Sansui AU-517 find / recap. (Pictures)

That's nice, I did something similar in the very narrow space in the pre-amp board of the AU-317...

For the fuse resistors I used the 1% metal film rated 1W. They fit in and will stay there for a long time...
 
You misunderstood my poor attempt at humor.

I meant that visually, from the top, the stripes weren't oriented exactly the same way. Functionally they're in properly. I'm OCD, anal-retentive that way. Pay no attention to me, carry on. :)

I'm so concentrated in this that a joke didn't even cross my mind, all I thought was that something was wired wrong :D
In fact, I did have them lining up perfectly but had to crock the ones at the end to to reach for the wires :D


As far as the fuse resistors, on the Au-717 I just competed they were F-2721/F2722 R23, R25 / R23, R25 all 150 ohms. I think the 717 and the 517 share the same amp modules.

R23, R25 were not populated on my driver boards. I guess that's only for the 717s. Thanks for letting me know, otherwise I'd still be looking for them.


I used a similar method as Karl's to pair my 1N4148's together, and then covered them with heat shrink tubing. Here's an example of how I fitted the 1212 replacement pairs to my AU-717:

You might have a few of it in your AU-517, I don't know how many. But you need 2x 1N4148 in series for every VD1212 replaced as John mentioned.
Try to isolate the duo with those heat shrinking little thermal plastic tubes (or whaterver it calls). Pete Mac taught me how to do it here. And here is how I put them to solder.

I'll be doing the same exact thing! Thanks!

And to give you a bit of more work, I recall what AUD101 recommended: to have a look at the Zeners in the Power Circuit Board:

Really?
Well, better do it one time and be over with it :D
According to the schematic I have the following zeners which can be sourced locally with NTE part numbers. Are NTE parts OK for this job?

Driver board each:
ZD01 and ZD02 Part#EQB01-22 - NTE equivalent NTE5080A 22V


Power Supply / Protection board:
ZD01 to ZD04 Part#RD33EB - NTE equivalent NTE5036A 33V
ZD601 Part#EQA01-06R - NTE equivalent NTE5011A 5.6V
ZD602 Part#RD6.2EB - NTEequivalent NTE5j013A 6.2V

As for the bypass caps, since they are already there I'm just going to leave them alone.
 
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R23, R25 were not populated on my driver boards. I guess that's only for the 717s. Thanks for letting me know, otherwise I'd still be looking for them.
Skippy mentioned four 82 ohms fuse resistors for the 517 model...

Really?
Well, better do it one time and be over with it :D
According to the schematic I have the following zeners which can be sourced locally with NTE part numbers. Are NTE parts OK for this job?

Driver board each:
ZD01 and ZD02 Part#EQB01-22 - NTE equivalent NTE5080A 22V


Power Supply / Protection board:
ZD01 to ZD04 Part#RD33EB - NTE equivalent NTE5036A 33V
ZD601 Part#EQA01-06R - NTE equivalent NTE5011A 5.6V
ZD602 Part#RD6.2EB - NTEequivalent NTE5j013A 6.2V
Here I wouldn't want give you incomplete info. If you did the search, they might be fine. But I see pretty low voltages for the last 2 ones, specially on the Power Supply and Protection boards, although these seem to have V close to the original, but... AUD101 recommended 30V ones to my AU-317.

And, yeah! Better do the whole thing now and close the box for the next 30 years... :D
 
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Skippy mentioned four 82 ohms fuse resistors for the 517 model...


Here I wouldn't want give you incomplete info. If you did the search, they might be fine. But I see pretty low voltages for the last 2 ones. AUD101 recommended 30V ones to my AU-317.


Yes, those 82 ohm are probably the resistors I mention on post#16 R47 through R50 on the EQ board.

I really don't know of the AU-317 but I think that it might use a different implementation compared to the AU-517. I got the zener part numbers from the service manual and then searched the web for equivalents. I even came with a search result from AK on one of the parts.

Also I found out that NTE parts are usually frowned upon around here so I'm just going to search for other equivalents and order them from Mouser.
I think that the zeners I posted before all all 500mA. Hopefully someone can confirm this before I buy them.
 
Yes, those 82 ohm are probably the resistors I mention on post#16 R47 through R50 on the EQ board.

I really don't know of the AU-317 but I think that it might use a different implementation compared to the AU-517. I got the zener part numbers from the service manual and then searched the web for equivalents. I even came with a search result from AK on one of the parts.

Also I found out that NTE parts are usually frowned upon around here so I'm just going to search for other equivalents and order them from Mouser.
I think that the zeners I posted before all all 500mA. Hopefully someone can confirm this before I buy them.
Oh, it comes from EchoWars! Trust and go ahead! :thmbsp:

If the Zeners you looked at to replace are 500mA rated, then they might be the ones! Those I put in my AU-317 are rated 250mA, BTW...

