Hello, I just purchased an EICO 147A signal tracer that did not come with any probes. I converted the RF connector to a BNC type. I made a probe out of a 1N34A diode and a 470K resistor. These components were soldered in series with the center wire of the RF cable and I solder a test lead with an alligator clip to the outside wire mesh. When using the probe if I do not ground the probe it buzzes when I touch anything including myself. If I ground the probe it goes quiet when I touch anything. I connected a antenna from a radio shack police scanner and using a EICO signal generator when bring the RF wire near the antenna on the signal tracer the tracer buzzes and the angle on the eye tube come together so not ever using one of these I don't have any idea how it should work. When I soldered the BNC connector in I did an OHMS test from the inside pin to the outside of the connector and it show continuity but then again I don't know if that is correct. Can someone educate me on how this signal tracer work and what I am supposed to hear when tracing a signal?
Thank you for your help. Terry N.

Terry, here's the manual for the 147a: http://bama.edebris.com/manuals/eico/147a/

Not sure how you are using the ground clip. It should be connected to the chassis ground of the set you are testing.

This instrument is essentially an untuned radio. The idea is to touch the probe's tip at various points along the RF signal path, including mixer and IF stages, to see if the signal is getting that far. You should hear the station that the radio under test is tune to.

Not sure about you police scanner experiment. Best to start with a tube-type AM broadcast-band radio that is working.
Doug

:Hello, I just purchased an EICO 147A signal tracer that did not come with any probes. I converted the RF connector to a BNC type. I made a probe out of a 1N34A diode and a 470K resistor. These components were soldered in series with the center wire of the RF cable and I solder a test lead with an alligator clip to the outside wire mesh. When using the probe if I do not ground the probe it buzzes when I touch anything including myself. If I ground the probe it goes quiet when I touch anything. I connected a antenna from a radio shack police scanner and using a EICO signal generator when bring the RF wire near the antenna on the signal tracer the tracer buzzes and the angle on the eye tube come together so not ever using one of these I don't have any idea how it should work. When I soldered the BNC connector in I did an OHMS test from the inside pin to the outside of the connector and it show continuity but then again I don't know if that is correct. Can someone educate me on how this signal tracer work and what I am supposed to hear when tracing a signal?
:Thank you for your help. Terry N.
:

Hi Doug and thanks for the reply. I did what you said and used the signal tracer on an AK model 55C that work but not very loud. I found if I touch the screws on the top of the right tuning capacitor there is no sound from the radio speaker anymore but the tracer comes in loud and clear. I found if I touch either one of the tuning capacitors the radio speak stops working but I just get a buzz out of the signal tracer. I am very new at this and I am not sure what components you are supposed to touch to trace a signal but am glad my signal tracer works.
Thanks again Terry.
:Terry, here's the manual for the 147a: http://bama.edebris.com/manuals/eico/147a/
:
:Not sure how you are using the ground clip. It should be connected to the chassis ground of the set you are testing.
:
:This instrument is essentially an untuned radio. The idea is to touch the probe's tip at various points along the RF signal path, including mixer and IF stages, to see if the signal is getting that far. You should hear the station that the radio under test is tune to.
:
:Not sure about you police scanner experiment. Best to start with a tube-type AM broadcast-band radio that is working.
:Doug
:
:
::Hello, I just purchased an EICO 147A signal tracer that did not come with any probes. I converted the RF connector to a BNC type. I made a probe out of a 1N34A diode and a 470K resistor. These components were soldered in series with the center wire of the RF cable and I solder a test lead with an alligator clip to the outside wire mesh. When using the probe if I do not ground the probe it buzzes when I touch anything including myself. If I ground the probe it goes quiet when I touch anything. I connected a antenna from a radio shack police scanner and using a EICO signal generator when bring the RF wire near the antenna on the signal tracer the tracer buzzes and the angle on the eye tube come together so not ever using one of these I don't have any idea how it should work. When I soldered the BNC connector in I did an OHMS test from the inside pin to the outside of the connector and it show continuity but then again I don't know if that is correct. Can someone educate me on how this signal tracer work and what I am supposed to hear when tracing a signal?
::Thank you for your help. Terry N.
::

