Your video is inspirational I will do some more studying before finding my multi meter and "working under the hood" My recently acquired AU-517 is having issues.
Thanks for your comment. What issues does your amp has? Is the speaker relay clicking (out of protection mode) when you turn on the amp. Maybe I can help you in terms of the directions you should take for repairing your AU-517.
@@antdav3923 If memory serves I bought mine at the USNA midshipmen store while I was a student. I graduated in 1976.Perhaps the US Navy was able to get some before they were generally released.
Yes. If the protection relay won't kick in, then you won't be able the check DC offset at speaker terminals. But you can connect one end of meter to the joint of resistors R43 (.22) and R44 (.22) on power amp PCB and the other end of meter connect to ground. If you can't adjust reading to close to 0V, usually means somewhere is short in the PCB. Regarding to the bias adjustments, it can be measured as shown in service manual (not affected by protection mode).
I have one of these, just refurbished but could do with a replacement power transformer. Any ideas where I might find one, or an alternative ? It sounds fantastic but cuts off at high volume.
The best place to find replacement is in eBay. However, it only comes up when someone are selling their AU-719 as for repair or parts. As an alternative, I checked the AU-719 is required 2 sets of 44V-0-44V outputs from transformer in two separate transformers. You have to find similar output of transformer to make it works.
Hi- thanks for this video. I have the same unit with (at least superficially) the same problem. I followed you through the fuses (they are good) and tomorrow trying to check the bias values although not yet clear on where to put the probes. Can you provide more detail on that part of it? I saw another video that blamed two resistors on a similar problem with a Sansui receiver. Would appreciate what help you are willing to provide.
According service manual: put probes between emitters of TR701 and TR703 (Left channel), measure the value by using volt meter and adjust VR02 until the reading to 23mV. Use the same procedure on right channel to adjust bias. Hope this info. helps.
@@VintageAudioFan Updating- the amp is back in service but today after sitting for 24 hours it stayed in protection for a long time. Relay clicking away for about 5 minutes. Then it came out of protection and worked fine. Do you think the relay itself may be faulty? I was thinking about just spraying contact cleaner inside it if that is possible. This does not seem to be the same problem that you had, because it's associated with a cold unit. Appreciate any further insight.
@@jmcgowan6253 I have to apologize for the late response (I did not notice that you leave a message after my response). To isolate the problem, I suggest you to measure the voltage at power amp outputs (not speaker outputs) when you turn on the power of AU-719. If both channels stay close to 0 V, then the problem is in the protection circuit. You can start at cleaning relay first, but I think you also should check the parts in PCB (F-3101). The problem may occurs at faulty parts (ie. aged transistors, resistors or capacitors).
Good morning Sir!/ thank you very much for this great videos. I really wish to learn how to read the electric diagrams. i deeply regret not listening during the Electrical Engineering Classes at school! ( i am a mechanical engineer)
Thank you for your comments. There are many basic electronic components and schematic reading videos available in RUclips channels. I suggest the followings: (1) ruclips.net/video/6Maq5IyHSuc/видео.html (2) ruclips.net/video/Dl1gFBNa0Ik/видео.html (3) ruclips.net/video/_HZ-EQ8Hc8E/видео.html. Hope the above information helps.
Hi, thanks for the nice video. I have a AU-719, sometimes the right channel is not sounding correctly ("flaky?"), whereas the left channel is perfect. I switch off and on again, normally issue is solved. I suspect the protection relay may not be closing nicely for the right channel, any suggestions as how to test this? Spray cleaner, which brand? I may try to bypass the relay completely (short cut the protection circuit, but then I may get sound on the speaker because of initial settling voltages. anybody tried this? Any other suggestions?
Based on your descriptions, it has a very good chance that speaker relay may have a bad contact issue (see my other video - Accuphase E-202 repair). I suggest to replace instead of clean it. If it doesn't solve the problem, then the issue may occur in the amplifier or preamp circuit.
can i ask, for my Amp au 417...does it look same with au 719?...because, i have problem 3 months already, red blinking power...i tried to change R607 and R606,..still the same problem.
