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Advise on restoration/recap Sansui AU 719

RossMD

RossMD

New Member
Dear Sansui owners, i am here to ask for your valuable help on restoring and recaping a Sansui AU 719. It is my first Sansui amp but even though it had one "dead" chanel and obviously a few more problems i still got impressed and wish to hear what she's really capable of, when properly restored. The 'dead' chanel has been cured by new output transistors (originals blown) and a bunch of small electrolitic & ceramic caps that my tech has thrown in (also the black flag in that chanel). But i know he used whatever he had got on hand (for the sake of bringing it alive) and that's definitely not the way i want to go. So i made some home work and put toghether a list of parts to be ordered which i will then let my tech put in as i am almost "0" skilled.
Please take a look at my list and let me know if i should add or choose another part than stated. Since i am located in eastern eaurope it's inconvenient making multiple orders.
The amp is stable and working now but there are some more performance issues: there is a strong "hiss" sound from both speakers unrelated to volume level, it pops a little when i shut it down, it goes extremely loud when i switch to phono.
 

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Your list looks OK to me, apart from a slight description error on line 23 of 'order1' for a 1N4148, as "D035, 100V, 4A" - this is not correct, should be 0.4A

I notice from the list that you have clearly done some research - which is good. :thumbsup:
RossMD said:
it goes extremely loud when i switch to phono.
Click to expand...
The phono input is extremely sensitive, due to the comparatively low output from phono cartridges, example:- 'Phono input' sensitivity = 2.5mV, whereas 'Aux input' sensitivity = 150mV.
 
Hyperion said:
Your list looks OK to me
Click to expand...
Thanks a lot for your time Hyperion, this list is almost entirely inspired from your great job in "Sansui au 719 on the bench". Extremely helpful...
Would you recomend to get some surplus part, e.g. KSC1815YTACT in order to be able to match hfe? or maybe i missed something...
Unfortunately my tech wouldn't accept to test every part to judge if good or no and then have the unit apart untill the order comes in.
 
RossMD said:
KSC1815YTACT in order to be able to match hfe?
Click to expand...
This is the correct substitute for a 2SC1313 in ANY position, however in most locations you can use KSC1845 instead - IF you can get hold of them. Farnell have 2,100 at present - but unfortunately for you that represents another supplier order, as both Mouser and Digikey have none.

As regards ordering extra so you can match them, yes that is quite a good idea - things work better when obviously 'paired' transistors are matched for hFE, (or vBE in some cases).
 
Was almost ready to put the order, but the 4.7uf 63V wima films for C05,08 (driver board) and C17,19,18,20 (control board) are now out of stock. Woul it be ok to pick the 10% tolerance (same value) or go for 50V 5% or should i look somewhere except mouser and digike?
 
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