Hi Doug,
I better quit while I am ahead I was probing around with the rf probe with the signal tracer and I touched something it did not like. It quit working for awhile but is working again. I really could use some pointers if you got time.
Thanks Terry.
:Terry, here's the manual for the 147a: http://bama.edebris.com/manuals/eico/147a/
:
:Not sure how you are using the ground clip. It should be connected to the chassis ground of the set you are testing.
:
:This instrument is essentially an untuned radio. The idea is to touch the probe's tip at various points along the RF signal path, including mixer and IF stages, to see if the signal is getting that far. You should hear the station that the radio under test is tune to.
:
:Not sure about you police scanner experiment. Best to start with a tube-type AM broadcast-band radio that is working.
:Doug
:
:
::Hello, I just purchased an EICO 147A signal tracer that did not come with any probes. I converted the RF connector to a BNC type. I made a probe out of a 1N34A diode and a 470K resistor. These components were soldered in series with the center wire of the RF cable and I solder a test lead with an alligator clip to the outside wire mesh. When using the probe if I do not ground the probe it buzzes when I touch anything including myself. If I ground the probe it goes quiet when I touch anything. I connected a antenna from a radio shack police scanner and using a EICO signal generator when bring the RF wire near the antenna on the signal tracer the tracer buzzes and the angle on the eye tube come together so not ever using one of these I don't have any idea how it should work. When I soldered the BNC connector in I did an OHMS test from the inside pin to the outside of the connector and it show continuity but then again I don't know if that is correct. Can someone educate me on how this signal tracer work and what I am supposed to hear when tracing a signal?
::Thank you for your help. Terry N.
::

Hmmm. Terry, you better study the 147a manual and see if you can follow the operating instruction.

Typically, you will touch the probe to signal grid of each tube in the signal path. You will need to refer to the schematic for the radio under test, and look at the tube's data sheet (available here on this site) to identify which pin is which. It's a little easier with a later model set where the RF tubes' grid caps are on top of the tube.

As far as touching one of the AK 55's tuning caps with your finger, that will normally cause the set to stop receiving because the tuned circuit is thrown off by the capacitance of your finger - nothing abnormal about that.

The AK 55 has three RF stages - the signal should get stronger as you march down the signal path, checking the grid of each RF amplifier tube.

Best to use a systematic approach, avoiding just sticking the probe here and there.
Doug

:Hi Doug,
:I better quit while I am ahead I was probing around with the rf probe with the signal tracer and I touched something it did not like. It quit working for awhile but is working again. I really could use some pointers if you got time.
:Thanks Terry.
::Terry, here's the manual for the 147a: http://bama.edebris.com/manuals/eico/147a/
::
::Not sure how you are using the ground clip. It should be connected to the chassis ground of the set you are testing.
::
::This instrument is essentially an untuned radio. The idea is to touch the probe's tip at various points along the RF signal path, including mixer and IF stages, to see if the signal is getting that far. You should hear the station that the radio under test is tune to.
::
::Not sure about you police scanner experiment. Best to start with a tube-type AM broadcast-band radio that is working.
::Doug
::
::
:::Hello, I just purchased an EICO 147A signal tracer that did not come with any probes. I converted the RF connector to a BNC type. I made a probe out of a 1N34A diode and a 470K resistor. These components were soldered in series with the center wire of the RF cable and I solder a test lead with an alligator clip to the outside wire mesh. When using the probe if I do not ground the probe it buzzes when I touch anything including myself. If I ground the probe it goes quiet when I touch anything. I connected a antenna from a radio shack police scanner and using a EICO signal generator when bring the RF wire near the antenna on the signal tracer the tracer buzzes and the angle on the eye tube come together so not ever using one of these I don't have any idea how it should work. When I soldered the BNC connector in I did an OHMS test from the inside pin to the outside of the connector and it show continuity but then again I don't know if that is correct. Can someone educate me on how this signal tracer work and what I am supposed to hear when tracing a signal?
:::Thank you for your help. Terry N.
:::

