Help with a Silvertone Model 7007

11/21/2010 12:27:40 PMDaniel

Hi!! I am working on a Silvertone, Model 7007. I replaced the V1 a 12BE6 converter and V2 a 12BA6 1st if amp. I also had to replace V5,a 35W4 rectifier.
I applied power and all I get is static through the speaker. This static will vary as the volume contol is changed. This radio wants to bring in many stations but all I hear is static. I then input a 455KHz signal to see if I could hear the tone, still static. Can anyone here give me some advice on where to go next. This chassis in usng a combination circuit labelled as K1 which is the audio circuit in one unit. I also have the schematic and list the measurements in a chart. I am going to check these measurements next. I am very greatful for any help I can have with this chassis. All have a great day!!!

Yours Truely,
Daniel

11/21/2010 12:59:40 PMWarren

Test for B+ on pin number 7 of the 12AV6. If there no voltage there,a 470K resistor is open in the compact circuit. you can add an external resistor from pin 6 of the 50C5 to

11/21/2010 1:08:05 PMWarren (the rest)

Test for B+ on pin number 7 of the 12AV6. If there no voltage there,a 470K resistor is open in the compact circuit. you can add an external resistor from pin 6 of the 50C5 to pin 7 of the 12AV6. This resistor is usually open if the IF transformers have the silver mica migration problem. You then need to take the IF transformers apart and remove the built in mica disks. replace with 100PF mica disks, then re-align the radio

11/21/2010 2:39:26 PMDaniel

:Test for B+ on pin number 7 of the 12AV6. If there no voltage there,a 470K resistor is open in the compact circuit. you can add an external resistor from pin 6 of the 50C5 to pin 7 of the 12AV6. This resistor is usually open if the IF transformers have the silver mica migration problem. You then need to take the IF transformers apart and remove the built in mica disks. replace with 100PF mica disks, then re-align the radio
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Dear Warren Thank you Sir for the input. I am going to check this now!! Thank you again!!!!

11/21/2010 3:05:31 PMWarren

Here is a link with pictures showing how to repair the mica capacitors inside the IF cans. It's about half way down the page. It also shows the "Audet" module with the inside components values. R2 is the suspect resistor that may be open. The problem you describe is the silver mica migration. Happens a lot to this kind of IF transformer.

http://www.wa2ise.com/radios/repair.htm#if

11/21/2010 4:57:53 PMDaniel

:Here is a link with pictures showing how to repair the mica capacitors inside the IF cans. It's about half way down the page. It also shows the "Audet" module with the inside components values. R2 is the suspect resistor that may be open. The problem you describe is the silver mica migration. Happens a lot to this kind of IF transformer.

Dear Warren, You are right on the money, I found the 470K ohm resitor, replaced it and the radio began to play. Thank you for the link, I will go there read this and work on the IF Cans. Thank you Kindly for your help!!! Have a great day!
Daniel
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:http://www.wa2ise.com/radios/repair.htm#if
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11/21/2010 6:11:49 PMWarren

When you are removing the IF transformers be sure to mark everything as to the can to board, and bottom of the insides to can. It is possible to put the insides back together backwards. There is a Primary and secondary winding. You can use 100pf mica disks at 50 volts on the bottom of the IF cans. Across each winding.

11/21/2010 6:26:23 PMDaniel

:When you are removing the IF transformers be sure to mark everything as to the can to board, and bottom of the insides to can. It is possible to put the insides back together backwards. There is a Primary and secondary winding. You can use 100pf mica disks at 50 volts on the bottom of the IF cans. Across each winding.

Thank you again Warren for all the help. I will post a summary of the project to let you know how it came out.
Daniel
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11/22/2010 7:59:37 PMPhil

I ate too much at lunch and dinner today and feel bloated, yuck!

::When you are removing the IF transformers be sure to mark everything as to the can to board, and bottom of the insides to can. It is possible to put the insides back together backwards. There is a Primary and secondary winding. You can use 100pf mica disks at 50 volts on the bottom of the IF cans. Across each winding.
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:Thank you again Warren for all the help. I will post a summary of the project to let you know how it came out.
:Daniel
::
:

11/22/2010 8:02:30 PMPhil

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:I ate too much at lunch and dinner today and feel bloated, yuck!
:
:::When you are removing the IF transformers be sure to mark everything as to the can to board, and bottom of the insides to can. It is possible to put the insides back together backwards. There is a Primary and secondary winding. You can use 100pf mica disks at 50 volts on the bottom of the IF cans. Across each winding.
::
::Thank you again Warren for all the help. I will post a summary of the project to let you know how it came out.
::Daniel
:::
::
:

11/22/2010 8:03:46 PMphil

learning to code in html. thanks for the forum to let me play

::::When you are removing the IF transformers be sure to mark everything as to the can to board, and bottom of the insides to can. It is possible to put the insides back together backwards. There is a Primary and secondary winding. You can use 100pf mica disks at 50 volts on the bottom of the IF cans. Across each winding.
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:::Thank you again Warren for all the help. I will post a summary of the project to let you know how it came out.
:::Daniel
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:::
::
:

11/22/2010 8:05:08 PMPhil

:learning to code in html. thanks for the forum to let me play
:

:::::When you are removing the IF transformers be sure to mark everything as to the can to board, and bottom of the insides to can. It is possible to put the insides back together backwards. There is a Primary and secondary winding. You can use 100pf mica disks at 50 volts on the bottom of the IF cans. Across each winding.
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::::Thank you again Warren for all the help. I will post a summary of the project to let you know how it came out.
::::Daniel
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