous searches, I have however been unable to determine the type of signal going into this R2A chip. I am not sure if maybe the R2A chip is not getting the correct signal to switch thus no output to the speakers (which would indicate an issue upstream with an MCU chip). Or alternatively, the R2A chip is outputting ADCL and ADCR to be digitally processed but the somewhere along that circuitry something is wrong and returning no signal back to this R2A chip.
- From studying the board, the R2A chip is one of the last components followed by some operational amplifiers and then the signal goes to the pre-amp circuitry to be amplified.

- In FM Tuner mode, I am getting absolutely no reading on the REC OUT channels.
- In Analog input mode, I am getting the same signal (which appear to be a direct bypass feed from the source) on the REC OUT channels.
- When I have the whole AV receiver fully assemebled, plugging in the HDMI cable to my Win 11 computer, the computer sees that the connected device is a MRX500. On the receiver, I see that the AVR is seeing 720p on video feed. However, on audio, the AVR shows No Signal.
- Probing directly on the R2A chip on all of the speaker out FROUT, FLOUT, COUT, etc, I'm reading 0.

At this stage, I'm pretty stumped and stuck as to how to proceed any further and would appreciate any help/input/assistance on what to do next.

This AVR was working absolutely fine before it went into storage in a box for a few years. There are some signs of corrossion but nothing too excessive.

Please help?

[budwich]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

Good pictures of the areas of interest might help. Checking or retouching soldering joints may help. Certainly tough without any schematics ... I hate manufacturer's that won't provide document support. I guess they are afraid people will see how poor their designs / builds really are... :-)

what is the front panel showing with an analog input... post a picture of the panel please.

[benspawn02]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

Good pictures of the areas of interest might help. Checking or retouching soldering joints may help. Certainly tough without any schematics ... I hate manufacturer's that won't provide document support. I guess they are afraid people will see how poor their designs / builds really are... :-)

what is the front panel showing with an analog input... post a picture of the panel please.

Thank you for your reply budwich.

The front panel doesn't provide much of any information with an analog input. It appears to be a passive setup without any monitoring/feedback if any input is registered.

I've attached photo of the front panel with input on Analog 4. I set the video to be on HDMI 1 although there is no feed in. I have also tried disabling video input but still there is no difference in terms of sound output to the speakers.

I also attached a photo in FM tuner mode. The radio station is received along with the station name.

[benspawn02]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

Additionally not to clutter up the reply above.

Here are more photos of the MCU/DSP board with photos of the underside of the board as well as close up of relevant areas.

I managed to trace the DATA pin (pin 51) on the underside of the board which eventually terminates somewhere near the ARM STM32F MCU.

[benspawn02]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

HDMI board (4 inputs, 1 output) along with the daughterboard that is next to it for the composite video in, component video in, as well as monitor out.

[benspawn02]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

This is the Multi-Media board that sits below the HDMI board. It connects to the HDMI board via the black Dupont header.

This board houses the Ethernet input, USB, as well as a proprietary Anthem Dock.

[budwich]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

Not sure how much I can help with this... sorry. Hopefully someone will come by.

Probably a dumb question, but as part of your checks, did you set your "main source" to analog to see if that helps with the analog side of things... although I would have expected a tuner selection to cause an output of some sort. Maybe you have more than one issue (or a root cause that is impacting a wide range)?

Did you try the headphone jack?

Depending on how serious you are, you might consider burrowing a scope or even buying a scope (used or otherwise)... a hand held model can be had for less than $100... I got one that has helped a lot as tracing for a 1khz input signal along a circuit path is a quick way to find a "blockage" especially without help from non-existent schematics.

Lastly, have you tried reloading the firmware?

[benspawn02]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

Not sure how much I can help with this... sorry. Hopefully someone will come by.

Probably a dumb question, but as part of your checks, did you set your "main source" to analog to see if that helps with the analog side of things... although I would have expected a tuner selection to cause an output of some sort. Maybe you have more than one issue (or a root cause that is impacting a wide range)?

Did you try the headphone jack?

Depending on how serious you are, you might consider burrowing a scope or even buying a scope (used or otherwise)... a hand held model can be had for less than $100... I got one that has helped a lot as tracing for a 1khz input signal along a circuit path is a quick way to find a "blockage" especially without help from non-existent schematics.

Lastly, have you tried reloading the firmware?

Hey budwich, no worries. Yes, I've tried a few different analog sources as my input to test. I did not try the digital coaxial or optical in as I did not have an optical output source to feed into the AVR.

