Sony Audio Receiver in Protect mode Repair Fix STR-DG720
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- Опубліковано 30 лип 2024
- The repair of a Sony STR-DG720 audio receiver in the protect mode. involves replacing power amplifier output transistors, emitter resistor and base drive resistors.
- Наука та технологія
8 years later and your still helping people 😍
I replaced a blown 125-volt, 6.3-amp slow-blow fuze in my aging Sony STR-DE597 7.1 receiver and when I powered it up, after a few seconds it went into protect mode every time. I was stumped, but I think you may have told me how to fix it. The info and the lesson are greatly appreciated. If you're still checking this video after 5 years, thank you, NorCal715.
Enjoyed watching the entire video. I like the feeling of success when there's a fixed equipment after a repair..
Excellent video! Always you are posting high quality and knowledge based videos. I know video shooting and editing is a tedious process but by this way we are helping our friends. Great effort. Regards,
LearningZone hi.
I m vinay
I got one receiver. Model ...STR- K870P in protection mode. In cold testing every part normal condition. Problem is after starting
Showing PROTECTION.
What can I do.
Thanks for this video. It was a perfect place to start in getting a Sony receiver that I pulled out of a junk pile working. Nothing like checking it after a repair and seeing a unit come right back to life!
Keep looking around. That's where mines going
Absolutely wonderful of you to post a video like this. Much appreciated. We are expected to just throw these out and buy new units, with a little troubleshooting and effort someone could save hundreds in replacement units. I have 3 older units handed down with this same issue, and personally have a
Norcal is one of the top guy in this business such a knowledgeable and professional technician. Following him for years now. Good job my brother. Cheers!
Nicely done Steve; When logic is deployed, troubleshooting becomes easier.
Another great repair video. I have 2 Sony receivers that go into protection mode. Now I am motivated to fix them.
My Sony str de685 display light is not Comeing on the store comes on but the display light don't how do I fixs that
Man U are one of the best I’ve seen with explaining how to work these
I have an Sony SR-k750P with the same problem. Happened to find your excellent video and sure enough the exact same problem with the same readings even. Ordered replacement transistors off Amazon and will soon be trying the repair. You certainly saved this Receiver from the dump as without schematics I didn;t even no where to begin except looking for the obvious. Thank you for taking them time to share.
Did it work?
Unfortunately, No. It must have been something more.
@@kikcodog i have the same amp but it got much worse, some problem before, a transistor almost burned, the heat compound got darker and smell very bad, even some smoke got out, but weirdly enough, re solder every transistor, put everything back, power and got sound, but then i tested the headphone connection to find any parasitic signal but suddenly, the screen showed PROTECT but before blinking, the unit went off, the transformer got killed, nothing blow yet, replaced the step down converter to power it up again, relays work but now i have no image on the VFD and i don't know what went wrong here.
Absolutely top notch - clear precise how-to. My STR-KS1300 (slimline 5.1 amp) is now showing the exact same thing. This video gives me a great place to start, and by the looks of it might fix it. the Ks1300 was working but noticed I had a different issue, as it takes random amount of button presses to get it to power on but I'd not hear that relay click but it did produce sound. Although now I get protect mode so I could be a different issue. still work checking the components you showed me though.
I congratulate you, straight to the problem excellent explanation and proper sequence, and NO drama ...
other videos do much theater for something so easy to end up confusing and frightening apprentices, thanks for your videos
Excellent video. Well explained all details. Nice to see a professional skills to avoid recycling in electronics.
It's next to impossible to find useful information on this for early 2000's Sony AVR's. Thank you so much! I'm much more confident that I will be able to fix my STR-DE885's center channel now
Hi! Thank you very much for this video.
My Sony STR-KM3 (Argentina model) is turning off right after power on, displaying a "USB FAIL" error message, despite the model DOES NOT having any USB connector?
(I have once repaired the same model, but with USB. The problem was a faulty relay (RY901)).
Any suggestion or hint?
Thank you.