The design of protection circuit on 417 and 917 is similar but different, so I suggest to find where is the problem first before replacing parts. There are two reasons cause the protection mode on (light blinking): 1. The power amp output DC offset is too high. 2. The protection circuit board is malfunction ( usually cause by the power supply). Recently, I will publish a video regarding how to check DC offset and repair the protection mode on. Maybe it will help you on this type of issue.
Fantastic job, good video! Congrats! I have the same amp and have a problem :( , the power transistor breaks down from time to time. they tried to repair it several times, spent a lot of money on it, but the problem always came back. now unfortunately useless. And i have no idea how to repair it. Maybe i will show Your video to the guys in the service :D
Sorry to hear that your AU-719 had so many problems. I think your amp needs an overhaul specially at power amplifier section. To repair them are not that difficult as long as following the MFR's service manual. First, I usually check the DC offset of amp's output. Then, check the amp's idling bias. I live in California, USA. I wish I can repair for you if the shipping is not very costly. However, I appreciate your comments. Hope keep in touch.
@@VintageAudioFan Thank you very much for your prompt reply! Frankly, I didn't expect such a quick and professional response. Thank you for the opportunity! :) To be honest, I dont want to loose this amp, its with me since 15 years, and have a spirit, hard to explain it to someone who never heard it in its best shape. I will find out how much it would cost to ship this 16 kg beauty. :) I live in Poland. Thanks again and let's stay connected. The videos are super good, it's a pleasure to see someone handling such technical masterpieces with such accuracy, dedication and respect! :)
@@MrJakigabi To me, these vintage audio gears are priceless. I have saved so many of them from junk yards, waste land or someones's backyard, garage and storage. Most of them were being abused because they were defective due to the age and deteriorated parts. Check out my Yamaha C-2A repair video which documented how I saved it and became my most favorite preamplifer. I understand your passion toward your AU-719. Hope your issue can be resolved. Thanks.
My amp turns on fine, my problem is when I turn volume up or a change in the volume on the music itself. The protection kicks in and blinks. I then turn off amp then back on and it works until bass and does it again. But then I can't play it low because I get no sound. Any suggestions what to look for?
My suggestion is to download the manufacturer's service manual from : www.hifiengine.com/manual_library/sansui/au-719.shtml. Do the DC offset and bias current adjustments as showed in the page 4 (Section 3-1 Driver Circuit Adjustments). If you can't make it works as showed in the manual, then you have defective parts in the driver circuit board.
Yes. The AVR850 can be used as pre-amplifier by using pre out to hook up other external power amplifiers. The built-in 7.1.4 pre out includes: stereo (front right & left) , centre, surround (left & right), surround (rear right & left), sub woofer & 4 high (ceiling) channels. You can select source decoding mode to play "stereo" or "surround" sound effects. I suggest you look up the AVR850 user's manual for more details.
@@jackryder6732 I am sorry I mistakenly answered the previous question. The A-719 doesn't have the pre-out/main-in jacks which can separate pre-amp and power amp sections. However, you can still hook up the AVR850's pre out to AU-719 's AUX input jacks (at rear panel) but the signal may be too strong because hooking up to AUX input jacks can't bypass AU-719's preamplifier section. That is my mistake to answer your question without checking out AU719's back panel layout.
@@VintageAudioFan Thank you for your correction. Got it now. I am trying to find a good old school integrated amplifier to go with my Arcam. These days the variety of integrated amplifier is just going up. Same time not cheap. Marantz model30 came out recently. Anyway, thanks for your time.
It takes time and patience. First, remove the PCB from chassis. Second, use a vacuum cleaner sucks dust out from PCBs and chassis. Third, use damped Q-tips swab clean each parts and PCBs. I suggest you take the photos before every steps. So you can put it back in case of wires/cables broken accidentally. Also label every connection pins and sockets before you dissemble them (as shown in my video). It will save you time when you try to put every thing back.
The speaker relay circuit of AU-D77X uses an IC HA12002 as the main protection component. I have looked up the diagram of HA12002 which has 8 pins. Pin 7 (+B) connected to power supply with a resister R38 (1.2k ohm) which requires +24 V from power supply board. I suggest using a multimeter to measure the IC power supply by connecting (+) probe to R38 and connecting (-) probe to Pin 2 (ground) when the power is on. If the reading shows as required +24V, then the problem must come from the high current loading from either right or left channel power amplifiers. If the reading is not shown as required +24V, then you need to check the power supply circuit board which may have defective parts. Hope this info. helps.
