Technics SA-1000 repair/refurb started!

rBuckner

Luv 2 Restore
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Hey Big Watts fans, I started this project a couple of days ago. Here's a size comparison, this guy is huge! It was 105 pounds all packed up. It is 25" wide by 19" deep by 7-1/2" tall. It will do 330 watts per channel.

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The inside views, the 4 main filters were already replaced, the old ones had leaked out and did some corrosion damage. I'll likely add some "meat" to the fix already done.
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The issue was smoke followed by no audio. Before I ever powered it up I checked all 12 output transistors. Brought it up via a DBT / variac combo and all seemed well for about 30 seconds then the bulb went full bright and a wisp of smoke appeared. It led me to the source which was on the pre-driver amp board. There are two traces burned open and a good sized burn spot.
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I dug out the burned board section and checked all the semi's on the board, all were well. I replaced the only two caps on this board and the other channel's as well. I ended up cutting the traces all the way back to the pads and running insulated wire, tacked down with epoxy. I also replaced two other caps for each channel on the driver/output boards. They are very swollen and one lead was corroded out.
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This time the DBT power up was sucessful. With much bravery I started it up and the front panel lit up and I got that satisfying "click". After checking the DC level of the output terminals I plugged in some headphones and got audio. Today I hooked up some test speakers and gave it a bit of a workout. There's a fair level of hum going on with both channels, probably some bad cap(s) in the power supply. It's on the pre-amp side for sure.

I had already washed the chassis two weeks ago when I first got it and now it's on to a total recap. Also it will get a detailed cleaning and some experimenting to see if the main lighting will convert to warm white LED. DeOxit treatment will be done as controls and switches are exposed during the recapping. There's 11 toggle handle switches on this model!

More to follow as work progresses.
 
What, you fixed it already? I was looking forward to an adventure here. Man, this thread went out with a whimper. I would've preferred a bang... a literal one. ;)
 
He he! Well, it still has a pretty good hum out of the preamp end to get fixed.

I pulled the tuner all-in-one board to get at the power supply section. That was actually pretty easy as they made it to do that. The antennas plug in and the other connections are all on labelled sockets. There's still a board in the way that'll need pulled but needs to be anyway for recapping and DeOxit fun. So far this is easier than the Marantz 2500 to work on but there's plenty to go! :D
 
Wow, first time I actually see someone working on the nec plus ultra power receiver:ntwrthy:.

One could say this is the ultimate receiver ever made, but I would even go further than that; it's the most ultimate receiver ever made :).

I wish I had one, that's for sure.

I'm not surprised those caps have passed away, my experience is that these old Panasonic caps are prone to overheating damage and I guess the 1000 can get rather warm inside. I repaired an 8099 some time ago (it really became a complete overhaul); over 50% of the electrolytes were either out of spec or completely broken.

Good luck with this machine, it's worth it (but I guess you know :)).
 
Good luck on the refurb/repair :thmbsp:
Sure is a monster.. I'd give my right arm for a SA-1000.
 
@Daunia70: Sold! How much to ship your arm to the western part of the USA? :D BTW, hope you're healing well Paul. :thmbsp:

@just dave: The front is very good, the cabinet okay, you can see some marks in the first photo. Surprisingly (to me) the cabinet in vinyl clad, not real wood. If it were mine I'd be making some solid wood side panels and do real veneer on the top panel.
 
Note that there some adjustment pots that need to aligned before you put the tuner assy back in, power meters maybe? It's nice that it comes so easily as I'm sure it will in and out a few times before you're done.

Craig
 
that thing is huge

what is written on that caution sticker

oh wait i can blo the picture up
 
Thassa good one BKR!

OK, got more work done last weekend. Spent some time cleaning the boards and chassis off some more after these pictures.

