car radio

1/24/2013 4:00:24 PMAl

Hi: I appreciate the help on my last car radio project. I was able to recap it and it sounds great. My brother in law liked it so much he asked me to do another one for him. This one is for a 1942 chevy radio model #985793. The vibrator appears to be bad in it. How can I tell if the vibrator is a positive or negative ground before I order one? Thanks for any help you can provide. Al

1/24/2013 4:32:59 PMLewis

:Hi: I appreciate the help on my last car radio project. I was able to recap it and it sounds great. My brother in law liked it so much he asked me to do another one for him. This one is for a 1942 chevy radio model #985793. The vibrator appears to be bad in it. How can I tell if the vibrator is a positive or negative ground before I order one? Thanks for any help you can provide. Al

Al:
The vibrator couldn't care less about the polarity of the car battery.
Lewis

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1/24/2013 7:28:32 PMCarl T

::Hi: I appreciate the help on my last car radio project. I was able to recap it and it sounds great. My brother in law liked it so much he asked me to do another one for him. This one is for a 1942 chevy radio model #985793. The vibrator appears to be bad in it. How can I tell if the vibrator is a positive or negative ground before I order one? Thanks for any help you can provide. Al
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:Al:
:The vibrator couldn't care less about the polarity of the car battery.
:Lewis
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Al,
Here's the OEM service info for the radio:
http://chevy.oldcarmanualproject.com/radios/pdf/6D840ums.pdf
Carl T

1/24/2013 8:37:24 PMJohn K

A '42 Chev would be a military vehicle, wouldn't it? Green with a star on the door, and covers over the headlights? Oh yeah, the radio. It would be negative ground if I'm not mistaken. For parades, he could use it to broadcast Winston Churchill and Roosevelt speeches.

1/24/2013 10:12:36 PMCarl T

:A '42 Chev would be a military vehicle, wouldn't it? Green with a star on the door, and covers over the headlights? Oh yeah, the radio. It would be negative ground if I'm not mistaken. For parades, he could use it to broadcast Winston Churchill and Roosevelt speeches.
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Actually, 1942 models were released in Sept. 1941 and civilian production, I believe ran through Feb. 1942
Carl T

1/25/2013 9:16:28 AMAl

Thanks Carl - great information on this radio! Radio Daze apparantly cares about polarity since they ask that you state whether the vibrator is positive or negative ground. I'm guessing it's negative since the other components are grounded to the chassis. Would you agree? Thanks again.

:::Hi: I appreciate the help on my last car radio project. I was able to recap it and it sounds great. My brother in law liked it so much he asked me to do another one for him. This one is for a 1942 chevy radio model #985793. The vibrator appears to be bad in it. How can I tell if the vibrator is a positive or negative ground before I order one? Thanks for any help you can provide. Al
::
::
::Al:
::The vibrator couldn't care less about the polarity of the car battery.
::Lewis
::
:Al,
:Here's the OEM service info for the radio:
:http://chevy.oldcarmanualproject.com/radios/pdf/6D840ums.pdf
:Carl T
:

1/25/2013 9:32:17 AMCarl T

Al,
The chevy old car manual project is useful again:
http://chevy.oldcarmanualproject.com/electrical/wiring/images/42csm1232a.jpg
Carl T

:Thanks Carl - great information on this radio! Radio Daze apparantly cares about polarity since they ask that you state whether the vibrator is positive or negative ground. I'm guessing it's negative since the other components are grounded to the chassis. Would you agree? Thanks again.
:
::::Hi: I appreciate the help on my last car radio project. I was able to recap it and it sounds great. My brother in law liked it so much he asked me to do another one for him. This one is for a 1942 chevy radio model #985793. The vibrator appears to be bad in it. How can I tell if the vibrator is a positive or negative ground before I order one? Thanks for any help you can provide. Al
:::
:::
:::Al:
:::The vibrator couldn't care less about the polarity of the car battery.
:::Lewis
:::
::Al,
::Here's the OEM service info for the radio:
::http://chevy.oldcarmanualproject.com/radios/pdf/6D840ums.pdf
::Carl T
::
:
:

1/25/2013 10:05:33 AMClifton

Agree with Lewis that the vibrator wouldn't know the difference radio supply voltage polarity unless one built or ordered a solid state vibrator.

Clifton

::Hi: I appreciate the help on my last car radio project. I was able to recap it and it sounds great. My brother in law liked it so much he asked me to do another one for him. This one is for a 1942 chevy radio model #985793. The vibrator appears to be bad in it. How can I tell if the vibrator is a positive or negative ground before I order one? Thanks for any help you can provide. Al
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:Al:
:The vibrator couldn't care less about the polarity of the car battery.
:Lewis
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::
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1/25/2013 10:31:26 AMNorm Leal

Hi

Agree the vibrator doesn't care about polarity unless it has more than 4 pins. Some vibrators also take the place of rectifier tubes. In these polarity matters.

As mentioned with solid state vibrators polarity is important to get right. Wrong polarity can destroy a solid state type.