Yes, previously when this thing was working, when the tuner is not locked in to a station, there would be the radio static sound. Also, I am able to tune to various FM channels so it's evident that the tuner is working. I also traced from the R2A chip back to the tuner board and probed at the input of the R2A chip and I'm getting a signal from the tuner.

The signal is going into the R2A chip (from the FM tuner and analog) however it does not seem to be outputting. . . speaking of which you just gave me an idea to try and probe the input into the R2A chip when sourcing from the HDMI. . . although that would be quite difficult as the R2A chip is situated under 2 levels of board so it's not so easy to probe. However, I suspect that there would be no signal as the Anthem is reporting "No Signal" on the front panel so it is probably detecting that somewhere. . .

I did not try the headphone jack as I didn't have the right headphones with a 1/4" jack. Yes, I have been browsing the marketplace for a used scope or maybe just buying a cheap one from China. . .

Reloading the firmware is next on my list but have yet to do it.

Thanks for your replies and suggestions thus far.

[budwich]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

I haven't tried this but since you only have a DMM.... maybe on the analog this will work. Get your hands on some "low frequency" audio files (50-60 hz type for testing sub woofers). Input those on the analog side... your meter should be able to pick it up "easier". I use an audio test cd that has a couple of different signals generated. You may be able to see it on at the input side of things more readily.

On scope side... here is a listing sample....
https://www.ebay.ca/itm/115834078101...Bk9SR8z-t7i-Yg

Mine doesn't have the device tester portion type capability but it functions well for the things that I need it for... mostly audio. The other good thing is there is not any need to worry about isolation since the unit is self powered and the chances of "coupling" is reduced.

Based on some of your tests so far and a quick look at the limited info that I found on the chip that your are looking at, I am not sure the "rec output" means much especially with respect to analog signals as it appears that "path" is always there as long as voltage is provide to the op amps in the system / chip. Having said that, the front end selector of the chip most be working to cause a signal switch of the incoming signal "choice". :-)

One other thing... maybe a language issue between north and south...:-) You responded about trying various analog sources... but my question previously was about a system setting not choice of different analog inputs. I saw that in some posts around the net.

[benspawn02]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

I haven't tried this but since you only have a DMM.... maybe on the analog this will work. Get your hands on some "low frequency" audio files (50-60 hz type for testing sub woofers). Input those on the analog side... your meter should be able to pick it up "easier". I use an audio test cd that has a couple of different signals generated. You may be able to see it on at the input side of things more readily.

On scope side... here is a listing sample....
https://www.ebay.ca/itm/115834078101...Bk9SR8z-t7i-Yg

Mine doesn't have the device tester portion type capability but it functions well for the things that I need it for... mostly audio. The other good thing is there is not any need to worry about isolation since the unit is self powered and the chances of "coupling" is reduced.

Based on some of your tests so far and a quick look at the limited info that I found on the chip that your are looking at, I am not sure the "rec output" means much especially with respect to analog signals as it appears that "path" is always there as long as voltage is provide to the op amps in the system / chip. Having said that, the front end selector of the chip most be working to cause a signal switch of the incoming signal "choice". :-)

One other thing... maybe a language issue between north and south...:-) You responded about trying various analog sources... but my question previously was about a system setting not choice of different analog inputs. I saw that in some posts around the net.

Yeah the measurement side of things are fine so far. The only part where I can't really rely on proper measurement is the DATA pin if it's a high frequency PWM or a pulse signal for example.

Yeah, I agree with you there. The block diagram that I found for the chip (assuming it is correct) seem to show that the REC path is always present. However, it is peculiar that the REC signal is no longer present on Tuner input vs Analog Input. I am not sure if the front-end of the chip is working properly or if the entire chip is working properly for the signal to go from input and make it all the way to the output.

Sorry, I don't understand what you mean by system setting? Can you elaborate further? Your previous reply asked if I set my main source to analog? Did you mean as in I select Analog on the AVR? If that's the case, then yes, I switched the AVR to the particular analog input that I'm measuring. There is a Zone 2 setting but I disabled that. You can program the AVR for each setting (BDP, CD, TV, SAT, Aux, etc). I already set it to analog for some of them and HDMI for one other. When setting the AVR to receive on Analog, there is an advanced menu option where you have to select which analog channel you're wanting the AVR to receive the input as well.

[mmartell]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

Are the chips beside each dsp ram or storage devices ?

I don't know if these TI dsp's are factory programmed or if they get initialized at boot but kind of common for the storage to corrupt resulting in no audio.

