I found this Sansui 1000A receiver at a garage sale. I was pretty much :banana: before I even got out of the car.

Now that I've got it home, I've determined that it likes to blow a fuse whenever it's powered on. Peering under the hood, there is definitely one blown cap, and possibly some blown tubes. I don't know diddly about tube gear, but I'm guessing a darkened/burnt-looking top indicates the tube is no longer good, correct?

Would a blown tube or capacitor be enough to make the whole unit blow it's fuse when turned on, or is that more likely a problem with the transformer or other piece of the power supply?

I'll get some picture up after church :smoke:

Other than the 'issues' and the need of a good bath, this unit is in fantastic shape, with no dents or missing knobs, so I'd love to get it working. My cousin manages a high-end audio store that I'm sure could get it running, but that could be a spendy path so I'd rather tinker myself first.

DON'T plug it in again. Powering up old tube gear after it's been sitting around with caps going bad is likely to create more problems than you can fix by just replacing a bad cap. You're going to want to have it serviced or prepare to get acquainted with repair procedures.

I can't tell without a picture, but your tubes are probably looked like that when they were new.

Get a variac before you cook any more good components, shorted caps are cheap to replace in and of themselves, but shorted caps can also destroy tubes and transformers that otherwise would have likely lasted another 40 years.

I'm just a tube novice/beginner, but i understand one of the cardinal rules is NOT to keep putting full AC line voltage to an amplifier with known problems, it just makes the restoration that much more extensive and expensive, unless you fry the power tranny in which case you can just move on to the next piece of tube gear.

Just my .02 y'all understand....................

I am not a teckie type, but I do know that what winters860 said is VERY important. Your 1000A needs some love and repair before it will be ready for plugin. You sure don't want to toast the OPT.

When it gets the love it needs, you will have a great old tube receiver. 40 watts per channel too. Very nice tuner and the phono sections are very decent. Take your time and get it healthy and then enjoy.

When you powered it up, did you have speakers attached?

Oh, and don't open it up and go poking around in there unless you know what you are doing. That thing can put a major hurt (if not kill ya) on ya.

It is certainly possible to restore your own piece of tube gear but you'll need equipment - soldering station, digital volt meter and variac (could be the homemade version) - at a minimum. Many capacitors, probably diodes/rectifiers and some resistors will need to be replaced with appropriate value/size replacements.

Here's the kicker though. Are you trained or prepared to work with voltages that can be lethal even after the unit is unplugged? Capacitors in tube amps store a LOT of energy and the lethal part is not an overstatement or joke. Restoration is definitely possible to do but it will take time, study, and care on your part. If you are doing this to get into the audio hobby and will be doing more pieces in the future, it can be fun but if it's a one shot deal, pay someone. If you still want to try yourself, then get a schematic, start studying it and start searching/reading on here about what people do to restore a tube amp.

The oil coupling caps in the 1000A are always bad at this late date. You may well have other cap problems, too.
The dark tubes may be just fine; but you can be sure they've been run long and hard.

Bravo on your new find!:thmbsp:

The 1000A is one sweet receiver, clear out all the bad caps, check the tubes and do a fan mod. and you are good to go (mine has been going for a year now with no failures).

The Sansui 1000A is not the "best" starter project for an electronics "beginner" but it can be done, but you have to proceed slowly and pay special attention to the high voltages present, you must "learn the ropes" by reading all you can on tube gear safety before you "go in".

As for replacing capacitors (mandatory for the oil filled caps.) you may employ what I like to call the "clip and hook" technique, that is just cut the lead(s) of the old capacitor near the caps. body and form a hook in the lead(s) still going to the receiver, then position your new cap. in the open space, form hooks in the new leads, hook them together, solder the junctions and clip the excess leads (hold onto the free end, they tend to fly!)

You now have a good mechanical\electrical connection for the new capacitor.

