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 Post subject: Zenith auto changer issue
PostPosted: May Sun 30, 2021 4:07 am 
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Joined: Dec Mon 28, 2020 11:52 pm
Posts: 419
Location: Davenport, Iowa
I have a 1965 Zenith Z940 that I'm refurbishing. Everything about the record changer works except 1 annoying thing. It drops the record and puts the needle down fine. It plays fine. When it gets to the end of a side, it will lift the tone arm and put it back in the holder just fine, too. The only thing it does not do is switch the knob to "off" at the very end.

Here is the service manual:
https://drive.google.com/file/d/1qokbYd ... sp=sharing

I can see how this is supposed to work. The trip link is not hitting the control arm to shut it off at the end. I tried bending the trip link so that it would hit, but then it would trip the off switch early in the cycle. I could not find a sweet spot where it would NOT trip that control arm early in the cycle, but still hit it at the end. So I just bent it back straight and left it that way for now.

The last time I had it out of the cabinet, a small c-clip fell out of it. I have not gotten it back out to try to figure out where it came from, but my best guess is it is probably the one that holds post part #56 in the manual. I'll have to dig into it to verify.

I can get that c-clip back in, but it seems like there has to be some other kind of adjustment that I'm missing here. Any insight you can provide would be appreciated.


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 Post subject: Re: Zenith auto changer issue
PostPosted: May Sun 30, 2021 12:45 pm 
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Joined: Feb Wed 04, 2015 12:26 am
Posts: 1652
Have you disassembled and cleaned the old grease out? This must be done. The next step is to send the power switch and idler to Gary at thevoiceofmusic.com to be refurbished.

The issue is more than likely the power switch.


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 Post subject: Re: Zenith auto changer issue
PostPosted: May Sun 30, 2021 4:10 pm 
Member

Joined: Jan Wed 16, 2013 12:04 am
Posts: 2573
Location: 77001
As Artcurus stated it could be the plastic
On/Off/Rej switch is broken internally.
It is not uncommon.

You can check b/t the switch contact posts for
continuity as a first check, with switch in "On"
position.

Also, when you turn the switch on and off,
does it move very freely ?
The On/Off/Rej knob should spring back very
quickly.

Hotwax

https://thevoiceofmusic.com/catalog/vm_ ... itches.asp


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 Post subject: Re: Zenith auto changer issue
PostPosted: May Sun 30, 2021 4:59 pm 
Member

Joined: Dec Mon 28, 2020 11:52 pm
Posts: 419
Location: Davenport, Iowa
I have taken this partially apart and cleaned out all the old grease as best I could without doing a complete rebuild.

The idler wheel was already sent to V of M and had it refurbished. It was hard as a rock lol.

I am going to put this clip back in and and see what happens.

Regarding the on/off/reject switch - actually does take a lot of force to flip from "on" to "off". When I was messing with this thing, I could get it to work intermittently, but often it would get stuck between the off/on positions when the trip link was trying to flip it to "off".

As far as continuity goes, the switch still works electrically. It will turn the unit on and off just fine when I flip it manually. It just takes too much force to go from "on" to "off" for the trip link to be able to do it. Does that mean it's broken? Or can it be cleaned or something?


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 Post subject: Re: Zenith auto changer issue
PostPosted: May Sun 30, 2021 8:28 pm 
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Joined: Jan Wed 16, 2013 12:04 am
Posts: 2573
Location: 77001
pioneer07 wrote:
I have taken this partially apart and cleaned out all the old grease as best I could without doing a complete rebuild.

Regarding the on/off/reject switch - actually does take a lot of force to flip from "on" to "off". When I was messing with this thing, I could get it to work intermittently, but often it would get stuck between the off/on positions when the trip link was trying to flip it to "off".

As far as continuity goes, the switch still works electrically. It will turn the unit on and off just fine when I flip it manually. It just takes too much force to go from "on" to "off" for the trip link to be able to do it. Does that mean it's broken? Or can it be cleaned or something?