I have a Sony reciever str-av570, that keeps going into protect mode intermittently, even when the reciever is off, will intermittently do relay click and amber leds on the front will glow gradually, off, and repeat till I unplug it. Back in 2003-2004(before UA-cam), I took my reciever to a authorized sony service center that did not know how to fix it, but charged me $35 to inspect device anyways. From this vid you posted, looks like a good place to start. Thanks for sharing!
Why i like this video ? Because you explain the complete diagnostic procedure... And from that i learn alot ! Thanks ! Looking forward for the next one !
I recently finished repairing a STR-DE135 with protect on symptom. Upon visual inspection, I saw two obvious issues . The driver IC701 area and the Q801 24v regulator had overheated resulting in bad solder connects and
a darkening of the circuit board. IC701 did not test bad but I replaced it and c740,741 and c742. Protect still on.
Next I replaced c802. Protect still on. Finally, confident that both circuits were restored to fully operational condition I replaced r740 10 ohm and Shazam ! Solid fix ! The takeaway is overheating is often caused by bad
capacitors .
Thanks so much for making this video and the in depth troubleshooting explanations. I was able to get my Sony STR DN1000 AVR back up and running again thanks to your video. I had no experience with any of this and very little soldering experience. Using a $10 multimeter, I was able to find that I had a bad emitter resistor and a pair of bad output transistors. Ordered some new ones from aliexpress and carefully soldered them in and it powered up!
I connected all 5 of my speakers and I found that the front right speaker sounded like it was badly blown. I then moved both front speakers from "Speaker A" to "Speaker B" and the sound is perfect again.
I don't know if my "blown" front right speaker when using speaker A is due to poor quality parts from aliexpress, my poor quality soldering job, some other small resistor needing to be replaced, or something else, but I only have 5 speakers in a 7.1 channel receiver, so it's not bothering me.
Thanks! I can't wait go get started on the repair. Do you have any recommendations on a reliable brand or model of receiver/amplifier, based on your experience of repairing them? Are there any to avoid or any that you'd recommend that should hopefully outlast others?
Your video helped me to fix a dead home theater receiver. THANK YOU!
MAN THIS IS A LIFE SAVER!! I HAVE A SONY STR-DH130 RECEIVER !! It is stuck in protect mode and I just so happen to have a solder gun and volt meter I'm going to fix my own receiver ASAP !! NOW I got to order the Transistors !!
This video is exactly what I was looking for, many thanks your videos are great.
Hi, what wattage are the 100ohm base resistors you changed? I found 6 bad transistors and replaced all the base resistors but all of the bases resistors, except for the transistors I changed exploded. I guessing the 0.5w ones I am using might be too low.
As a footnote, I did some voltage checks with the unit powered up, looking at the 6 ic's mounted to the main heatsink. Base idle voltage on two of the three 2488's tested at +1.15v and -1.05v on the 1620's. The 2488 collectors tested +52v and 1620's at -52v. Emitter outputs tested at 0v.
On the last pair of ic's (nearest the front of the receiver) the 2488 had -51v base, +52v collector and -50v emitter. The 1620 tested at -51v base, -52v collector and -50v emitter. I tripple checked them for shorts and both tested fine with all diode junctions intact. What would allow 50 volts to show on the base side of the transistors other than a short? I believe the base voltages are effectivly "turning on" the transistors and thru-putting 51 volts (less the v drop thru the diodes) ending up as 50v on the emitters. Hmmm....
Again, thanks ahead of time for any help you or your subscribers may be able to lend to my troubleshooting. Reguards, Jim
These old sonys have the Vacuum Fluorescent Displays(VFD) that I think look beautiful and don't exist as much on newer receivers making these a very beautiful receiver to continue to keep functioning.
Another thing I've been a fan of on Sonys is that they take a signal and can be set to put it back out without effects as clean as the signal they were given except amplified for speakers which is great if your DAC or something is an external device that wants to do it's own effects/has better effects.
Great! Question, I had disassembled my str-dh520 (very similar) before I found this video and had tested all vrms and op amps and found the lm7805 to be faulty. I swapped it and reassembled and now I hear a solenoid click and I get no power up. I checked the voltage on the 7905 and 7805 and 7v one (forgot the vrm number) and they all check good (-5v,5v,7v respectively). Where should I proceed from here? I've rechecked all connections multiple times. Also will the unit power up without the hdmi board? I have to remove that every time to get to the vrms.
nice one sir your the best technician i've ever seen your my idol because i learn a lot from you thanks
The best video on repair so far. Thank you very much.
