STR-DE675 Home theater amplifier protect mode repair - in this case all of the amplifier channels were OK and the cause of protect mode was a very easy fix - took a while to work it out, but got there in the end!
Hi and thank you. Saved a DE475 from the charity shop (different board layout but same design). Worked for a few days then the protection racket started. Followed your video sequence. Exactly the same outcome. Checked that R732 resistor and it showed 1.3 ohms. Not having a 1 ohm job, paralleled two 10 ohms to give me 1.03 by the meter. Guess what, works fine. Simply that resistor had gone out of spec. Thanks for your pointers, appreciated.
Nice repair! Got a Sony reciever with the same problem, hope this video helps! It's always a good idea to fix the old solder joints before they give you problems in the future.
I have a STR-K502P with the same issues. Internals are very similar. Cold/broken solder joints in the same place. All fixed now, thanks to your video. Great info and explanation!
After having it disconnected for 3 or 4 days, it went back to work without having done anything to it. I am placing it in a better ventilated place and removed the self turn-off timer limit because protector mode happened after equipment turned off automatically.
Just had a problem with my Sony amp STR K740P, so I’ve brought a replacement STR DE475, a head scratcher but it’s old I brought this amp way back in 1998 fro the Sony store, it’s been absolutely brilliant until now, just checked everything cleaned it out and rechecked some screws, so I’m going to leave it on for a bit, normally trips out at 10mins fingers crossed
I had exactly the same problem. Except the one I got was full of water. Believe it or not, I had to wash the biggest pcb with the pressure washer to be able to clean it properly. It was all green inside. I wish I could add some pictures before/after. After cleaning it the problem persisted. But after some soldering rework and changing that resistor, it got back to life. Thank you!
i have the protect mode kick in sometimes , i am using different ohm speakers which probably messes up the power amp but the preamp output still works, and sometimes the sound quits without the protect kicking in so i increase the volume and the sound comes back on, could be a resistance problem?
i knew that the receivers sony are good receiver, they have 20 years and still working good, i prefer old technology than new technology because unfortunately everything are made in china and thats not good, congratulations !!! you have a gold technology
Nice job and great video, thanks for sharing your "hunt" with us. No doubt will answer a few questions other guys may be having with thier amps. Cold solder seems to be an issue with a lot of these older amps, that about the time manufacturers were switching to lead free solder (like anyone is going to be eating a pcb any time soon) . I had the same issue with my 2016 Jeep Patriot stereo, I had to reflow a cpu chip on the main board (man talk about a pain in the back side). Once I reflowed the connections with "old school 60/40" the stereo worked like a charm, actually a bit better to be honest. Thanks for the video very well done and clear to follow. Cheers!
@DanTubez, In the video at position 2.50 you found the -52.7 volts. I have also found the same on my amp. Both power transistors and dual resistor check out fine. Was also able to track down the 2 ohm resistor under the two rails but it was also reading fine. All my solder joints appear perfect. Can you offer some direction as to where I should look next. I seem so close because I found the DC volts on the resistor. Its funny because it turns out to be the same set as yours (first from the left). My amp is the Sony STR DE-697.
G'day! I suggest thoroughly checking that IC701, IC702 and IC501 all have a solid +/-~54V. You can do this by monitoring the voltage on C616/617, JW702/702 or JW706/707. It seems that if any of these ICs lose the positive rail, it will trigger a similar kind of fault (~ -52V on R516). Check all the solder joints on these ICs thoroughly, in fact just touch them up anyway as you can't always see a fatigued dry solder joint with your eye. Also check the solder joints on JW702/702 and JW706/707. Might also be worth checking C732 and C733, I replaced these at some point because one was reading ~20k out of circuit. Failing that, it may be worth replacing IC501 (they're pretty inexpensive and available on ebay). Good luck - I hope you manage to revive your amp :)
Thank you for this video now I have a good idea where to start. My STR-DV10 turns on and sometimes goes to protect after about an hour and sometimes it doesn't all day. Lately it seems to be doing it more frequently like about an hour or so. Would this be a different problem or should I still go after the same things as you describe in this video? Where do you get your service manuals please?
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
Saludos amigo, gracias por tu explicación y metodo de reparación. Tengo problemas de voltaje en un DC-DC board converter de mi Sony SDT-DH-540. No produce los 13.5 voltios requeridos solamente 12Voltios;, ni los 3.5 voltios, solamente 1.6Volt. Me ayudaría usted? (Do you help me? My DC-DC converter is not give 3.5Volt nor 13.5V DC for get up on my Sony HDMI amplifier.) I am from Dominican Republic, I need repair mi Sony, please.