1. The switch could be sprayed with electronics lube/cleaner.
I've seen some bound up by oxidation.

2. The control lever assembly # 40 and locator # 43 may
be gunked up with old dried grease.
It's best to do a frame dis-assemble to access
those parts for cleaning.

But, I have had success by spraying de-greaser onto these
parts' pivot points, working the parts, clean up gunk, and
repeat several times.

Then I used Zoom-spout turbine oil because it has a
long spout to lube those pivot points.
It usually releases the old grease to allow for
free movement.

Here's video of a V-M 1297 serviced. The one in the
video has the older metal switch in it.

Just to be clear: does your Zenith V-M have the plastic
switch in it ?

Hotwax

https://www.youtube.com/watch?v=B-HqO_mOdac


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 Post subject: Re: Zenith auto changer issue
PostPosted: May Sun 30, 2021 9:25 pm 
Member

Joined: Dec Mon 28, 2020 11:52 pm
Posts: 419
Location: Davenport, Iowa
Hotwax wrote:
pioneer07 wrote:
I have taken this partially apart and cleaned out all the old grease as best I could without doing a complete rebuild.

Regarding the on/off/reject switch - actually does take a lot of force to flip from "on" to "off". When I was messing with this thing, I could get it to work intermittently, but often it would get stuck between the off/on positions when the trip link was trying to flip it to "off".

As far as continuity goes, the switch still works electrically. It will turn the unit on and off just fine when I flip it manually. It just takes too much force to go from "on" to "off" for the trip link to be able to do it. Does that mean it's broken? Or can it be cleaned or something?

1. The switch could be sprayed with electronics lube/cleaner.
I've seen some bound up by oxidation.

2. The control lever assembly # 40 and locator # 43 may
be gunked up with old dried grease.
It's best to do a frame dis-assemble to access
those parts for cleaning.

But, I have had success by spraying de-greaser onto these
parts' pivot points, working the parts, clean up gunk, and
repeat several times.

Then I used Zoom-spout turbine oil because it has a
long spout to lube those pivot points.
It usually releases the old grease to allow for
free movement.

Here's video of a V-M 1297 serviced. The one in the
video has the older metal switch in it.

Just to be clear: does your Zenith V-M have the plastic
switch in it ?

Hotwax

https://www.youtube.com/watch?v=B-HqO_mOdac



Yes, it has a plastic body with the electrical connector. It has a metal contact coming out of it that I can see which is activated by the control arm, but the body of it is plastic.


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 Post subject: Re: Zenith auto changer issue
PostPosted: Jun Tue 01, 2021 1:46 am 
Member

Joined: Dec Mon 28, 2020 11:52 pm
Posts: 419
Location: Davenport, Iowa
I got the switch out and I'm looking at it, and I can't see what could possibly be wrong with it. The spring is too stiff maybe? I'm hesitant to send it back because it still works when I operate it manually. I just can't see why old age would increase the force needed to turn this off unless I'm missing something. Does the spring metal harden over time (with corrosion)?



The other issue I still have with this one is it has quite a bit of background noise when there should be silence. You can hear some noise even running it without the needle on a record. I cannot figure out where the rubbing is happening. The idler wheel has been refurbished already. I've already thoroughly cleaned the bearing race and washers that the platter rides on. I've already disassembled the motor and relubricated it. I also replaced the rubber motor mounts. There is a ramp and a button on this platter that I'm told has something to do with 10" records. Other record players I've worked on do not have this feature. I just tested it where I taped that ramp in the "up" position so it could not possibly rub on the chassis, but that made no difference, either.

Prior to getting the idler wheel refurbished and doing a lot of this lubrication, this record player was making an awful grinding sound. So it has come a long ways, but it still has more background noise than you'd want.


