Vintage PROTON AI-3000 Stereo System All-in-One Take Two! Er, Three!

February 9, 2018

#231

Gentle reader,

Some time ago, I purchased a PROTON AI-3000 all-in-one stereo receiver. It, to my knowledge, was the most expensive (1989-1990) system of it's type, retailing for $1,300 which included two bookshelf speakers. These units themselves are slightly narrower than the standard 17" and extremely heavy! The majority of them are missing a door that covers the controls that span most of the bottom front of the unit, as seen below.

(The photo above, is not mine, but was found with a Google search. If the person who made the image wishes credit, please let me know.) Covers are removed. There are a pair on eBay right now, new still in the box. They appear to be of high quality.

 

The seller listed the first one I bought as a 3000II. I had written about this previously here:

Trying the minimalist route: PROTON AI-3000 II All-in-one Stereo Reciever and NOTHING ELSE! It was a bargain priced $69.99 with free shipping. What could go wrong? Someone along the shipping route had dropped the box, resulting in bending the front/left bottom corner. Plus, the CD player has "ERR" when trying a CD. The seller quickly refunded the full amount and I found another one, this one a proper series II for $99.99. Plus, that stated everything worked. It is seen below:

As you can see, it is in a lot nicer physical condition than the first one. Also missing the panel, but for a fully functioning one, I could live with that. After a time, CDs started skipping. Not all CDs, but most. I cleaned the laser, to no avail. See the very bottom of the article to see what else went wrong.*

There are two differences I can determine between the original series and series II. On the front, the type of CD transport/tray is different. Below is the original type:

These original series units have a door similar to what a lot of PCs have that flips open, pushed by the CD coming out, the tray itself is thinner too, top to bottom.

The other difference is on/in the back of the units. This is the original series. Note the are of the back between the AC plug socket and round fuseholder is flat with slits in it? Better seen below:

The back on the series II has a large protrusion and the AC plug socket is directly next to the fuseholder and AC power cord, as seen below. Inside is a much larger AC transformer than the original series has. Thus the "bump-out".

CD tray is one piece in series II as seen in these three images. One piece and much thicker.

So what happened after the CD player started acting up was this; I have long been watching eBay looking for a PROTON DC player. They are highly regarded and sought after and thus do not come up for sale often. To my surprise when I looked that day, there were TWO on eBay! One was newer and fancier and more expensive than the other. The less expensive one had somehow had most of the black anodizing rubbed off the face plate. He wanted $99.99 with free shipping AND it had the remote!

Here it is in all it's funny looking glory. It has the same time of CD door/tray as the original series AI-3000 units do.

Interestingly, it's model number is AC-300II. It must have been Karma that I found it. Even better it is the exact same width as the AI-3000II!

Strange that the play button is red and stop is tan. Counter intuitive.

More strange is it has a heat sink (black thing with fins) on the back of it. I've never seen that on anything that does not have a power amplifier. I opened it up and sure enough there is a transistor attached to it. Heat sinks are made of aluminum and excellent metal for heat transfer. They take the heat generated by the transistor and it flows through the heat sink into the air, thus cooling the transistor. The fins are for more surface area for cooling.

The larger fins above are for the power transistors in the amplifier on the AI-3000 units. On the other side are four transistors screwed to it with white heat transfer substance applied to insure the best conductivity.

See, the white stuff below? That's the heat transfer goo. I can't recall the correct name for it. Oddly, the transistor to the right appears to be exactly the same, yet it does not need a heat sink. 

But all this is HISTORY, building up to the present. I still wanted a fully working AI-3000II. To my delight, one showed up on eBay listed as fully working AND it still had the door, but it had issues. The door, not the rest of it. Better yet, $99.99 with free shipping! Bought it, I did. Weirdly, it took 14 days to get to Virginia from Florida! Poor mail carrier must have literally carried it the whole way! Poor guy.

Whatever device(s) that secured the hinges to the receiver are missing. By looking at it, I realized a couple of black wire ties might do the trick. And they do. It does not open fully, but I can still reach the controls just fine. Oh, and it had that cassette in it. I'm listening to it now and it has Tom Scott and Steely Dan on it. Right up my alley!

It was so dirty inside and out, especially inside the cassette well. A lot of time with rubbing alcohol, cotton swabs and paper towels cleaned up everything. At least I thought so until seeing these pictures! I also cleaned the cassette heads and transport equipment and demagnetized the heads. I also cleaned the CD laser. As advertised, everything works! The rear views:

Below it sits where the previous two did, to the right of my PC. That watch is solar charged Seiko, thus the window placement. Oh! Also on top is the icing on the AI-3000II cake!

Taped to the outside of the huge box was.......wait for it, the owner's manual! I've had a watch on eBay for the manual and the remote. But the former never appeared. The latter did, for $25.00, so it came here, too. Seen further below.

This remote is different from the multitude of remotes I have had. It is comfortable to hold and easy to read and use. Below, note how the front folds down and the narrow battery compartment underneath? Plus the sides are rubberized so it is easier to hold. In profile, which of course I forgot to shoot, the transmitter window points downward at about a 15 degree angle. It allows one to hold the unit comfortably and I really like it.

So, there you have it. Third time IS the charm in this case. *OH, I forgot the OTHER reason I had to get a third one! On the back of these are "PRE-OUT" RCA terminals which can be used to supply a subwoofer or a second power amplifier. When the previous unit was OFF, I was trying something out, that was attaching the really vintage SWTPC power amplifier to the Series II. When I touch one RCA cable to one of the plugs (below) a spark jumped to it. After that, the darn thing would NOT turn on! I'd forgotten about that. Thus, the need to get another AI-3000II unit. I opened it up and checked all over for a fuse, but it remains a mystery.

I plan to put the original unit back on eBay clearing explaining the inoperative CD player. And I will keep the PROTON CD player, just in case. Plus, as I wrote, they are RARE.

Thanks for looking,

Scott

February 9, 2018