Philco 610

6/8/2003 10:13:47 AMbill beyrer

I have re-capped and replaced resistors on my Philco 610 (Type 2). I turn the set on (and turn the control to furthest counter clock-wise position). Regardless of strong station or not I get a high freq oscillation -measured resistance at this point and get infinite reading. Turn control a smidgen to the right get fairly louder than what would be considered normal volume (resistance is about 398K).Turn control to right about a quarter turn and get higher clear volume (resistance about 340K. After that Oscillations begin again up to full volume. If I tune in a really strong station I get the same results except I am able to run control to 3/4 of range before oscillations begin. I have taken the control apart by removing switch assy and cleaned with cleaner. Can anyone give me an idea as to where oscillation is coming from and how I can cure it. Tubes all check out at least good. I believe I read somewhere that the Philco volume controls in early models are not standard- my thought was to replace the current control with a 500K audio taper - but I thought I better check with a Philco expert first. I know that John Kendall does have a replacement control-which I might try as a last resort.
Obviously it was really neat to get the thing working again especially since someone really did a number on replacing the original electrolytics (both big can 8 ufd are missing - one replaced by an axial 16 ufd - the other replaced by a 8 ufd can expoxied to the top of the chassis.

6/8/2003 11:10:04 AMTHE PHILCO RESTORER

Hi Bill,
The 610 went tough 10 changes, some important, some not. There are 2 schematics for the 610 #217 and 217A.
Have E/Mail you all the information and the 217A schematic

Rick

Never a charge for PHILCO Information

oscillation -measured resistance at this point and get infinite reading. Turn control a smidgen to the right get fairly louder than what would be considered normal volume (resistance is about 398K).Turn control to right about a quarter turn and get higher clear volume (resistance about 340K. After that Oscillations begin again up to full volume. If I tune in a really strong station I get the same results except I am able to run control to 3/4 of range before oscillations begin. I have taken the control apart by removing switch assy and cleaned with cleaner. Can anyone give me an idea as to where oscillation is coming from and how I can cure it. Tubes all check out at least good. I believe I read somewhere that the Philco volume controls in early models are not standard- my thought was to replace the current control with a 500K audio taper - but I thought I better check with a Philco expert first. I know that John Kendall does have a replacement control-which I might try as a last resort.
:Obviously it was really neat to get the thing working again especially since someone really did a number on replacing the original electrolytics (both big can 8 ufd are missing - one replaced by an axial 16 ufd - the other replaced by a 8 ufd can expoxied to the top of the chassis.

6/8/2003 11:50:56 AMbill beyrer

Rick
Appreciate the info - especially the changes.

My question is Why would I be getting the oscillation with the volume control turned up only about 1/3 to 1/2 of its range? Perhaps have I missed a component or have a bad solder joint ?
Any help you can give to a novice would really be appreciated.

Also note on the schematic that the high end of the control supposedly goes to a phono switch - I don't have that switch. I go directly to the 51K resistor and .00011 ufd capicitor.

Bill

6/8/2003 12:19:41 PMTHE PHILCO RESTORER

Bill , Go though all the changes and check the schematic you have used for the rebuilding against the 217B schematic. And yes it could be a cold solder joint! I still do it !!
Rick

:My question is Why would I be getting the oscillation with the volume control turned up only about 1/3 to 1/2 of its range? Perhaps have I missed a component or have a bad solder joint ?
:Any help you can give to a novice would really be appreciated.
:
:Also note on the schematic that the high end of the control supposedly goes to a phono switch - I don't have that switch. I go directly to the 51K resistor and .00011 ufd capicitor.
:
:Bill