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 Post subject: Re: Zenith auto changer issue
PostPosted: Jun Tue 01, 2021 2:30 am 
Member

Joined: Feb Wed 04, 2015 12:26 am
Posts: 1652
pioneer07 wrote:
I got the switch out and I'm looking at it, and I can't see what could possibly be wrong with it. The spring is too stiff maybe? I'm hesitant to send it back because it still works when I operate it manually. I just can't see why old age would increase the force needed to turn this off unless I'm missing something. Does the spring metal harden over time (with corrosion)?



The other issue I still have with this one is it has quite a bit of background noise when there should be silence. You can hear some noise even running it without the needle on a record. I cannot figure out where the rubbing is happening. The idler wheel has been refurbished already. I've already thoroughly cleaned the bearing race and washers that the platter rides on. I've already disassembled the motor and relubricated it. I also replaced the rubber motor mounts. There is a ramp and a button on this platter that I'm told has something to do with 10" records. Other record players I've worked on do not have this feature. I just tested it where I taped that ramp in the "up" position so it could not possibly rub on the chassis, but that made no difference, either.

Prior to getting the idler wheel refurbished and doing a lot of this lubrication, this record player was making an awful grinding sound. So it has come a long ways, but it still has more background noise than you'd want.


Check the spring under the 10 inch selection button. Sometimes they hang too low and drag.

Also verify the bearing sandwich at the bottom of the platter itself is in the correct order and all the washers are in place.


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 Post subject: Re: Zenith auto changer issue
PostPosted: Jun Tue 01, 2021 2:38 am 
Member

Joined: Jan Wed 16, 2013 12:04 am
Posts: 2573
Location: 77001
Re: Switch

The switch may be OK.
The spring should be firm when lever
fork is moved on or off by hand.

1. Did you clean it as I posted ?

2.Did you clean the other parts I posted ?

Re: noise

3. Is the noise constant, or repeats at an interval ?

4. Who refurbed the idler wheel ?

Remove the idler wheel, and see if the
noise is there when you spin the platter by
hand clockwise.

Check idler height when it contacts the stepped
speed turret. Idler edge should be flat on each step
and approximately in top middle of each step.

5. Are bearings and thrust washers void of any
bad scratches or indentations ?

Look at the platter flat hub and toothed gear to see if any
damage there.

Hotwax


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 Post subject: Re: Zenith auto changer issue
PostPosted: Jun Tue 01, 2021 2:48 pm 
Member

Joined: Dec Mon 28, 2020 11:52 pm
Posts: 419
Location: Davenport, Iowa
Artcurus wrote:
pioneer07 wrote:
I got the switch out and I'm looking at it, and I can't see what could possibly be wrong with it. The spring is too stiff maybe? I'm hesitant to send it back because it still works when I operate it manually. I just can't see why old age would increase the force needed to turn this off unless I'm missing something. Does the spring metal harden over time (with corrosion)?



The other issue I still have with this one is it has quite a bit of background noise when there should be silence. You can hear some noise even running it without the needle on a record. I cannot figure out where the rubbing is happening. The idler wheel has been refurbished already. I've already thoroughly cleaned the bearing race and washers that the platter rides on. I've already disassembled the motor and relubricated it. I also replaced the rubber motor mounts. There is a ramp and a button on this platter that I'm told has something to do with 10" records. Other record players I've worked on do not have this feature. I just tested it where I taped that ramp in the "up" position so it could not possibly rub on the chassis, but that made no difference, either.

Prior to getting the idler wheel refurbished and doing a lot of this lubrication, this record player was making an awful grinding sound. So it has come a long ways, but it still has more background noise than you'd want.


Check the spring under the 10 inch selection button. Sometimes they hang too low and drag.

Also verify the bearing sandwich at the bottom of the platter itself is in the correct order and all the washers are in place.



I tested it where I actually taped that 10 in selector button "up" so it could not possibly drag and there is still some background noise.

The bearing is in place. My only question is: the bearing race has one side that is "open" and the other side that is closed. Does the race go with the open side up or down? Or should it even matter?

