Buying Used QRX

Buying a used 9001

I get a lot of questions from people about what to look for in a used 9001.  After working on a bunch of them, here are some suggestions.

First of all, let me tell you about the nicest, best condition 9001 that has been through our shop.  Everything on it worked, even all the quad switching.  This 9001 was a one owner unit, that had been sitting and getting used in the owner’s living room since new.  And here’s the interesting part, the owner lived in Tucson Arizona.  Low humidity, and because of the heat and subsequent air conditioning, fairly constant temperatures.  All the dial lights were good, none of them turning black, which means that it was used when listening to music, but not turned on and left on for days at a time.  Internally, there was no corrosion of any kind on the chassis.

So here’s a list of attributes to look for.

As little corrosion on the chassis as possible.  As mentioned above, this comes from being in a high humidity environment.  Sadly, the real problems with humidity come when the 9001 stops getting used and sits in the basement or the garage for years.  The corrosion tells the story.

If you can play the unit, the more functions that work, the better.  I would be more concerned with scratchy controls, as that kinda relates to the humidity problem above.  That can be fixed, but you’re looking for an excellent unit.

And of course everyone cares about the cosmetics, how it looks.  I would be most concerned with the front panel, as you would be amazed at how nice a wood cabinet can look with very little work.  Knobs and buttons are the hardest thing to get when they’re missing, especially those little button caps that pop off and fly across the room, when the glue dries out.

If you’re technical, measure the outputs for offset.  Put the unit in 4 ch mode and measure,  even if the unit is in protection (measure at the headphone jacks), if the outputs are less than a few hundred mv, then the outputs are probably ok and will come back with the simple chore of changing out the fusible resistors.

If you’re going to restore it (hopefully have us do it), don’t worry too much about missing channel outputs that move around and are intermittent with the quad function switches, or the dolby switches.  These are cold solder joints on the double sided board and will get worked out when that board is pinned and soldered.

Not much to go on, but I hope it helps

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