Great video ! I have a 517 too. I've taken it to several technicians to find a defect, there is a background hiss even with the volume knob at 0 (-∞). I even think that this must be normal because no one can fix it, I'm almost giving up on the device because this wheezing bothers me a lot.
Excellent video, thank you very much for your valuable information. I want to make a clarification. The layout of the pins. NTE234 (1-E, 2-C, 3-B) 2SA906 (1-B, 2-C, 3-E With NTE234 you have to change the position. Greetings.
Hi! Last night my au-417 just started making a crackling sound with a background hissing on left channel. Since the pre amp board for both the 517 and 417 are the same I will try replacing t01 and t05. My questions is: ive read somewhere the fuse resistors on this board (R 47, 48, 49, 50) show similar symptoms when they fail and open, wouldnt that be a possibily?
Are you sure the problem coming from Head amp which is the vinyl (phono) output? To isolate the problem, I suggest to hook up a functional integrated amp to test. Use a RCA cable connects TAPE REC of AU-417 with the AUX input of the functional int. amp, then playing vinyl record to check if the noise comes from Head amp of AU-417. The resistors R47 - R50 on Head amp PCB keep DC balance for head amp output. They may affect the sound if output voltage not close to 0 V.
@@VintageAudioFan thanks for replying :) I dont have another functional amplifier to proceed with your suggestion. But Im quite sure it comes from the 2723 board (head amp) as no table needs to be plugged in and the symptoms show up on both phono 1 and phono 2 stages (left channel) only. Other than that it's working perfectly, considering I normally use all the functions (got a cd player on aux, tuner, r2r on tape 1 in and out and a cassette deck on tape 2 in and out). When I posted yesterday I actually hadn't yep opened the unit. But last night I did so and could read all the resistors which are perfect (reading precisely 82 ohms). Also took tr01 and tr05 off the board, hfe around 500 as it should. Havent replaced them yet. In case my assumptions are right, can I try replacing those 2 components with 2sa992's (easily found where i live)? The code you gave in the video or the ksa992 often mentioned in sansui forums are hard to find online, and the options shipping to Brazil have prohibitive costs! Another question: suppose this replacement fixes the bad symptoms. Would I see any sort of "unbalacing" between the channels if leave the right channel's respective transistors untouched (they are very hard to reach, so if it isn't really necessary i wouldn't disassemble the unit to that extent). I apreciate you time and experience!
@@marcosblasius Sometime the leakage of transistor is hard to detect. So it is a good option to replace old differential pairs of transistors to improve the stability of the circuit. To replace 2SA906, there are some selections you can choose as long as they matching 906's data. The data for 2SA906: (Pc): 0.2 W, |Vcb|: 40 V, |Vce|: 40 V |Veb|: 5 |Ic max|: 0.1 A (Tj): 150 (ft): 100 MHz (hFE), MIN: 250. I found A992-Emeets the data of A906 (only Ic 0.05A a little bit under). Also you can consider KTA1268-BL which also works too. Other suggestion is to replace coupling capacitor C41 and check capacitors C23,C13, and C15 in NF circuit. They also are big part of sound quality of head amp.
@@VintageAudioFan i could not find the c41 capacitor neither on service manual or by looking for it on board. is it on the head amp board? also, those capacitors you mention have any filtering functions? besides de the popping and hiss there’s a timid static hum on both phono channels, maybe the capacitors can mitigate the humming? or the transistor subs can do the job?
@@marcosblasiusYes. C41 is on Head Amp PCB. If both channels developed the hum noise, it may cause from power supply PCB or grounding problem. I suggest to check power supply PCB (3043). Make sure there is +30V at "D" and -30V at "E".
all older amps,receivers will get the TIN WHISKER disease of the small signal pnp and npn xsistors, replacements are cheap. replace them all, especially in phono preamps. symps. are poping and hiss.
você está certo. Eu também tenho um sansui au 719, a qualidade do som é muito semelhante à au 517. O design do diagrama de circuitos deve ser da mesma pessoa ou grupo, e é por isso que eles são tão populares nos anos 70-80. (Translate by using Google)
Great video ! I have a 517 too. I've taken it to several technicians to find a defect, there is a background hiss even with the volume knob at 0 (-∞). I even think that this must be normal because no one can fix it, I'm almost giving up on the device because this wheezing bothers me a lot.