I have done repair work for AU-517 before. You can check out my other video regarding the issues of 517/717. They both are very similar in their circuit design. Please let me know if you need any help. Thanks for the comments.
@@VintageAudioFan I wouldn't even open it. I'm just a welder mate. I don't go near what I don't have a clue about. Can make things worse. I reckon she's gonna cost me a few hundred to get her better than right. Its all money ain't it
Maaf, saya tidak mengerti komentar (bahasa) Anda sampai hari ini ketika saya menggunakan Google Translate. Ada banyak alasan mengapa tidak ada suara yang keluar dari amplifier Anda: (1) Catu daya rusak (2) Penguat daya rusak (3) Kontrol nada / preamp rusak dan (4) Kontak yang salah dari sakelar. Anda dapat melihat video saya menunjukkan cara mengisolasi masalah dan mencari solusinya.
Yes. This video is not for every one. To perform this type of repair needs some basic knowledge about electronic and component testing skills. I recommend who wants to do repair DIY to take electronic learning class first. Thanks for the comment.
Your video is inspirational I will do some more studying before finding my multi meter and "working under the hood" My recently acquired AU-517 is having issues.
Thanks for your comment. What issues does your amp has? Is the speaker relay clicking (out of protection mode) when you turn on the amp. Maybe I can help you in terms of the directions you should take for repairing your AU-517.
Amazing work and knowledge! Would you have any idea why the resistor on slot R04 is overheating on my protection board ? Keep up the great work!
excellent work...i have 2 of these amps....monsters with class...from Mauritius
I also love this amp. It is one of my favorite equipment in my collections.
@@VintageAudioFan I have owned mine since it was new in 1973
@@jmcgowan6253 The AU-719 wasn't released until 1979.
@@antdav3923 If memory serves I bought mine at the USNA midshipmen store while I was a student. I graduated in 1976.Perhaps the US Navy was able to get some before they were generally released.
Very useful video. Thank You very much !
Thank you for your video. I have the exactly same issue on my AU-D9. Can you check DC offset and Bias even when the relay doesn't kick in?
Yes. If the protection relay won't kick in, then you won't be able the check DC offset at speaker terminals. But you can connect one end of meter to the joint of resistors R43 (.22) and R44 (.22) on power amp PCB and the other end of meter connect to ground. If you can't adjust reading to close to 0V, usually means somewhere is short in the PCB. Regarding to the bias adjustments, it can be measured as shown in service manual (not affected by protection mode).
@@VintageAudioFan Thank you for your quick reply. I will try it.
I have one of these, just refurbished but could do with a replacement power transformer. Any ideas where I might find one, or an alternative ? It sounds fantastic but cuts off at high volume.
The best place to find replacement is in eBay. However, it only comes up when someone are selling their AU-719 as for repair or parts. As an alternative, I checked the AU-719 is required 2 sets of 44V-0-44V outputs from transformer in two separate transformers. You have to find similar output of transformer to make it works.
Hi- thanks for this video. I have the same unit with (at least superficially) the same problem. I followed you through the fuses (they are good) and tomorrow trying to check the bias values although not yet clear on where to put the probes. Can you provide more detail on that part of it? I saw another video that blamed two resistors on a similar problem with a Sansui receiver. Would appreciate what help you are willing to provide.
According service manual: put probes between emitters of TR701 and TR703 (Left channel), measure the value by using volt meter and adjust VR02 until the reading to 23mV. Use the same procedure on right channel to adjust bias. Hope this info. helps.
@@VintageAudioFan Updating- the amp is back in service but today after sitting for 24 hours it stayed in protection for a long time. Relay clicking away for about 5 minutes. Then it came out of protection and worked fine. Do you think the relay itself may be faulty? I was thinking about just spraying contact cleaner inside it if that is possible. This does not seem to be the same problem that you had, because it's associated with a cold unit. Appreciate any further insight.