Terry, I have the EICO 147 which has a speaker and the eye tube. I believe that the 147A had the eye tube only, no speaker. Basically the unit is a AF/RF amplifier. You check the stages in the radio by starting at the front end and pick up the RF signal at first amp tube. You adjust the level for low response then probe at next stage, signal should be there and stronger then previous stage. You continue along until AF stage then switch over to AF signal and again adjust level low then check next stage which should be stronger. Draw back is if you have a set that is not working (no signal) you cant use the tracer unless you have a signal generator. If you have signal generator, you induce a signal at ant and using probe see how far signal travels before losing signal. Obviously point between signal no signal is problem area. On the 147 you can use both the eye tube and spkr (your ears) to see/hear gain. On 147A you only have eye tube to check level. Get the manual as it explains testing procedure. If you can find the manual for the Precision 202 signal tracer that has an extensive explaination of operation with diagrams.
I have both the EICO 147 and the Precision 202. If you think the probe on the EICO was a PITA to make, the 202 ha a tube in the probe! Fabricating that was fun! As an aside, the 147 has a cap in the RF line in so if you probe on a B+ supply it can't get into the unit. On the 147 I added a .01mfd in the AF circuit for that margin of safety. Having said all that the center pin of the RF should not read continuity. The center pin goes through a .01mfd cap to the 6SQ7 grid then to ground through a 470K resistor. That pin to ground should read infinity on ohmmeter.

:Hmmm. Terry, you better study the 147a manual and see if you can follow the operating instruction.
:
:Typically, you will touch the probe to signal grid of each tube in the signal path. You will need to refer to the schematic for the radio under test, and look at the tube's data sheet (available here on this site) to identify which pin is which. It's a little easier with a later model set where the RF tubes' grid caps are on top of the tube.
:
:As far as touching one of the AK 55's tuning caps with your finger, that will normally cause the set to stop receiving because the tuned circuit is thrown off by the capacitance of your finger - nothing abnormal about that.
:
:The AK 55 has three RF stages - the signal should get stronger as you march down the signal path, checking the grid of each RF amplifier tube.
:
:Best to use a systematic approach, avoiding just sticking the probe here and there.
:Doug
:
::Hi Doug,
::I better quit while I am ahead I was probing around with the rf probe with the signal tracer and I touched something it did not like. It quit working for awhile but is working again. I really could use some pointers if you got time.
::Thanks Terry.
:::Terry, here's the manual for the 147a: http://bama.edebris.com/manuals/eico/147a/
:::
:::Not sure how you are using the ground clip. It should be connected to the chassis ground of the set you are testing.
:::
:::This instrument is essentially an untuned radio. The idea is to touch the probe's tip at various points along the RF signal path, including mixer and IF stages, to see if the signal is getting that far. You should hear the station that the radio under test is tune to.
:::
:::Not sure about you police scanner experiment. Best to start with a tube-type AM broadcast-band radio that is working.
:::Doug
:::
:::
::::Hello, I just purchased an EICO 147A signal tracer that did not come with any probes. I converted the RF connector to a BNC type. I made a probe out of a 1N34A diode and a 470K resistor. These components were soldered in series with the center wire of the RF cable and I solder a test lead with an alligator clip to the outside wire mesh. When using the probe if I do not ground the probe it buzzes when I touch anything including myself. If I ground the probe it goes quiet when I touch anything. I connected a antenna from a radio shack police scanner and using a EICO signal generator when bring the RF wire near the antenna on the signal tracer the tracer buzzes and the angle on the eye tube come together so not ever using one of these I don't have any idea how it should work. When I soldered the BNC connector in I did an OHMS test from the inside pin to the outside of the connector and it show continuity but then again I don't know if that is correct. Can someone educate me on how this signal tracer work and what I am supposed to hear when tracing a signal?
::::Thank you for your help. Terry N.
::::

