Sansui au 919 psu caps! - diyAudio
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Old 15th December 2007, 12:23 AM   #1
voah is offline voah  Serbia
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Default Sansui au 919 psu caps!

Hi,I need some help.
It was easy to find problem with bad PSU capacitors on that au919 but
i don`t know what capacitance those are.Simply it isn`t written.I believe those voltage is rated at 63V.
Any information is well appreciated.
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Old 15th December 2007, 05:09 AM   #2
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I have some data on a 517 and 717 (I own a 717).

AU517 65W/ch into 8 ohms

Output rails are +/- 51V Used 12,000uf@63VDC rating

AU717 85W/ch into 8 ohms

Output rails are +/- 56V. Used 15,000uf@63VDC rating

AU919 was 100W/channel into 8 ohms.

http://www.sansui.us/toc.htm

http://www.sansui.us/images/Manuals/au919_spec.JPG

They would have likely scaled the rails and caps as they did
in the jump from the 517 to the 717 plus a few other enhancements like voltage regulation for some of the stages. The caps may have been increased to the next standard value (18,000uf).

63VDC rating would be marginal (in my opinion) at any rail
above 55V (although my 717 continues to function). This may
be mitigated if the VDC rating of the cap is at a high
temperature (say 85 degrees C). This is a calculated risk on the
part of a manufacturer to do this however (warranty issues).

A manual can be obtained from http://www.agtannenbaum.com/s_cat.html
for about $20.00 (ish)
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Old 15th December 2007, 09:35 AM   #3
Netlist is offline Netlist  Belgium
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Have a look at classicsansui.net

/Hugo
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Old 15th December 2007, 11:43 AM   #4
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15,000f 63V each. Manual says the rails are +/-55V.
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Old 15th December 2007, 11:55 PM   #5
voah is offline voah  Serbia
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Many thanks.
I expected these are 18000uF@63 ,but the rail voltage is the same as Au717(+-56VDC) that has 4x15000uF@63V filtering caps.
AU919 uses unique shape filtering caps,especialy made for Sansui.
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Old 18th December 2007, 01:46 PM   #6
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Default IS THERE

a chance that some of you know exactly the three trimers existing on au717 bords what exactly they do ???

one of them should be the offset voltage the other one will be idle and the third one ??? i dont know ....

also i wonder if anybody knows what was the original values

like how much idle ....... ok ofset as less is possible
and the third one ????
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Old 18th December 2007, 04:37 PM   #7
ilimzn is offline ilimzn  Croatia
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Two are offset voltage (the two that are close together) coarse and fine, the third is output stage standing current.
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Old 18th December 2007, 05:24 PM   #8
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Default thank u

i found out my shelf also ......

since i havent the abilty to locate 2sa747 and 2sc1116 i thought puting 2sa1302 and 2sc3286 for outputs !!!

what do you thing about that ????

( i do have really original from them and a lot he he he )
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Old 18th December 2007, 05:46 PM   #9
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Default one other thing

i did idle first ...then i did ofsset ( very fine way to ajust it !!!!!! )

i am so happy working this machine they donet make them like that any more

do you thing that i have to look idle again ???
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Old 18th December 2007, 06:22 PM   #10
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Default guys help please

i play with au 717 sansui.....

made everything in original condition rail voltage is 57+57 volts for out i used very original 2sa1302+2sc3281 ....

cleaned all very carefully
recaped the all amplifier boards.most of secondary power board

switches and everything is very clean pots also
but sound is kind of strange

bass section sounds like there is short of deep rush arround 60hz like bass is added ( almost a lot ) also if you press loudness then it really gets very a lot !!!!
but only in one frequency arround 60hz
resulting also that midle sounds like is too deep ( kind of far away )

and as about the high something like a hiss exists arround 4-5 khz .....

not really clean sound

any tips ?????
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