I found prob on str de 675 .when I keep it stby there r no memory problem but whet i off main power and sw on after some time demonstration mode apper and memory missing .what to do sir .pls advice
Very helpful - I've got an STR-DE475 and have touched up the solder joints on the board. Quite a lot looked dry, or tending that way, and the joints on that STK IC were particularly bad. I noticed that R732 - mine has gone open circuit as well - is a fusible resistor. Did you use one of those, or just a standard resistor? Want to err on the side of safety, but also want to get the job done, lol.
Thanks for the feedback. R732 is listed in the parts list as a 1R 5% 1/4W carbon resistor. It is noted as non-flammable. I can't quite remember what the damaged part I removed looked like - either way, I've placed a resistor there. If you've got any additional info, please share. It's more than 3 years later, and the amp is still running almost every day - no issues so far :)
@@Justfixitmate Good to know, I replaced the resistor and the receiver is still a bit odd - goes in and out of protection. The heavy-duty connecting wires right next to IC501 and IC502 show -52V when it's in protect mode, I'm wondering if capacitors next to those ICs are faulty, as I moved one and it came out of protection and the meter stopped showing a negative voltage. Have touched up pretty much every solder joint on the board! Intriguing, will keep working away at it. Thanks for your reply!
I have the same amp but mine has a different problem. I hear all the channels at 1/10 from the original volume, except the center channel. All other functions are working. If you have any idea where to start looking that would be great.
You could try checking the output of IC201 at R373, 74, 76 & 78. Should be similar voltage to the center channel R375. That might help you work out where to focus. Perhaps the power mute circuit is somewhat active? (R744, R743), this circuit connects to the channels you're experiencing trouble with.
I have a problem where the front right channel is extremely low compared to the front left (And I think that all of the channels are generally out of wack but I only care for the front channels), I tried the balance adjustment and it does almost nothing. Where do you suggest I start looking inside?
I should probably mention that it has the same balance issue with headphones. I tried reflowing the only cracked solder point I saw which was right next to the front right channel output on the bottom as well as a few others, but no change
for me is brown there too but is not disconnected something just i lost bass channel, that thing on 10 last second of video u did not show really witch one was, there are 3st under
I have similar protect problem in my Sony STRDE345 (Someone abandoned it on street). I am trying to give a shot and revive it. The receiver has two of those 1 ohm resistor as you described in the video, they are R732 and R733. I checked them and they are fine, both at 1.2 Ohm, no short or open. All the solder joints on IC701, IC702, IC501 and three of the voltage regulators were touched up. All the solder joints through out the board have been inspected. All the power transistors checked out ok, but do notice the right channel pair of transistors seem to be replaced before. I also find the voltage supplying the power transistors does not match what is shown in the circuit diagram. B+ line is +52V, B- line is -75V. Could this be the problem? I am stuck, Please help.
Hey, nice work trying to save this amp. I would focus on the right channel output in this case. The only way you'll measure -75V is if your ground reference is at approx +25V. Something in this channel is out of balance. Have you measured the resistance of the big power resistors near the outputs transistors? (0.22R * 2)
@@Justfixitmate Hi, thank you for replying. I checked all the power resistors for all channels (the 0.22 ohm * 2 big white rectangular resistor), they are all good, measuring at 0.7 ohm end to end. I also removed the bridge rectifier next to to 2 big 10000uF caps and check to see. It looks ok too, 4 diodes all reads something like 0.5 to 0.6, no short. I put it back and remeasure its DC output, it reads 125V. However, when measuring the rectifier's DC positive side to ground, I get +50V; but then when measuring the negative to ground, I get -75V. I don't know if this is normal because I have another known good Sony STRDE receiver that doesn't do that. On that good receiver, the bridge rectifier's DC outputs read +55V and -55V when check referenced to ground respectively. Anyway, since you mention to check the right channel first, I will definitely go after that first. I have a feeling something is going on in that right channel driver (Also the left channel driver too). Maybe either one or both are outputting some funny input voltage to the base of the power transitor/s, causing the power transistor to turn ON mistakenly. I will try that tomorrow, thanks again.
Hey there. Check that you have -30V on the display board. I've had this issue before - I recall replacing a resistor. Check R803 on the main board (4.7R).
Hello sir ji my sony's music system is its volet problem, it is completely closed but its 1 swich o switch 230v 220v 120v like this, if i use 120v for a second then power comes on 220v and 230v pe does not have any power, what can be the problem in him, thank you for telling your opinion
Is only for a 120v. Just leave it in that position . The others are for countrys that use higher voltages. The U.K.uses 220v for homes & the usa is 110v120v.
Dominic Fong This amp has been used almost daily for 20 years so I'd say wear and tear. However, I have found over the years that some of the resistors on this board are somewhat close to their power limits and will fail eventually.
infohacker info10 some of these amps have a setup menu if you hold down the power button for 5 seconds. It could also be designed to only operate with small speakers and a sub. Not familiar with your model.
I had the same issue with mine. I'd highly advise you to redo all the soldering and check the 78XX regulator soldering too. I found some cold soldering on the dolby board. and on the rca board too. the rca has a LM7905 negative 5v regulator. this is a good receiver but with time it melts its on soldering on the pcb.
Bonjour , super le diy que vous faites , cela se perd, de tout réparer , je cherchais des infos sur cet ampli que je compte acheter , mais je m apercois que l on ne peut pas regler les basses et les aigus. vous pouvez me confirmer? d avance merci
Bummer Dude! Try a boxers "body bag" to work out your frustrations on instead of expensive electronics. Also folks may think you are in need of professional mental health evaluation I.E.- think you're crazy or something & call the bad guys in blue to do a "health check" on you. Breaking into your place if you dont answer the knocking on your door. Then possibly seeing something innocent like a a jewelry scale & thinking they can now go through every single place in your home saying stuff like after witnessing what appeared to be drug distribution paraphernalia, we then had the right to search for criminal activity . So 15 guys in boots stomp around brwaking stuff,getting into your underware drawer, snacking from your fridge,all while making fun of you for being ...anything, just notta cop! Destroying your home & putting u in cuffs & making everyone of your neighborhood think you are a bad guy. Ruining an entire evening, & being antagonized, humiliated,& of course threatened to not retaliate against them by contacting the local tv news station ,or filing a lawsuit, cause that may make em look like a gang of thugs that broke in & violated your constitutional rights & intimidatIng with harassing questions over & over, like "Just tell us where the drugs are!" "Soooo, you work at '.....'s huh?" "Oh you like to hang out with 'so&so' huh?" "Be a shame if...OR "We cant have the people losing faith in us? Can we?" So maybe we just 'find' a stolen piece used in a robbery 2 towns over 5 years ago???? All because u got mad & smashed your radio. Strange, & unpredictable times we live in.
My Sony receiver got moisture inside because it was outside in the covered gazebo but the snow drifted in from the side and lightly dusted it. I noticed the receiver turned on by itself and then repeatedly turned off and on with "Protector" displayed. I wiped the snow off and then covered it with a towel but I didn't unplug it. So when it turned on by itself it got hot with no ventilation, which made it go into the on off mode. Everything seems normal on the front display when I first turn it on then it goes into the mute mode and keeps turning off and on every few minutes. I opened it up and there is some white corrosion deposits around some resistors. I am actually surprised the receiver has lasted several years outside until now. Not sure whether to try and fix it or buy another receiver.
It not going into protect mode, no he's trying to fool us. He's using video editing magic to make it look like he fixed it when really he probably just bought a new one from circuit city. He's what you call a sneaky pete
@@philhalo66 At any given moment I'm as high as I've ever been. So right now for example I'm as high as a kite end as I wrote that I got even higher and I don't know about you but I go to circuit city all the time. Besides they're better than best guy
After watching all these repairs I'm only singing songs to myself from now on. Just me and my dumbass phone. My receiver just randomly started flashing protect so its due for bashing.
There were no dry solder joints on the Center channel IC... so I'm not sure it's related. My feeling is these 1/4W resistors are simply under rated from a power dissipation point of view and give up after years of service.
Power pusch Protector in sony audio system is really one of the headache problem. So sony should develop a button which this problem is rectified manually by users.
The Protect mode function is a mechanism to protect your speakers from a hardware failure. It's a necessary function. Considering most of these Amps are 20+ years old, I think it's reasonable to consider the possibility of hardware issues due to aging components / solder joints. I'd prefer protect mode over burnt out speaker coils.
I just bought a used Sony STR-DH810 and it looks like it works but NO SOUND WTF should I do? I have tried this resetting thing mine does not say Protect mode