Hello and thanks for the reply. My signal tracer does have a speaker and I also have a EICO 324 signal generator. I stopped playing with them though. Seems I got enough equipment now to get me in trouble because I don't know what I am doing. Right now I am reading the manuals and a radio repair guide trying to learn. I am having fun though. The last time I used the signal tracer I touched something it didn't like and it quit working for a while so until I edumicate myself a little more I got my nose stuck in a book. Thanks for the help.
Terry

: Terry, I have the EICO 147 which has a speaker and the eye tube. I believe that the 147A had the eye tube only, no speaker. Basically the unit is a AF/RF amplifier. You check the stages in the radio by starting at the front end and pick up the RF signal at first amp tube. You adjust the level for low response then probe at next stage, signal should be there and stronger then previous stage. You continue along until AF stage then switch over to AF signal and again adjust level low then check next stage which should be stronger. Draw back is if you have a set that is not working (no signal) you cant use the tracer unless you have a signal generator. If you have signal generator, you induce a signal at ant and using probe see how far signal travels before losing signal. Obviously point between signal no signal is problem area. On the 147 you can use both the eye tube and spkr (your ears) to see/hear gain. On 147A you only have eye tube to check level. Get the manual as it explains testing procedure. If you can find the manual for the Precision 202 signal tracer that has an extensive explaination of operation with diagrams.
: I have both the EICO 147 and the Precision 202. If you think the probe on the EICO was a PITA to make, the 202 ha a tube in the probe! Fabricating that was fun! As an aside, the 147 has a cap in the RF line in so if you probe on a B+ supply it can't get into the unit. On the 147 I added a .01mfd in the AF circuit for that margin of safety. Having said all that the center pin of the RF should not read continuity. The center pin goes through a .01mfd cap to the 6SQ7 grid then to ground through a 470K resistor. That pin to ground should read infinity on ohmmeter.
:
:
:
:
::Hmmm. Terry, you better study the 147a manual and see if you can follow the operating instruction.
::
::Typically, you will touch the probe to signal grid of each tube in the signal path. You will need to refer to the schematic for the radio under test, and look at the tube's data sheet (available here on this site) to identify which pin is which. It's a little easier with a later model set where the RF tubes' grid caps are on top of the tube.
::
::As far as touching one of the AK 55's tuning caps with your finger, that will normally cause the set to stop receiving because the tuned circuit is thrown off by the capacitance of your finger - nothing abnormal about that.
::
::The AK 55 has three RF stages - the signal should get stronger as you march down the signal path, checking the grid of each RF amplifier tube.
::
::Best to use a systematic approach, avoiding just sticking the probe here and there.
::Doug
::
:::Hi Doug,
:::I better quit while I am ahead I was probing around with the rf probe with the signal tracer and I touched something it did not like. It quit working for awhile but is working again. I really could use some pointers if you got time.
:::Thanks Terry.
::::Terry, here's the manual for the 147a: http://bama.edebris.com/manuals/eico/147a/
::::
::::Not sure how you are using the ground clip. It should be connected to the chassis ground of the set you are testing.
::::
::::This instrument is essentially an untuned radio. The idea is to touch the probe's tip at various points along the RF signal path, including mixer and IF stages, to see if the signal is getting that far. You should hear the station that the radio under test is tune to.
::::
::::Not sure about you police scanner experiment. Best to start with a tube-type AM broadcast-band radio that is working.
::::Doug
::::
::::
:::::Hello, I just purchased an EICO 147A signal tracer that did not come with any probes. I converted the RF connector to a BNC type. I made a probe out of a 1N34A diode and a 470K resistor. These components were soldered in series with the center wire of the RF cable and I solder a test lead with an alligator clip to the outside wire mesh. When using the probe if I do not ground the probe it buzzes when I touch anything including myself. If I ground the probe it goes quiet when I touch anything. I connected a antenna from a radio shack police scanner and using a EICO signal generator when bring the RF wire near the antenna on the signal tracer the tracer buzzes and the angle on the eye tube come together so not ever using one of these I don't have any idea how it should work. When I soldered the BNC connector in I did an OHMS test from the inside pin to the outside of the connector and it show continuity but then again I don't know if that is correct. Can someone educate me on how this signal tracer work and what I am supposed to hear when tracing a signal?
:::::Thank you for your help. Terry N.
:::::