Hi there. wondering if you can help me! i have a sony str-565 with distortion on the left hand output. i think is the preamp because i can here it on the headphones to. but have no diagrams and i had forgotten how to check some circuits sins i graduated electronic technician and never did some actual repairs. thank you! and excellent video
I have the protect msg on my HK AVR130, disconnected all spkrs except main R and L and it worked for a few hrs, now I get the protect msg and it shuts down every time. Works fine with Headphone jack. Should I follow the same procedure you have here?
Best video yet . that's explain and really broke down the process of repairing your receiver...... I ready to buy my pieces and fix my sony and denon receivers.
I have similar Sony Muteki 1510 Watts receiver. It looks same as this unit from inside and outside. But this is 6.2 channel amplifier. I have issue with center channel which have some noise and sound is not clear. Rest all channels are working fine. I did check the center speaker in other channel and speaker is good. I strongly suspect the noise is being introduced in center channel. Please guide me how to troubleshoot this issue. Which all components could be problem?
Thanks for all explanations. I need to watch this video again :-)
I just had the weirdest experience with a sony receiver. It was connected to my pc and i was watching a video. Suddenly no audio/video. Thing is, i tried every possible input none of them output any sort of sound. But no protect mode no nothing. Just no audio. Any clue what may have happened?
I fixed a doomed STR-DG520 with this tutorial this is gold! 105Ohm is within tolerance tho I found one that read 2MOhm instead of 100
Great video, thank you! I have an STR-DE597 that goes into Protect mode, but seemingly only when it's cold. Can't wait to get stuck in.
Could this also be a reason for almost no bass coming from one side? I have swapped speakers and inputs to no avail.
Thank you, once again another cracking lesson. Keep up the good work
I have an Onkyo tx nr 1009 9.1 ch amp that goes into protection mode (check spkr wire) only when using the 2 (LF and LFH) channels. - definitely not a speaker wire issue.
Any advice will me much appreciated.
i have the exact stereo but the menu selection ir volume does not work for some reason
Question the transistor on my reciver. Model str-d790 have a number on them does any other will work? Or it has to be the exact same ones which are a1672 c438 a1264n and c3181
You mentioned the danger the large capacitors pose, but you still worked on the opened unit while powered on with no gloves or anything. How do you know its safe to work on? I want to try to fix my Sony STR-DE545 but I don't want to get a shock.
Also, is it possible that a receiver can short out and go to Protect mode simply because of dust? My receiver is 16 years old. And looks dusty inside. I have not taken the cover off yet. Thanks.
Hey,
Great video. I am trying to use these steps to help determine my issue with a NAD 7400 PE receiver. I checked the emitter resistors (white) and found one out of spec with an ohmmeter. It was open. During the voltage check I found that that one and another emitter resistor was out of range. Both were reading 52.0v. I do have a question on the output transistors. When I try your diode check my results are different than yours. I get readings in forward and reverse bias. The readings are between 0.5-0.7v. Does this seem normal for output transistors? I have two b940a and two d1264a.
I have a Sony DA80es with the Protect message problem. While not the same as the one in your video I followed your procedure. There are two emitter resisters showing 24 ohms when power is on and all the rest are very low voltages. But the component that emitter resister connects to has 5 leads on it. The component is a Sony NEP250. Could you tell me how I can check this like you did the transistor on the unit in this video. Thank you!
Hello my amp str k1600 the left channel doesn't work u till you turn up maximum volume then it works like normal, possibly dry/cold joint?
Great video!I have the same problem with SONY HT-DDW840. There are five big white noble resistors. When I test the central lead with DC voltage range I get the following readings: 3.383v on four of resistors and 0.52.4v on one of them.Based on this, can I conclude that this fifth one is damaged?
so if a sony unit is in protect mode you can expect a prob with the outputs and related components. or could it be somewhere else?
