Forums :: NEW! Web Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives
Support This Site: Contributors :: Advertise


It is currently Dec Sat 04, 2021 9:52 pm


All times are UTC [ DST ]





Post New Topic Post Reply  [ 57 posts ]  Go to page 1, 2, 3  Next
Author Message
 Post subject: Zenith ZP-8L Music Very Faint
PostPosted: Aug Mon 09, 2021 3:42 pm 
Member

Joined: Aug Mon 09, 2021 3:24 pm
Posts: 26
I have a Zenith ZP-8L from 1957. I've had it about a decade and it's worked very well. I replaced the cartridge when I got it ten years ago, but other than that I have not done anything. However, when I went to play a record yesterday, the sound was incredibly faint. I have also tried different records, including the one that I played last time and worked. They all were faint. There are two dials on the front. The second controls volume and I am not sure about the first. The second, volume one does seem to be working (albeit from very quiet to quiet). I cannot tell if the first dial is changing anything. I am not super knowledgable about record players so I am not sure what could be causing this issue. If you have any questions, I'll do my best to answer them. If it's a lost cause, that's also fine-- certainly got a lot of out of this machine!


Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Mon 09, 2021 4:38 pm 
Member

Joined: Aug Mon 09, 2021 3:24 pm
Posts: 26
I found a schematic online and took a quick picture of the interior. I have attached both below in case that helps. The two dials do not seem to align perfectly with any of the three dials, but there are certainly closer to the first two.


Attachments:
File comment: Part schematic
Parts.pdf [249.12 KiB]
Downloaded 42 times
File comment: Image of the interior tubes
interiorTubse.png
interiorTubse.png [ 428.35 KiB | Viewed 1325 times ]
Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Mon 09, 2021 5:34 pm 
Member

Joined: Jan Wed 16, 2013 12:04 am
Posts: 2573
Location: 77001
The amplifier needs service,
with new capacitors and resistors checked.
Very possibly the source of your problem.

It's possible a tube has malfunctioned,
but voltage checks need to be done
to do some basic troubleshooting.

Don't throw this Zenith away, if you're
done with it.
Someone would love to fix it up and play it
some more.
Hotwax


Attachments:
Zenith ZP8L.pdf [494.04 KiB]
Downloaded 46 times
Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Mon 09, 2021 6:49 pm 
Member

Joined: Aug Mon 09, 2021 3:24 pm
Posts: 26
Thanks @Hotwax! I certainly have no intention of throwing this record player away if it can be fixed! When it comes to buying new capacitors and resistors (and maybe a new amp if I understand?), do I just buy another of that same type of that item/one of its replacements (as listed in the specs)? Or will I run into the issue that they'll all be 60 years old and not as effective? I've never messed with the internals of a record player (or really anything that had tubes and capacitors and resistors) before so any guidance would be greatly appreciated.


Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Mon 09, 2021 8:02 pm 
Member

Joined: Jan Wed 16, 2013 12:04 am
Posts: 2573
Location: 77001
Tfkalk wrote:
Thanks @Hotwax! I certainly have no intention of throwing this record player away if it can be fixed!

When it comes to buying new capacitors and resistors (and maybe a new amp if I understand?), do I just buy another of that same type of that item/one of its replacements (as listed in the specs)?

Or will I run into the issue that they'll all be 60 years old and not as effective?

I've never messed with the internals of a record player (or really anything that had tubes and capacitors and resistors) before so any guidance would be greatly appreciated.

Glad you're going to keep the Zenith !
Get ready for lots of info !

1.You will not require a new amp. The capacitors and needed
resistors will be bought new from a reputable electronics
part house.
I recommend Mouser Electronics.

1.a. So, I'll do your homework on what capacitors you'll need.
Modern capacitors will have values that are slightly
different than capacitors made 60-70 years ago.
New capacitors are also much smaller in size.

Capacitors' values are measured in microFarads (mF),
or smaller values such as nano, pico Farads.