Norm

:Hi: I appreciate the help on my last car radio project. I was able to recap it and it sounds great. My brother in law liked it so much he asked me to do another one for him. This one is for a 1942 chevy radio model #985793. The vibrator appears to be bad in it. How can I tell if the vibrator is a positive or negative ground before I order one? Thanks for any help you can provide. Al
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1/25/2013 12:18:21 PMAl

Thanks Norm. If I order a replacement vibrator from Radio Daze, should I order the 4 pin 6 volt negative ground or as you note does it really matter whether it's positive or negative? In their add they make to to make sure to identify it as positive or negative. Not sure I understand the principles behind the vibrator. When I tested the tube pins it had no voltage except for the heaters and dial bulbs and no noise from the vibrator so I'm assuming that's at least part of the problem. As always I do appreciate your help. Al

:Hi
:
:Agree the vibrator doesn't care about polarity unless it has more than 4 pins. Some vibrators also take the place of rectifier tubes. In these polarity matters.
:
: As mentioned with solid state vibrators polarity is important to get right. Wrong polarity can destroy a solid state type.
:
:Norm
:
::Hi: I appreciate the help on my last car radio project. I was able to recap it and it sounds great. My brother in law liked it so much he asked me to do another one for him. This one is for a 1942 chevy radio model #985793. The vibrator appears to be bad in it. How can I tell if the vibrator is a positive or negative ground before I order one? Thanks for any help you can provide. Al
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1/25/2013 1:41:30 PMJohn K

Al, the vehicle wiring diagram clearly shows that the '42 Chev uses negative ground, so yes, order the negative ground solid state vibrator. The vibrator interrupts the DC voltage from the battery. This acts as a 6 volt AC input to a step-up transformer. The transformer steps the voltage up to 100 vac or more. Then that is converted back to DC with a diode tube. That is your B+ for the plate circuit, 100 or more VDC.

:Thanks Norm. If I order a replacement vibrator from Radio Daze, should I order the 4 pin 6 volt negative ground or as you note does it really matter whether it's positive or negative? In their add they make to to make sure to identify it as positive or negative. Not sure I understand the principles behind the vibrator. When I tested the tube pins it had no voltage except for the heaters and dial bulbs and no noise from the vibrator so I'm assuming that's at least part of the problem. As always I do appreciate your help. Al
:
:
::Hi
::
::Agree the vibrator doesn't care about polarity unless it has more than 4 pins. Some vibrators also take the place of rectifier tubes. In these polarity matters.
::
:: As mentioned with solid state vibrators polarity is important to get right. Wrong polarity can destroy a solid state type.
::
::Norm
::
:::Hi: I appreciate the help on my last car radio project. I was able to recap it and it sounds great. My brother in law liked it so much he asked me to do another one for him. This one is for a 1942 chevy radio model #985793. The vibrator appears to be bad in it. How can I tell if the vibrator is a positive or negative ground before I order one? Thanks for any help you can provide. Al
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1/25/2013 2:39:37 PMLewis

:Al, the vehicle wiring diagram clearly shows that the '42 Chev uses negative ground, so yes, order the negative ground solid state vibrator. The vibrator interrupts the DC voltage from the battery. This acts as a 6 volt AC input to a step-up transformer. The transformer steps the voltage up to 100 vac or more. Then that is converted back to DC with a diode tube. That is your B+ for the plate circuit, 100 or more VDC.

OK, if you are using a solid state vibrator, you have to think about polarity.....but one thing you have to do, solid state or mechanical....REPLACE THE BUFFER CAPACITOR!!!!! Either vibrator puts out a square wave that produces tremendous spikes in the secondary winding of the transformer, and the buffer protectes the rectifier, as well as the vibrator from these spikes. Pardon the caps, but this is important.

Lewis
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::Thanks Norm. If I order a replacement vibrator from Radio Daze, should I order the 4 pin 6 volt negative ground or as you note does it really matter whether it's positive or negative? In their add they make to to make sure to identify it as positive or negative. Not sure I understand the principles behind the vibrator. When I tested the tube pins it had no voltage except for the heaters and dial bulbs and no noise from the vibrator so I'm assuming that's at least part of the problem. As always I do appreciate your help. Al
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:::Hi
:::
:::Agree the vibrator doesn't care about polarity unless it has more than 4 pins. Some vibrators also take the place of rectifier tubes. In these polarity matters.
:::
::: As mentioned with solid state vibrators polarity is important to get right. Wrong polarity can destroy a solid state type.
:::
:::Norm
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::::Hi: I appreciate the help on my last car radio project. I was able to recap it and it sounds great. My brother in law liked it so much he asked me to do another one for him. This one is for a 1942 chevy radio model #985793. The vibrator appears to be bad in it. How can I tell if the vibrator is a positive or negative ground before I order one? Thanks for any help you can provide. Al
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1/26/2013 1:35:41 PMAl

Outstanding guys! Thanks for the help on this. I did order a solid state negative ground and the correct buffer cap. Al

:Al, the vehicle wiring diagram clearly shows that the '42 Chev uses negative ground, so yes, order the negative ground solid state vibrator. The vibrator interrupts the DC voltage from the battery. This acts as a 6 volt AC input to a step-up transformer. The transformer steps the voltage up to 100 vac or more. Then that is converted back to DC with a diode tube. That is your B+ for the plate circuit, 100 or more VDC.
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::Thanks Norm. If I order a replacement vibrator from Radio Daze, should I order the 4 pin 6 volt negative ground or as you note does it really matter whether it's positive or negative? In their add they make to to make sure to identify it as positive or negative. Not sure I understand the principles behind the vibrator. When I tested the tube pins it had no voltage except for the heaters and dial bulbs and no noise from the vibrator so I'm assuming that's at least part of the problem. As always I do appreciate your help. Al
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:::Hi
:::
:::Agree the vibrator doesn't care about polarity unless it has more than 4 pins. Some vibrators also take the place of rectifier tubes. In these polarity matters.
:::
::: As mentioned with solid state vibrators polarity is important to get right. Wrong polarity can destroy a solid state type.
:::
:::Norm
:::
::::Hi: I appreciate the help on my last car radio project. I was able to recap it and it sounds great. My brother in law liked it so much he asked me to do another one for him. This one is for a 1942 chevy radio model #985793. The vibrator appears to be bad in it. How can I tell if the vibrator is a positive or negative ground before I order one? Thanks for any help you can provide. Al
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