There was a bunch of black gunk on the bearing race. I've done the best I can to get it all cleaned off, but maybe there is still some in there causing problems. Suggestions on cleaning out a bearing?


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 Post subject: Re: Zenith auto changer issue
PostPosted: Jun Tue 01, 2021 3:18 pm 
Member

Joined: Dec Mon 28, 2020 11:52 pm
Posts: 419
Location: Davenport, Iowa
Hotwax wrote:
Re: Switch

The switch may be OK.
The spring should be firm when lever
fork is moved on or off by hand.

1. Did you clean it as I posted ?

2.Did you clean the other parts I posted ?

Re: noise

3. Is the noise constant, or repeats at an interval ?

4. Who refurbed the idler wheel ?

Remove the idler wheel, and see if the
noise is there when you spin the platter by
hand clockwise.

Check idler height when it contacts the stepped
speed turret. Idler edge should be flat on each step
and approximately in top middle of each step.

5. Are bearings and thrust washers void of any
bad scratches or indentations ?

Look at the platter flat hub and toothed gear to see if any
damage there.

Hotwax



Re: switch/cycle issue
Yes I did cleaned the switch as you posted. I tried using some deoxit on it in case it was a corrosion issue. For the other parts, I have done a partial disassembly but not an entire one. I have sprayed in there many times and cycled the gear by hand many times trying to understand how this works. There is one other thing in this cycle that confuses me a bit, and maybe this points to an issue. See the photos. When the record support bracket (that holds the stack on the changer) is in the "on" position for the stack, that is when one of these control arms comes into play. There is a piece that moves over, and then the slide assembly will push it back down, and another latch will occur clicking it in place. SOMETIMES at the end of a cycle, this will automatically unlatch again. But other times, it will stay latched unless I manually press the little lever by my thumb in picture #2. Should this unlatch automatically every cycle? If so, then there is an issue there because it only unlatches on its own maybe 30% of the time. Maybe there is some binding somewhere despite all the cleaning and lubricating I've done.
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 Post subject: Re: Zenith auto changer issue
PostPosted: Jun Tue 01, 2021 3:27 pm 
Member

Joined: Dec Mon 28, 2020 11:52 pm
Posts: 419
Location: Davenport, Iowa
Re: noise issue
The idler wheel was refurbished by VM. There is a small rough area on it that suggests it may have rubbed on the lower turret level at one point, but right now it is dead center where it should be. I just removed the idler wheel so I can cycle this as many times as I want without worrying about damaging it.

I'm spinning the platter with no idler and nothing but the spindle and platter and bearing touching, and there is still noise. I have a brand new bearing that is the right size for the shaft but is a bit taller. I would not use it as a permanent fix because it's not an exact match (it's like 0.3mm taller). I'm concerned it could cause some misalignment. However, I put it in place of the original bearing just to see if it made a difference in the noise but the noise is still there. It's some kind of issue between the platter and spindle, I think.

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 Post subject: Re: Zenith auto changer issue
PostPosted: Jun Tue 01, 2021 3:52 pm 
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Joined: Dec Mon 28, 2020 11:52 pm
Posts: 419
Location: Davenport, Iowa
Re: noise issue
Here is a video of the platter free spinning by hand with no idler wheel. Is this a normal amount of noise? It's not this loud when it's spinning at normal speed with the idler engaged and a record on it, and the wobble is not as noticeable...Although the sound is quieter, the sound gets picked up by the needle and amplified, too. I put the little rubber piece on the spindle to see if that would dampen the sound but it didn't seem to matter.

https://drive.google.com/file/d/17XUqDp ... sp=sharing


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 Post subject: Re: Zenith auto changer issue
PostPosted: Jun Tue 01, 2021 4:11 pm 
Member

Joined: Jan Wed 16, 2013 12:04 am
Posts: 2573
Location: 77001
Execellent photos !

