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Post by Deleted on Feb 27, 2021 12:26:19 GMT -5
Having got a couple of faulty Pioneer AVRs working I decided (perhaps foolishly...) to bid on a Onkyo TX-NR807 that was on eBay listed as having no sound. A quick check with the seller confirmed the video section is ok and the unit does power up.
I was the only bidder and won it for not a lot, so I'm waiting for it to arrive. I've downloaded the user and service manuals and had a read through the previous threads on this model. It looks like I will need to reflow or replace the usual TI DSP chip like the Pioneers and check/replace a number of electrolytic caps to get it working. I also found some detail on a voltage regulator daughter board that was fitted as an upgrade, so I will do this as well if I can get it working.
I can't however find any reference to firmware issues with this model (maybe there wern't any?) and there isn't anything listed in the 'Onkyo Firmware Repository' thread. This may not be a bad thing unless it turns out to have a corrupted flash chip. Has anyone got a copy of the firmware for this model, either OE Onkyo and/or the decrypted version?
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Post by Deleted on Mar 2, 2021 14:31:17 GMT -5
This receiver arrived today and after a quick power up to confirm there was no audio out I pulled the main digital/HDMI board out for a look. All the caps looked ok physically with no signs of bulging or leaking.
I decided to reflow the BGA DSP chip as thats been the cause of most of my Pioneer receiver problems. This has an earlier chip (D830K013BZKB3) which isn't in the TI 'early failure' bulletin but I figured being a BGA and lead free, it could still have developed bad solder joints.
I preheated the board to 125 degC for about 10 minutes and then used my heat gun at 430 degC for 90 seconds with plenty of liquid flux flowed under. After allowing it to cool, it was reinstalled and the unit powers up fine with all audio and network functions restored.
How long this lasts, remains to be seen... I had a look at the service manual to see if I could find how many hours it had logged but there doesn't appear to be any info on a service mode for this model. I think the file I have is the complete manual so maybe it doesn't have a service mode on this model unless anyone knows better??
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Post by tibimakai on Mar 3, 2021 11:01:02 GMT -5
I don't know, but I know, that it is pretty old unit.
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Post by Deleted on Mar 4, 2021 8:10:47 GMT -5
I don't know, but I know, that it is pretty old unit. It is a pretty old unit dating back to 2009 but I got it quite cheap:
It's in very good condition and came with the original Onkyo remote. Despite it's age is a nice specification (unless you want 4K, Dolby Atmos, built in WiFi and Bluetooth!) and a it's a heavyweight amp with bags of power.
I think it must have failed quite early in life as its clean and dust free inside too. What baffles me is this model was covered by the extended warranty program and doesn't appear to have been sent back for the free repair or upgrade.
The main digital board is the original one with the early DSP chip D830K013BZKB300 and doesn't have the daughter board mod fitted either. I looked into some photos of the daughter board I found online and it appears they replaced an onboard 3.3V regulator with an external board that dropped the voltage to 3.2V... seems a bit peculiar to me?
I haven't had to replace any capacitors like others say they did and all it took was to reflow the BGA DSP and it burst into life. Being an older model there doesn't appear to be any service mode on it, which is a shame as it would have been nice to find out how many hours it logged before failure.
What I don't know is if the early DSP, D830K013BZKB300 suffered any problems and whether it can be replaced with one of the later more reliable versions, like the D830K013DZKB400. I've compared the schematics for the TX-NR807 and TX-NR809 that uses the '400' variant and they are pin for pin compatible, so I see no reason why not?
#EDIT: My mistake... another look at the TI bulletin and the '300' variant chip is listed as premature aging if it's the 'B' version, which this one is. Hopefully the later '400' 'D' version chip will work as a replacement if and when it fails again.
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Post by tibimakai on Mar 4, 2021 11:21:59 GMT -5
That picture, it may have been mine, but it was for a newer unit(TX-NR616 if I remember correctly). An Ebay repairman did that for me.
I'm not sure, if your receiver had the same issues, as the newer ones. Tjmotter knows way more about this than me. I try to stick to amp repairs.