1.b. The Zenith has a metal can ( C1AB in schematic ),
that contains 2 electrolytic filter capacitors.
One is 80 mF, rated @ 150 Volts
Second is 20 mF rated @ 150 Volts.

You will buy 2 separate capacitors to replace these.
Modern equivalents:
82 mF @ 160 Volts
22 mF @ 160 Volts

Electrolytic capacitors have to
be installed with their correct polarity,
with a scant few exceptions.
This means there is a positive side and a
negative side to the capacitor.
This is covered in the tutorials below.

The below capacitors are not polarized, and do
not have a particular installation orientation:

There are three 0.01 mF capacitors @ 200 Volts
C3,C5,C6
Modern value is the same: 0.01 mF, but use a 630 Volt rated cap.

For C7, 0.06 mF cap, modern equivalent is 0.068 mF,
again use 630 Volt rated cap.

C8 (0.1 mF) is a special situation. It is called a line to chassis capacitor,
or a line to ground capacitor.
It has particular filtering properties in the circuit.
BUT, it cannot be replaced with a regular 0.1 mF cap.

As this capacitor is connected to 120 VAC and the metal
frame (chassis) of the amplifier, if it failed, there would
be a bad risk of shock.

So, first, the value of the capacitor is reduced to 0.01 mF.
Second a special safety capacitor will be used.

A commonly used type is the 0.01 mF X1Y2 capacitor.
It will have a different system for its voltage rating.
Using a 250 VAC voltage rating is fine.

These safety capacitors are designed so that if they fail,
there will be no conduction between the AC line, the
capacitor, and the chassis.

2. There is some basic electronics you must learn to
safely and properly replace the capacitors.

Electrolytic capacitors, for example, can store
dangerous voltages after the amplifier power
is turned off. There are methods to safely discharge
those caps, if you need to work on the amplifier.

You will need to be able to read a schematic diagram,
to identify the parts and their proper orientation.

I recommend you look around in your locale for
a vintage radio club. Those members will know all
about how to assist your Zenith restoration.

You will need a soldering iron and solder, along
with some tools to cut out the old parts in
the amplifier.

I recommend you buy a reasonably-priced digital multi-meter,
so you can do basic checking of parts such as resistors.

Here are 2 tutorials on all you need to know about
capacitors. Though they are from tube radio websites,
the information is the same for your amplifier, since
radios also have an amplifier circuit in them.

https://www.wjoe.com/capacitorinfo.htm

https://www.justradios.com/captips.html

Phil has tips on stuffing can caps:
https://antiqueradio.org/recap.htm#replacing

This forum is here to support you, and if you take
small steps to build your vintage electronics
knowledge, you can enjoy fixing the Zenith.

I don't expect you to understand much of what
I posted right now, but use it as reference info.

There is NO dumb question, period.
Hotwax


Last edited by Hotwax on Aug Mon 23, 2021 9:37 pm, edited 1 time in total.

Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Mon 09, 2021 11:32 pm 
Member

Joined: Aug Tue 24, 2010 8:56 pm
Posts: 6202
Location: Northeast Florida
I'd like to see a pic of the cartridge so I can determine if it's crystal or ceramic. If it's crystal, they absorb moisture over time and die a slow death, until the point where there is no output at all

_________________
William


Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Tue 10, 2021 2:27 pm 
Member

Joined: Aug Mon 09, 2021 3:24 pm
Posts: 26
Sorry for the delayed response, I thought I hit submit last night! :oops:

@Hotwax: oh my word, thank you so much!! This is incredible and I will certainly make great use of it as I begin this process.

@tubes4life: I have attached an image of the needle. If you need me to remove it for a better picture, let me know.

Also, a (hopefully general enough) question about restoration-- there are cables connecting the actual turntable part with the rest of the chest (like the dials and the speaker). As a result, I can't really get into the interior that well because I can only lift the turntable up a couple of inches. Is there a good way to handle this?


