AU-717 rebuild thread - I could use some assistance

It's actually this one (see link below) you need - your link referenced a 390pF.

This is the 330pf.

http://uk.mouser.com/ProductDetail/Xicon/23PS133/?qs=Txz0Knfx5nM0cPEt0WLgxQ==

And yes, use the axial - you can still stand it up like the old one, and it might be a good idea to sleeve the exposed lead. (leave around 3-5mm of lead at the lower end of the capacitor - don't mount it tight to the board)

Agree with John, this will help prevent damage when soldering (that is the reason why the originals are spaced up off the board with sleeving, helps prevent excessive temperature on the capacitor body via the leads)
 
Agree with John, this will help prevent damage when soldering (that is the reason why the originals are spaced up off the board with sleeving, helps prevent excessive temperature on the capacitor body via the leads)

Perfect, thanks, guys!

Skippy, I had a question regarding power supply transistor subs (TR01 thru TR04) a few posts back. John (Hyperion) was kind enough to specify what he used, and I'll be happy to order them. But I do have some transistors on-hand that might work - do you have any insight, or should I just order the MJ15031/32 types and be done with it?

Those transistors are B526 and D356 types. I have replaced similar transistors in Pioneer gear - B536 and D325. are the B526/B536 and D356/D325 similar enough that I can replace them with the parts I have on hand...SA940 and SC2073 respectively?
 
Hi John,

The 2SB526/2SD356 originals are 90V, 0.8A 10W, and the 2SA940/2SC2073 are 150V 1.5A 25W. The major difference between the two is that the originals are a much faster transistor - ft of 70mhz, vs an ft of 4 mhz, but these are being used as series DC regulators so this should not be a issue. I reckon that these would be fine as a sub in this application.

Cheers

John
 
Thanks again!

A little update..... I pulled the power supply board out yesterday - boy, that was fun. :no:

It looks like I got fairly lucky with the glue. It is very dried and cracked and is easily flaking off, so it shouldn't be too big an issue to clean it all the way off.

Counting the capacitors, I have 39 components that need to be removed and replaced on the PSU. 13 resistors have light to severe green fuzz/corrosion, 14 diodes are either glue damaged or zeners that get replaced, and two transistors (2SC1708's) that have at least one leg with gangrene. I plan on using KSC1845's to replace those.

I've cataloged them all, checked values, identified current replacements and am putting together a shopping list as we speak. Doing advanced searches on AK and living off the archived work of those that have gone before has been a huge help, as have all you folks that are helping "real-time".
 
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Ok - I have my parts list together, and ready to order. Before I pull the trigger, three questions:

Some of the rectifier diodes are glue damaged, so I'm going to replace all 8. I have on-hand 10 1N4004E 400v 1a rectifier diodes 4 1N4004GP diodes, and 3 1N4004G diodes. I see there are several variations of the 4004 diodes but do not know their correct applications.

Question 1 - Are the "E" variants good for this application?
Question 2 - Do I need to replace all 8 to make sue they are all the same type, or do I just change the damaged ones?
Question 3 - The Bourns 2Kohm trimmer Mouser part#652-3386H-1-202LF is back-ordered... can anyone suggest an alternative?
 
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Ok - I have my parts list together, and ready to order. Before I pull the trigger, three questions:

Some of the rectifier diodes are glue damaged, so I'm going to replace all 8. I have on-hand 10 1N4004E 400v 1a rectifier diodes 4 1N4004GP diodes, and 3 1N4004G diodes. I see there are several variations of the 4004 diodes but do not know their correct applications?


Question 1 - Are the "E" variants good for this application?

I cant see any difference between the 'E' version and the others - so, as good as any of the others it seems.

Question 2 - Do I need to replace all 8 to make sue they are all the same type, or do I just change the damaged ones?

Personally I would change all 8 (take a pic before you remove the old ones).

Question 3 - The Bourns 2Kohm trimmer Mouser part#652-3386H-1-202LF is back-ordered... can anyone suggest an alternative?

Other than ordering from another supplier..... (expensive option)..... this needs to be "top adjust" IIRC...

I used these ones (note this is a 'multi-turn' type - which I prefer)
http://uk.mouser.com/ProductDetail/...=sGAEpiMZZMvygUB3GLcD7rufck0TIBKyyxzUYQ1NBRc=

(Mouser P/No 652-3266W-1-202LF)
 
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Thanks John.

Looks like the "E" version it is. I assumed that it would be best to change all 8, just to make sure they all had the same "mileage" on them. Just wanted to see what others thought, and they are cheap enough.....

I happened to find a relatively local supplier for the pot. They don't have much, but they had that. 25 miles each way....... I cheated a bit on my lunch hour to scoot there and back.

Parts are on order, and this project is on hold until everything arrives. Also - I found a Sony donor unit that has some nice speaker lugs, so after I make this unit ship-shape I'll likely do the upgrade as outlined by Skippy and others.
 
OK - the parts arrived today, and I'm just about finished with the power supply rebuild.

There is one part left to replace - ZD601, the 5.6v zener part# EQA01-06R. Before I go ahead with the replacement I have a question.....

Before ordering, I did an advanced Google search, and saw that Echowars and others recommended a 1N5232B as the replacement, so that's what I ordered.

Now that I have it in-hand I notice that when I physically compare it to the zener at ZD601, the original one is much bigger and beefier looking. I just want to confirm - is this the right replacement zener? It looks awfully small, and I'm afraid it might not have the needed dissipation.....
 
