Matt's Sansui AU-317rebuild

Hey all -

After a successful AU-505 rebuild (and a Marantz 2220B before that) I've figured out that one of things I really enjoy about this hobby is working on classic gear and bringing it back to life. So I decided to pick up another project amp and document my restoration here. I'm sure I'll have questions along the way, so I'd like to thank everyone here in advance for any advice and guidance provided. Hopefully this thread will be helpful to others in the future.

The AU-505 turned out so well that I decided to look for an AU-*17 series amplifier to refurbish since most people seem to love them, the build quality is supposedly excellent, and I've always admired the look. I ended up with a tired AU-317 which arrived earlier this week. Unfortunately it was not working when it arrived, which was a real let down since it was advertised as tested and working.

Here are a few pictures of the amp as received, fresh from the shipping box. As you can see this thing is just downright filthy, with some serious gunk and fading on the knobs and a heavy layer of dust and critter guts inside the chassis.

So it looks like I've got a real project on my hands, which is exactly what I wanted. Hopefully it turns out as well as the 2220B and AU-505 I've already got under my belt.

-Matt

Hi,

You will be very happy once you have the 317 restored and working, they are a great amp.

Here is a thread on another forum of a restoration I did a while ago

http://www.stereo.net.au/forums/index.php?/topic/44937-sansui-au317-restoration/

Cheers

John

Well I hope she cleans up nice

Initial cleaning

The first order of business is to clean this unit up. So today I took it apart and blew out the majority of the dust and spider carcasses using a compressor and a paintbrush. This is only a first pass - I'll do a deep clean later - but at least I don't have to worry about something nasty crawling out of it now.

The knobs were extremely sun faded and while a soak in simple green got most of the grime off it did not restore the color. For that I used a little polish, gently applied with my finger and then buffed out with a clean cloth. This worked very well, and I'll probably polish them again before putting it all back together. Check out the pictures for a before and after of the knobs.

This amp was listed as tested/working, but it was basically DOA when I received it. It does power up and come out of protection, which is good. Wiggling the tape monitor switch produces intermittent sound from one channel via speakers or both through headphones. I believe none of the major components are toast, which is why I kept the unit instead of sending it back. I'm hoping it just needs a solid cleaning and a little attention. We'll see how it all turns out.

So I think I'm going to start by removing and recapping the main amplifier board. It looks like this board can be removed entirely from the unit without much trouble, which I'm planning to do since it will be much easier to clean and work on. The good news is that this unit appears to have had minimal damage from the evil Sansui glue. I'm going to hunt down the service manual and schematic tonight, and then the next order of business will be:

1. Remove the main amp board, clean and inspect for glue damage

2. Replace mica and grease on outputs with new sil-pads (good ones)

3. Recap main amp board and replace any components the glue may have impacted; also replace any fusistors and possibly bias trimpots

4. Replace the main filters with either Panasonic TS-HA or Nichicon KG caps

5. Install and test

-Matt

:nerd:

Also replace the VD1212's on the Head Amplifier Board – F2751 with two 1N4148's in series

The Panasonic TH-A Series have the correct 4-pin drop in replacements for the two main cap's

For ref see this post - has some good info in there :thmbsp: ---> AU-317: a noobs first restoration project

Thank you AUD101! I cam across that thread earlier where you recommended the Panasonic TH-A series as a drop in replacement. I'll either go with those or the Nichicon KGs I've used in the past.

One question for the experts .. I've downloaded the service manual and unfortunately the parts list for the F-2754 board is incomplete. Only about half of the capacitors on the board are in the parts list, and I'm having a hard time reading the values from some of the smaller ones on the board. Why would the parts list not include all of them, and if anyone knows, what are the values/voltages of C613, C614, C26, and C36?

I'm going to put together a Mouser order tonight with at least the parts for the F-2754 board. I'll probably use Silmic IIs in most spots and then either the Panasonic recommended by AUD101 or Nichicon KG for the main filters. I'm also going to order new trimpots, new zeners (again from AUD101's other post), and some 1N4148s. Should I replace and small signal transistors while I'm at it?

-Matt

I usually refer to the schematic for component values as most of them (if not all) will be printed, then make up a draft list...and confirm with what's on the PCB's

Power Amplifier Board – F2754
C613 = 100u 6.3V (Bipolar)
C614 = 1u 50V (Bipolar)
C25 & C26 = 1u 50V (Electrolytic) - Could be replaced with a small film cap of same value
C35 & C36 are not on the schematic and although the PCB overlay confirm their positions, I have never seen these positions populated on any of the AU-317's I have recapped/restored

The schematic of the AU-317 pretty much agrees with what is actually on the PCB which is kinda good for Sansui!

Edit:
Also consider replacing the speaker relay ---> Mouser Part No: 653-MY4-02DC24

eedork said:

...............

The knobs were extremely sun faded and while a soak in simple green got most of the grime off it did not restore the color. For that I used a little polish, gently applied with my finger and then buffed out with a clean cloth. This worked very well, and I'll probably polish them again before putting it all back together. Check out the pictures for a before and after of the knobs.

.....................

Click to expand...

Amazing how much those knobs improved. What kind of polish did you use?

Nichicon KGs require mods to the PCB to accommodate the larger solder tabs, but with the right gear it is not too hard to do. I fitted KGs to my 317.

Mother's wheel polish

roger2 said:

Amazing how much those knobs improved. What kind of polish did you use?