This method does not look as neat as a more "purest" way of cleaning the terminals the caps. go to, but avoids the strain to possibly brittle terminal strip connections and is a little faster in connection.

I will leave the choice of common or "exotic" types of capacitor to others, but get the uF value as close as you can, and don't go below the Voltage rating, higher is OK.

These are just some overall tips for the broader subject of tube equipment restoration.

mark T.:music:

And the tubes are most likely good.... the "burned look" could be a lot of perfectly normal conditions.

John

If you can find a good tech who can work on tube gear that may be the way to go. A good tube guru will explain what the problems are and tell you how to maintain vintage gear properly. You can also reverse engineer some of his work. It will probably need an fm alignment which few hobbyist can really do anyway. If you have a basic understanding of electronics then you may see if he will get it working reasonably well for you then replace the rest of the critical parts yourself, that will save you some labor costs. Also some of these repair places can take a while to get to your unit which can give you time to save money for the repair costs. I went that route years ago and have been restoring all my gear myself, though I'm still far from an expert. I rotate two tube receivers in and out of my system, (Scott 340B & Fisher 400) they can sound jaw dropping good and the 1000A is supposedly one of the best, I would love to have one of my own in my collection.

Thanks for the input, guys. I've decided not to touch anything myself. I'll get my cousin's shop to look at it when I save up some money. Tubes scare me a bit, so I'll probably stick to my Model Eleven II for the present.

Pictures as promised:

http://img220.imageshack.us/img220/7606/sansuiaqr4.jpg
http://img140.imageshack.us/img140/2360/sansuibfu4.jpg

Where are you located?

Wicked receiver!

Are you talking about the silver tops as being "burnt" ? If so, thats perfectly normal. Its from the getter action, and they look like that when brand new.

Looks like you have a late edition there --I'll bet you have the 4 pot model for adjusting the bias on each output tube.If so you've got a keeper.
What is that added switch between the power and balance control?
Can you post a picture of the underside?
James ------And I do love my 1000A - wouldn't trade it for anything.:yes:

Looks like you have a late edition there --I'll bet you have the 4 pot model for adjusting the bias on each output tube.If so you've got a keeper.
What is that added switch between the power and balance control?
Can you post a picture of the underside?
James ------And I do love my 1000A - wouldn't trade it for anything.:yes:

The added switch is labeled "speakers"...I assume to cut off the speakers when you want to use the headphone jack below it.

Here's a picture of the underside. Is there something unusual about it?

http://img90.imageshack.us/img90/5202/sansuicpo6.jpg

I think the switch he is referring to is the gold deal below the speaker switch and to the right of the power button. On my 1000A that is where the headphone jack is.

I think the switch he is referring to is the gold deal below the speaker switch and to the right of the power button. On my 1000A that is where the headphone jack is.

Ah, there is a gold-plated adapter there to plug in headphones with a mini-plug.

The "gold switch" is nothing more than an adapter for 1/8 stereo headphones like Walkman types for use in a 1/4 inch standard sockets, it can be pulled out for a 1/4 inch jack use.

As for the bottom view, I think we wanted to see the wiring as this is the clue as to the vintage of the unit and the number of bias pots used to adjust the output tubes operating points.:yes:

Not stealing anyones thunder, just wanting to help!:thmbsp:

Mark T.:music:

Thanks Mark -------------Yes I want to see the underside guts with the bottom off.
But looking through the cracks --I believe you have a 4 pot unit. James

Echoing what Gadget said. Lots of "miniature" type tubes (the smaller-sized ones in your receiver) have a darkish silvery coating on the inside of the top of the tube called the "getter" which maintains the vacuum inside the tube. If this coating appears white or gray, the tube has "gone to air" (lost its vacuum) and is bad.:yes: You can tell on "octal" tubes (the larger ones with black bases) if the tube has been heavily used by looking at the top. If there is a small silver spot, the tube is hard-used.:yes:

Awesome score, BTW. Hope it's running nicely soon!:thmbsp: