I have a passion for audio equipment and seeing you folks repair these machines brings me great joy. This is such a low end unit, but you went ahead and fixed it just the same. Saved from the landfill!

I just completed a second repair of this unit using your video. The first one failed for the following reason: The problem with the circuit board grounding via the two screws that connect the heat sink to chassis is not that the screws are loose. The issue is that the contact point of the circuit board ground connections with the chassis cross brace are corroded over many years of use. I removed the heat sink (2 screws) and the cross brace that it is attached to (4 screws on chassis bottom). I cleaned the ground contact points of the circuit board and the brace with contact cleaner and steel wool. I then used a contact preservative. I reassembled everything and the receiver is now operating perfectly. Mine also had been repaired previously as it had the glob of solder on the heat sink tab. The shop had even applied a sticker with it's name on it. No shame I guess. A neighbor had given me this when it quit working so I now have a nice working receiver for free! I couldn't have done it without your video so THANK YOU!

@12voltvids

7 жыл бұрын

You're welcome. Yes ground issues very common for Sony. That and the driver ICs coming unsoldered. I do feel under appreciated though. I give away valuable knowledge only known by people in the service industry, and trolls give thumbs down. Makes we want to rethink giving away trade secrets.

@robertmasterson7771

7 жыл бұрын

Please ignore the trolls. Feel sorry for them. They have no life and can only criticize others that do. By the way, last night I found another way to accomplish better grounding on the Sony STR-AV570. I ran a short wire with ring terminals on each end. I attached one terminal between the circuit board ground contact and the brace that the heatsink screws into. The heat sink attachment screw is then used to tighten the connection. The other terminal attaches to the nearest chassis screw outside the bottom plate cover. This allows for ground connection directly from the circuit board ground point to a chassis screw via a ground wire. Just thought I would share with you as you did for the rest of us. Basically once I saw that it was a grounding issue (thanks to you) I ran with that and modified it to a better design. Thanks again and keep up the good work!

@12voltvids

7 жыл бұрын

The trolls are loosers. Simple as that. They are nobody's, and nobody would miss them if they just vanished.

@madmanmechanic8847

Жыл бұрын

@@12voltvids I am sorry . I just barely found your channel I make sure to give you a like button and watch till the end to give you a goo alltharithum , sorry spelled that wrong

Last night i was on my bed watching this video and i heard you say that the two worst failures of STK power modules are broken solder joints and shorted speakers. Today i was due to clean my amplifier, a Denon AVC - 1000g, I cracked it open, and the first thing i checked were the solder jonits, and the three modules had cracked soler joints!. The amp worked just fine, but it was a matter of time until they would eventually fail. I resoldered all the STK units and the amp is as happy as ever, very good advice man, you just saved my amp, keep it up!.

@12voltvids

6 жыл бұрын

The 3 nastiest letters in electronics.... STK

@santi0797

6 жыл бұрын

LOL, it still amazes me how denon got these modules to sound so damn good, i also have a Yamaha RX-V 2090 (which is simiar to a Yamaha RX-V870 you did a video on), and the Denon amp with the STK modules sounds better to my ear, i wish i had the schematics for the Denon to analyze the circuits but it seems it is not available, anyways im going to watch more of your videos, have a good night.

@djijspeakerguy4628

5 жыл бұрын

santi0797 These Sony’s also sound awesome! Especially the stk ones.

@cardelljordan8695

5 жыл бұрын

Your right and the STK modules sounds a lot better than some of these new receiver they make today. I don't think they make new receivers with the stk modules in them anymore

Can't be this simple. But, I tightened the screws beside the heat sink...after more than a decade not working. Been using it for an afternoon now. It would go into protect mode and the light above the surround button would flash. Waiting for the other shoe to drop, but works great so far. Can't believe it!!!

I cant believe you dont have more subscribers I just found you and love your channel , Thank you

@12voltvids

Жыл бұрын

I wish i did.

