Pioneer SX-1080 Tuning meter stuck? Need help

[rocknroller]

Picked up this receiver today and other than some bulbs and detailed internal control cleaning it seems to be in great operation with one exception - The tuning meter, which is a dual unit connected as one piece to the signal meter) does not move at all. I see a range of 4-6vdc at the terminals as I traverse up and down the dial, but the needle stays complete upright , dead center, never moves. I thought it might just be "stuck" as the signal source meter seemed to be initially when I turned on, but it is operating perfectly now.

Tried some gentle tapping - no change. I was going to try and pull it out and look at it closer but the second issue I am having is I can't seem to remove it. I took the mount bracket off the back but it simply won't move. It's almost as if there is a screw coming up from the bottom of the dial panel, but the service manual doesn't show any there. I guess it could be glued, but if it is - it is very very strong. I didn't want to force it and risk breaking it.

Any thoughts/experience on how to remove this meter as well as why it might be stuck? Do the voltages seem reasonable?

 

[markthefixer]

Take an ohmmeter reading of the meter, with one wire disconnected, you may get huge deflection, or none at all if the meter has gone open circuit.

One of the pivot points is an electrical contact. the other contact is the hair spring.

Actuation may clear the pivot point, mechanically at first. I have had to go as far as using a bent wire to transfer a hanging drop of deoxit beck to the pivot. Then I set it up on a pulser for a few days, increasing the width of the deflection (which carries it into the dead zone, and back out by spring pressure and inertia) until I had command of the entire meter's deflection range.

 

[rocknroller]

Well the good news is the ohmeter did the trick. It dislodged whatever was stuck and now the meter works fine.
The BAD news is - really bad news - is in my clumsiness with the soldering iron I burned right through the damn dial cord. So F'in pissed. Especially since I was otherwise 100% done with this. Now I have to figure out where to get dial cord, the right length etc , restring this and make sure the tuner marker is at the correct place. Never done that before. What will I break in the process of that.....
But thank you for the tip. Hopefully the dial cord will end up being less cost in the end than a replacement meter!

 

[rocknroller]

Ok - some good new and bad again. Found some dial cord in my parts stash. Followed the same path as before (I think) but haven't quite got it tight enough to be consistent for both directions yet though. One direction definitely is smoother than the other.
Bad news is the meter stopped again! Unsoldered the wire, ohmeter has it moving - though as before (which I didn't mention) as the ohms are counting up it first does a small jump to the left (about 11.5 o'clock) then a larger second jump (to about 10 o'clock). Stops there and ohmeter read about .6K. Solder the wire back on, doesn't move when tuning. It did the first time is had solder it back on when I first posted it work, but not since. Still measure roughly 5volts at the meter, moving around and the dial turns. I don't know how I could get dexoit in there because a) it's sealed and b) I still can't figure out how to remove it from the chassis without breaking it.

 

[rcs16]

I think I have the same problem with my center meter on my qx-9900. I think it is a intermittent contact inside.
Those meters use 2 sided tape to hold them against the chassis = PITA. Basically have to gently pry them off. a bit of heat might help, but be careful not to melt them. Possibly acetone might loosen up the glue but I have never done so and acetone might melt the plastic, have to do a test with some on a q-tip to see what it does.

The dial string is another PITA, I start with the dial at the right, var caps fins fully meshed.

 

[rocknroller]

Yeah - I figured out it was some sort of double side tape. Pried it away and got it off. Tried a little deoxit on it but no change. Saw a you tube video about heating up the center screw with an iron. Did that and it worked the first time, but the second time I powered on back to stuck. Tried to gently turn the screw int he center but didn't really have a fine enough driver for it, but did give a fractional turn on the Philips to right of it and some combination of all the above seems to do the trick. Turns on and moves every time now. Started machine 20-30 times without issue. Will let it sit overnight to see if there is any change before buttoning it up completely.

Went through the service manual and realized I had one turn to few around the tuning dial. Also realized I hadn't clamped all my wires back down and they were interfering with movement. Works great now, though I'm wondering how to put a drop of glue on the pointer now that it's set in place. and dial face is bolted back down

 

[rocknroller]

Unfortunately still not solved. Came back hour later, now the signal meter side stuck. Repeated this many times throughout the night and again today. After sitting, one of both get stuck. Have deoxed and lubed and once they start they work fine but then sitting for a while one gets stuck. No idea what is going on.

 

[rocknroller]

The answer seems to be the pointer sticking on the shaft due to some corrosion or dried grease etc that my deoxit and lube is not resolving or reaching properly. I found loosening the screw slightly worked past areas it was "sticky" so that the pointer now floats freely. My guess is after sitting this area cools down just enough to make it stick again. Another reason why the solderign iron seemed to free it too (temporarily anyway, until it cooled down again. I let it sit for a while now that the contact point of location is slightly different and hopefully more free...

 

[rocknroller]

Arg - thought I had these fully working but just keeps freezing. then I tried to open it up a bit to clean better and now can't meter the meter lever assembly back on the pivot point and float correctly. If I get it there, it's just stuck and doesn't bounce. I think I've ruined it, or it just needs to sit somehow magnetically perfect in the field and I can't figure it out. Can't find anyone selling one either except one person in Canada at a stupid crazy price which I refuse to even consider.