@@jmcgowan6253 I have to apologize for the late response (I did not notice that you leave a message after my response). To isolate the problem, I suggest you to measure the voltage at power amp outputs (not speaker outputs) when you turn on the power of AU-719. If both channels stay close to 0 V, then the problem is in the protection circuit. You can start at cleaning relay first, but I think you also should check the parts in PCB (F-3101). The problem may occurs at faulty parts (ie. aged transistors, resistors or capacitors).
Malam bos mau nanya ampli sansui au 11000 relay cetak cetik bos, kira2 apanya ya yang harus dicek? Terima kasih
Good morning Sir!/
thank you very much for this great videos.
I really wish to learn how to read the electric diagrams.
i deeply regret not listening during the Electrical Engineering Classes at school! ( i am a mechanical engineer)
Thank you for your comments. There are many basic electronic components and schematic reading videos available in RUclips channels. I suggest the followings: (1) ruclips.net/video/6Maq5IyHSuc/видео.html (2) ruclips.net/video/Dl1gFBNa0Ik/видео.html (3) ruclips.net/video/_HZ-EQ8Hc8E/видео.html. Hope the above information helps.
@@VintageAudioFan thanks 1million.
will look at it.
Hi, thanks for the nice video. I have a AU-719, sometimes the right channel is not sounding correctly ("flaky?"), whereas the left channel is perfect. I switch off and on again, normally issue is solved. I suspect the protection relay may not be closing nicely for the right channel, any suggestions as how to test this? Spray cleaner, which brand? I may try to bypass the relay completely (short cut the protection circuit, but then I may get sound on the speaker because of initial settling voltages. anybody tried this? Any other suggestions?
Based on your descriptions, it has a very good chance that speaker relay may have a bad contact issue (see my other video - Accuphase E-202 repair). I suggest to replace instead of clean it. If it doesn't solve the problem, then the issue may occur in the amplifier or preamp circuit.
can i ask, for my Amp au 417...does it look same with au 719?...because, i have problem 3 months already, red blinking power...i tried to change R607 and R606,..still the same problem.
The design of protection circuit on 417 and 917 is similar but different, so I suggest to find where is the problem first before replacing parts. There are two reasons cause the protection mode on (light blinking): 1. The power amp output DC offset is too high. 2. The protection circuit board is malfunction ( usually cause by the power supply). Recently, I will publish a video regarding how to check DC offset and repair the protection mode on. Maybe it will help you on this type of issue.
Fantastic job, good video! Congrats! I have the same amp and have a problem :( , the power transistor breaks down from time to time. they tried to repair it several times, spent a lot of money on it, but the problem always came back. now unfortunately useless. And i have no idea how to repair it. Maybe i will show Your video to the guys in the service :D
Sorry to hear that your AU-719 had so many problems. I think your amp needs an overhaul specially at power amplifier section. To repair them are not that difficult as long as following the MFR's service manual. First, I usually check the DC offset of amp's output. Then, check the amp's idling bias. I live in California, USA. I wish I can repair for you if the shipping is not very costly. However, I appreciate your comments. Hope keep in touch.
@@VintageAudioFan Thank you very much for your prompt reply! Frankly, I didn't expect such a quick and professional response. Thank you for the opportunity! :) To be honest, I dont want to loose this amp, its with me since 15 years, and have a spirit, hard to explain it to someone who never heard it in its best shape. I will find out how much it would cost to ship this 16 kg beauty. :) I live in Poland. Thanks again and let's stay connected. The videos are super good, it's a pleasure to see someone handling such technical masterpieces with such accuracy, dedication and respect! :)
@@MrJakigabi To me, these vintage audio gears are priceless. I have saved so many of them from junk yards, waste land or someones's backyard, garage and storage. Most of them were being abused because they were defective due to the age and deteriorated parts. Check out my Yamaha C-2A repair video which documented how I saved it and became my most favorite preamplifer. I understand your passion toward your AU-719. Hope your issue can be resolved. Thanks.
My amp turns on fine, my problem is when I turn volume up or a change in the volume on the music itself. The protection kicks in and blinks. I then turn off amp then back on and it works until bass and does it again. But then I can't play it low because I get no sound. Any suggestions what to look for?