I picked up a Sony STR-AV210 out of the trash out by the street a few years ago. It looks to be very similar to the one you fixed in this video, with the buttons and small knob locations reversed. It works but has an annoying buzz. The volume of the buzz doesn't vary with volume, so it could be used with the volume up a bit and some nearby street noise. Today I soldered (with a silent L where I come from) several bad looking connections and it sounds a lot better. There is still a high pitched buzz that varies when I wiggle some of the wire connectors. So thanks for the tips on what to look for. I bet I'll find some more joints to re-solder. I'll be putting it out in the garage where I am setting up a home wood shop.

Thanks, I had a different Sony amp that was acting up, cutting sound and going into protective mode, so I reflowed some of the transistors as you did, and now it seems to work, fingers crossed!

This is my favorite receiver I own for 3 reasons. One, I got it for $24:99 (USA) at the thrift store, which is a good deal. Two, the bass boost works 5x or more better than our higher end Sony from the same time period, which just sounds hollow, even with a subwoofer, and for more than twice the price. Three, the tone controls are better than any EQ in my opinion. I’m not lying, this is enough for a large bedroom.

As an owner of this product, I found some more information about this unit. Apparently, it was released in 1991, and the stk4192II amplifier IC that it contains puts out, (or at least claims to put out) 50 watts per channel, quite a bit more than I thought! Of course, I had some grounding problems with mine. The reason: I had the ground screw that connects the face plate to the heat sink mixed up with another, shorter screw so it wouldn’t reach. It took me the longest time to figure out, too.

@12voltvids

3 жыл бұрын

Guess what! Mine did the same thing again, and that screw I tightened down very tight had worked its way loose again. I just serviced that same amp again today after it went into protection mode again and changed the super cap for station memory. Will be putting up the new video later once I edit it.

i have the protection problem str-av760. when this happen the IC blows? thanks 4 your help

Hey would you possibly know what is going on with my unit? I turn it on but the b set of speakers cuts in and out. I've checked all the bad areas you've talked about in this video. Re solider and couple spots. Still having problems.

Hey do you still have this sony our any other amp i could get cheep im in port hope ontario .....thx

can you re flow a board?

Hi.Thanks for video.I have str d 965.No power (stand by led on) no display.I check power supply board.All transistor ,condanser , diode & resistor & IC work fine.What is the problem ? Can I change IC 801,803 (12v reg) ? thanks (Nec 79m12 - 78m12)

thank u for another video.....

Hi, such a case, it always has the error that it enters a kind of emergency program during operation and significantly limits the performance? Sony TA-AV570

My experience with amplifiers using STK type output ICs is that people always seem to short out the speaker wires, causing the IC to fail. About 90% of the amplifiers with STK chip I ever got would just output the B+ voltage on one (or even both!) of the speaker outputs.

@12voltvids

9 жыл бұрын

Shorted speakers will do it for sure, but failing solder connections, especially on the Technics amps was even a bigger problem. I have a Technics that I am going to put on the bench next and go over it. And a Technics tuner that has a problem.

I have the identical reciever, str-av570, same issue where it keeps going into protect mode intermittently , even when it’s off, the relay will click along with the amber loudness light will glow and turn off, then repeat. I took it to a Sony authorized service center back in 2003-2004, but they couldn’t find out what was wrong. I will try what you done, and see If it will fix it, thanks for sharing!

i did this with mine but still in p mode is the stereo ic blown up ? or is bad mosfit"s has no sound when it was working they was loud volume boom basting bass then it stopped working with blinking red p just asking ?

Stk厚膜不错。挺耐听的，声音比较暖－Stk thick film is good. Very resistant, the sound is warmer

Great, I really like seeing skilled people fixing things, especially receivers. I'm working on some problems with my sony str-de315 with a channel dropping in and out. Could it really be a grounding problem (heat sink screws?), or more likely the main filter capacitors? When I push on them, the sound returns. Any ideas?

@12voltvids

Жыл бұрын

It will be a connection

@bennyandersen742

Жыл бұрын

@@12voltvids I guess so, thanks for the reply.

Good documentary, worth every minute to watch.

A way to have max bass and DBFB on without clipping the amp is to turn the -20db setting on and just turn it up louder

how much you want for that receiver bro,nice video well done.

hey, my strav570 has output on the right channel of A speaker. the signal drops out with both A and B on, and there in no signal on B speaker channels. I will reflow as shown and tighten all grounds, do you think there may be something else going on?

