Hi,
My Philco 60 started motorboating, so I checked the tubes and the replacement caps I put in it last year (all are good). I also checked several of the resistors, which were good. When I touch the grid cap on the 78 tube, the motorboating stops and the local stations come in loud and clear. It also stops when I remove the grid cap from the 78. I tried a replacement 78, but no improvement. Anyone have any idea what might be ailing the radio? I'd rather focus on what the experienced folks out there suggest before I start taking out parts and testing them one at a time.
Thanks in advance,
Jeff

:Hi,
:My Philco 60 started motorboating, so I checked the tubes and the replacement caps I put in it last year (all are good). I also checked several of the resistors, which were good. When I touch the grid cap on the 78 tube, the motorboating stops and the local stations come in loud and clear. It also stops when I remove the grid cap from the 78. I tried a replacement 78, but no improvement. Anyone have any idea what might be ailing the radio? I'd rather focus on what the experienced folks out there suggest before I start taking out parts and testing them one at a time.
:Thanks in advance,
:Jeff

When you touch the grid of the 78, can you get any other stations besides the local one ??

::Hi,
::My Philco 60 started motorboating, so I checked the tubes and the replacement caps I put in it last year (all are good). I also checked several of the resistors, which were good. When I touch the grid cap on the 78 tube, the motorboating stops and the local stations come in loud and clear. It also stops when I remove the grid cap from the 78. I tried a replacement 78, but no improvement. Anyone have any idea what might be ailing the radio? I'd rather focus on what the experienced folks out there suggest before I start taking out parts and testing them one at a time.
::Thanks in advance,
::Jeff
:
:
:
:When you touch the grid of the 78, can you get any other stations besides the local one ??

Yes, it picks up the three local AM stations (910, 1320, 1390). Jeff

::Hi,
::My Philco 60 started motorboating, so I checked the tubes and the replacement caps I put in it last year (all are good). I also checked several of the resistors, which were good. When I touch the grid cap on the 78 tube, the motorboating stops and the local stations come in loud and clear. It also stops when I remove the grid cap from the 78. I tried a replacement 78, but no improvement. Anyone have any idea what might be ailing the radio? I'd rather focus on what the experienced folks out there suggest before I start taking out parts and testing them one at a time.
::Thanks in advance,
::Jeff
:~~~~~~~~~~~~~~~~~
:Initial thought , any possibility that there is no/poor grounding of that tubes shield.. if its of the old 2 part / spring compressed clamshell design that always seems to have an oxide coating creating on its surfaceparticularly in a humid environment ? How about a temporary ~.1 ufd test capacitor shunting across AVC bypass capacitor (Line item #7) or screen bypass capacitors (Line items # 20)on both the 6A7 and the 78 tubes. Or lastly, might the IF transformers need an ever so slight tweaking of one of their 4 tuning adjustments.
:73s de Edd
:~~~~~~~~~~~

:::Hi,
:::My Philco 60 started motorboating, so I checked the tubes and the replacement caps I put in it last year (all are good). I also checked several of the resistors, which were good. When I touch the grid cap on the 78 tube, the motorboating stops and the local stations come in loud and clear. It also stops when I remove the grid cap from the 78. I tried a replacement 78, but no improvement. Anyone have any idea what might be ailing the radio? I'd rather focus on what the experienced folks out there suggest before I start taking out parts and testing them one at a time.
:::Thanks in advance,
:::Jeff
::~~~~~~~~~~~~~~~~~
::Initial thought , any possibility that there is no/poor grounding of that tubes shield.. if its of the old 2 part / spring compressed clamshell design that always seems to have an oxide coating creating on its surfaceparticularly in a humid environment ? How about a temporary ~.1 ufd test capacitor shunting across AVC bypass capacitor (Line item #7) or screen bypass capacitors (Line items # 20)on both the 6A7 and the 78 tubes. Or lastly, might the IF transformers need an ever so slight tweaking of one of their 4 tuning adjustments.
::73s de Edd
::~~~~~~~~~~~

Edd,
Good call on the #20 cap bank. The "C" .05 mfd cap was out. As soon as I connected the test cap, the radio stations came in loud & clear. Thanks much for your help!

Jeff

:Hi,
:My Philco 60 started motorboating, so I checked the tubes and the replacement caps I put in it last year (all are good). I also checked several of the resistors, which were good. When I touch the grid cap on the 78 tube, the motorboating stops and the local stations come in loud and clear. It also stops when I remove the grid cap from the 78. I tried a replacement 78, but no improvement. Anyone have any idea what might be ailing the radio? I'd rather focus on what the experienced folks out there suggest before I start taking out parts and testing them one at a time.
:Thanks in advance,
:Jeff
~~~~~~~~~~~~~~~~~
Initial thought , any possibility that there is no/poor grounding of that tubes shield.. if its of the old 2 part / spring compressed clamshell design that always seems to have an oxide coating creating on its surfaceparticularly in a humid environment ? How about a temporary ~.1 ufd test capacitor shunting across AVC bypass capacitor (Line item #7) or screen bypass capacitor (Line item # 20). Or lastly, might the IF transformers need an ever so slight tweaking of one of their 4 tuning adjustments.
73s de Edd
~~~~~~~~~~~

::Hi,
::My Philco 60 started motorboating, so I checked the tubes and the replacement caps I put in it last year (all are good). I also checked several of the resistors, which were good. When I touch the grid cap on the 78 tube, the motorboating stops and the local stations come in loud and clear. It also stops when I remove the grid cap from the 78. I tried a replacement 78, but no improvement. Anyone have any idea what might be ailing the radio? I'd rather focus on what the experienced folks out there suggest before I start taking out parts and testing them one at a time.
::Thanks in advance,
::Jeff
:~~~~~~~~~~~~~~~~~
:Initial thought , any possibility that there is no/poor grounding of that tubes shield.. if its of the old 2 part / spring compressed clamshell design that always seems to have an oxide coating creating on its surfaceparticularly in a humid environment ? How about a temporary ~.1 ufd test capacitor shunting across AVC bypass capacitor (Line item #7) or screen bypass capacitors (Line items # 20)on both the 6A7 and the 78 tubes. Or lastly, might the IF transformers need an ever so slight tweaking of one of their 4 tuning adjustments.
:73s de Edd
:~~~~~~~~~~~

:::Hi,
:::My Philco 60 started motorboating, so I checked the tubes and the replacement caps I put in it last year (all are good). I also checked several of the resistors, which were good. When I touch the grid cap on the 78 tube, the motorboating stops and the local stations come in loud and clear. It also stops when I remove the grid cap from the 78. I tried a replacement 78, but no improvement. Anyone have any idea what might be ailing the radio? I'd rather focus on what the experienced folks out there suggest before I start taking out parts and testing them one at a time.
:::Thanks in advance,
:::Jeff
::~~~~~~~~~~~~~~~~~
::Initial thought , any possibility that there is no/poor grounding of that tubes shield.. if its of the old 2 part / spring compressed clamshell design that always seems to have an oxide coating creating on its surfaceparticularly in a humid environment ? How about a temporary ~.1 ufd test capacitor shunting across AVC bypass capacitor (Line item #7) or screen bypass capacitors (Line items # 20)on both the 6A7 and the 78 tubes. Or lastly, might the IF transformers need an ever so slight tweaking of one of their 4 tuning adjustments.
::73s de Edd
::~~~~~~~~~~~

Edd,
Good call on the #20 cap bank. The "C" .05 mfd cap was out. As soon as I connected the test cap, the radio stations came in loud & clear. Thanks much for your help!

Jeff