When the practice of using film cap bypasses for large electrolytic caps was initially introduced in the late 70s/early 80s, the electrolytic capacitors had increasing ESR with increasing frequency and the film cap improved this, but with modern low ESR capacitors, this is no longer necessary since these have low impedance out to 100kHz. In fact, a small film capacitor in parallel with an electrolytic capacitor NOT having high ESR will actually result in higher overall output impedance and ringing. Here is a link to a technical discussion of same: http://www.diyaudio.com/forums/power-supplies/126697-bypassing-psu-capacitors-effective-2.html Many hobbyists still use film bypasses, but I do not think that they are needed when a good low ESR cap is used. I believe that this is a case of "less is more" for better sound, of course YMMV.

This is actually very interesting! Doesn't take long to me to take them away from the back and see/listen any difference. The power caps I put (F&T GM 10,000uF 63V) are new and are performing very well to me. I wouldn't wish the 2 other 1uF bypass ones create any limitation to them. I'll do a test without the 1uF ones... :thmbsp:

P.S.: I've read somewhere F&T caps is manufacturing same caps and specs for Mundorf AG... :scratch2:
 
This is actually very interesting! Doesn't take long to me to take them away from the back and see/listen any difference. The power caps I put (F&T GM 10,000uF 63V) are new and are performing very well to me. I wouldn't wish the 2 other 1uF bypass ones create any limitation to them. I'll do a test without the 1uF ones... :thmbsp:

P.S.: I've read somewhere F&T caps is manufacturing same caps and specs for Mundorf AG... :scratch2:
Please post your findings/impressions.
 
Driver board each:
ZD01 and ZD02 Part#EQB01-22 - NTE equivalent NTE5080A 22V


Power Supply / Protection board:
ZD01 to ZD04 Part#RD33EB - NTE equivalent NTE5036A 33V
ZD601 Part#EQA01-06R - NTE equivalent NTE5011A 5.6V
ZD602 Part#RD6.2EB - NTEequivalent NTE5j013A 6.2V

Here's what I used for the 717 - looks like they are the same:

EQB01-22 ZENER ZD01 1W 22V Replacement# 1N4748A
EQB01-22 ZENER ZD02 1W 22V Replacement# 1N4748A

EQA01-06R ZENER ZD601 1/2W 5.6V Replacement# 1N5232B
RD-6.2E ZENER ZD602 1/2W 6.2V Replacement# 1N5234C
 
Please post your findings/impressions.

Started listening to a coulple of CDs this morning a bit loud. Repeated some favorite tracks for 2-3 times being as neutral as I could...

Removed the two 1uF bypass ones. Listened again same tracks... Out loud. Feelings are that I like "the whole machine" without the bypass caps. I didn't feel any need of them being there while listening again without them...

Highs are still nice, mids still balanced and lows even nicer! (LOL!)
 
For the AU-517 - Zeners - (according to the schematic):

Board F2675 - PSU & Protector Board
ZD01 - ZD04 - RD33E(B) (Min 29.68v/Max 33.11 0.5W - according to datasheet) - Replacement BZX55C33 or 1N5257B
ZD601 - EQA01-06R (5.6V 0.5W) - Replacement BZX55C5V6 or 1N5232B
ZD602 - RD6.2E (6.2V 0.5W) - Replacement BZX55C6V2 or 1N5234B

Board F 2721 - Driver Circuit Board (L-CH)
ZD01 & ZD02 - EQA01-22 (22V 1W) - Replacement BZV85C22 or 1N4748A

Board F 2722 - Driver Circuit Board (R-CH)
ZD01 & ZD02 - EQA01-22 (22V 1W) - Replacement BZV85C22 or 1N4748A


As previously mentioned, it is recommended to replace ALL VD1212's with 2x 1N4148's in series
Board F-2723 - Equalizer Circuit Board - D01 - D04
Board F-2673 - Tone Control Circuit Board - D01 & D02
Board F2675 - PSU & Protector Board - D604


hcruz said:
R23, R25 were not populated on my driver boards. I guess that's only for the 717s. Thanks for letting me know, otherwise I'd still be looking for them.
According to the schematic for the AU-517 & AU-717 - R23 & R25 are shown as 150R - Maybe fellow forum members who own or has access to an AU-517 can confirm both R23 & R25 exists on the driver boards etc
 
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Thank's AUD101 and Uncle Bambi!
Proper replacements are on order and should be here by Wednesday.


According to the schematic for the AU-517 & AU-717 - R23 & R25 are shown as 150R - Maybe fellow forum members who own or has access to an AU-517 can confirm both R23 & R25 exists on the driver boards etc

Hope someone does chime in.
 
AU-517 Recap Progress

With Pee-wee baseball on full swing, this project has taken a back seat. Nonetheless I managed to do some work.

Zeners and double diodes done.

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The 4 caps on this board took a loooong time to do, but with some patience everything came out good.