Great Video,I have this same STR-DG720 has been great,all of a sudden the 2 front speakers are very low volume,all others are ok.Even on 2 channel setting,I have to crank volume to like 40 or 50 to get any kind of volume on the 2 front speakers.It's just the 2 front speakers.All others are fine.Have you seen anything like this before on this receiver? Any idea's would be greatly appreciated.The 2 front speakers work,but very low volume.Speakers,wiring,and connections all good.Just noticed this a few days ago.All speaker lights on front panel are lit.Thankyou
That solder melted really fast and clean, what temperature did you use on the soldering iron?
Hello norcal, may i know the model of your soldering iron and its power and which temperature you set it? It seems to solder and unsolder so well.
Hi . I have the sony STR-DH800. Over time the master volume has needed to be increased to MAX to listen to at normal pleasent levels. It all sounds good, but its cranked up full wack now. The protection circuit sometime fires when I turn it on at these levels. It looks very similar to unit on your vid. What should I be looking at for repair. Kind regards. Kenny
where you located? can you fix my str1010? it has the protection mode message as well. and the speakers pop/click as you turn them up, before shutting down.
I have this model Receiver but a slightly different problem and need to know where to start repairing it. I have two 30 watt speakers hooked up to the front speaker output and no matter what input I use I barely get listening volume with the volume maxed. if i change to the center or any of the surround i nearly shred the speakers at 40. any insight would be helpful.
I lost all audio from 2 of the 4 HDMI inputs. Do these have seperate HDMI audio circuitry for each input?
Very informative video. You you tube producers are really helping teach people like me....well some of you are. Peace
Excellent Video, Great effort, let us look into actual remedy information rather than extra sounds,
thank you very much . I am an amateur and you helped me a lot with your video to repair a sony str-de595. Good for you
Thankyou helped me repair my Sony STR-DH590 same topology just 2 channels less, mirrored you step by step found bad solder joints, Seams to be a sony issue with bad solder due to heating and cooling, but thankyou again.
Where do you get these parts from? I would like fix my protector mode issues myself, but have no clue where to get the replacement parts...
hello there,
very nice and detailed video!
I have model STR-DE695 which has same symptoms as yours - goes out to protect on powering up.
I did all same as you instructed, but my output transistors and emiter resistors readings are fine.
I also did resolder drivers. What I find strange is that one element on digital board goes very hot while amp is blinking PROTECT, but its voltage readings are fine.... So, now im confused... What else should I check?
Many thanks!
Hi, just wondering if you can help please - I have a Arcam Alpha 10 that
is going into protection mode (Red flashing light) not all the time
though - sometimes i can power it up and play music for a good few hours
with no problem then other times it will go into protection mode after
15mins, 30mins no exact timing to it - any help would be massively
appreciated. Thanks
i have a sony ga7es it turns on but when i crank the volume it goes to protector
Excellent work, this is a very helpful video and the commentary really good -Thanks man!
Simply Lovely. Very impressive explanations reflect the work experience.
Is there away those emitter resistors can be put in backwards? I see some with the lettering outward and some face inwards.
thanks for the great video. I have an old sony STR-D565 that has gone on protect mode recently. I didnt use it for about a year but it was working great, it did over heat and go on protect mode on a couple of house parties I had.
I pulled it apart and did everything you showed, it all checked out good, what would you recommend to check afterwards?
Thanks!
Another very informative tutorial.Thank you.
sir norcal715 do you have any idea the cost of having reciever repaired ...my prob is lost sound on all speaker channels except surround rear channels and center..front and side not working...can hear tiny bit of sound coming from the front and side channels olwhen i crank it all the way but sound is distorted....reciever is same as this video all speaker levels are cranked and on and everything is hooked up correct.
Great Video!!!
I'm just wondering... I have a Sony DVD Receiver AVD-K800P and it stopped working a couple of years ago and just today I decided to give it a go. Based on what I'm seeing on the screen (which appeared blank those years before) everything appears to be working well, the only problem is I cant hear anything, checked and the speakers are working.
Any thoughts on what could be the problem? I suspect its audio related.
Also do you have any videos for my model though not related to my specific problem?
Thanks!
