Yamaha RX-A830 repair after lightning damage

[r-p]

Beware this is a work in progress, partly put here to write down my own steps. When you feel I have not done the necessary testing yet, to be asking for help, just refrain from helping/answering/spewing-ideas until you feel that I have!

First time poster who, after knowing of the site for years, finally figured out this wasn't about Energy Efficient Vehicles... (I did wonder why there was so much talk about electronics, but I mainly landed here through links on Priuschat, so that might explain the reason I thought it had to do with cars...)

So having said that I am not the sharpest pencel in the drawer, here's my problem:

I bought a cheap (60euro) Yamaha RX-A830 that the seller sold as being damaged by lightning. I *hoped*  the amplifier stage had died and I could just continue making my active speakers and simply hook them up to the pre-outputs.
I knew, before buying, the amp started up, the display and input selection worked, but it had no sound. And I had found the sevice manual online, so I figured I had a decent chance of succeeding.

So now that I actually have the amp (friend picked it up and stored it for a while to prevent shipmentcost), I did some quick testing. It has an internal testing menu, described in the service manual.

Main issue (without ever using a source or speakers yet) seems to be the digital board. Many of the communications tests between the processors come back with a NG (not good) instead of an OK.
(C1-1 ALL: NG, C1-2 BUS_FROM: OK, C1-3 BUS_FPGA: NG, etc.)
All HDMI-tests (where you loop the output to a random input) either failed completely (-- instead of NG or OK) or showed NG.

Preliminary conclusions:
There seems to be no visible damage, so that doesn't help me yet.
Some above mentioned communication checks come back with OK, so it is not just a simple supply-voltage question (that are more my cup-of-tea than data communication between >100pin microprocessors...)
I cannot find a price of a replacement digital PCB and I have no clue how to further investigate the digital board apart from just testing some voltages.
I still hope it might be something simple like the SMD capacitors that seem to fail on Onkyo boards*. But I have found no indication that Yamaha has similar issues and I doubt caps are the most likely fatalities in a nearby lightning strike.

Next steps:
I really have to test the analog part of the amplifier!
I have to test all supply voltages.

Questions:
Ideas on what is most likely to die and if it is deemed a lost cause, I may not want to hear it, but please do tell me...


If all else fails:
sell original remote for 20 euro's and pillage the amp for parts...

* I made a link from the "Onkyo boards" to a Youtube video, but the site chose to display the video instead of hiding the link behind the words "Onkyo boards" as I had clearly instructed it to do, so I changed it. Here's a Google search page to said video as I do not know how to link to it without it actually showing up in my posting (which I do not want! You, the reader, should decide whether or not to click the link instead of it showing up unrequested.)





EDIT: I forgot to mention that it did not show which firmware version it was running so I did an update. This update was succesfull (all 5 different software updates), but after this, it still did not show which version it was running within the self-diagnostic menu.
S4-1 SYS-VER. -----, S4-2 and S4-3 and S4-4 and S4-5 show a number, but S4-6 S-VER. --------, S4-7 S-SUM.-------- etc.
Some numbers are a versionnumber, some are a checksumnumber.

[mzacharias]

The RX-A830 and related models (20, 30, 40 series receivers) had common no audio - intermittent audio problems the solution to which, if any was never disclosed by Yamaha.

The only repair was to replace the digital board, and "teach" the new board which model it was.

Possibly reflowing the BGA chip(s) might resolve it.

I'm skeptical of lightning given the history of this model, but of course it's possible.

[r-p]

Again, this is mainly for keeping my notes in one place (on paper I tend to loose them), but I will obviously be extremely happy with any info that might help me!

I did some measuring. My eyesight is deteriorating fast (at 48) and the service manual has huuuuge schematics, so I find it hard to make sense of it all without scrolling back and forth and zooming in and out, skipping to the IC-pinout page, to the PCB-layout-page and then back to the schematic.

So I started simple: check the 5.6V from the switching powersupply to the HDMI/Digital board. At least that is present albeit just 5.53V. The 3.3V next to it is also present.

Then I started measuring voltage on  the SMD electrolytic capacitors on the upper side of the HDMI. And if I assume that they all *should* have a voltage, then there's at least an indication of what is wrong.

There are four 16V capacitors, one (C9423) has 4.99V on it and the other (batch of three, C9212, 9252 and 9253) have about 2.3V on them. Those last three seem wrong but I have yet to find them in the schematic to check.

The 10V capacitors (relatively big ones), both show 0V (C769 and C9476).

The 6V capacitors mostly show 3.3V or 1.2V, both logical voltages (some chips seem to run on (or need) 1.2V). But C9501 and C504 show 0.6V and C506 shows 0.15V.

Next step is to find where all these caps get their voltage from and what the voltage *should* be.

I did find three voltageregulators that didn't do their job: IC56 doesn't get an input voltage and IC63 and IC60 don't have an output voltage. So for IC60/63 (R1163N501B, Mouser PDF) I will trace what they should be feeding.
Wild guess would be that they supply some chip with power and the chip has died and has taken the voltage regulator with it. If this is true and I find a few of these, then I have a better chance of finding a replacement board than repairing it I am afraid, but we'll see.