Sansui AU-505 "Custom Wiring"

[Zach RC]

Hey everyone! While I do have experience in both job and personal restoration work, the one thing i just haven't had experience with in my job or in my experience in receiver fixing are with switches/potentiometer layouts...and this AU-Sansui 505's frontend wiring has had A LOT of custom wiring work to where it was so bad that the on/off high filter was desoldered to just be another on/off sound and phono turned on the aux left channel only. Does anyone have pictures of the wiring to the switches and of the F1303 board? just so I can better reference the schematics and learn how to read them since I'm having to solder everything from pretty much scratch? The pictures are just what I'm working with as of right now... I plan on recapping it ONCE i figure out the wiring. Thank you in advance!!

 

[raycarr00]

I google the model and switch to "images" then to "inside."

https://audiokarma.org/forums/index.php?threads/sansui-au-505-rebuild.598808/

 

[Zach RC]

I google the model and switch to "images" then to "inside."

https://audiokarma.org/forums/index.php?threads/sansui-au-505-rebuild.598808/

Thank you for the reply! Ive seen that post and tried to look at the soldered point of the switches but it's so blurry i just can't see them. I've tried all the searching tricks trying keywords, have literally pulled up every au505 thread i could find, and even looked through ebay,reverb, and hifishark for switches that have wires cut from them but colors still visible with no luck.

 

[Peter lye]

some pic i took last month

 

[Peter lye]

found some more pic

 

[Zach RC]

found some more picView attachment 2631760 View attachment 2631761 View attachment 2631762 View attachment 2631763 View attachment 2631769 View attachment 2631770

Omg this helps me so much, if you were closer I'd kiss ya! Thank you for the pics seriously though.

 

[Zach RC]

Just wanted to update this post, so the pictures definitely helped me understand schematics A LOT, and the au505is now back to original wiring. I made a dbt to use and it works as intended. Unfortunately when i hooked up the au505 in question it immediately shimmered brightly then blew the 160w bulb within 2seconds So there's definitely still a problem. The problem it had before was right channel fuse instantly blowing on power-on w/117v. I couldn't find any ground issues or shorted transistors/capacitors either.

 

[raycarr00]

look for soldering bridges where parts were replaced, wires connected(review wiring connections), cracks in traces...diodes. see if an area got burned where it shouldn't have touched the chassis.

 

[DougBrewster]

The only thing that can blow the DBT lamp is excessive voltage. Is the amp receiving excessive voltage?

 

[Jefft91]

Just wanted to update this post, so the pictures definitely helped me understand schematics A LOT, and the au505is now back to original wiring. I made a dbt to use and it works as intended. Unfortunately when i hooked up the au505 in question it immediately shimmered brightly then blew the 160w bulb within 2seconds So there's definitely still a problem. The problem it had before was right channel fuse instantly blowing on power-on w/117v. I couldn't find any ground issues or shorted transistors/capacitors either.

Wondering if you had a bad bulb in your dbt. A good bulb, if connected to the line voltage is made to handle it without blowing. If the DBT works like it should, even if you have a dead short, the dbt bulb should not blow out, but will glow brightly. I'd replace it with a 100W and try it again. Obviously (I think) there's a short in your amp, but at least you want to eliminate the dbt as a cause of confusion in your debug.

 

[Zach RC]

Wondering if you had a bad bulb in your dbt. A good bulb, if connected to the line voltage is made to handle it without blowing. If the DBT works like it should, even if you have a dead short, the dbt bulb should not blow out, but will glow brightly. I'd replace it with a 100W and try it again. Obviously (I think) there's a short in your amp, but at least you want to eliminate the dbt as a cause of confusion in your debug.

Ok so bare with me...I keep a bunch of bulbs in a cabinet where there is no light ironically enough, and I grabbed a LED bulb, after grabbing a correct 60w bulb, it did not blow and was just extremely bright. I'll be doing a detailed inspection of every board tomorrow though.