BA-3000 Died Last Night

cirtcele

Active Member
I was playing my system last night heard static out of one of the speakers then the thump of the protection circuit turning on. I turned the amp off then back on and the main fuse blew i'm guessing thats not good. So now i need advice on things to check and any good repair shops. Switched my speakers to my tube amp and they sound fine so no problems there.
 
Anyone with experience working on this unit willing to walk me thru troubleshooting the problem. I'm a electrician with an education in electronics i took the maintenance electrician route instead of repair tech so i'll need some help.
 
I have experience in the BA 2000 & AU 20K.. There are some BA-3K things that are that model specific... I ( Like others here ) would be wiling to help..

First things first.....For this ... make a DBT ( Dim bulb tester ) ..LOTS of how to's here... do a search..

2nd open up an account at HI FI engine It;s FREE and download the schematic. http://www.hifiengine.com/

3rd DO NOT ATTEMPT any more power ups until you have a working DBT...

4th Clean up a NICE working space to start opening the unit up and start taking detailed pictures...

( This should keep you busy for a while )

Mike
 
OH I NOW remember you...... we had the 4 ohm vs 8 ohm power discussion....
And you had popping / static issues prior..

Question... where these Sansui pieces "RESTORED" prior to your ownership?
OR
Are they ORIGINAL ??

Mike
 
I know of two versions of the BA-3000.

One has pass-through solder joints (vias) on the amp boards.
They need to be checked and repaired if you have that model.

You need to pull the amp blocks and unsolder the output connections and split the amp block to get to the boards.

Once there, if you have the vias, you need to suck the solder out of them, make a short piece of copper wire to pass through the hole, scrap a little coating off the trace on each side, insert and bend the copper wire to the bare trace and solder it in.

The other type amp did not use the vias.

I typically start trouble shooting an amp blowing fuses by checking the output transistors, drivers, pre-drivers, working backward through the amp transistors. To get to the output transistors, you need to get into the amp blocks, a good time to fix vias if they are in there.

Beyond/beside that, you'll need to get a dim bulb tester rigged up and start testing voltages. Since accessing the outputs is such a pain, you're probably better to attack this from the voltage trascing route.

Do you have a decent soldering station? Solder sucker and/or wick? Digital multi-meter (DMM)?
 
I have a decent soldering station, solder sucker and wick. I have several Fluke DMM. It looks pretty original but with some help from you guys we will figure that out. Do you have a picture of those pass thru solder joints so i know exactly what i'm looking for. I'll get a dim bulb tester built and i already downloaded the service manual. I bought from this from a local HFS so they can give me some info on any past repairs. The sub filter PB on the front sounds dirty when pressed so i'm guessing it has not had a complete restoration. Got to go to work i'll check back later today.
 
There is a bit of info here on AK about working on those.
Use the google option in the search tab above.

Here are results from "BA-3000"
http://www.google.com/custom?client=pub-9996023742202798&forid=1&ie=ISO-8859-1&oe=ISO-8859-1&cof=GALT%3A%23008000%3BGL%3A1%3BDIV%3A%23336699%3BVLC%3A663399%3BAH%3Acenter%3BBGC%3AFFFFFF%3BLBGC%3A336699%3BALC%3A0000FF%3BLC%3A0000FF%3BT%3A000000%3BGFNT%3A0000FF%3BGIMP%3A0000FF%3BLH%3A50%3BLW%3A250%3BL%3Ahttp%3A%2F%2Fwww.audiokarma.org%2Fforums%2Fimages%2Fmisc%2Fak3dheader2.jpg%3BS%3Ahttp%3A%2F%2F%3BFORID%3A1&domains=www.audiokarma.org&hl=en&q=ba-3000&sitesearch=www.audiokarma.org

I am going to be in the wind soon so I won't be here to hold your hand.
There is a thread running about an extensive restore by a member that may help a lot.

showthread.php
 
I'm not sure how to find the pass thru (vias) so i can verify if the model i have needs to be modified. Maybe someone can mark a photo because right now i don't have a clue. I feel dumb asking this but what the heck is a vias
 
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The board between the heat sinks on the power amp " Bricks" is a double sided printer circuit board. Sansui used a rivet kinda delio ( feed thru ) to jump from side A to side B. Due to heat ( expansion ) Cooling ( contraction ) these rivets loose connection from A to B ( which is a BAD THING) . The fix is easy, suck out the old solder, get a little chunk of wire and solder it to the side A & B for a better connection… Voila~
 
Thanks vigman by looking at the photos from the thread suggested by blhagstrom i got an idea what i'm looking for when i get that deep into it. I plan on posting some photos so everyone can see the condition and any thing that looks like it has been replaced before i start messing with anything.
 
Thanks vigman by looking at the photos from the thread suggested by blhagstrom i got an idea what i'm looking for when i get that deep into it. I plan on posting some photos so everyone can see the condition and any thing that looks like it has been replaced before i start messing with anything.

That's a great idea - we LOVE pictures and, harness the collective power of AK's eyes around the world to help you. :thmbsp:
 
The Sansui feed thrus (vias) look like an eyelet set into a solder pad, 'cause that's what they are. The first thing to do is test all the output transistors. The fuse blew for a reason. Do not power it up again until all bad parts have been replaced.
 
The first hurdle is to get to the outputs and boards to look for the vias.

You need to remove the amp "bricks" and open them up to even get started.

Bad vias are pretty easy to notice. Good solder joints are smooth "blobs". Bad solder joints have some kind of lines, as in cracks or in the case of vias, a circle where the rivet outline can be seen in the blob of solder.

NOTE, you CANNOT just touch up the solder and call it fixed. That will work...for a while. The rivet tends to come loose on both sides and soldering on one side does not fix the other side. Soldering on each side still doesn't get it because the joint doesn't re-flow right on both side properly. The hot solder tends to flow back and forth through the via and you start to get a blob growing on the "other" side.

Its best to find them all and do it right.

Now before going after all that. Check the power supply closely. Search the threads here. There are some big resistors on the power supply that may have gone south on you. There is a bit of info in that beginning of the long thread linked here.
 
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