Hi I have excact same unit, it went into protection mode, I somehow managed to get it to turn back on but missing front left channel. Now have soldering kit so going to check the emittor resistors. My question is, what qualification is required to know how all this works. I am very technical and mechanical, micro solder charge ports and xbox retimer chips etc. Need to learn the diagnostics side and how all these resistors, mosfet and capacitors work properly.
Thanks so much for this video. This fixed my issue on an STR DG-1000. The protect mode is now off, after replacing both transistors and the dual resistor. However, I now have distortion/static in that replaced right channel. I've tried new speakers/amps/etc.. so I'm confident its in the amp. Any idea what might be causing the distortion/static?
An update on my STR-KM7000
I've replaced all of the output transistors because I wasn't 100% sure about them.
Unfortunately, I still have the same issue. The tower speakers and one rear surround speaker is still very quiet.
The emitter resistors all read 1.3 ohms, which is higher than what you said they'd typically be. Is this strange for my model?
What would your next step be in my case?
Could this be a case of a damaged driver IC pack? If so, which one? How do I go about testing them?
an update on that HK receiver i had that shut off, it was a bad Center channel transistor. After taking it out, it worked! i got sound and it stayed on. Your video here helped me troubleshoot it! I sold it and the guy is gonna replace the bad parts in it.
Parabéns pelo ótimo vídeo. Vou tentar consertar o meu também, um SRT-DE885 que já está parado há mais de 2 anos pelo mesmo problema. Obrigado.
Congratulations for the great video. I will try to fix my receiver too, an SRT- DE885 it is stopped about two years with this same problem. Thank you very much.
Thank you for explaining how to test a transistor. I've been watching videos and everybody does it but no explanation gees.
Great vid! Question, would Kapton tape substitute for mica to insulate the fets???
Great video. I'm having a different issue with my AVR, but I can't find any troubleshooting on my problem. I have a Sony STR-DG720 and I am having speaker calibration issues. I attempt to calibrate and receive an error code 12, which means the speakers are not detected. Do I need a specific speaker connected and/or all the speakers connected? I will only be using it in 2 channel mode, only a front left and front right speaker. Have you experienced this before?
Question, can you use a 2 leg cement resistor instead of a 3 leg one, but with same ohms by jumping 1 leg? My cement resistor is 0.18 ohms, could I use 0.22 ohms?
Good day. I followed this video of yours and it's helped me alot, so thank you for that. But what I would like to ask and need some help with is a NAD T743. What it does is that it's stuck in the standby mode. Could you please just gie me an idea of where to start.
Regards
Cedric
Very good documentary and very informative lecture, love see more.
i have a Harman/Kardon AVR1700. When powered on it lights for a second
then shuts off with a blinking orange light. Now if i remove the cable
that goes to the amplifier board. it stays on as normal. I tested the
transistors with a multimeter in diode mode, most of them with the black
probe on "B" and i tested "E" and C" i get around 16-17.00, going to
18.00 and it keeps going up. I tested them backwards (reverse bias) and i
get readings too. Now i read somewhere if you reverse bias them, they
should not read anything. I am thinking the output transistors might be
shot? None of them test dead short. PSU gives out +45 and -45 volts which is in spec
Good communicator, well explained fault finding, loved your tip with the dental pick.............Liked, subscribed, and looking for more.
Ray H. from the U.K.
Is it ok with the double adhesive thermal insulation tape?
i loss bass power, will see if i can get from another one,, or what if i found the center channel and remove from center channel? it will work bass channel or they have different power?
Hi. I got a Sony STR-DB780 and for years when I turned it on , I got rumble in the sound and the rumble faded away and the sound was good for the rest of the day. During rumble I couldn't regulate the volume . (condensator?) Now , suddenly the volume is lower on all channels. Tip please . Thanks from Belgium.
Hey there. Thanks for the great video! I used this as a guide to check out why my STR-DE575 has decided to only have volume out my center and right surround. It does not matter the input source or the output mode. Only volume from the two mentioned channels.
I checked the resistor packs and they all read good for resistance and the centers all had really low voltage. It is difficult to get to the leads reliably on the transistors as my model unit has two shields between the row of resistor packs and the transistors. I set my meter to audible diode mode and it never beeped and I am pretty sure I made contact.