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Post by Deleted on Mar 4, 2021 11:42:51 GMT -5
I kept the pics as I figured it might be something I need to add to the board but having looked at the service manual and the photos I can't really see any gain in dropping the supply volts to the DSP by just 0.1V.. unless there was some issue with the voltage regulator that Onkyo originally fitted to it?? I googled TX-NR807 no sound and found some very long discussions on AV forums and some very unhappy owners! Attachments:
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Post by tibimakai on Mar 5, 2021 11:18:08 GMT -5
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Post by Deleted on Mar 5, 2021 11:43:10 GMT -5
Looks like a similar mod that is supplying a slightly lower voltage and/or a cleaner, better filtered supply to the DSP chip. Whether this made any significant difference to reliability is debateable. My 807 doesn't have this fitted and I have looked at the 3.3V supply; it is well regulated and clean.
On another discussion thread I noted that the '300' chips weren't deemed as problematic as the later '400's. Mine seems fine after being reflowed and is 12 years old, so hardly what I would call a premature failure... unless of course it's been sat in a cupboard for the last 10 years!
I have noticed this receiver runs quite hot though, even with the main cover off. The big BGA controller chip, Q8200 FLI30336 seems to run very hot, so I've bonded a decent size heatsink to that to try and help. The two TI DSP chips are also getting fairly hot with the cover on, so I may get some suitable heatsinks for those as well.
Other owners have fitted cooling fans into the top cover above the main digital board and I am thinking this might not be a bad idea with this model as excess heat is likely to be a factor in the problems it has as much as anything else.
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Post by tibimakai on Mar 8, 2021 11:01:52 GMT -5
The newer units have a fan in them, but they start up only at 60C, which in my opinion it is to late.
I have replaced the original fan(120MM), with another one from a laptop cooler that has RPM control( I have adjusted it, to don't be to noisy). I made a long extension cable for it with a USB plug at the end and I connected it to the TV.
So when the TV is on, the fan is on in the Onkyo.
Newer units do not use fans anymore.
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Post by Deleted on Mar 8, 2021 11:44:22 GMT -5
The TX-NR807 has two internal fans. One small one near the main transformer and output stages and a big one in front of the main heatsink. I've yet to see either turn so I don't know what temperature they are set to trip at.
While looking at the schematics I noticed there was provision on the digital board for a rear USB port (may be for service use...) but it hadn't been fitted. I checked for +5V and 0V at the board and fitted a socket as I wanted a DC supply for my wireless network adapter. This allows me to access internet radio without running a network cable. I did have to cut a hole in the panel but it was worth it.
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Post by Deleted on Mar 8, 2021 11:44:58 GMT -5
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Post by Deleted on Mar 10, 2021 11:29:53 GMT -5
Found how to access the hours logged on the 807 and it has less than 4500 so must have failed early in life unless it had a reset at some point.
The lack of dust inside would support the former. Attachments:
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Post by Deleted on Apr 17, 2021 11:49:31 GMT -5
Having used this receiver for a while now since acquiring and fixing it I've noticed how much hotter it runs than my similar spec Pioneer. A lot of my use is on headphones, which makes it all the more surprising how hot it gets as the main power amp isn't producing much if any heat. Measuring the temperature of the lid above the HDMI board around the DSP chips sees around 50degC after an hour or so. Opening the unit, the heatsink with the main 15V DC (78M15/79M15) voltage regulators is almost too hot to touch. The voltage into these is dropped by a 15ohm 5W resistor but is still much higher than required. Both regulators are having to drop about 10V each and are producing quite a few watts of heat between them. After making a few voltage and current measurements, I decided to fit another pair of 15ohm 5W resistor in series with the other two, to try and reduce the power dissipation at the relatively small heatsink the regulators are mounted on. This brought the temerature down by 4 or 5 degC but it was still running pretty hot after an hour and I figured I needed a better solution than this. The main power amp heatsink is massive and fan cooled with a thermocouple monitor, so I decided to relocate the two voltage regulators to this and do away with the small heatsink that was responsible for cooking the DSP chip on the HDMI board. This has dropped the temperature another 5degC or so and more importantly moved the heat away from the sensitive TI DSP which is prone to premature failure without being slowly baked to death as well. I had to strip most of the boards out so I could drill and tap a couple of M3 holes in the heatsink but the end result is well worth it as the receiver now runs almost as cool as my Pioneer. Hopefully this relatively simple mod will help improve reliability.   |
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