Click to expand...

I used what I had on hand which was some Mother's wheel/mag polish. I wasn't sure how the knobs would react to the polish, but mine were so faded that I figured I didn't have much to lose and gave it a try. As you can see, they came out great!

-Matt

Thanks!

pete_mac said:

Nichicon KGs require mods to the PCB to accommodate the larger solder tabs, but with the right gear it is not too hard to do. I fitted KGs to my 317.

Click to expand...

Thanks for the heads up Pete! I used the KGs on the AU-505 and the Marantz 2220B and was very happy with them. But I didn't have to make any modifications to the boards .. for this project I'll probably stick with the Panasonic's recommended by AUD101 since they are a drop in replacement.

I removed the outputs and and started cleaning the heatsinks today (see pictures). And yes, the bracket on the left is upside down - doh!

Here's BOM for the F-2754 power amp board:

Component -- Value -- Description

R35, R36, R45, R46 -- 150 ohm -- 1/4 W metal film
VR05, VR06 -- 1k multiturn -- bias pots
ZD601, ZD602 -- 1N5256B
ZD603, ZD606 -- 1N5248B
C603, C604 -- 10,000uF/50V -- Panasonic TS-HA
C11, C12, C29, C30, C605, C606 -- 470uF/50V -- Silmic II
C607, C608 -- 220uF/50V -- Silmic II
C609, C610 -- 100uF/35V -- Silmic II
C601, C611, C612 -- 47uF/50V -- Silmic II
C03, C09 -- 33uF/25V -- Silmic II
C25, C26 -- 1uF/50V -- Silmic II
C613 -- 100uF/6.3V -- Bipolar!! Nichicon MUSE ES
C614 -- 1uF/50V -- Bipolar!! Elna RBS
C616 -- 330uF/6.3V -- Silmic II
C901, C902 -- 1uF/100V -- Silmic II

I've started a spreadsheet with Mouser and Handmade part numbers. I'll probably get all of the Silmics from Handmade and everything else from Mouser. A few people have mentioned that I should replace the VD1212 diodes with a series pair of 1N4148s. I don't see any VD1212s on the F-2754 board though .. am I missing something?

Thanks!
-Matt

Hi Matt,

I don't think that there are any VD1212 diodes in the main amplifier (at least on the ones I have worked on there weren't any, and the service manual doesn't show any)

Cheers

John

Yep, your quite right! - the VD1212's are on the Head-Amp board – F2751 - (My bad! - I will amend my earlier post)
Your BOM list is coming along just fine - Add the following to your list
C4 & C10 - 33u 25V
C23 & C24 - 470u 50V
C601 - 47u 50V
C616 - 330u 6.3V

Note that C901 & C902 are film caps and do not need to be replaced if carefully removed

Excellent - thank you guys! I'll revise my BOM to include C601, C616, C901, and C902 (thanks AUD101!!). I'm excited to get started on this and will probably place an order or two tonight.

Once I have the main amp board done, I'll figure out the BOM for the other boards and do them all in a separate order.

-Matt

EDIT: It looks like C901 and C902 are the bypass caps across the main filters. Do these need to be replaced? Answered by AUD101 .. these are not required if the originals are carefully removed.

There are also VD1212 diodes on the control (tone) amp F-2752 board - and this board also has two fuse resistors, R17 and R18, 68ohm.

Cheers

John

Just found it! - I knew I had an Electrolytic re-cap list filed away somewhere for Power Amp PCB - F2754

C3 & C4 - 33u 25V
C9 & C10 - 33u 25V
C11 & C12 - 470u 50V
C23 & C24 - 470u 50V
C25 & C26 - 1u 50V
C601 - 47u 50V
C603 & C604 - 10,000u 50V
C605 & C606 - 470u 50V
C607 & C608 - 220u 50V
C609 & C610 - 100u 35V
C611 & C612- 47u 50V
C613 - 100u 6.3V (Bipolar)
C614 - 1u 50V (Bipolar)
C616 - 330u 6.3V

Note that C901 & C902 are film caps and do not need to be replaced if carefully removed

Thanks again!

Also, for VR05 and VR06, I'm thinking of going with this pot:

http://www.mouser.com/ProductDetail...=sGAEpiMZZMukHu+jC5l7YUFlGeeRde5S52LRbcKUl+I=

It's a 19 turn so I'll be twisting away with the screwdriver, but it should be quite accurate.

-Matt

AUD101 said:

Just found it! - I knew I had an Electrolytic re-cap list filed away somewhere for Power Amp PCB - F2754

C3 & C4 - 33u 25V
C9 & C10 - 33u 25V
C11 & C12 - 470u 50V
C23 & C24 - 470u 50V
C25 & C26 - 1u 50V
C601 - 47u 50V
C603 & C604 - 10,000u 50V
C605 & C606 - 470u 50V
C607 & C608 - 220u 50V
C609 & C610 - 100u 35V
C611 & C612- 47u 50V
C613 - 100u 6.3V (Bipolar)
C614 - 1u 50V (Bipolar)
C616 - 330u 6.3V

Note that C901 & C902 are film caps and do not need to be replaced if carefully removed

Click to expand...

I have used Type 3296W Multiturn trimmers as replacement for the VR05 & VR06 - The pins are in-line and need to be bent accordingly to fit ---> Mouser Part No: 652-3296W-1-102LF

Thanks again AUD101! I'll add these to the cart ..

-Matt