If you have the chance to reply, is it most likely that other electronics on the main board are fried/dead? Or if I am lucky one of the driver packs just has a cold solder. I will check that soon but was hoping to not have to tear it all the way down unless it was the same kind of repair as was needed in this video.
(I have owned my DE575 for 15 years. Right from original purchase)
Thanks in advance for any tips you may have!
Jason Price I have the exact same problem! has anyone found how to fix?
pyrophantome a Sadly no. I was in need of a new HDMI and component video capable unit and the boxing week sales here in Canada just a few short months later had a great Yamaha unit and I got it.
I still have the dead one downstairs so if I ever get the inclination, I may still yet try to fix it. Otherwise, I will salvage out the components for any little diy projects I have.
Hi, thanks for a informative video.
I wonder if you could help or point me in the right direction, have a Sony STR-DG910 which has some issues...
If you plug it in, you can turn it on using the power button on the front panel, and you can turn it off (standby) from the same power button, but it won’t turn back on again, if your pull the plug out for a second and re-power it, it will allow you to turn it on again, but it goes “dead” again after you put it into standby again.... the IR remote is also non responsive, all functions. I have checked signals with my scope and can are getting all the way onto the “digital board.
The front panel knobs work off the same IC, and they respond when the radio is on.... like vol/input/tone etc. so it means that ic must be running.
It’s almost like when the chip goes into sleep, it doesn’t want to wake up, unless you remove the power for a short time.
Any help would be greatly appreciated. Kind regards
I own this receiver, it went into protection mode and then the fronts both A and B no longer function. They do sound but a very small high pitch at very high volume. Any idea what parts I need to replace? Its not an issue with how its set up, its physically broken.
Really enjoyed watching this, looking for a solution though my Sony STR-DA50 ES isn't in 'protect mode'. Nobody on SONY community talking about these old (1997) models. Haven't used since 2008 then last week just plugged it in, and tape / phone/ CD all was working , then nothing. Display working, can hear the A/ B spkrs switching, but no audio signal from tape/ CD or phone monitorable , even at the headphone. Any ideas? All sources and headphones checked and working.
Hi I need to repair a Sony 5.2 ht-m55 it has a scrambling noise when I plug the speakers in it has a similar set up as to this 1
Hey that was great but I have one and I found the One of the speaker wires had grounded understand that I had it on and show on the bottom board on the right side of my problem I think cause I'm going to plug everything down by unplugging could you help me with that appreciate a lot in the heat and air-conditioning guy
very nice video I think I may have the info for what I need on my older amp I have a 70s pioneer sa 8500 it keeps going in and out of safety cut off when you turn it on it will take forever to click then it will click right back off if left on for a few mins it will cut off and on this is without a load or anything on the inputs after watching your vid im thinking my emitter resistors might be bad as well as possibly a few of the transistors
low volume level from one of the front speakers. what would be the cause?
Awesome video. Very clear. Are there any steps you take to make sure the filter caps are discharged or is there a discharge circuit on the unit?
Hi, I have a STR-DG720 with a small hum or buzz in the speakers (and headphones) that doesn't change regardless of volume or input. It's present with nothing but speakers or headphones connected. Is there something I can do to fix it?
hi, I have a Sony STR DA 4300 ES, it goes on but has no display, also I notice the fuse next to the back across the ES was blown when I replace it ,blows again...can you tell me where I can start to check..TY.
Nicely done Steve; i have a sony N9000ES with the same problem, it turns on some times and works fine for hours together but some times it goes to protector mode when i switch on. I checked the output NEP250/NEN250 five leg transistors and 0.22K (2Wx2) Resistors which are fine in all channels. What could be the reasons.
hi, i have a question i have a sony home theater sys. the problem is that when i turn the volume up to the max it stays at max but the sound level decrease to the min also some output ports stop working can u tell me whats the problem?
Great video. Any advice for an STR-DG720 that has low volume output on the mains? Center channel seems OK.
Hi great video. I tested all this on my receiver everything seems fine but it bows the 2 output fuses when it is turned on. What else could it be?