Denon AVR-S930H AV Receiver - Shuts down - Red blink of death - Another High DC Offset on one output
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- Опубліковано 24 лип 2024
- A Denon AVR-S930H that the customer drove up to me from 100 miles away, it came in with an immediate shutdown issue after power up, I found a bad transistor in the differential amplifier power supply on the Surround Back Left channel.
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00:00 Intro and a look around
00:32 First power up and red blinking light of death
01:13 Testing for DC offset on all channels
04:44 Are those cracks in the solder?
05:49 Amplifier removal
06:54 Testing the output transistors
08:59 The amplifier schematic
10:19 the power supply is connected to the amp board
12:18 That is an issue, Bad hum
13:00 I think I have found the issue
13:20 Testing the suspect transistor and comparing it to another one
14:09 Reflowing all of the output transistors
15:12 Time for reassembly
15:30 Testing after reassembly
16:37 Testing DC offset again
17:32 Testing after complete reassembly
18:29 Final thoughts/closing words - Наука та технологія
I am that customer and am very pleased with the attention to detail in the repair. I (and NorCal715) kept a 4-year old, $600 receiver out of a landfill. My bank account is happier, and should be for some time thanks to the quality of the work. I agree with some comments that the quality of electronics do not seem to be what it was. This is my 7th? receiver in 40+ years. (One sucker literally blew up and caught on fire. The manufacturer said "It shouldn't do that.")! I still have - and used during the repair - a 1980 Pioneer SA-7700 that still works perfectly in it's native audio-only, stereo mode. Thing's a beast. Why is that? Anyhow, I'm impressed by the business opportunity presented for Norcal715 and others with the skill.
Thank you Mark, I am glad you are happy with the repair!
Awesome video! I have a Denon that keeps shutting off so I came across this video but your trouble shooting is way above my level haha. Might just jump in and see what I see and use it as a learning experience
Great job with your trouble shooting skills. Its always fun to watch you work. 🙌
Your diagnosis method is simply good.
That . Was a clean diagnosis sir. I had an old rare top of the line Nikko receiver with the same issue. It had a regulated power supply . I changed the output transistors on the bad channel but still hummed bad. Took it to Star Track audio repair. A year later I called inquiring about it. HE TOOK IT TO THE DUMP! You have a new subscriber here. You earned it!
Great work! I see this unit is much easier to disassemble comparing to AVR-17xx series. Those ones are complete nightmare.
Love your videos too. I learn things when I watch them. I used to work on recievers when I was younger. But those back then were much simpler to diagnose. No computer or anything just pure analog circuits
amazing as always. loving the drum and bass btw
Great skill!
Nice work! Thanks!
Thank You So Much.
Excellent, I recomend to buy the Peak Atlas DCA75 Pro, this is a very powerful component tester.
My parents have a s940h. It's already been in the shop once for a faulty wifi and Bluetooth module. But now again it's failing. Sometimes it won't connect sometimes u can't even find the unit when you search for Bluetooth devices to pair. Onkyo also had a similar issue as well. It seems these units nowadays aren't meant to last long anymore. All other functions work fine. It has great sound too and plenty of power to back it up. I ran a set of infinity crescendo cs-3009 floor speakers on it and they sounded great.
Exellent trouble shooting.
I love your youtube video.
🐨APU I dropped a like..
Look how light is that aluminum heatsink in comparison to older models - The manufacfurers are cuting costs as low as possible
Nice fix. I was wondering about the resolder of all the pins. Did you use lead free replacement? I've found the lead free stuff doesn't preform the same when redoing a joint and always have to resort to getting rid of as much of the original solder as possible and by that stage, it's then just easier to put back leaded solder. Mixing leaded and lead free doesn't seem to work for me either for long term.
I use Kester 60/40 or 63/37 mostly. I used to remover the old solder but after many years I have not seen any difference if you remove it or not.
Great video, was this transistor in a power regulator circuit? It looks like it was connected to a half wave rectifier circuit with a 16 volt filter cap
It was in the differential amplifier regulation circuit.
Would these good readings be the same on all amps?
Where do you find the schematics for these old monsters?... I never have any luck so they go to the landfill
hifiengine.com and elektroyanya.com
hello great video , i have similar issue , with X2700h , my reciever working sometimes 1 minute , sometime 30-40min and turn off in protect . When i go in developer mod say “DC” is displayed (DC output of the power amplifier is abnormal.
If the power is turned on during this abnormality, protection is activated after around 6 seconds and the power is turned off) is it the same problem ?
Could that bad transistor have been discovered with a multimeter opposed to your transistor tester?
I did find the defect with a voltmeter then tested the transistor to confirm, I wish I could have recorded it but I already had about 2 hours into it and that's a lot of video to edit.
Made in Korea?
I have a different model:avr-710w but it has the same problem I will check if it will be the same I have a different model but it has the same problem I will check if it will be the same .