Attachments:
IMG_3550.png
IMG_3550.png [ 370.91 KiB | Viewed 1264 times ]
Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Tue 10, 2021 3:11 pm 
Member

Joined: Jan Wed 16, 2013 12:04 am
Posts: 2573
Location: 77001
Tfkalk wrote:
Also, a (hopefully general enough) question about restoration-- there are cables connecting the actual turntable part with the rest of the chest (like the dials and the speaker). As a result, I can't really get into the interior that well because I can only lift the turntable up a couple of inches. Is there a good way to handle this?

1. Cartridge:
The cartridge is an all-in-one plug-in type, probably
an Electro-Voice 56.
It is ceramic, and no problem usually with output,
unless the stylus (needle) that is mounted on it,
is broken or very worn down.

2. Access the amplifier and record changer removal:
Please take a photo of the top inside of the Zenith where the
record changer sits.

There probably are wood screws holding the
plinth on the top of the cabinet.
The plinth is a wood cut-out that the changer sits on.

You will need to access 2 shipping bolt retainer
clips that lie underneath the record changer,
so the changer can be removed, and you can
access the amplifier for its removal.

The clips may look like a large bobby-pin, or
a large C-clip, that will be on the end of
the shipping bolts.

The bobby-pin clips can be flipped vertical from
their horizontal orientation, so that they can
be pulled through the mounting holes in the
plinth.

If there are C-clips, you will need a flat edge
screwdriver to pry them off of the bolts.

To continue after you post new photos.
Hotwax


Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Tue 10, 2021 10:16 pm 
Member

Joined: Aug Tue 24, 2010 8:56 pm
Posts: 6202
Location: Northeast Florida
That's a ceramic cartridge, which should still be good and have plenty of output. But that particular style of cartridge are what many refer to here on the forum as 'record chewers'. They're fine for playing mono records from the 50's--mid 60's, but later records would most likely be damaged by it (especially stereo ones). A Pfanstiehl P228 is a nice upgrade.

Agree that the amp needs serviced, with all paper capacitors replaced

_________________
William


Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Wed 11, 2021 2:15 am 
Member

Joined: Aug Mon 09, 2021 3:24 pm
Posts: 26
Hotwax: I have attached the picture below. I was looking at the cables to try to find clips, but I don't think I have those clips. I attached a picture (cables.png), but basically they seem to run through a bent piece of metal so I am not sure I'll be able to unbend that to get more flexibility. If that black wrapping around the wires was not there, I could probably loop them out, but my guess is that it's there exactly to prevent that.

tubes4life: Awesome, thanks! I was looking at Voice of Music and they had two results for Pfanstiehl P228. https://www.thevoiceofmusic.com/catalog/part_detail.asp?PNumberBase=P228&SearchType=MfgNameCartridges&MfgName=Pfanstiehl&Categories= It seems the only difference between the two is what replacement needle they use. Is that correct? And I can use either?


Attachments:
File comment: Interior of the record player
interior.png
interior.png [ 432.94 KiB | Viewed 1233 times ]
File comment: Three cables that connect the record table to the rest of the box
cables.png
cables.png [ 447.98 KiB | Viewed 1233 times ]
File comment: Underneath the screwed in wood panel
underneathWoodPanel.png
underneathWoodPanel.png [ 454.39 KiB | Viewed 1233 times ]


Last edited by Tfkalk on Aug Wed 11, 2021 3:52 am, edited 1 time in total.
Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Wed 11, 2021 3:16 am 
Member

Joined: Aug Tue 24, 2010 8:56 pm
Posts: 6202
Location: Northeast Florida
Do you play 78's? If so, keep in mind that only one of those needles has a 78 tip on it

_________________
William


Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Wed 11, 2021 3:54 am 
Member

Joined: Aug Mon 09, 2021 3:24 pm
Posts: 26
I do not have any 78s. However, I notice that there is only a dollar difference in the two so that feels worth it to be able to play them all. I presume the P228-DS73 is the one that can play them all?


Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Wed 11, 2021 4:49 am 
Member

Joined: Jan Wed 16, 2013 12:04 am
Posts: 2573
Location: 77001
Tfkalk wrote:
Hotwax:
I was looking at the cables to try to find clips, but I don't think I have those clips.

I attached a picture (cables.png), but basically they seem to run through a bent piece of metal so I am not sure I'll be able to unbend that to get more flexibility.

If that black wrapping around the wires was not there, I could probably loop them out, but my guess is that it's there exactly to prevent that.

Question:
Have you released the record changer from its
plinth ? I cannot tell from the photo.

If you have, go to steps 1 and 2.

If not, do steps 1, 2, and 3.

1.On top of the amplifier chassis, there is an
pronged plug that looks like audio signal
into the amp from the tonearm cartridge.
Unplug that.

2.There is an AC motor power plug on the side of the amp
near the speaker.
Unplug that.


3.The 2 shipping bolts are visible on top of the changer.
They probably screw through a threaded metal piece that is
embedded in the wood plinth.
Some record player cabinets are like this.

With a screwdriver, turn the bolts counter clockwise, and
I think they should release free.
There are springs under the record changer
that you may feel release from the lock-down
pressure, as you unscrew the bolts.

Hotwax


Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Wed 11, 2021 5:45 pm 
Member

Joined: Aug Mon 09, 2021 3:24 pm
Posts: 26
Hotwax wrote:
Hotwax:
2.There is an AC motor power plug on the side of the amp
near the speaker.
Unplug that.

Thanks! Sorry, I misunderstood what part you were talking about because the record changer is on plastic, but there is also a wood panel that is over the amp and output (I believe that whole part is the chassis?). I was able to get the two plugs unplugged and remove the record changer from the unit. However, I am struggling to unplug the power cord from the unit because it is plugged in at the bottom, aka underneath the electrolytic capacitor and output tube. The space between those tubes is just big enough that I can get one finger in, but that does not give me enough force to unplug the cable. Do you have any recommendations on how to get it unplugged? I didn't think pulling the cord would be a good idea and I'm hesitant to break something so I figured best to ask the experts. Thanks as always for your help. It is greatly appreciated.


Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Wed 11, 2021 7:35 pm 
Member

Joined: Jan Wed 16, 2013 12:04 am
Posts: 2573
Location: 77001
Tfkalk wrote:

I was able to get the two plugs unplugged and remove the record changer from the unit.
However, I am struggling to unplug the power cord from the unit because it is plugged in at the bottom, aka underneath the electrolytic capacitor and output tube.
The space between those tubes is just big enough that I can get one finger in, but that does not give me enough force to unplug the cable.
Do you have any recommendations on how to get it unplugged?
I didn't think pulling the cord would be a good idea and I'm hesitant to break something so I figured best to ask the experts.
Thanks as always for your help. It is greatly appreciated.

Photo of what you're talking about will help.

Hotwax


Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Wed 11, 2021 7:58 pm 
Member

Joined: Aug Mon 09, 2021 3:24 pm
Posts: 26
Sorry! I’ve uploaded a picture and labeled where the power cord is.


Attachments:
D3324037-0313-4E55-B5EF-44E79F31CD5F.jpeg
D3324037-0313-4E55-B5EF-44E79F31CD5F.jpeg [ 523.21 KiB | Viewed 1184 times ]
Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Wed 11, 2021 8:52 pm 
Member

Joined: Jan Wed 16, 2013 12:04 am
Posts: 2573
Location: 77001
Thanks for the photo.

DO NOT try to disconnect that power cord.

It is held connected to the amplifier chassis
by a plastic strain relief plug.

To free up the amplifier :

Look around the metal amplifier chassis.
The amplifier chassis (metal box) may be held
down by screws onto the bottom of the
cabinet.