So, the platter hub and thrust washers and bearing
race all look normal to me.

You said it might be the spindle and platter
interacting, but after hearing the video, I don't
think so.
I listened to the video, and that noise may be normal
for it. I cannot be sure, as it may be more pronounced
in person.
These V-M's have some innate platter/motor vibration noise due to design.

Make sure to grease the spindle lower
shaft that holds the platter hub.
Also, grease the thrust washers.
The bearing race faces down,so ball bearing
faces are all you see.

Re: the lever coming through the bottom of the slide
assembly #55 on exploded diagram.
You wrote:

"There is one other thing in this cycle that confuses me a bit, and maybe this points to an issue. See the photos. When the record support bracket (that holds the stack on the changer) is in the "on" position for the stack, that is when one of these control arms comes into play. There is a piece that moves over, and then the slide assembly will push it back down, and another latch will occur clicking it in place. SOMETIMES at the end of a cycle, this will automatically unlatch again. But other times, it will stay latched unless I manually press the little lever by my thumb in picture #2. Should this unlatch automatically every cycle?"

That is the shut-off lever #68 which should reset
automatically.
It may be still gunked up with grease.

With the slide removed, there would be a few
parts and springs to dis-assemble there for cleaning.
#64 reset lever, #67 the 7-inch selector lever, #46 retard assembly.

Dis-assembly procedures in the links I posted for you.

With those above basic parts of the mech cleaned, more sources of
problems are eliminated. (hint, hint)

Once that is done, we could return to the trip-link,
and try to adjust the formed nub on it which
is brought to proper position for switch shut-off.
It is a delicate operation, as the trip link is
aluminum.

Best,
Hotwax


Last edited by Hotwax on Jun Tue 01, 2021 4:21 pm, edited 1 time in total.

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 Post subject: Re: Zenith auto changer issue
PostPosted: Jun Tue 01, 2021 4:14 pm 
Member

Joined: Feb Wed 04, 2015 12:26 am
Posts: 1652
pioneer07 wrote:
Re: noise issue
Here is a video of the platter free spinning by hand with no idler wheel. Is this a normal amount of noise? It's not this loud when it's spinning at normal speed with the idler engaged and a record on it, and the wobble is not as noticeable...Although the sound is quieter, the sound gets picked up by the needle and amplified, too. I put the little rubber piece on the spindle to see if that would dampen the sound but it didn't seem to matter.

https://drive.google.com/file/d/17XUqDp ... sp=sharing



Wait, does the platter rock back and forth on the spindle when installed?

First, clean the old bearing with brake cleaner, place the first washer down on the spindle, oil the bearing with lightweight oil such as sewing machine oil, then place the bearing over the spindle with the open end up, place the second washer on top the bearing, then place the platter on the spindle> if the problem persist, then you might have actually have a worn platter shaft, espeically if the platter rocks back and forth.


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 Post subject: Re: Zenith auto changer issue
PostPosted: Jun Tue 01, 2021 4:29 pm 
Member

Joined: Jan Wed 16, 2013 12:04 am
Posts: 2573
Location: 77001
Artcurus wrote:
Wait, does the platter rock back and forth on the spindle when installed?

First, clean the old bearing with brake cleaner, place the first washer down on the spindle, oil the bearing with lightweight oil such as sewing machine oil, then place the bearing over the spindle with the open end up, place the second washer on top the bearing, then place the platter on the spindle> if the problem persist, then you might have actually have a worn platter shaft, especially if the platter rocks back and forth.


And you can check that the record spindle is not loose
in its mount.
Spindle is held in place by 2 allen set screws.
They should be down tight.
Hotwax


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 Post subject: Re: Zenith auto changer issue
PostPosted: Jun Tue 01, 2021 7:00 pm 
Member

Joined: Dec Mon 28, 2020 11:52 pm
Posts: 419
Location: Davenport, Iowa
Hotwax wrote:
Artcurus wrote:
Wait, does the platter rock back and forth on the spindle when installed?