Hi John

They are both 500mW zeners so there is no problem using the 1N5232B as a replacement for the EQA01-06R

Cheers

John
 
Thanks Skippy. Sure doesn't look like it, though....... The original is huge compared to the replacement. :)

OK - the power supply is finished. Damn, that was fun...... NOT. Just getting it out and then back in was a major pain in the ass, and I really didn't care for changing so many components without intermediate testing.

I replaced all the zeners, the VD1212 diode, and all the electrolytic capacitors. Because of glue damage, I also replaced all the rectifiers, 13 resistors, 2 diodes and two transistors. While I was in there I installed a new relay as well as the relay transistor and diode. The glue wasn't too hard to clean up once I got access to it, but several of the components came out in two pieces as a result of corrosion on the legs. 63 separate components altogether - 64 if you count the second 4148 in series for the VD1212.

I just finished re-assembling and connecting up everything, and am getting ready to fire it up on the DBT as soon as I double, triple, and quadruple check my work.

Wish me luck.

I still have to pull and replace the big transistors with heat sinks on the top edge, but that can wait until I give the amp a test as they are easily accessible with everything assembled.
 
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More progress.......

Both amp boards have been cleaned and de-glued. All corroded components have been replaced, as have all the capacitors. The outputs were removed, cleaned and re-greased, and re-installed.

I'm leaving the trim pots for the last step - on to the Tone Control and Equalizer!

Before:
SansuiAU-720_zps74fe8468.jpg


After:
AU-7171-30-20131-33-52PM_zps59ddfd01.jpg


Power Supply before:
SansuiAU-722_zps118c3918.jpg


Power Supply after:
AU-7171-25-20134-55-04PM_zpsc92eb367.jpg


AU-7171-25-20134-54-56PM_zpsad1c46d1.jpg


Amp modules before:
SansuiAU-719_zps550e09d5.jpg


SansuiAU-721_zps8649b08f.jpg


Amp modules after:
AU-717ampboards1-30-20131-33-40PM_zpsedb6c5d0.jpg


AU-717ampboards1-30-20131-34-14PM_zpsb5e19320.jpg
 
OK - all finished except for the trim pots and final offset/bias adjustments. Right now I'm listening to it for a while and just basking in the smoothness of EC Was Here before finishing it up. This thing is a beast, but in a good way. :)

On the Tone Control and Equalizer, I preemptively changed all the SA726 transistors, as a bit of searching reveals that they can be problematic and noisy. The 992's I used as replacements are well regarded and quiet, and should give years of reliable service.

I made an error with the fuse resistors - I ordered 1/2w instead of 1/4w. The 1/2w work OK, but they were a bitch to install because the wires are larger than the holes. I had to use a dental pick to gently swage the holes a bit larger in order to get them in. I probably should have mounted them on end, but they're in now and working fine so I'll leave them be.

For the VD1212's I made up the requisite pairs and then covered them in shrink tubing. They look like little red teepee's.

Some pics:

VD1212 replacements, and the HUGE fuse resistor replacements:
vd12122-2-201312-52-44PM_zps96b039d4.jpg


vd12122-2-201312-52-10PM_zps3af73984.jpg


Almost done:
SansuiAU-7172-2-20131-09-35PM_zps8ca348ba.jpg
 
Uncle Bambi. Very nice Job.

One thing to consider when using a DBT is that the input voltage at the amp is going to be lower than normal, so that a protection circuit that wants to see a minimum operating voltage during normal use, will see a lower operating voltage and NOT totally engage (or disengage as the case may be), hence the blinking lights (see 1st post.). Just an observation.

Larry
 
Uncle Bambi. Very nice Job.

One thing to consider when using a DBT is that the input voltage at the amp is going to be lower than normal, so that a protection circuit that wants to see a minimum operating voltage during normal use, will see a lower operating voltage and NOT totally engage (or disengage as the case may be), hence the blinking lights (see 1st post.). Just an observation.

Larry

Good to know!

As it happens, the blinking light in the first post was as a result of something in the power supply - probably a marginal cap, as it went solid if left on long enough. I rebuilt the PS first, and after I did the light went solid after the relay clicked (see video). I have yet to power this unit up without the DBT.

As an aside, I was planning on getting the power supply caps from Michael Percy, but he has yet to answer my couple of emails. Does anyone know of an alternate source? Mouser does not have the Nichicon KG Gold 15,000µf 63V caps.
 
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Great work and I applaud you for bringing her back to her glorious self. I love reading threads like this. Is this your first Sansui?
 
Nice work John, and great photos.

Try partsconnexion for the caps - their part number NICHICON-73638

15000uF / 63V, KG Series, Gold Tune, 40mmD x 100mmH, Solder Lug

http://www.partsconnexion.com/capacitor_ele_nichicon_kg.html

Thanks, John!

Great work and I applaud you for bringing her back to her glorious self. I love reading threads like this. Is this your first Sansui?

My 1st Sansui was a 317II that skippy124 and others helped me bring back from the dead a year or so ago. That was the one that turned me from being a Pioneer fan-boy to really digging the Sansui experience. The next one was a Sansui 771 receiver that I overhauled and gifted to my best friend. That receiver sounded so awesome that I hated to give it away. Sansui #3 was a sweet little AU-D7 that I overhauled and sold to make money to buy this one.

This is my 4th, and is slated to replace the 317II which has been my main amp ever since I got it running. Sansui's look cool, sound fantastic, and are laid out very well for servicing..... no wire-wrapped pins, modules the easy to unplug and remove, excellent silk-screened labeling on the PCB's.

I like them.:D
 
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