[budwich]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

not sure... it was just a clip that I read. I think what you describe is probably what I read.... basically, you have to "assign" inputs to "source X" ... from there you choose what the video and audio will come from... the audio can be either analog or digital even for a hdmi video signal selection.

what are the listening modes setup for the source that you have selected?

[benspawn02]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

Are the chips beside each dsp ram or storage devices ?

I don't know if these TI dsp's are factory programmed or if they get initialized at boot but kind of common for the storage to corrupt resulting in no audio.

Hey mmartell, I am not sure about whether these are factory programmed or gets written during boot. . . There are 2 chips directly beside the DSP chips. They are MX 29LV320DTTI. Would the storage chips be used strictly for the DSP? Shouldn't other errors show up if the DSP chips essentially are reading blanks or corrupt data? Also are these DSP chips just strictly for sound processing?

[benspawn02]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

not sure... it was just a clip that I read. I think what you describe is probably what I read.... basically, you have to "assign" inputs to "source X" ... from there you choose what the video and audio will come from... the audio can be either analog or digital even for a hdmi video signal selection.

what are the listening modes setup for the source that you have selected?

Yeah that's it then, yeah I set up the correct sources for the modes that I was selecting on the AVR. It isn't an issue of not routing the correct input into the AVR at this stage. But good to be checking the common errors.

There are various listening modes, DTS, Dolby etc. I've gone through all of them. I believe depending on the listening mode, the sound either gets further digitally processed or not. I'm assuming there's a direct mode. . . although I am not entirely sure without technical info from Anthem themselves.

[budwich]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

have you check the mute to see what voltage is there? Depending on what it is, finding a way to change the value (ie. cut a track, or add some small voltage)?

[benspawn02]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

have you check the mute to see what voltage is there? Depending on what it is, finding a way to change the value (ie. cut a track, or add some small voltage)?

I checked the mute by probing pin 51 on the R2A15218FP chip, I believe I read documentation somewhere that logic low means no mute applied. When I probed it, it read 0V. Also when I press the MUTE on the front panel, it still reads 0V and nothing changes. However, when I turn off the AVR from the front panel switch, the AVR goes into standy mode and as soon as the relay clicks, I read 3.3V on the pin.

I am not sure if the MUTE control utilizes this pin or it is achieved via some other method.

I also managed to trace Pin 49 (DATA PIN) and Pin 50 (CLOCK PIN) on the R2A15218FP chip going to the STM32F103ZE MCU (Pin 97 and Pin 96) which are designated IO pins (PC7 and PC6)

[benspawn02]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

Just an update.

I tried reflashing the Anthem MRX500 firmware today. However, I cannot seem to make any progress. I am running the recommended USB-Serial adapter (Tripplite Keyspan USA-19HS).

The process is supposed to take around 10 minutes according to the read-me.

Unfortunately the firmware reflash is not verbose and there is very little feedback. However, it states DSP-1 Writing. . . 0KByte and I let it run for a good 30 minutes but still no progress. One of the posts on the owner's thread pointed to a similar issue with a DSP 2 chip.

I think that's it for this AVR. I don't think there's any way to reflash the DSP chip from the end-user.

[budwich]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

:-( does not sound good. you might try some "creative" heating in the area. Maybe some sort of problem with connections (cold joint, oxidized, etc) or a poor capacitor (dried or otherwise).

[mmartell]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

Hey mmartell, I am not sure about whether these are factory programmed or gets written during boot. . . There are 2 chips directly beside the DSP chips. They are MX 29LV320DTTI. Would the storage chips be used strictly for the DSP? Shouldn't other errors show up if the DSP chips essentially are reading blanks or corrupt data? Also are these DSP chips just strictly for sound processing?

Not sure.
Not sure, and, wait for it...
Not sure.

I can't say they're used STRICTLY for the DSP's but follow some of the traces I bet they do go to there.

Many mainstream brands have active diagnostic functions available through their panel buttons. No idea what Anthem does but clearly a technician would have access to that information even if an end user can't get it.

Depends on the design whether these chips perform functions outside of what you might expect from them. I definitely have no way of knowing that.

This might be some interesting reading...

https://www.badcaps.net/forum/showth...ht=denon+sound

Watch for posts by sparx_59

[mmartell]

Re: Anthem MRX500 - no sound. R2A15218FP issue??

btw I had a no sound problem with a Marantz SR7011. There are four DSP ic's on that board and each has it's own serial flash. The flash for DSP3 had become corrupted (partially erased) and I was able to rebuild it with the dumps from the other flashes. After reprogramming it the receiver worked fine and I still use it a few times a week in my movie room. It replaced an aging Newcastle R-972 because I wanted to try out Auro3d.