Yamaha rxa2070 lost hdmi out 1 and in 1... :-(

[budwich]

Re: Yamaha rxa2070 lost hdmi out 1 and in 1... :-(

I think that I got the smaller of the two chip mounted. It remains to be seen if there is an issue associated with the 3.3v type powers in the one corner.

Not looking forward to trying the larger, more pins and closer together on the other chip.
I can certainly see why "board swapping" is a regular technique for repair although I guess if one gets proficient at various solder techniques along with hot air and other tool (hot plate, oven), success is only a "board away"... :-)

One question, how would I know IF the ground pad on the bottom of the chip successfully bonded to the pad on the board... during the heating process, it is more than likely side array pins potentially may have soldered also stopping the chip from moving and thus one can't readily directly know that because the chip doesn't move, that it has successfully soldered to the ground pad.

[budwich]

Re: Yamaha rxa2070 lost hdmi out 1 and in 1... :-(

not much success so far. I had to demount my first attempt on the bigger chip. One of the "looser" pads got caught when I tried to gently move the chip over a little bit when it was being heated / just when the ground pad solder was melting. As a result, the pad got stuck in between two pins with not much hope of freeing it without further risking more issues. I decided to re-heat and demount the chip again. Now thinking on this some more. It is a tough job as any tiny bit of movement during any "sag" (ie. when the solder moltens) makes it difficult to maintain the correct alignment with such small / tiny pin spacing.... :-(

I am hoping my "chip ain't cooked" at this point.

Sure wish there was no under chip ground pad, then I could just solder a couple of side pins on a "far side" from the current working / soldering side, to hold the chip in place and then move from there, one side at a time.

[budwich]

Re: Yamaha rxa2070 lost hdmi out 1 and in 1... :-(

I continue to march along. Both chips are mounted and hopefully soldered on all pins BUT not on any pins together... :-) and hopefully good solder connections to the boards tracks.

The big chip went a bit easier than I thought once I used very little solder to drag along the pins. At the end, a bridge of couple of pins was quickly solder wicked off.

Did some continuity checks on the smaller chip towards the hdmi connectors (inputs 1,2,3). They seemed OK and impedance checks reflected similar conditions at each hdmi. I have to do similar checks on the big one both to the two output hdmis and some interchip lines.

I haven't mounted back the heat sinks yet (soldered at two corner). I was hoping to do a very short "operational run" to see if my work has succeeded. Hopefully, it won't cause an overheat.

[budwich]

Re: Yamaha rxa2070 lost hdmi out 1 and in 1... :-(

Well, one step forward. I powered things up and it appears that I have two outputs happening (I haven't verified any resolution difficulties yet... 1080 versu 720 etc). One step sideways as it doesn't appear any of the inputs (3) on the first chip that I installed are outputting any signal at least not that the output chip is recognizing. Either the chip is toasted or my soldering is suspect... probably later... :-(.

[budwich]

Re: Yamaha rxa2070 lost hdmi out 1 and in 1... :-(

Further investigation shows that the transmitter chip "787" doing the outputs has problems with doing any video processing other than the setting "direct" which seems to work fine. IF "processing" is chosen as a video option, significant "blocking" happens. Not sure if the processing is done "in chip" or is sent somewhere else and brought back to be output there after.

[budwich]

Re: Yamaha rxa2070 lost hdmi out 1 and in 1... :-(

Precessing appears to be done "off chip". I sink further into the "quick sand". Tried "fluxing and touchng up soldering" of all edge pins with hope that perhaps some pins may not have taken the "solder drag" originally. Result: no longer any outputs working :-(
Back to the drawing board / schematic and bench checking work and paths.

[diif]

Re: Yamaha rxa2070 lost hdmi out 1 and in 1... :-(

Check the continuity of adjoining pins and also if they make contact with the board.
Easy with decent magnification, it depends what you're using.

[budwich]

Re: Yamaha rxa2070 lost hdmi out 1 and in 1... :-(

Right, thanks. I was going to verify continuity for all power and ground pins at both chips. My cheap magnification "headband" has three levels of magnification although the quality is "limited". :-) Anyway, I thinks is strange that a "reflow" made matters worse as oppose to better. Hopefully, some "simple issue" will jump out. I was encourage with the first attempt that brought back both outputs so I am thinking its got to be some powering trace has gone astray.

[budwich]

Re: Yamaha rxa2070 lost hdmi out 1 and in 1... :-(

Didn't find anything visually. Did a few resistance / continuity measurements to see if pins are connected to tracks as opposed to poor / no solder joints. Nothing dropped out. Did some "sweeps" with lead on v3.3h source to see if multiple pins along the edge "beep". Didn't find any adjacent leads sounding out, so it does appear to have "bridging" (numerous pins along the side have continuity but as far as I could count, seemed to agree with those connections). Of course, I didn't check all 256 / 144 independently.

Plugged the board back in to do some voltage checks. Preliminary check of the v3.3h voltage at pin 38 on the 788 chip (switcher) shows only 2.4v. According to the circuit, that feed comes "directly" from the 3.3H feed (thru an inductor). That seems rather low... possibly "loaded" / too much draw causing a lower voltage.

[budwich]

Re: Yamaha rxa2070 lost hdmi out 1 and in 1... :-(

I will probably throw in the towel on this one for the time being. I removed the "switcher" chip (smaller one) and measured the v3.3H voltage, it was still 2.4v. Impedance didn't change much... 400-500 ohms. Not sure what to expect. Removed the other chip, but didn't plug the card back in (tired of replugging, and worried about damaging cabling / connectors along with any other damage to subtending circuitry). Measured impedance where the 3.3h would have been... impedance is higher towards .5M. Possibly I had damaged the chip during the various soldering attempts or there was some bridging somewhere. Anyway, the removal left the board area / pads more damaged in a couple of places with more pads "floating" around / no longer anchored to the board. It is likely that the route left for me is a replacement board... :-(
It has been an interesting learning experience. Thanks Diif for the various "hints" / help along the way.

[budwich]

Re: Yamaha rxa2070 lost hdmi out 1 and in 1... :-(

Well... I finally got around to proceeding with this. Ordered a replacement card from yamaha and it showed up yesterday. It appears to be the same but there are a couple of "differences". On the new card, there is a couple of areas "added" when compared to the old. In the pictures, in the bottom left, there is a "piece of pcb attached" that is likely a board for the front hdmi (based on the connector). On the bottom of the card (right side), there is a "strip" of pcb that looks like it prevents a person from installing the card without removing the strip. I guess this is protection of the "I never installed it" type return where a person orders the card, tries it, it doesn't solve the problem so they decide to return it.

Anyway, the question is how to break / cut this pieces off (or connecting pcb tabs) so that one does not damage the main board. They don't seem to readily flex so you can easily "wiggle" them back and forth to break.

Hopefully, I don't have to replace the front hdmi board... I don't remember testing it before hand to see if it worked.

[budwich]

Re: Yamaha rxa2070 lost hdmi out 1 and in 1... :-(

I used side cutters in a couple of strategic tab areas and then gently flexed the "extra" pcb material which then broke free from the main board.... so far so good.

[budwich]

Re: Yamaha rxa2070 lost hdmi out 1 and in 1... :-(

Plugged in the new board. Got an "internal error" on the display. :-( I guess, based on the SM, that it would appear that no model or serial number has written into the board. Its just a "raw" board. I will attempt to get the input via the front panel sequence (and associated "solder jumper" on r896) using a youtube video guide.