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SX-950 1050 1250 Selector Switch Assembly rebuild

HairySatchel

HairySatchel

Active Member
I'm seeking words of wisdom in regards to switching out the old switches on the AWS-094 and AWS-095 boards. They no longer stay engaged. Has anyone tried to use a modern 6PDT and similar as a replacement? Which brand works best with the least amount of modification?
SX-950 Input Selector Board

SX-950 Input Selector Board

AWS-094
This is the board in question
Sx-950 Replacement Switch

Sx-950 Replacement Switch

This is a possible replacement candidate.

Thanks everyone.
 
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You are apparently unaware of the mechanical interlock which holds the selected switch in, and pops the others out.

Faderlube the front metal channel where the transfer bar resides, in the front of the switch.

WATCH OUT for the spring!!
 
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markthefixer said:
You are apparently unaware of the mechanical interlock which holds the selected switch in, and pops the others out.

Faderlube the front metal channel where the transfer bar resides, in the front of the switch.

WATCH OUT for the spring!!
Click to expand...
I am aware of that. But I'm also aware that when they get worn out they do not stay fully in the "in" position thus causing dropouts. It a known issue with these switches.
 
Interlocked switches? Well known issue? Pioneer? News to me. I was a Pioneer dealer tech in the late 70's and have kept up.

Been on AK for 12 years.Never stopped working on Pioneer gear, that's what, (YIKES!!!) 40+ years.

The switch issue that DOES come up is the push, push NON-interlocked switches on the RG and SG processors.
THAT is a completely different locking mechanism. And "our" banzerg has that covered. On AK and on eBay.

Now don't mistake my skepticism for disinterest, I looked at the thread title and momentarily HOPED you had found something compatible WITH the interlock mechanism and was modern - because modern means that gold contacts could be obtained. I would LOVE to be able to just BUY switches and install them on a refurb job, instead of removing the originals, disassembling them, cleaning and then ultrasonically chemically cleaning them, and then reassembling and reinstalling them. If I could get gold contacts (even if I had to shell out some heavy bucks for a minimum "not stocked" order quantity) that would be fantastic because almost ALL of the switching in these models is of a low enough current density to allow the gold contacts.



HOWEVER, there always IS a first time - and if yours fails to stay in -
after a thorough cleaning and mechanical inspection for any other reason, it fails to stay in.

I undoubtedly have these switches in my spares boxes, would you be interested in a trade to get yours working? Or a loan of your failing switches for a thorough engineering analysis of what is amiss?
 
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Thanks Markthefixer. I appreciate the condescending tone, followed by an arrogant filled lecture, possible solution, then generosity. But no thanks, Your'e attitude has spoiled it for me. I'll just go back to EEVblog were I belong.
 
Relax Hairy,
Just they way MTF works.

for your interlocking switch I say to try spraying the heck out of that switch with contact cleaner. It is not the actual switches that are causing the problem, it is the interlock mechanism that needs to be taken apart and figure out why it is not latching if cleaning does not work. if you can not figure out why the latching is not working, then you will have to get the parts from another unit or just a new assembly.
 
The way MTF works is when he steps on someones toes with a brain fart, he apologizes.

What I had on my mind was if I just expressed skepticism about what I thought was a very rare fault, I would anger you.
The response I typed would not have angered me, but then I suspect that I have an un diagnosed case of "Engineer's disease", also known as the Spock syndrome. Sometimes I get so wrapped up in the facts, I forget what type of feelings they can invoke. It can be said I am "poorly socialized".

HairySatchel, I apologize, unreservedly.

I should have said something like:

In my 40 years of extensive Pioneer experience, I have never encountered a fault like that.
There is always a first time.
As such, it would be valuable to me, to be able to deep dive into the whys and wheres of the fault that is occurring.
If you want to KEEP the bad switch assembly, could you LOAN it to me for examination.
Or I will trade you a good switch assembly (straight up less postages) for your malfunctioning one.
 
HairySatchel, are you 100% sure it is the switch and not the alignment with the front panel aluminium buttons and the captive springs? The switch PCB must be carefully installed to centre the switches with a test fit of the front panel. This should be done for each switch bank.