If you don't see anything like that, then
the chassis may also be held on by washers
and nuts that go over the stems of the
2 controls in front of the cabinet.

The controls' parts are called
potentiometers, or pots.

Removing the knobs will expose the stems
of the pots.

Come back with more photos as needed.
Hotwax


Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Wed 11, 2021 10:33 pm 
Member

Joined: Aug Mon 09, 2021 3:24 pm
Posts: 26
Looking around, it seems like there are three places the chassis is screwed in via. One is a screw that comes from the bottom of the unit (although I cannot access the head of that screw because of the case) with a nut. I theoretically could remove the nut and there seems to be a hole in the chassis that would go over the screw. The other two are indeed through the knobs (it’s too thin to get a good photo). How do I safely remove the knobs? I would like to be able to preserve them and continue using them, if possible.

Also, I have a general question for my understanding. We’ve talked about removing the chassis in order to access the amp. However, the amp is plugged into the metal chassis (picture attached). So how does removing the chassis help?


Attachments:
File comment: Screwed into the bottom to secure the chassis with a nut as well
FB3556BD-7048-4B85-B088-AEEB90432252.jpeg
FB3556BD-7048-4B85-B088-AEEB90432252.jpeg [ 2.08 MiB | Viewed 1180 times ]
File comment: The amp fully plugged into the chassis
EFC19958-49CC-4BFC-8EC1-03AAF53C4BA1.jpeg
EFC19958-49CC-4BFC-8EC1-03AAF53C4BA1.jpeg [ 1.85 MiB | Viewed 1180 times ]
Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Wed 11, 2021 10:51 pm 
Member

Joined: Aug Tue 24, 2010 8:56 pm
Posts: 6202
Location: Northeast Florida
Tfkalk wrote:
I do not have any 78s. However, I notice that there is only a dollar difference in the two so that feels worth it to be able to play them all. I presume the P228-DS73 is the one that can play them all?


That's correct

_________________
William


Top
 Profile  
 
 Post subject: Re: Zenith ZP-8L Music Very Faint
PostPosted: Aug Wed 11, 2021 10:54 pm 
Member

Joined: Jan Wed 16, 2013 12:04 am
Posts: 2573
Location: 77001
Tfkalk wrote:
Looking around, it seems like there are three places the chassis is screwed in via.
One is a screw that comes from the bottom of the unit (although I cannot access the head of that screw because of the case) with a nut.
I theoretically could remove the nut and there seems to be a hole in the chassis that would go over the screw.

How do I safely remove the knobs? I would like to be able to preserve them and continue using them, if possible.

Also, I have a general question for my understanding.
We’ve talked about removing the chassis in order to access the amp.
However, the amp is plugged into the metal chassis (picture attached).
So how does removing the chassis help?

1. Free the chassis #2.
You can remove the vacuum tubes from the chassis,
to access that retaining nut/washer.

2. Knobs:
Normally, just pull the knobs off of the shaft of
the control.
If there is no set screw, they are held on by friction.

If they are really tight, you can place 2 flat end screwdrivers
on opposite sides under the knob.
Then gently pry up the knob by twisting each of
the screwdrivers.

3. You're confused about the amplifier, OK.
The amplifier parts are mounted and wired
together in and on the metal box, the chassis.
When you free up the chassis, then you will have
access to those components that need servicing.

The power to the amp has to come via the AC cord,
which is fastened securely through a hole
in the chassis. As I mentioned already, it is kept in
place by the strain relief.
The strain relief keeps the soldered ends of the AC
cord from being pulled off the connection in
the amplifier inside the chassis.

Hotwax


Top
 Profile  
 
Post New Topic Post Reply  [ 57 posts ]  Moderator: Alan Voorhees Go to page 1, 2, 3  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 14 guests



Search for:
Jump to:  




































Privacy Policy :: Powered by phpBB