My suggestion is to download the manufacturer's service manual from : www.hifiengine.com/manual_library/sansui/au-719.shtml. Do the DC offset and bias current adjustments as showed in the page 4 (Section 3-1 Driver Circuit Adjustments). If you can't make it works as showed in the manual, then you have defective parts in the driver circuit board.
Sir, I have arcam avr850 receiver which has pre out. Can this amp take pre out...in to play stereo and also use for surround system.
Yes. The AVR850 can be used as pre-amplifier by using pre out to hook up other external power amplifiers. The built-in 7.1.4 pre out includes: stereo (front right & left) , centre, surround (left & right), surround (rear right & left), sub woofer & 4 high (ceiling) channels. You can select source decoding mode to play "stereo" or "surround" sound effects. I suggest you look up the AVR850 user's manual for more details.
@@VintageAudioFan Thank you so much. Where do I connect at the back of Sansui. From Arcam I would connect to pre out left and right
@@jackryder6732 I am sorry I mistakenly answered the previous question. The A-719 doesn't have the pre-out/main-in jacks which can separate pre-amp and power amp sections. However, you can still hook up the AVR850's pre out to AU-719 's AUX input jacks (at rear panel) but the signal may be too strong because hooking up to AUX input jacks can't bypass AU-719's preamplifier section. That is my mistake to answer your question without checking out AU719's back panel layout.
@@VintageAudioFan Thank you for your correction. Got it now.
I am trying to find a good old school integrated amplifier to go with my Arcam. These days the variety of integrated amplifier is just going up. Same time not cheap.
Marantz model30 came out recently.
Anyway, thanks for your time.
How did you clean the inside please?
It takes time and patience. First, remove the PCB from chassis. Second, use a vacuum cleaner sucks dust out from PCBs and chassis. Third, use damped Q-tips swab clean each parts and PCBs. I suggest you take the photos before every steps. So you can put it back in case of wires/cables broken accidentally. Also label every connection pins and sockets before you dissemble them (as shown in my video). It will save you time when you try to put every thing back.
@@VintageAudioFan Ah, thank you!
Any tips for AU-D77X protection mode?
The speaker relay circuit of AU-D77X uses an IC HA12002 as the main protection component. I have looked up the diagram of HA12002 which has 8 pins. Pin 7 (+B) connected to power supply with a resister R38 (1.2k ohm) which requires +24 V from power supply board. I suggest using a multimeter to measure the IC power supply by connecting (+) probe to R38 and connecting (-) probe to Pin 2 (ground) when the power is on. If the reading shows as required +24V, then the problem must come from the high current loading from either right or left channel power amplifiers. If the reading is not shown as required +24V, then you need to check the power supply circuit board which may have defective parts. Hope this info. helps.
@@VintageAudioFan Thanks for your reply! Hope it will help!
Good...thank master....
I have a mint sui au 717 here in London. she's not working though. the "dreaded glue.
I have done repair work for AU-517 before. You can check out my other video regarding the issues of 517/717. They both are very similar in their circuit design. Please let me know if you need any help. Thanks for the comments.
@@VintageAudioFan I wouldn't even open it. I'm just a welder mate. I don't go near what I don't have a clue about. Can make things worse. I reckon she's gonna cost me a few hundred to get her better than right. Its all money ain't it
Mas sya mu tanya. Sya punya amplipier Sansui. Power nyala. Tpi kok gk keluar suara. Kira2 pa kerusakanya pa ya??
Maaf, saya tidak mengerti komentar (bahasa) Anda sampai hari ini ketika saya menggunakan Google Translate. Ada banyak alasan mengapa tidak ada suara yang keluar dari amplifier Anda: (1) Catu daya rusak (2) Penguat daya rusak (3) Kontrol nada / preamp rusak dan
(4) Kontak yang salah dari sakelar. Anda dapat melihat video saya menunjukkan cara mengisolasi masalah dan mencari solusinya.
After watching this video, my conclusion: don’t DIY, take it to an expert.
Yes. This video is not for every one. To perform this type of repair needs some basic knowledge about electronic and component testing skills. I recommend who wants to do repair DIY to take electronic learning class first. Thanks for the comment.
@@VintageAudioFan Where re you located?
@@DennisMurcia If you have any questions regarding the repairs, you can contact me via email as shown in "ABOUT" in my RUclips home page.