Here the tuner is removed, it was really easy to do.
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I thought it wise to tape the arm on as it slides right off.
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This is where the tuner arm goes, into the two circular holes. So the tuning cord stays in place.
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So here's what you can see now. The switching board needs to come out still.
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There's a heat shield and likely there for hum shielding too. Note the heat marks from the hot stuff below it. It took a bit of work cleaning the board below it.
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The switch board hanging out after it was unfastened. I removed the three wires (after taking notes!) and set it aside. Then I could set it up on it's side to recap that lower board which contains the power supply and some preamping circuitry.
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There, now it's accessible!
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Much of the board is now recapped and I'll finish it this evening. It's really not bad at all to work on so far! The manual is very helpful on how to remove the major boards and assemblies. What was REALLY nice was that the owner printed and bound me a large print version of that manual and some blown up schematic prints separately. That was VERY appreciated!! :thmbsp:
 
That is one bad*ss tuner board! Nice to see you are making good progress, I hope it sounds great.
 
Last night the recapping was completed on the board I had started. I didn't have some of the values but pulled the parts anyway, marking the value and polarity.
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Here it is from the top, partially done.
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Here's the speaker switching control and power meter buffer, old caps still in there. The actual speaker switching is done with relays at the back of the unit, like a Marantz 4400 and it's kin.
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The tuner board was the project of the evening along with spinning some vinyl on Mr.Jones' refurbed 2230. I noticed almost as soon as I started the smell of cigarette smoke. The owner had noticed an unpleasant smell to the unit and I bet this was contributing. It also explains the yucky yellow-brown gook on the bottom of the tuner and on top of the power supply section. I'll be takinh the tuner section and that loose switching board to work for an alcohol scrubbing tomorrow!
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We're having some bedrooms remodeled soon so this last weekend was move out and teardown time so this project was on hold. Tonight I had two more caps to change - manufacturer mods with parts in the air. Over the weekend I actually did soak the two (easily) removable boards in some alcohol and got the flux and cigarette gook off. Here's some pix of the fun I've been having!

These two resistors are 18 ohms 1/2 watt and measure okay but got overly toasted.
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I got some 1 watt parts and raised them off the board maybe 5-6mm with some tubing.
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Here's the tuner board soaking. I had to keep flipping ends and scrubbed with a toothbrush each time.
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I spent some time this evening looking for two different shapes of LEDs to no avail. One shape is for the function indicator board and one is for the power meters. The yellow ones in the power meter are barely visible any more and the others are just dull anyway. LEDs degrade over time and will eventually fail so I wanted to replace them all. Looks like I'll be turning some T1-3/4 LEDs down on the lathe! I'll post what I end up doing.
 
You are undoubtedly aware, but just in case, hopefully you didn't get any liquid into the coils. If the tuner section is wonky after you get it hooked up again that could be it. It doesn't take much...happened to me once.
 
Thanks "39". I did get them wet and usually do. I blow them out very well with compressed air and let them dry several days and never had a problem. There's always a first time though!
 
I took a look at the LEDs with replacing them in mind. I think I have a plan on the function indicator board. The idea is to take a T1-3/4 LED and chuck it in a small lathe and turn off the base flange so it can be chucked the other way around. Then turn the lens end down in diameter until it fits the front panel holes. For the heigth to work out the pc board will need drilled out which will clobber some traces. They can be redone with wire or buss wire. The LEDs would insert from the back and be glued in, taking care to get the heigths even. I e-mailed the owner for his input on the colors as to wheteher they are to be the original clors or switch things up a bit. Unfortunately he is out of the country this week so I may not get my answer for awhile.

The LEDs need to be diffused type so that limits the color choice somewhat. I suggested for the functions: SAFETY-blue, AM-red, FM-orange, PHN1-yellow, PHN2-green, AUX-yellow and STEREO-red. Sound cheesy? Any suggestions?

Here's the function board, the lone green LED is SAFETY.
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Weird LED package
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Turned down T1-3/4 LEDs
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Front panel section
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Power meter display board, again a weird package! I suggested to the owner to maybe limit the red ones to 1-2 and add to the green ones or maybe one additional yellow one as well.
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Front panel power meter scale with the highest range's watt values on the bottom. Better watch it if you're banging the "700" LED much!
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