6/8/2003 12:25:45 PMTHE PHILCO RESTORER

Bill, what did you use in the 00011 Mica ??
Rick

:Bill , Go though all the changes and check the schematic you have used for the rebuilding against the 217B schematic. And yes it could be a cold solder joint! I still do it !!
:Rick
:
:
:
:
:
:
:
::My question is Why would I be getting the oscillation with the volume control turned up only about 1/3 to 1/2 of its range? Perhaps have I missed a component or have a bad solder joint ?
::Any help you can give to a novice would really be appreciated.
::
::Also note on the schematic that the high end of the control supposedly goes to a phono switch - I don't have that switch. I go directly to the 51K resistor and .00011 ufd capicitor.
::
::Bill

6/8/2003 1:11:48 PMJohn McPherson

Hi,
Also C15 might be leaky, this is the cap on the 6A7 cathode. I would also check the value of that cathode resistor too to make sure it has not shifted much in value.

:Bill, what did you use in the 00011 Mica ??
:Rick
:
:
:
:
::Bill , Go though all the changes and check the schematic you have used for the rebuilding against the 217B schematic. And yes it could be a cold solder joint! I still do it !!
::Rick
::
::
::
::
::
::
::
:::My question is Why would I be getting the oscillation with the volume control turned up only about 1/3 to 1/2 of its range? Perhaps have I missed a component or have a bad solder joint ?
:::Any help you can give to a novice would really be appreciated.
:::
:::Also note on the schematic that the high end of the control supposedly goes to a phono switch - I don't have that switch. I go directly to the 51K resistor and .00011 ufd capicitor.
:::
:::Bill

6/8/2003 1:14:47 PMNorm Leal

Be sure tube shields are in place on your 75 & 78.

Norm

:Hi,
:Also C15 might be leaky, this is the cap on the 6A7 cathode. I would also check the value of that cathode resistor too to make sure it has not shifted much in value.
:
:
::Bill, what did you use in the 00011 Mica ??
::Rick
::
::
::
::
:::Bill , Go though all the changes and check the schematic you have used for the rebuilding against the 217B schematic. And yes it could be a cold solder joint! I still do it !!
:::Rick
:::
:::
:::
:::
:::
:::
:::
::::My question is Why would I be getting the oscillation with the volume control turned up only about 1/3 to 1/2 of its range? Perhaps have I missed a component or have a bad solder joint ?
::::Any help you can give to a novice would really be appreciated.
::::
::::Also note on the schematic that the high end of the control supposedly goes to a phono switch - I don't have that switch. I go directly to the 51K resistor and .00011 ufd capicitor.
::::
::::Bill

6/8/2003 5:06:18 PMbill beyrer

My thanks to all of you since no one indicated as such about the control being special I will replace the Control with a standard 500K audio taper - since the current control obviously has an open at full counter clockwise position.

Norm yes the tube shields are in place

John I have replaced both the capacitor and resistor but I will recheck the values (PS-for what it's worth I did put the outside foil to ground)

Rick I think I will resolder joints like crazy also
the .00011 capacitor was one of two in a Philco block that I re-stuffed using to disc ceramics that I matched to .00011 - but here again I will recheck the values.

:Hi
:
: Be sure tube shields are in place on your 75 & 78.
:
:Norm
:
::Hi,
::Also C15 might be leaky, this is the cap on the 6A7 cathode. I would also check the value of that cathode resistor too to make sure it has not shifted much in value.
::
::
:::Bill, what did you use in the 00011 Mica ??
:::Rick
:::
:::
:::
:::
::::Bill , Go though all the changes and check the schematic you have used for the rebuilding against the 217B schematic. And yes it could be a cold solder joint! I still do it !!
::::Rick
::::
::::
::::
::::
::::
::::
::::
:::::My question is Why would I be getting the oscillation with the volume control turned up only about 1/3 to 1/2 of its range? Perhaps have I missed a component or have a bad solder joint ?
:::::Any help you can give to a novice would really be appreciated.
:::::
:::::Also note on the schematic that the high end of the control supposedly goes to a phono switch - I don't have that switch. I go directly to the 51K resistor and .00011 ufd capicitor.
:::::
:::::Bill