@joshclapper6292

7 жыл бұрын

so I did the solder touch up on the regulators and caps and I now have audio out to both right channels on both A and B speakers, just not at the same time. left channels do not work what soever. any thoughts?

@benmeuninck7410

3 жыл бұрын

@@joshclapper6292 check the speaker jacks for cracked solder joins

Great video. I'm having some issues with my not so spectacular Yamaha R-3 receiver the right speaker channel cuts in and out randomly. Any idea on how to I would go about fixing that? I tried cleaning all the pots with contact clearer still on luck.

@12voltvids

7 жыл бұрын

Check the speaker relay for broken solder connections, or pitted contacts. (tap it and see if the sound cuts out)

@MrSilv55

2 жыл бұрын

@@12voltvids Thanks for the video , i have an old Sony receiver str k850 that won't memorize preset radio stations no more, i have to manually put in frequency in order to tune in station ,but if i try to set up another frequency it looses the first one and so on, this might be old caps, what you guys experts on radios think i should look for, thanks

@12voltvids

2 жыл бұрын

@@MrSilv55 memory battery. Might be a super cap. Usually on the display board.

@MrSilv55

2 жыл бұрын

@@12voltvids thank mate, but i learned that this module# has no battery cap mem, it's stored in the EEpron ,if that info was given to me correct, well i still have another Str DE335 that still works ok and probably has that battery Cap.

@12voltvids

2 жыл бұрын

@@MrSilv55 Not familar with the model off hand. A few did use static RAM and i remember changing a bunch on a few tv models that used them. They were pretty unreliable and resulted in losing the ability to save channels.

I bought a Sony STR-DN1070 off a guy and i trusted him and didn't try it out. Plug it in and it's on right away and says clearing did power reset factory reset what ever you want to call it and nothing. So i left it on and it power cycles about every 3 minutes.I haven't left it on for more that 10 mminutes at a time. what do you think the problem is. I'm not bad at fixing tv's this should be about the same

Why did you sold a capacitor in the circuit back?

@12voltvids

7 жыл бұрын

I paralled 2 smaller ones to make up the required capacity, as I didn't have a correctly sized replacement. With capacitors it is OK, and actually preferred in many cases to use multiple smaller capacitors in parallel, as it lowers the ESR. In many power supply designs for example you will see 3 1000 uF capacitors in parallel instead of a single 3300. Why? Because 3 x 1000 has a lower effective ESR than the single 3300, and the capacity is similar.

I have seen a similar (but much older) Sony str vx1 receiver where one channel is distorting crazy and it is not the speakers. Pretty sure it is the left channel. No sound when volume is down BLAAAAH when volume is in normal listening level it uses a similar STK amp just larger with a TINY heat sink.

@djijspeakerguy4628

3 жыл бұрын

I looked at the VX1 again recently, and the heat sink is definitely smaller, but still good enough for its purpose. It is based on a stk460, and seems to be similar to this av570, just with a manual tuner and silver. (And of course exactly a decade older.) I think the STK is the most likely fault, others had that issue with stk460 based products. The distortion is the right channel on both A and B, (of course A and B are the Same thing, just wired in series.) it basically has no sound at low volume, and once you get to around the 2 of 10 mark on the volume, it makes sound, but distorted heavily enough to not be able to tell the song. The left speaker outs work fine. For the time being, the family member who owns it has the right speaker hooked up to left side B, so they are just playing the left channel twice. (Or mono on the tuner.) I will probably get around to fixing it. (That is, if I can find a good STK460 for sale somewhere.)

I'm liking that lamp. I think I'll stop by Crappy Tire and have a look at one.

@12voltvids

8 жыл бұрын

+Audioquest56 Its a nice little magnifier. I use it all the time. I did modify it though, I put it on a boom from an old boom lamp, so I can position it exactly where I need it.

@12voltvids

8 жыл бұрын

+Audioquest56 The dam bulb burned out, and I haven't been able to find another one.

@ElectoneGuy

8 жыл бұрын

I ended up buying a nic one from Princess Auto.

Why do they have a copper heat sink? Isn't aluminum usually used?

@12voltvids

5 жыл бұрын

Because of cost yes. High end gear will quite often use copper, after all you are paying for it, and copper is a better conductor of electricity and heat.

