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 Post subject: BSR StereoMaster Flip Down Record Player -No Audio, Just Hum
PostPosted: May Wed 22, 2019 1:42 pm 
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Joined: May Tue 21, 2019 9:06 pm
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EDIT 2: Solution: Dead cartridge. Go to http://www.thevoiceofmusic.com for a possible replacement. See the bottom of this post for all I have learned during this adventure.

Got a BSR StereoMaster flip down record player here. The only identifying text I have found on it says "Stereo Master" on the back wall. Great shape! No idea what the model number is.

Issue:

Can only hear a hum from the speakers, no music. Music can be heard from the cartridge.

Notes:

Deoxit was applied to the two POTS and pretty much every connection. No change other than no crackle can be heard from twisting the knobs.

First thing I tried was removing the main filter capacitor and setting up a replacement using this as a guide: (removed, site won't let me post link because I'm a new user, youtube search "How to Repair Vintage Tube Radio Filter Capacitor Fix Hum Antique Receivers
"). After all of that, there was no change.

I removed a .05 mfd 400v axial cap to get its info and instead of putting it in safe place, I put it in my pocket and lost it. Yes, I know. Duh.

Reseated the tubes after they cooled down. No sign of carbon. No change.

Next, I noticed how yellow and old the output transformers looked. Voltage is getting to them but there's isn't any output from what my multimeter is telling me. I guess these can go bad with age? They aren't warm to the touch.

This is my first vintage record player project. I'm okay with not being able to find parts for this but I'd like to prove to myself what is broken before I perhaps Ebay the unit. Any help is appreciated. Thanks!

EDIT: Figured out it was a BSR StereoMaster, not "no-name" as I had before.

EDIT 2A: Things I've learned/to pass on:

-Never power up any older piece of equipment without looking under the hood first. Look for damaged capacitors, transformers, wiring, tubes. Does something look bad? When in doubt, change it out.
-Start taking pictures of it. Document everything.
-Write down what it is doing/not doing. Tackle that issue.
-Draw a wiring schematic of what you're working on first. It only has to make sense to you for now.
-Capacitor replacements should be at least 200V rated. You can get away with using close uF rated caps. For example, I used a 75 uF cap in place of a 60 uF.
-Deoxit is your friend but not the cureall. You don't need to use a lot. Squirt a little into a potentiometer and twist it back and forth 100 times.
-SuperLube Multi-Purpose Synthetic Grease for greasing, Tufoil Lubit-8 for oiling.
-Simple Green or Mean Green for degreasing.
-Is it solid brass or brass-plated? Use a magnet; magnet won't stick to brass.
-Only YOU can figure out what went wrong during reassembly. In the words of my father: "get used to it..."

Special thanks to all who helped out in this post!


Attachments:
Unit.jpg
Unit.jpg [ 121.39 KiB | Viewed 556 times ]
Inside Back Wall.jpg
Inside Back Wall.jpg [ 82.98 KiB | Viewed 556 times ]
File comment: 60 Red 30 Blue 10 Yellow 150V
Original Filter Cap.jpg
Original Filter Cap.jpg [ 91.68 KiB | Viewed 556 times ]
File comment: 75 Red 33 Blue 10 Yellow
Closeup Filter Capacitor Replacement.jpg
Closeup Filter Capacitor Replacement.jpg [ 131.41 KiB | Viewed 556 times ]
Left Speak Assembly.jpg
Left Speak Assembly.jpg [ 135.25 KiB | Viewed 556 times ]
Right Speaker Output Transformer Closeup.jpg
Right Speaker Output Transformer Closeup.jpg [ 156.61 KiB | Viewed 556 times ]
Left Speaker Output Transformer Closeup.jpg
Left Speaker Output Transformer Closeup.jpg [ 132.41 KiB | Viewed 556 times ]


Last edited by Jdc on Jun Sat 15, 2019 3:44 pm, edited 3 times in total.
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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Wed 22, 2019 5:13 pm 
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Joined: Jan Tue 10, 2012 8:39 am
Posts: 238
What tube types are used? It appears to be a simple repair job except for the rat's nest construction.

It would probably have a crystal or ceramic cartridge, a preamplifier tube, and a power amplifier tube. The volume control and tone control between the two.

Since there is hum, the power supply is working as well as the power amplifier. How loud is the hum? My first thought is to check the cartridge connections as well as the first amplifier stage. If the hum is very loud the problem is around the cartridge. If it's a gentle hum then I'd look between the two amplifiers or even make sure the first amplifier is getting anode voltage.

Be careful if this is a hot chassis design. If so, use an isolation transformer to prevent shock.


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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Wed 22, 2019 6:32 pm 
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Joined: Jan Wed 16, 2013 12:04 am
Posts: 1510
Location: 77001
Agree with bob91343 that if there's a crystal cartridge, it may be
going bad or is bad, as they will with time.
Ceramic carts go bad with age, also.
Disconnect leads from cart, and see what the hum does.
Touch each cart lead with a screwdriver and see if you
get hum/buzz increase. Make sure leads/cart pins aren't oxidized.

I doubt the output transformers are bad.
With age, they always yellow.

A bad tube may cause hum. Clean tube sockets
well, and check wiring connections for bad solder points.

Does the hum increase when the tonearm or changer
metal is touched ?

At some point, would consider replacing that old selenium
rectifier with a silicon diode one.

Hotwax


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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Wed 22, 2019 7:52 pm 
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Joined: May Tue 21, 2019 9:06 pm
Posts: 24
bob91343 wrote:
What tube types are used? It appears to be a simple repair job except for the rat's nest construction.

It would probably have a crystal or ceramic cartridge, a preamplifier tube, and a power amplifier tube. The volume control and tone control between the two.

Since there is hum, the power supply is working as well as the power amplifier. How loud is the hum? My first thought is to check the cartridge connections as well as the first amplifier stage. If the hum is very loud the problem is around the cartridge. If it's a gentle hum then I'd look between the two amplifiers or even make sure the first amplifier is getting anode voltage.

Be careful if this is a hot chassis design. If so, use an isolation transformer to prevent shock.


Both tubes are Raytheon 6OFX5 (60FX5?) 2800 65-25. I've never worked with tubes before. The hum gets louder as a volume control is increased.


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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Wed 22, 2019 7:55 pm 
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Joined: May Tue 21, 2019 9:06 pm
Posts: 24
Hotwax wrote:
Agree with bob91343 that if there's a crystal cartridge, it may be
going bad or is bad, as they will with time.
Ceramic carts go bad with age, also.
Disconnect leads from cart, and see what the hum does.
Touch each cart lead with a screwdriver and see if you
get hum/buzz increase. Make sure leads/cart pins aren't oxidized.

I doubt the output transformers are bad.
With age, they always yellow.

A bad tube may cause hum. Clean tube sockets
well, and check wiring connections for bad solder points.

Does the hum increase when the tonearm or changer
metal is touched ?

At some point, would consider replacing that old selenium
rectifier with a silicon diode one.

Hotwax


I removed the leads from the cartridge one at a time, no change. Touched each with a screwdriver, no change. Hum does not change when I touch the tonearm or changer metal.

To be clear, the hum sounds like what you'd hear out of a guitar amplifier or PA. Bad ground?


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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Wed 22, 2019 10:17 pm 
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Joined: Feb Wed 04, 2015 12:26 am
Posts: 883
If I had to make a educated guess, this is probably a Westinghouse.

Reverify your connections to make sure the caps were installed properly, especially if the hum is on both sides, focus on the power supply. As others have pointed out, get rid of that selenium rectifier, they can fail rather spectacularly.

As others have also pointed out, this is a fairly simple unit. You might be able to do a search using the tube layout, and find a similar amp's shematic.


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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Wed 22, 2019 10:19 pm 
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Joined: Feb Thu 28, 2019 7:48 pm
Posts: 253
Location: Lawrenceville, Illinois 62439
I'll ask what may be a dumb question: Is there a phono - aux switch of any kind that could be dirty? Or a shorting aux input jack (RCA type) on the back?
Dan


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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Wed 22, 2019 10:22 pm 
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Joined: Feb Wed 04, 2015 12:26 am
Posts: 883
Yarehobbiesso$ wrote:
I'll ask what may be a dumb question: Is there a phono - aux switch of any kind that could be dirty? Or a shorting aux input jack (RCA type) on the back?
Dan


Dan

Not on this unit, to be honest it's barely a phono amp.

HOWEVER, I just thought of something else-

to the OP-

Have changed the tubes? A heater/cathode short would cause hum. You be surprised how many of these high voltage 50-60v filament tubes are bad.


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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Wed 22, 2019 10:47 pm 
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Joined: May Tue 21, 2019 9:06 pm
Posts: 24
Artcurus wrote:
If I had to make a educated guess, this is probably a Westinghouse.

Reverify your connections to make sure the caps were installed properly, especially if the hum is on both sides, focus on the power supply. As others have pointed out, get rid of that selenium rectifier, they can fail rather spectacularly.

As others have also pointed out, this is a fairly simple unit. You might be able to do a search using the tube layout, and find a similar amp's shematic.


I'll look into replacing that rectifier.

EDIT: Didn't know exactly what you were talking about ask I've never heard of a "selenium" rectifier. I can replace that with an appropriate silicon diode?


Last edited by Jdc on May Wed 22, 2019 11:02 pm, edited 1 time in total.

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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Wed 22, 2019 10:48 pm 
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Joined: May Tue 21, 2019 9:06 pm
Posts: 24
Artcurus wrote:
Yarehobbiesso$ wrote:
I'll ask what may be a dumb question: Is there a phono - aux switch of any kind that could be dirty? Or a shorting aux input jack (RCA type) on the back?
Dan


Dan

Not on this unit, to be honest it's barely a phono amp.

HOWEVER, I just thought of something else-

to the OP-

Have changed the tubes? A heater/cathode short would cause hum. You be surprised how many of these high voltage 50-60v filament tubes are bad.


May as well at this point. Thanks for everyone's help!

EDIT: Would these work? https://www.ebay.com/sch/i.html?_from=R ... itleDesc=0


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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Wed 22, 2019 11:37 pm 
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Joined: Feb Wed 04, 2015 12:26 am
Posts: 883
Jdc wrote:
Artcurus wrote:
If I had to make a educated guess, this is probably a Westinghouse.

Reverify your connections to make sure the caps were installed properly, especially if the hum is on both sides, focus on the power supply. As others have pointed out, get rid of that selenium rectifier, they can fail rather spectacularly.

As others have also pointed out, this is a fairly simple unit. You might be able to do a search using the tube layout, and find a similar amp's shematic.


I'll look into replacing that rectifier.

EDIT: Didn't know exactly what you were talking about ask I've never heard of a "selenium" rectifier. I can replace that with an appropriate silicon diode?



The selenium rectifier is that green device with the plates. One of the failure modes for these is output voltage slowly dropping. You can replace it with a silicon diode but someone else will have to have to chime on to make sure its done properly.


Here's a schematic that should be fairly close to yours

https://tvforfree.files.wordpress.com/2 ... =640&h=476


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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Wed 22, 2019 11:48 pm 
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Joined: May Tue 21, 2019 9:06 pm
Posts: 24
Artcurus wrote:
Jdc wrote:
Artcurus wrote:
If I had to make a educated guess, this is probably a Westinghouse.

Reverify your connections to make sure the caps were installed properly, especially if the hum is on both sides, focus on the power supply. As others have pointed out, get rid of that selenium rectifier, they can fail rather spectacularly.

As others have also pointed out, this is a fairly simple unit. You might be able to do a search using the tube layout, and find a similar amp's shematic.


I'll look into replacing that rectifier.

EDIT: Didn't know exactly what you were talking about ask I've never heard of a "selenium" rectifier. I can replace that with an appropriate silicon diode?



The selenium rectifier is that green device with the plates. One of the failure modes for these is output voltage slowly dropping. You can replace it with a silicon diode but someone else will have to have to chime on to make sure its done properly.


Here's a schematic that should be fairly close to yours

https://tvforfree.files.wordpress.com/2 ... =640&h=476


Thank you!


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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Thu 23, 2019 1:14 am 
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Joined: May Tue 21, 2019 9:06 pm
Posts: 24
Two other questions (see pics):

1) (poor pic, I know) A red wire connects from a POTS to pin 4 of the tube. Schematic says that's the "heater"? It's the only connection that doesn't have any voltage. As far as I can tell, there is no voltage getting to the cartridge.

2) I've read that if I"m going to replace that old rectifier, I need to put a resistor in front of it. As you can see from the pic, there's one already there? Leave it or...?


Attachments:
tube.jpg
tube.jpg [ 231.55 KiB | Viewed 483 times ]
resistor.jpg
resistor.jpg [ 276.18 KiB | Viewed 483 times ]
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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Thu 23, 2019 3:21 am 
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Joined: Jan Wed 16, 2013 12:04 am
Posts: 1510
Location: 77001
Here's an interesting article & ARF thread on replacing selenium rectifiers.

That 100 ohm resistor after the rectifier, if tested good, can stay.

One thing to remember is to make sure to disconnect the
selenium rectifier from the circuit. You can still use it as a
component connector, but only one side of it.

Hotwax

http://w3hwj.com/index_files/RBSelenium2.pdf


viewtopic.php?f=6&t=331649&p=2776950&hilit=selenium+rectifier+replacement#p2776950


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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Thu 23, 2019 12:41 pm 
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Joined: May Tue 21, 2019 9:06 pm
Posts: 24
Hotwax wrote:
Here's an interesting article & ARF thread on replacing selenium rectifiers.

That 100 ohm resistor after the rectifier, if tested good, can stay.

One thing to remember is to make sure to disconnect the
selenium rectifier from the circuit. You can still use it as a
component connector, but only one side of it.

Hotwax

http://w3hwj.com/index_files/RBSelenium2.pdf


viewtopic.php?f=6&t=331649&p=2776950&hilit=selenium+rectifier+replacement#p2776950


That's the article I read from concerning the resistor. Pretty interesting.


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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Thu 23, 2019 1:13 pm 
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Joined: May Tue 21, 2019 9:06 pm
Posts: 24
In my first post, I stated that I could hear music from the cartridge. I should have specified that I can't hear the music from the speakers. If I put my ear up to the cartridge, I can hear the record.

Sorry for going all over the place. Just want to be sure I'm clear.


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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Thu 23, 2019 1:26 pm 
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Joined: Feb Wed 04, 2015 12:26 am
Posts: 883
Jdc wrote:
Two other questions (see pics):

1) (poor pic, I know) A red wire connects from a POTS to pin 4 of the tube. Schematic says that's the "heater"? It's the only connection that doesn't have any voltage. As far as I can tell, there is no voltage getting to the cartridge.

2) I've read that if I"m going to replace that old rectifier, I need to put a resistor in front of it. As you can see from the pic, there's one already there? Leave it or...?



If you can hear music coming from the cart, the cart is at least somewhat working. The cartridge doesn't receive voltage from the amp, it's the other way around. The amp takes the voltage from the cart and amplifes it.

Heater is actually the filament for the 60FX5, the heaters are connected directly to the line. In other words 60+60=120volts. You'll see this layout at the bottom of the shematic I sent.


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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Thu 23, 2019 1:48 pm 
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Joined: May Tue 21, 2019 9:06 pm
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Artcurus wrote:
Jdc wrote:
Two other questions (see pics):

1) (poor pic, I know) A red wire connects from a POTS to pin 4 of the tube. Schematic says that's the "heater"? It's the only connection that doesn't have any voltage. As far as I can tell, there is no voltage getting to the cartridge.

2) I've read that if I"m going to replace that old rectifier, I need to put a resistor in front of it. As you can see from the pic, there's one already there? Leave it or...?



If you can hear music coming from the cart, the cart is at least somewhat working. The cartridge doesn't receive voltage from the amp, it's the other way around. The amp takes the voltage from the cart and amplifes it.

Heater is actually the filament for the 60FX5, the heaters are connected directly to the line. In other words 60+60=120volts. You'll see this layout at the bottom of the shematic I sent.


I'll check them again but I'm pretty sure the tubes are fine. They glow, get hot to the touch, I don't see any cracks, nothing white inside, nothing sounds loose when I shake them. I'm going to go for replacing the rectifier tonight.


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 Post subject: Re: No Name Flip Down Record Player - No Audio, Just Hum
PostPosted: May Thu 23, 2019 2:36 pm 
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Joined: Feb Wed 04, 2015 12:26 am
Posts: 883
Jdc wrote:
Artcurus wrote:
Jdc wrote:
Two other questions (see pics):

1) (poor pic, I know) A red wire connects from a POTS to pin 4 of the tube. Schematic says that's the "heater"? It's the only connection that doesn't have any voltage. As far as I can tell, there is no voltage getting to the cartridge.

2) I've read that if I"m going to replace that old rectifier, I need to put a resistor in front of it. As you can see from the pic, there's one already there? Leave it or...?



If you can hear music coming from the cart, the cart is at least somewhat working. The cartridge doesn't receive voltage from the amp, it's the other way around. The amp takes the voltage from the cart and amplifes it.

Heater is actually the filament for the 60FX5, the heaters are connected directly to the line. In other words 60+60=120volts. You'll see this layout at the bottom of the shematic I sent.


I'll check them again but I'm pretty sure the tubes are fine. They glow, get hot to the touch, I don't see any cracks, nothing white inside, nothing sounds loose when I shake them. I'm going to go for replacing the rectifier tonight.



It's more complicated than "it's glowing". 60FX5 is a power pentode with 5 seperate structures supported by sheets of mica and rods. These structures consist of three different coils of wire, or grids, a metal structure visible through the glass, this is the plate, and the filament and cathode. The cathode produces the electrons when heated by the filament, the "glow". The grids control the flow of electrons to the plate.

Shorts between the cathode and filament are common with these high voltage filament tubes. This will introduce 60 cycle hum into the audio. The only way to find out for sure if the tube is shorted is with a tube tester.

For right now, the best option is to replace them, keep the old tubes as backup, clearly marking the boxes as "pulled on this date 5/23/19". If the hum continues, we move on to the rest of the amp.


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 Post subject: Re: BSR StereoMaster Flip Down Record Player -No Audio, Just
PostPosted: May Tue 28, 2019 6:56 pm 
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Joined: May Tue 21, 2019 9:06 pm
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EDIT: Rectifier has been replace with a IN4007 diode, no change.

Both tubes have been replaced, no change. I have not replace the rectifier with a diode yet. Any other ideas?

To review:

1) Can hear music coming from cartridge if you put your ear up to it. No music is coming from speakers.
2) Hum (like a badly grounded PA speaker) gets louder as knobs are turned.
3) There is an additional hum that occurs if you touch the metal of the turntable.


Last edited by Jdc on May Tue 28, 2019 7:23 pm, edited 1 time in total.

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