8556646562_9d4071b92e_c.jpg


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I knew that the 220uf caps on the power supply board were taller than the originals, but it was at assembly time that I realized they were too big :no:. Still they'll probably do OK.

8556646460_020bf73e31_c.jpg



Now to do some more cleaning and build the dim bulb tester.
:yes:
 
Fabricated my dim bulb tester, tested it, plugged the amp, fired it up and the bulb kept lighting bright.

8567471776_ac98985a08_c.jpg


Not really sure of what to expect I plugged a pair of Baby Advent II speakers and an mp3 player through the aux input and music came through.

Not even a minute playing and noticed that peculiar burning smell of electronic components so I turned it off in a hurry.

Heat came from one of the driver boards. A 470uf cap on one of the driver boards was warm to the touch. Very warm.

8567404250_7f2fdebe8c_c.jpg


I installed the cap backwards :yikes:
Removed the cap and the capacitance dropped from 470uf to 322uf.
Installed a new cap (proper polarity this time :D) and checked every component on the board. Everything seemed fine so I proceeded to test again with the dim bulb.

This time the bulb was bright when the amp started then went to an orange low-dim state a couple of seconds later.

Connected the speakers again and sound came up. 2 minutes into playing there was only music and no burning smells or smoke :).

From prior readings I remembered that I should check the bias and offsets.
A google search gave me this thread.
Measured offset was 12mV and 21mV. Bias was 35mV and 56mV.
Offset was adjusted to 1mV and bias to 20mV on both boards.

The 100 watt bulb had no glow whatsoever after adjusting.

2 hours playing and all seems good.
The sound is night and day compared to when I first got the amp. Very clear and... fast? (for lack of a better word).

Cool to see how the bulb lights up when playing heavy bass music.

This project has been a huge learning experience. Having the dim bulb tester while adjusting DC offset and bias has been very revealing :thmbsp:

As side note, I redid all the 10uf caps on the eq/phono and tone control boards with Nichicon KL (low leakage) trying to keep the recap as close to the original specs as possible.

Would like to thank all the people that helped me throughout this thread and also the "gurus" of the AK community that have posted so much useful information in other threads that were found through searching.

Next on the recap list is a Sansui 9090 receiver that has been playing in the garage for a year. Although I recently acquired a Pioneer SA-9500 II that keeps distracting me :D It should be a good shootout between the two.
 
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Fabricated my dim bulb tester, tested it, plugged the amp, fired it up and the bulb kept lighting bright.

Not really sure of what to expect I plugged a pair of Baby Advent II speakers and an mp3 player through the aux input and music came through.

Not even a minute playing and noticed that peculiar burning smell of electronic components so I turned it off in a hurry.

Wait.... am I missing something? You had a DBT shining brightly and didn't rush to unplug the unit? :yikes:

I think you dodged a bullet there. you were lucky to escape with the minimal (and easily addressed) damage.
 
I think you dodged a bullet there.

Yes I did :stupid:

Next time I really should look up what the idle current consumption is before firing up, hopefully I would somewhat know what to expect with the DBT (so I finally know what DBT means :D ). But for the most part I guess I should be expecting low to no brightness on the bulb.

Are there any guidelines around on what to expect using the Dim Bulb Tester?
 
Are there any guidelines around on what to expect using the Dim Bulb Tester?

Yeah, just one rule of thumb - "If the bulb burns bright, it ain't right". :D

Basically, the bulb acts like a current sink. If the device is demanding too much the bulb will burn brightly as it absorbs the inrush, and you get a few seconds grace period to shut things down before a meltdown occurs. It won't save you indefinitely, just for short while...... and as I understand its chief purpose is to protect the outputs. Using a DBT doesn't guarantee something else won't go up in smoke.

When you initially fire up a unit on the DBT, you want to see momentary brightness followed by dimming. Anything else is "Danger, Will Robinson".
 
Yeah, just one rule of thumb - "If the bulb burns bright, it ain't right". :D ...

Thanks for the info it does make a lot of sense.

Here is a bad picture all cleaned up before putting the cover.

8570411276_2249129de8_c.jpg
 
Beautiful!

How it sounds?

Have you got a parts' list?


IMO sound appreciation is subjective and very dependent on the speakers (and the listener :thmbsp:), but with that said I find the mid-range and treble very clear sounding with the bass having "that color" I note on other Sansui gear I've heard (Currently own a 9090 receiver and had a 9000DB :tears:).
One difference I noticed is that this one doesn't forgive compressed recordings as the 9090.

I'll try to make a list from the notes I took and the invoices from Digikey/Mouser.

Something that made me really proud:
My wife had seen and heard this unit before I cleaned and recaped it. When she came back from work today she saw it back in the house and complained why I bough a newer unit if I had the older one that played fine. The clean out worked well :lmao:
 
Hey there did anyone ever come up with a parts list for one of these I'm having a problem locating some resistors on f2721 boards that are not on the schematics. Like r19 and r25 thanks.
 
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