@infinitecanadian

5 жыл бұрын

@@12voltvids Oh, I didn't know that copper was a better conductor of heat.

@12voltvids

5 жыл бұрын

@@infinitecanadian Yes less resistance to both electrons and heat. Silver and gold better still

Onkyo Receivers have no service panel.

My father would like to know if you are still repairing?

@12voltvids

3 жыл бұрын

Yes

@joelpaez323

3 жыл бұрын

@@12voltvids fantastic! We will let you know.

I have a Sony SA-W2500 powered sub woofer that cuts out after 3 seconds when volume is applied. I have been all over the internet and there is nothing about this model on repairing the amp. Please msg me if you can, I'm out of options --__--

Hows that Chevy Volt doing now? Asking for a friend.

@12voltvids

Жыл бұрын

12 years old 190000 miles no issues. I have had all the software updates done. Those that didn't have had problem

Dim going to try to fix my dads Sony amp like this one, the speaker connections are not working anymore, only one works lol

@joshclapper6292

7 жыл бұрын

TAVOR VICEROY VALDOR my amp only has the right channel of A speakers. did this fix your issue? and was that the same channel that you had working?

Hi! You should not breathe smoke tin with lead, lead is dangerous. In Spain lead free tin is used. Good job!.

@12voltvids

8 жыл бұрын

+Paul Ford Hammer Lead free garbage is used everywhere now. That is the leading cause of premature failures. The problem with lead is not the smoke when soldering, that smoke comes from the rosin flux in the solder. The solder is just heated to the melting temperature not the gaseous temperature. The problem with lead is when electronics are disposed of. If they are incinerated at high temperatures, the lead could become gaseous and enter the atmosphere, but the real problem is with land fills. The lead leaches into ground water. The way lead from solder gets into your system is from improper handling. Touching lead solder and then eating or smoking without washing your hands first. Lead residue will get on your skin, and then if you pick something up and eat it, will into you. Its a little late for me to worry about that now. I spent 20 years in a shop that the owner was too cheap, or stupid to put in any ventilation. The techs there, myself included would solder all day, and use cleaner sprays that back ini the 80's and 90's were pretty toxic by todays standards. The really bad stuff, with carbon tetrachloride and other nasty stuff was loing gone when I got into repairs, but back then nobody cared. So just like asbestos workers of 30 years ago, if I get sick, I get sick. Not much I can do about it now. I have been out of the industry for 13 years now, and the little bit of work I do now I am pretty careful. I solder for example with good ventilation, and same goes for when I use powerful cleaners. I open the doors, and let the breeze blow through.

@paulfordhammer3165

8 жыл бұрын

+12voltvids Thanks for your explanation, when I was student my teacher never told me that lead is poison.

@12voltvids

8 жыл бұрын

+Paul Ford Hammer When I was in school they used to let us play with liquid mercury!We would drop it on the floor, the janitor would vacuum it up and spray mercury vapour out the vacuum exhaust.They used to put mercury in tooth fillings too. I still have a few of those from when I was a kid. My current dentist is removing them.There were lots of things that are now deemed harmful that a few years ago were not considered bad. Cigarettes is a classic example. The Tabaco industry is still arguing that one. Gasoline used to have lead in it, and that lead would go straight into the air.Piston engine aircraft gas, also known as AVGAS still does have lead in it, because it lubricates the cylinder head and valve stems.

@paulfordhammer3165

8 жыл бұрын

+12voltvids It certainly, we are surrounded by toxic. One question: what you think about Class D on audio ampli? in the school use class A and AB for audio and C, D for hertzian transmission signals, all LCD tv use class D.