First, clean the old bearing with brake cleaner, place the first washer down on the spindle, oil the bearing with lightweight oil such as sewing machine oil, then place the bearing over the spindle with the open end up, place the second washer on top the bearing, then place the platter on the spindle> if the problem persist, then you might have actually have a worn platter shaft, especially if the platter rocks back and forth.


And you can check that the record spindle is not loose
in its mount.
Spindle is held in place by 2 allen set screws.
They should be down tight.
Hotwax



The spindle is definitely not loose, but sadly, yes, there may be a little bit of wobble when this thing spins. The rubber mat and that metal circle are not perfectly centered on the platter, so those make it look worse than it may actually be...when I watch the very edge of the platter, there is a tiny bit of wobble. It's hard to say how much of that might just be variation in the rubber cover though


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 Post subject: Re: Zenith auto changer issue
PostPosted: Jun Tue 01, 2021 9:29 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 4815
Location: Boston, MA USA
The noise sounds to me like a worn-out ball bearing. The balls may be spalled, or the races (what have been referred to as thrust washers) my be pocked. You might be able to solve the problem by turning them over to their unused sides, but if the problem is within the bearing cage the bearing will have to be replaced. You can probably get it from Gary.

Try rocking the turntable on the center bushing. There should be some clearance, but only a very small amount. It is normal to see the edge of the turntable rise and fall a bit as it turns. It is not perfectly flat.

I'm not used to greasing the races of a ball bearing. Yes, pack grease within the cage, but not on the races. That is because the balls are intended to roll on the races, not slide.

-David


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 Post subject: Re: Zenith auto changer issue
PostPosted: Jun Wed 02, 2021 12:06 am 
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Joined: Dec Mon 28, 2020 11:52 pm
Posts: 419
Location: Davenport, Iowa
Regarding the on/off issue:
I did everything in the 2 basic service videos:
https://www.youtube.com/watch?v=B-HqO_mOdac

That was an afternoon! I did find some old grease, and I found that the one small piece on the cam was seized but otherwise things were in pretty good shape. I also watched the advanced service video, but I did not do any of the steps in that one yet. At the very end of the advanced video, he says "Oh and one more thing" and mentions a mechanism with a tiny spring and says you need to clean that as well, that he forgot to mention during the basic service videos. He said that it could impact your on/off switch during a cycle. I did not clean that one when I had it apart but that is one you can see from the outside. I can shift it with a screwdriver. It doesn't seem stuck. Here is where he talks about that:
https://youtu.be/CIDnUnMdeNc?t=750

I don't regret doing that cleaning since I did find a couple things, but it did not change the performance as far as I can tell. It will go through an entire cycle fine but it won't turn the switch off at the end. When I have the record player out of the cabinet and on it's side or upside down and I'm turning the gear manually to test the cycle, it turns the switch off at the end every single time now. When I put this back in the cabinet and test it out with a record that the switch never turns off at the end. Gravity is playing some kind of role.

I also still have the same issue where that mechanism in the picture with the red arrow and my thumb does not always trip at the end, either. That issue is even more intermittent. It probably clicks off about 30% of the time when I'm manually turning the gear.



Re: Noise issue: I did ask VM if they had a bearing for this platter they'd be willing to sell me, just to give that a shot and see if it reduces the noise. I might be willing to live with the noise (and both issues frankly). This noise is just a bit louder than my other players. It honestly could also have to do with amplification. I think this one may just be more sensitive to this frequency than my other consoles. I've never had a speaker system with "horns" on each channel before.


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 Post subject: Re: Zenith auto changer issue
PostPosted: Jun Wed 02, 2021 1:52 am 
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Joined: Sep Thu 20, 2007 3:16 am
Posts: 1080
Location: Winter Park, Florida
I have had several of that model Zenith changer and that noise is not normal, they run quiet.

FYI, the Z940 is a 1969 model, not 1965.


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