I have picked up this receiver, with shorted amp channel. I'm also repairing another one, with no HDMI input(another thread on this forum). What I have thought, is to replace the HDMI board and have a working receiver, but to my surprise, the receiver does not have any kind of output, no video(no menu either), and no audio either. This receiver, looks like it's working otherwise. I have even made a firmware update. Didn't measure anything yet. I'm thinking, that maybe the Q8000(MN864788) is bad? I can't believe, how many HDMI issues are out here. A blown audio channel, can take out an HDMI IC? Any help would be appreciated.
I have repaired the amp. To my surprise, only the final transistors were blown. I never had an amp repair, that was so easy to repair. Maybe a car amp, a while back. What I have noticed, that Q8000 is getting hot.
The only measurement I did last night, it was to check for short/voltage, at pin #36 of Q8302(HDMI SII IC). The 1.3V is there, but resistance is 293 Ohm. What that means? If it's shorted, the 1.3V shouldn't be there, right? Not the SII IC is the cause this time, it is the MN Q8000, since is getting hot? What should I check at Q8000? There are some weird voltage markings there, like 777_COM3. What should be that?
You are correct, since you have 1.3V, the chip is not shorted on the 1.3V line but that doesn't mean that it isn't shorting out the 5V line.
HDMI Receivers/Transmitters run on 3.3V (typically) but they must pass 5V through to the HDMI port to meet the spec. For some reason, this is often a weak point in the design and lack of 5V often means that one of the HDMI chips has blown. They often run hot so this isn't a huge concern. I would be suspicious of the SiI part only because you have a low resistance on the 1.3V line but Q8000 could be the culprit. The only thing I could suggest would be to remove one of them (probably the SiI) to see if the 5V turns on. If not, remove the second one (Q8000) to see if that is the culprit.
I have a question about this "short". When the board is mounted into the receiver, I measure 293 Ohm. If I remove the board, there is no short. I have noticed, that if I connect the HDMI connectors to the metal back cover, than when the "short" shows up. It is still considered short, and I should remove the IC?
Last Edit: Nov 15, 2018 11:40:07 GMT -5 by tibimakai
I would suspect so. The 5V signal is only used for HDMI handshaking (no processing at all) so if it shows a short when connected to an HDMI cable, it would seem to indicate that the 1.3V signal is shorted to the 5V signal. You can test this by using your meter to read the resistance between the 5V rail and the 1.3V rail. It should be very high. If it measures a short, it would indicate that the HDMI chip has an internal short between these two rails.
I have removed the SII IC(Q8302), but the 5V did not show up. Q8000 (MN IC) is getting too hot. At some pin #18s, I measure 0.23V, 0.007V, 1.3V, etc. Should I remove now, Q8000? I have another question about the amp. There is a need, to even check the idle current? The connectors are there, but there is no adjustment for them.
OK, I have replaced both HDMI chips and there is still no audio or video from an HDMI source. There is no 5V at pin #18 at the HDMI ports. At the two outputs I measure 0.27V , but at the rest, only 0.019V. At least, none of the HDMI chips are getting hot. What else could I do next? If I pair my phone via Bluetooth, the audio works great. If I hold the Display for a couple of seconds, it will show Unknown and than ----. With the Directv box plugged in and turned on. Also the TV is plugged in and turned on. No HDMI sign, shows up on the display. Any help would be appreciated.
mastertech: Merry Christmas to you too. Not many holiday people around any more.
Dec 26, 2018 14:37:50 GMT -5
stridsvognen: Merry christmas everybody...
Dec 24, 2018 19:10:58 GMT -5
mastertech: Sounds nice. Would love to have many more pictures.
Oct 20, 2018 20:31:04 GMT -5
greg1292: Greetings from Denmark. Lots of ideas knowledge and bucket list. Gabor boards looking very nice indeed
Oct 20, 2018 16:38:34 GMT -5
kevin5418: Anyone has the Velodyne hgs12bg MPS board schematic ? thank U
Oct 6, 2018 0:58:34 GMT -5
mastertech: According to the SM ic711 must be installed with the firmware already in it. It can then later be upgraded. The correct ic is around 50 dollars. If you installed a blank ic it will not work.
Aug 19, 2018 20:01:39 GMT -5
ralph: Hello mastertech, sorry for the delay, if I replaced that IC, I was with short circuit, blocked the 3.3 volt regulator, put a new one but still do nothing, what could I do? Thanks for the reply
Aug 18, 2018 21:48:51 GMT -5
mastertech: Did you replace ic711?
Aug 12, 2018 18:55:42 GMT -5
mastertech: Just to clarify you replaced ic711 (STM32F101ZG), correct?
Aug 10, 2018 20:58:16 GMT -5
ralph: Hello, Mastertech, I'll send it to you
Aug 10, 2018 18:58:46 GMT -5