Inside a AU-919 project

[scottrt]

Just thought some of you might find it interesting to peruse thru pics of a 919 restoration. I apoligize for the seeming lack of proper chronology in their ordering.

Scott T.

http://s694.photobucket.com/albums/vv306/scottrt/Sansui AU-919 restoration/?start=all/

 

[jeffe]

Wow! Nice work!

Looks like a full "frame off" resto to me! Full recap? and, I think a few other components (diodes & fusistors IIRC?)

All back together and making beautiful music?

 

[scottrt]

I replace most of the TO-92, TO-126 and half of the TO-220 transistors too. This baby really is dynamic.

Scott T.

 

[Robisme]

Looks like a lot of work went into that AU-919.
Great job.

What ever became of your G-9000? (I think it was a 9000)

Rob

 

[kevzep]

Wow, thats a full rebuild indeed. Oval caps and all...............
Looks like a lot of work went into that.............
Very nice job indeed.
Its very satisfying when you can finally sit down and appreciate the fruits of all your hard work, theres nothing quite like it.........

 

[scottrt]

Geez Rob, you gotta good memory. Yeah, That G 9000 still sits in the corner awaiting a serious go-thru. I traced a good signal to the driver boards back in the day, but wasn't of the spirit or experience to go beyond that point at the time.

I hope to do a 'frame off' on that baby this fall. I figure it will weigh less if I take it all apart. GOD, what beasts they are.

Scott T.

 

[anderslober]

Scott T........amazing job. Fantastic pictures too.

Regarding the transistors......TO-92/others.....were they direct swaps for new ones? OR did you use good sub's?

Great job.

 

[scottrt]

Transistor subs were for modern parts numbers as discussed and conferred upon so many times here at AK. A real popular 'buy them by the dozens' transistors for this whole series is A992F
and C1845F. Amongst others, I keep plenty of those on hand.

Thanks for the kind words, all. I put over 60 hours into the job, and enjoyed most every minute of it. Could not have done it without the knowledge and advice of the senior AK members.

Funny moment: when I first fired it up, I had my face right in there so I could watch and listen as I counted to 10 expecting the protection relay to go 'Ping". One hand on the off switch, one on the power cord, it was late at night and dead silent in the room. At eleven seconds the relay went 'ping', and even though I was doing a countdown, I jumped outa my chair with such a start I damn near completely knocked over a drafting table located behind me. The amp worked great... took me 20 minutes to get my heart-rate back into double digits....

 

[noveltone]

Great job! Very complete! Thanks for sharing all this great info, especially the images. Let me ask you, does the DC offset at the speaker terminals move much from the time you first turn it on to an hour later when it's warmed up?

 

[scottrt]

The bias changes some as it warms up, but the DC offset stays within a 2 mv range.

Scott T

 

[Hyperion]

The bias changes some as it warms up, but the DC offset stays within a 2 mv range.

Scott T

Now 'that' is a properly done re-cap - excellent job Scott.

 

[noveltone]

The bias changes some as it warms up, but the DC offset stays within a 2 mv range.

Scott T

Thanks for providing that little piece of information. So glad to hear your 919 is running well after all your hard work. My 919 persists in having offset issues, and this is a helpful comparison. I noticed your unit also has some internal bracing that some fool long ago removed from mine. Cheers and thanks again for sharing your images.

Collin

 

[scottrt]

Collin: It is important to confirm you have the proper + - 10 volts on the MC head-amp, then zero the DC trimmers on the head amp, then zero the DC trimmers on the flat amp, before you mess with the trimmers on the driver board, or all is for naught. You have installed new trimmers....no?

Scott T.

 

[noveltone]

Scott, thanks for your comment. I don't want to hijack this, so I sent you a PM.

Collin

 

[jhoyt]

Wow, that looks like a TON of work. But eminently worth it!

Makes me glad I was "only" working on an AU-717...:scratch2:

 

[ghamilton]

As a 919 self-rebuilt owner I'm glad to see this worked out for you.

 

[xoaphexox]

Funny moment: when I first fired it up, I had my face right in there so I could watch and listen as I counted to 10 expecting the protection relay to go 'Ping". One hand on the off switch, one on the power cord, it was late at night and dead silent in the room. At eleven seconds the relay went 'ping', and even though I was doing a countdown, I jumped outa my chair with such a start I damn near completely knocked over a drafting table located behind me. The amp worked great... took me 20 minutes to get my heart-rate back into double digits....

That is great, I have been there!! :thmbsp:

 

[xoaphexox]

Also, did you happen to replace the connected/separated switch on the back? If so what part # did you use? My AU-919 has a funky switch that I am bypassing with RCA patch cables for now but I would like to replace the switch some day.

Excellent work, thanks for the pics! I finished my AU-919 rebuild a while ago but looking at this makes me want to put it back on the bench for more tweaks!

 

[scottrt]

I did not replace the switch. There is a solid state relay (green in color) that the switch energizes, and power comes in via two brown wires from the protection board. Make sure those are working properly... might not be the slide switch.

Scott T.

 

[xoaphexox]

I did not replace the switch. There is a solid state relay (green in color) that the switch energizes, and power comes in via two brown wires from the protection board. Make sure those are working properly... might not be the slide switch.

Scott T.

I see, thanks - I may have some replacements for this reed relay on hand if it is the same kind used in the Sansui CA-3000 or the Pioneer SPEC-1.

You would just clip off the two NC leads:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=Z649-ND