You can send your questions to my email for more assistance options. My email address is listed in my TH-cam home page under "About" item.
Excellent video, thank you very much for your valuable information.
I want to make a clarification.
The layout of the pins.
NTE234 (1-E, 2-C, 3-B)
2SA906 (1-B, 2-C, 3-E
With NTE234 you have to change the position.
Greetings.
well done...i have one of these amps...great amp
Hi!
Last night my au-417 just started making a crackling sound with a background hissing on left channel. Since the pre amp board for both the 517 and 417 are the same I will try replacing t01 and t05. My questions is: ive read somewhere the fuse resistors on this board (R 47, 48, 49, 50) show similar symptoms when they fail and open, wouldnt that be a possibily?
Are you sure the problem coming from Head amp which is the vinyl (phono) output? To isolate the problem, I suggest to hook up a functional integrated amp to test. Use a RCA cable connects TAPE REC of AU-417 with the AUX input of the functional int. amp, then playing vinyl record to check if the noise comes from Head amp of AU-417. The resistors R47 - R50 on Head amp PCB keep DC balance for head amp output. They may affect the sound if output voltage not close to 0 V.
@@VintageAudioFan thanks for replying :) I dont have another functional amplifier to proceed with your suggestion. But Im quite sure it comes from the 2723 board (head amp) as no table needs to be plugged in and the symptoms show up on both phono 1 and phono 2 stages (left channel) only. Other than that it's working perfectly, considering I normally use all the functions (got a cd player on aux, tuner, r2r on tape 1 in and out and a cassette deck on tape 2 in and out). When I posted yesterday I actually hadn't yep opened the unit. But last night I did so and could read all the resistors which are perfect (reading precisely 82 ohms). Also took tr01 and tr05 off the board, hfe around 500 as it should. Havent replaced them yet.
In case my assumptions are right, can I try replacing those 2 components with 2sa992's (easily found where i live)? The code you gave in the video or the ksa992 often mentioned in sansui forums are hard to find online, and the options shipping to Brazil have prohibitive costs! Another question: suppose this replacement fixes the bad symptoms. Would I see any sort of "unbalacing" between the channels if leave the right channel's respective transistors untouched (they are very hard to reach, so if it isn't really necessary i wouldn't disassemble the unit to that extent).
I apreciate you time and experience!
@@marcosblasius Sometime the leakage of transistor is hard to detect. So it is a good option to replace old differential pairs of transistors to improve the stability of the circuit. To replace 2SA906, there are some selections you can choose as long as they matching 906's data.
The data for 2SA906: (Pc): 0.2 W, |Vcb|: 40 V, |Vce|: 40 V |Veb|: 5 |Ic max|: 0.1 A (Tj): 150 (ft): 100 MHz (hFE), MIN: 250. I found A992-Emeets the data of A906 (only Ic 0.05A a little bit under). Also you can consider KTA1268-BL which also works too. Other suggestion is to replace coupling capacitor C41 and check capacitors C23,C13, and C15 in NF circuit. They also are big part of sound quality of head amp.
@@VintageAudioFan i could not find the c41 capacitor neither on service manual or by looking for it on board. is it on the head amp board? also, those capacitors you mention have any filtering functions? besides de the popping and hiss there’s a timid static hum on both phono channels, maybe the capacitors can mitigate the humming? or the transistor subs can do the job?
@@marcosblasiusYes. C41 is on Head Amp PCB. If both channels developed the hum noise, it may cause from power supply PCB or grounding problem. I suggest to check power supply PCB (3043). Make sure there is +30V at "D" and -30V at "E".
all older amps,receivers will get the TIN WHISKER disease of the small signal pnp and npn xsistors, replacements are cheap. replace them all, especially in phono preamps. symps. are poping and hiss.
Eu tenho o sansui au519 e bem parecido com esse modelo au517....
você está certo. Eu também tenho um sansui au 719, a qualidade do som é muito semelhante à au 517. O design do diagrama de circuitos deve ser da mesma pessoa ou grupo, e é por isso que eles são tão populares nos anos 70-80. (Translate by using Google)