@12voltvids

8 жыл бұрын

+Paul Ford Hammer Class D goes against everything we were taught about amplifier designs!Class c is used mainly in RF applications such as FM transmitters where your tank circuit will make up for the missing half of the waveform.Class D is known as the switching amplifier. The incoming signal essentially FM modulated a relatively high frequency carrier, 100-200KHz which drives a pair of MOSFET transistors that are switching back and forth at the carrier frequency. The efficiency is very high in this design, because the transistors are either ON or OFF, so there is essentially no loss due to heat production as would be the case in class A, AB and B linear amplifier circuits.Many class D operate at full line voltage and you will see the switching signal at full line power even when it is producing no sound. The strength of the incoming waveform causes a frequency shift of the carrier. The stringer the negative going waveform drives the frequency down and the upward swing of the input signal drives it up, but the amplitude of the output signal doesn't change.This in effect causes a duty cycle change (phase) of the stitching mosfets, and once the signal is passed through a low pass filter, an dthe HF components removed, the original audio sugnal is recovered. They actually work quite well, despite them going against everything we learned in audio. That is turning your nice audio signal into a dirty square wave, and then filtering it back to a sign wave, which is essentially what a class D does.

Despite all opposite opinions this video shows how a fully functional electronic laboratory workbench has to be set up.

cool mini sony trinitron tv on the background

I have a receiver needs work

Took a kickin' and kept on tickin'

I got the same thing and the same problem

Wonder how many peoples houses have been burnt down with bodge jobs like this

You shouldn't really parallel speakers like that. Assuming they are 8 ohm speakers, paralleling them will present the amp with only a 4 ohm load! Not good for the output transistors!

@12voltvids

4 жыл бұрын

I wasn't paralleling speakers. There are only 1 pair. I was creating a test connection lead so I can hook up another amplifier to the speakers to test it on my bench speakers. ( the speaker switch on the bench amp is obviously off when i am connecting to a second amp.

@lstein3372

4 жыл бұрын

@@12voltvids the reason has changed, the fault hasn't. The output of an amp has impedance too. Even if one is off it will still change the impedance seen by both amps.

@12voltvids

4 жыл бұрын

@@lstein3372 so what. It is a test bench amp. And incidentally, I would like to see your proof that a 2 foot length of open ended wire is going to cause a noticable change in impedance. To the bench amp it would appear as a 2 foot unloaded wire. To the amp under test connected to that chunk of wire, it would see about 2" of wire from the speaker binding posts to the open relay contacts on the inside of the non powered bench amp. To let's see the calculations as to how this is going to affect operation if either in any negative way. You brought it up, put your money where your mouth is.

@lstein3372

4 жыл бұрын

I am not saying the cable will cause an inductive load, I'm saying if you attach another amp to the output of the first amp and then the speakers, the output circuitry of the amp which is switched off will act as a load impedance. Generally a switch is used to isolate each amp output connection from each other and select which amp is connected to the speakers.

@12voltvids

4 жыл бұрын

@@lstein3372 and how is this possible. When the test amp is off, the speaker protection relay is open and the speakers disconnected from the outputs. If the amp is on the relay is closed. If the speaker switch is off, the speakers are disconnected. Obviously if I am using the "fly leads" to connect an amp under test to my speakers, my bench amp will be off and thus the speaker relay is open and the outputs totally disconnected.

These Sony’s have good bass, but they clip easily.

@12voltvids

6 жыл бұрын

DJIJ SpeakerGuy IMHO all solid state amps clip too easily until you get into big power. That is why I and serious music listeners perfer tubes. You simply can't beat the sound. I know I will draw fire from those that disagree, but those that will argue specifications just have not listened to a tube amp. If they had they would have a different opinion.

@djijspeakerguy4628

6 жыл бұрын

12voltvids yeah I kinda knew that. I have this EXACT receiver and searching the net for it brought me to this video. I actually also have a possible cap leak in mine after I removed the service panel because I was curious. One thing is for sure is that this amp gets pretty hot and needs proper ventilation.

@Popart-xh2fd

6 жыл бұрын

Tubes also clip the difference is that they do it gracefully and not in an acute way!

@12voltvids

6 жыл бұрын

Popart 2015 Yes they round off the sharp Edges when they clip but that is only in the output stage as the output transformers saturates.

@Popart-xh2fd

6 жыл бұрын

I'm pro solid state :), firstly tubes are very dangerous to service due to high voltages, and secondly speakers are much more critical to sound than amplifiers. Amplifiers sound all the same while speakers don't and they can be really bad due to "sound coloration"... That Sony is pretty neat, no spaghetti wires! PS: I had a Jolida SJ502A!

We want these comment in french! Please.