That, along with the lack of lube in the self-cancelling slide mech that MTF spoke of will give you headaches.

The springs on the aluminium buttons are IMO installed by Pioneer the wrong way around. They are tapered and the wide end should be installed against the panel with the narrow end facing the switch shaft. That way, the wide end, never gets caught under those nasty little retaining clips that 'stick' the button in a depressed position.

I too, have never seen a self-cancelling switch bank mechanical failure apart from a snapped off shaft.
 
restorer-john said:
I too, have never seen a self-cancelling switch bank mechanical failure apart from a snapped off shaft
Click to expand...
I have one doing the same thing on a HP 5316A freq counter, it is a bitch to take apart. I think it is from extreme moisture getting in there corroding the mechanizm. I bought it used on ebay of course :-) but for $100 it is a good deal since it has the 1GHz prescaler option. I sprayed the heck out of it, it freed it up a bit but it still manages to not latch in a few positions, it has more gangs than the pioneer one does so that makes it worse.
 
Old thread, I know, but I rarely let that stop me...

My symptom is that one channel gets very low volume periodically. Pressing the function button ALL THE WAY in solves the problem temporarily but often when I let off it goes back to low volume. It is fiddly and sometimes requires multiple presses.

Does anyone have experience with this issue?

Is there a reliable fix that doesn't involve replacing the entire board?

Thanks.
 
hopefully this time I don't offend someone.

This assumes that you have deoxited the switches in question. If not, deoxiting is the FIRST step in just about anything.

Deoxiting plows a clean path through the Deoxit loosened corrosion, which then the sliding contact that floats in the center shaft recess can jump out of with mechanical shock.
Which means that taking the deoxited unit off the bench, OR shipping, can undo the deoxiting.
So I remove the board, desolder the switch from the board, and disassemble the switch - then use an eraser to polish the blades in the body of the switch clean.

Over the years I have gotten pretty good at disassembling them, cleaning them and successfully reassembling them.

One MUST distinguish between the model years, the xx50 series switches can be mechanically polished,
while the xx80 contacts are shrouded and pretty unreachable so I remove, partially disassemble and ultrasonically clean them with a custom cleaning solution.
 
Mark, through the years I’ve been hesitant to ask about this custom proprietary solution. Maybe a clue?
Have you been reluctant to share due to the combustible formulation? You didn’t want to loose any AK members that have grown to enjoy your Spock like traits? :dunno: :D
 
Thank you @markthefixer for the input. I recalled as I looked at the schematic that though I had made a very crude attempt at Deoxit-ing these buttons, I never got in there due to the board being blocked from the bottom. I was uncomfortable removing the board to access the buttons. Well a few years later and I'm gained some experience on less desirable pieces.

Long story short, Deoxit appears to have done the trick at least for now. We'll have to see if it reemerges, but for now it's solid as a rock.

It really wasn't that tough getting the board out but it did require unbolting two boards and removing the wiring from the holders. Didn't require desoldering anything or cutting any wires.

Thanks again, Mark.
 
Does anybody have any experience replating switch contacts? Gold or silver? I have seen it done in the factory on gold PCB edge connector fingers, it was electroplating with a special solution and what looked like a soaked foam applicator that was one of the electrodes. There are kits available on the retail market for "replating" jewelry. Might be a way to recover switches with worn contacts . . .
 
Gee sometimes I wish I still worked in the plating shop that I did my apprenticeship in as we had all these precious metal baths at our disposal along with copper, nickel, chrome etc.
 
I wish it was easy, but it ain't, they plate in silver for lowest contact resistance, but we know it oxidizes way to easy. Gold is too soft for longevity, it usually requires a barrier layer of nickel. The gold can leach into soft metals like copper. that is the extent of my plating knowledge :-)
 
I have a similar problem with my 1250. The selector buttons have no problems staying pushed in, but eventually my left channel goes silent, leaving the right as the only sound. I have to click through the switches a couple times and then the left channel comes back on and will stay for a good while. Is the solution just a contact cleaning with deoxit? If so does anyone have a link to the best way to dismantle the unit to get a good spray shot at the contacts?
 
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