Can't get Allen Screws loose on SX-1050

jeffpaletz

jeffpaletz

AK Subscriber
I picked up a Pioneer SX-1050 which needs a Deoxit treatment. I can't get the allen screws loose. The Allen wrench I use in my other SX-1050 doesn't fit the allen screws in the SX-1050 I just picked up.

The one I just got is a multi voltage unit 120/240 and also has 3 different FM deemphasis settings on the back.

Any idea how to get the allen screws loose?
 
Register to hide this ad
Are we talking knobs or somewhere else? First, you need to get a tight fitting hex key, and there were a few odd metric sizes used that are hard to find unless ordered from an industrial supplier like MSC, McMaster-Carr or Travers Tool. Once you have a tight fitting hex key (Allen is a brand, even though everybody uses it as a description) it sometimes helps to grind the end square and sharp. That should be routinely done when used wrenches get a bit rounded. Use a bit of WD-40 or other penetrating oil and let it soak on the threads for a while. Finally, use the tight fitting hex key and hope you don't strip the hole! Any efforts with the wrong size hex key will prevent the screw from ever coming out. I'll admit that in a pinch or when a screw is already rounded a bit, I've carefully ground down each flat on the next size up to get a tight fit, even tapering them a bit so they bite in to what's left of the hole. Still, you're way better off with the correct hex key.

If we're talking hex drive button head screws, those are a PITA. I usually end up cutting a slot with a Dremel and cutoff wheel, then removing them with a standard screwdriver. They get replaced with something more sensible.
 
Last edited:
jeffpaletz said:
I picked up a Pioneer SX-1050 which needs a Deoxit treatment. I can't get the allen screws loose. The Allen wrench I use in my other SX-1050 doesn't fit the allen screws in the SX-1050 I just picked up.

The one I just got is a multi voltage unit 120/240 and also has 3 different FM deemphasis settings on the back.

Any idea how to get the allen screws loose?
Click to expand...

Most likely 1.5mm or 2mm allen.Got my allen drivers at Mcmaster-carr.
 
Once you get a good fitting wrench, heat the knob with a paint gun or hair dryer. The expansion might be enough to free it up.
 
All very good and sensible tips. :thmbsp:

One thing to bear in mind if purchasing hex keys; they're available in flat end or ball end versions. Flat end is the way to go for maximum engagement. Ball end is useful if you can't gain access to a fastener straight on and need to tilt the wrench to reach the fastener. Ball ends can be handy in a pinch but should only be used as a last resort. If I were working on any piece of equipment where stripping out a fastener would be a major headache, I'd sooner cut and shorten a flat hex wrench than use a ball end. They're cheap wrenches and easily replaced.
 
Last edited:
It is the tuning and volume knob hex nuts that I'm trying to remove. I'll by some hex keys today. If I can't get the right size I'll try sanding one down. That's an interesting idea I didn't think of. Thanks.
 
In the meantime, get some penetrating oil in there. The longer it soaks in, the better your odds.

The BEST you can buy is a product called Kroil.
 
Kroil is the best you can buy, WD40 in fourth place, PB Blaster in third, Liquid Wrench in second much better than the former two and close to the first place Kroil, but the 50/50 mixture of Acetone and ATF was considerably better than Kroil.

But that mixture is not available to buy it must be made.
 
Local hobby shop usually has a selection of good Allen metric tools, used to wrench RC equipment.
 
"Kroil is the best you can buy, WD40 in fourth place, PB Blaster in third, Liquid Wrench in second much better than the former two and close to the first place Kroil, but the 50/50 mixture of Acetone and ATF was considerably better than Kroil. "

Interesting. Also interesting that LPS is not on that list. It is MILSPEC and all y'know. It (LPS-2) actually works well on pots and switches but you need to rinse it out with something residue free. I used to use a TF type spray to do that until people got the ozone scare and decided to make money on it like global warming. (both are true but we can't do anything about it so they just gouge our wallets for the "cause")
 
Note LPS-2 is not a penetrating oil. I think you want 3 for that or something. And I think PB is better than Liquid Wrench but then maybe I just worked on diffeernt thinigs than you.
 
LP-1 is the penetrating fluid. LP-3 is a corrosion protection spray film.
If you can get a good lock/engagement in the screw the combination of the Kroil or Mouse milk and MTF's suggestion of heat, should get it.

The grub/set screw may have been changed over the years to a standard size.

The knob can be removed (An alternate method, I think? I'v done it on other Pioneer sets.) by loosening the set screws on the weighted flywheel and pulling the tuning knob out through the glass front (Stem and all). After loosing the set screws, grasp the knob and flywheel. Begin twisting in opposite directions while pulling it apart.

Restringing would be required with this method.
 
Last edited:
In case someone reads this thread looking for the correct size, get a 1.5mm hex key. It is a perfect fit, both in the Pioneer SX-1050 I fixed up to sell and my own Pioneer SX-1050. 1.5mm is a perfect fit in both of them.

I got one at my local Ace hardware store for a total of 79 cents. Having the right tool makes such a difference. No need at all to spray anything into the knobs, I just needed the right size tool.

I spent part of the day cleaning the pots with Deoxit Faderlube and switches with Dexoit so this receiver sounds great. I love the deep bass these Pioneers put out. As soon as I get new dial lamps I ordered from dgwogo this one will be ready for sale.
 
i just went through this on an overseas 850. all the previous posts are completely valid. i would add that my knob on the tuner was either super glued or loctite fastened as well as the set screw. i was not the first to attempt removal as the socket on the set screw was already mostly rounded out. i used a propane torch to heat the knob. if you do this keep the heat away from the glass! i eventually got the screw to move but it finished rounding itself out before i could get it out. having some cobalt drill bits i drilled the setscrew out clean through. it was then i discovered that the shaft was was still firmly wedded to the knob! i removed the capstan end of the shaft and that was difficult as it was gooed with some sort of loctite as well. this allowed me to extract the shaft through the front with the knob . thank god they didnt loctite the the flywheel as well! i then held the shaft in a vise and further heating with the torch , a rag around the knob and a pair of channel locks FINALLY alowed me to remove the knob! all this screwing around took 4 hrs. when the time comes to reassemble i will re tap the drilled out screw bore to 6-32 and put in a new screw. BE WARNED that good quality set screws can be case hardened and impossible to drill. the stock screw ISNT. i realize you solved your problem. i threw this in so others might benefit from my tedious experience.
 
I said to myself when I first read this thread: He's GOT to know the standard size is 1.5mm, and when I saw Avionic's post I figured if you didn't know, you would soon, and that the problem was with a messed up 1.5 mm hex socket in the "grub screw"...

We have said the 1.5mm hex is the one so many times I couldn't conceive of anyone with a few years and a few hundred posts not seeing that...

:sigh:
 
Yeah, I thought the one I had was correct since it worked in my receiver. I didn't know the correct size was 1.5mm. Apparently the one I had was a little big so it didn't quite fit the receiver I just got. At the hardware store I brought the one I had that didn't quite work and got one just slightly smaller which turned out to be 1.5mm.
 
You must log in or register to reply here.
Back
Top Bottom