 

[kramden]

As stated in post #2, one of those pivot points is an electrical contact. If you have loosened that screw to relieve some sort of believed undue pressure, what you have actually done created an open in the meter circuit. On a lot of the Pio meters, they use the body or frame, if you will, to conduct the positive meter input from #1) a wire #2) connected to a pin held on by a rivot #4) which contacts the frame;conducting the positive #5)through the frame which may be made up of more than one piece of metal #6)to the piece that houses the pivot catch #7)through to the needle and onto the windings. What I'm saying is there are many opportunities for an intermittent connection in that path from the input to the armature. The most common I've seen is the connection between the rivet and the frame. 9 out 10 times the incorrect meter movement is not being caused by a mechanical issue but rather an electrical issue. To prove this, take a can of air and barely squeeze out a hint of breeze at the end of the needle.(power off) If this low pressure is enough to move the needle to where it deflects freely, it is adjusted properly so let it be. If it does move freely, run a piece of kynar from the positive input wire to the closest area of the pivot catch which will bypass all of the frame contacts entirely. Your meter may not be constructed as stated but could still be suffering from similar circumstances. It takes a steady hand and knowledge of how to create both the pivot mechanical adjustment and how and where to 'land' the added wire to the closest point near the pivot. A temperature controlled iron is an absolute must and it would help to practice on a dummy meter rather than trying to learn on something worth hundreds of dollars.

 

[rocknroller]

The issue at the moment is the armature/arm is no longer "floating" at at. It's like it need to be in the middle of the magnetic field and and I can't get it to go back to that position.

 

[kramden]

More than likely the rear pivot point or axle, is not sitting correctly in the catch. Hard to see at all unless the entire meter is removed from the plastic housing. You are at the point of no return then...once it leaves the plastic housing, it either gets fixed and reassembled to be used or you are buying a new one. It could still be gunk as MTF stated tho.

 

[rocknroller]

That sounds like it could be it. it's definitely not seating correctly. I was wondering if there was something on the back side of that magnet thing. Other then desoldering the wires on the back, anything else to pulling that assembly out? Once out I will also look into the connectivity isue as well, but first thing is simply getting it seated back normally.

 

[kramden]

A bit of finesse is needed when preparing the meter leads before pushing through. The plastic of the housing can be easily melted by too much heat applied during desoldering. I found it best to simply cut the leads and shave off the remaining solder with an exacto blade. You have to get all of it off of the lead or it won't slide through the slots in the housing. If I remember correctly there are two small screws holding the movement on the other side. It's always best to be able to push on just the two leads through the slots WITHOUT any help from pulling on the movement from the front. That's how fragile these things are. Once it is out, clamp one of the movement ears in your panavise or helping hands before alignment begins. Good luck. (Hopefully you have the meter that I am describing here.There are variants so be aware). The ultimate goal is to leave no evidence that you were ever there.

 

[rocknroller]

OK - i got it out safely, able to see where it came off the back pivot point and successfully put back on (temporarily) to confirm meter is still alive and well. Ohm meter shows deflection both directions. Attached a pic of each side as I'm not clear where I should be checking for a poor contact at this point that is the cause of inconsistent sticking. I do see some greenish corrosion? on the T bar that crosses the front. Is that where it need to be cleaned up to get a solid 100% connection?

 

[zebulon1]

If you decide to call it quits these guys are awesome.
They've done several Phase Linear meter's for me and a few Sansui receiver meter's.
$39 evaluation fee and in some cases they can fix it within the evaluation fee. If not they will call with an estimate.
https://metersales.com/

It may pay to wait for a used one to show up.

 

[rocknroller]

It's weird. Sprayed all contact points. Ohm meter makes the meter move but in circuit does not - even though I have 4-6 volts going through it measured. I think at this point what I might do, since I can't fidn a replacement dual meter anywhere, is buy another single pioneer tuning meter and transplant it to this box, now that i know how to take one out.

 

[rocknroller]

This current meter has "165 12K" printed on it. i assume the 12K is the resistance of the coil and need to be matched if replaced with another meter. What does the 165 represent? Every meter I have found so far has different values...

 

[rcs16]

This current meter has "165 12K" printed on it.

I do not think that this is anything meaningful other than a mfg part number or lot code. Usually meters are spec'd in full scale current rating not ohms, although the ohms can be derived from the FS current and voltage required to do so.
It might take some time to find a exact replacement. Transplanting another meter is a stop gap but not a good solution in the long run. The meter part number is used on a few sx-x80 series, 880,980,1080,1280. The lower models only had one meter and it functioned as a center tuning for FM and signal strength for AM.

 

[rocknroller]

The issue is they are scare to find. Whereas I can get a single (dual fm/am purposed) one for less than $10 and transplant the meter and be done with this - *IF* the meter is expected to react the same in circuit as the old one, given the voltage to it. That's what I don't know. One of my concerns was that "K" reading was actually ohms, thus affected the voltage reading to it, thus pointing the indicator someplace other than expected. Is that why you consider this approach to be stop gap?