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Pioneer SX-424 knob trouble.

JRosenb88

JRosenb88

Well-Known Member
I just purchased an SX-424. This is my first vintage pioneer unit, and let me say i just LOVE it's warm sound, it sounds almost as good as my A-35R! The only downside is that one of the lamps is burned out. I read that i have to take all the knobs off... and my selector knob won't come of... any ideas?
 
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I have had luck wrapping stubborn knobs with fabric and then using slip-lock pliers to firmly pull. You have to be careful - go slow... I think there are several other techniques - i think i saw a post that talked extensively about removing face plates
 
I had pliers on it and it wouldn't budge... pulled hard enough to the point where i felt almost uncomfortable. If i pull harder it will probably slide off but i don't want to bust this vintage beauty!
 
I think I read about prying with a wooden spoon.
You also might be able to spray something that will help free it.
I've never worked on a 424 - i have worked on an 828 though and i think its the same (there are no screws on the knob you are talking about - right?)
 
I think you will really enjoy the sx 424. I picked one up at a thrift place untested because of the speaker connections which I modded some spade connectors to fit & every thing worked, lamps were all working and no scratchy pots. I run it thru a pair of baby advents ll. Hooked up in my rv all the power I'll ever need in that space. Haven't had to tear into it yet, keep us posted in case I have to try the same method in the future.
 
yeah - they would be visible from the outside - i don't think it has them - the tuner knob should though.
 
There are NO Screws on any of the Knobs on the 424. Flip the Unit on it's back. Take some old washcloths and put on either side of the offending knob. Then take TWO spoons, and slip them under the knob on opposite sides. Push DOWN on the handles evenly. The knob will pop off eventually. The problem is galvanic corrosion of the brass pot shaft and the aluminum knobs.

Once the knobs are off, undo the 2 or 3 nuts on the front (1/2" or 12mm box wrench), then 2 screws on the top of the face, and IIRC 2 on the bottom.

There is a plate that secures the dial glass to the frame. remove that (2-3 screws), then remove the dial glass.

There are 5 Fuse type bulbs. 8V .3a rating. also the meter takes 1. Either replace the bad ones or all of them and keep the good ones for spares.

Reassemble and enjoy. I've got the 424 and 434 and like the 24 a little better for it's sound, but like the 34 better for it's speaker connectors. Granted i've got all the connectors for the 24, but they are a PITA, excpet when I change to the QX747A or QX-9900, then it's plug and play!

Larry
 
Use a PAIR to lift from each side. Saves from bending the shaft.

I use a pair of plastic "spudgers" with a taper, the plastic preserves the faceplate and knob, and if too much force is used they bend rather than break the pot.

reluctant knobs WITH a set screw are caused by the set screw making a bump OUT on the shaft that has to be carefully filed flat again after the knob is off, and then don't gorilla tighten the set screw afterward.

The last case try for lifting a knob is to use thick string and wind it and wind it and wind it around the shaft tightly, using the leverage of the string bundle under tension as more string is added to force the knob up.
 
the spoon trick worked!!!! thanks larry! now time for an led upgrade! and hopefully i can find some knobs that are in better shape thanks mine!
 
I bought new knobs for my Pioneer and a can of deoxit fader lube to clean up some scratchy pots and i will be buying a full led conversion from haywood and also some of the special speaker connectors. The only thing i don't think i will be able to fix is the tuning rod that connects to the tuning knob is bent so when i turn the tuning knob it spins like a spinning coin does. Anybody know somebody who has a bunch of old pioneer parts i could ask?
 
jRosenb88; You mean the shaft that the knob is connected to is bent? You can remove the whole shaft (you'll need to undo the tuning cord). Once the shaft is out, heat it up in the area of the bend with a Paint heat gun. Then with 2 pair of pliers with rags on them(to prevent scoring of the shaft) on either side of the bend, carefully work the bend out. You won'tget it 100%, but it will be better than it is now. I wouldn't try and do it cold. The shaft has more chance of snapping that way.

The only way of finding another shaft is from a parts donor.

How about a link to "HAYWOOD".

Larry
 
larryderouin said:
jRosenb88; You mean the shaft that the knob is connected to is bent? You can remove the whole shaft (you'll need to undo the tuning cord). Once the shaft is out, heat it up in the area of the bend with a Paint heat gun. Then with 2 pair of pliers with rags on them(to prevent scoring of the shaft) on either side of the bend, carefully work the bend out. You won'tget it 100%, but it will be better than it is now. I wouldn't try and do it cold. The shaft has more chance of snapping that way.

The only way of finding another shaft is from a parts donor.

How about a link to "HAYWOOD".

Larry
Click to expand...

That sounds like it would without a doubt work... but i don't own a paint heat gun of any sort and i have no idea where i would get one. But lots of people on this forum have my receiver and ones like it. I may be able to find a suitable replacement on ebay.
 
What you want is to heat it up. Not red hot but about 200-250* or so. Even boiling it for 10-15 minutes will work. Also a Hair Dryer will work.

Larry
 
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