:Hmmm. Terry, you better study the 147a manual and see if you can follow the operating instruction.
:
:Typically, you will touch the probe to signal grid of each tube in the signal path. You will need to refer to the schematic for the radio under test, and look at the tube's data sheet (available here on this site) to identify which pin is which. It's a little easier with a later model set where the RF tubes' grid caps are on top of the tube.
:
:As far as touching one of the AK 55's tuning caps with your finger, that will normally cause the set to stop receiving because the tuned circuit is thrown off by the capacitance of your finger - nothing abnormal about that.
:
:The AK 55 has three RF stages - the signal should get stronger as you march down the signal path, checking the grid of each RF amplifier tube.
:
:Best to use a systematic approach, avoiding just sticking the probe here and there.
:Doug
:
::Hi Doug,
::I better quit while I am ahead I was probing around with the rf probe with the signal tracer and I touched something it did not like. It quit working for awhile but is working again. I really could use some pointers if you got time.
::Thanks Terry.
:::Terry, here's the manual for the 147a: http://bama.edebris.com/manuals/eico/147a/
:::
:::Not sure how you are using the ground clip. It should be connected to the chassis ground of the set you are testing.
:::
:::This instrument is essentially an untuned radio. The idea is to touch the probe's tip at various points along the RF signal path, including mixer and IF stages, to see if the signal is getting that far. You should hear the station that the radio under test is tune to.
:::
:::Not sure about you police scanner experiment. Best to start with a tube-type AM broadcast-band radio that is working.
:::Doug
:::
:::
::::Hello, I just purchased an EICO 147A signal tracer that did not come with any probes. I converted the RF connector to a BNC type. I made a probe out of a 1N34A diode and a 470K resistor. These components were soldered in series with the center wire of the RF cable and I solder a test lead with an alligator clip to the outside wire mesh. When using the probe if I do not ground the probe it buzzes when I touch anything including myself. If I ground the probe it goes quiet when I touch anything. I connected a antenna from a radio shack police scanner and using a EICO signal generator when bring the RF wire near the antenna on the signal tracer the tracer buzzes and the angle on the eye tube come together so not ever using one of these I don't have any idea how it should work. When I soldered the BNC connector in I did an OHMS test from the inside pin to the outside of the connector and it show continuity but then again I don't know if that is correct. Can someone educate me on how this signal tracer work and what I am supposed to hear when tracing a signal?
::::Thank you for your help. Terry N.
::::

This post is over two years old, doesn't anyone ever check the dates anymore?

Dave

:Hmmm. Terry, you better study the 147a manual and see if you can follow the operating instruction.
:
:Typically, you will touch the probe to signal grid of each tube in the signal path. You will need to refer to the schematic for the radio under test, and look at the tube's data sheet (available here on this site) to identify which pin is which. It's a little easier with a later model set where the RF tubes' grid caps are on top of the tube.
:
:As far as touching one of the AK 55's tuning caps with your finger, that will normally cause the set to stop receiving because the tuned circuit is thrown off by the capacitance of your finger - nothing abnormal about that.
:
:The AK 55 has three RF stages - the signal should get stronger as you march down the signal path, checking the grid of each RF amplifier tube.
:
:Best to use a systematic approach, avoiding just sticking the probe here and there.
:Doug
:
::Hi Doug,
::I better quit while I am ahead I was probing around with the rf probe with the signal tracer and I touched something it did not like. It quit working for awhile but is working again. I really could use some pointers if you got time.
::Thanks Terry.
:::Terry, here's the manual for the 147a: http://bama.edebris.com/manuals/eico/147a/
:::
:::Not sure how you are using the ground clip. It should be connected to the chassis ground of the set you are testing.
:::
:::This instrument is essentially an untuned radio. The idea is to touch the probe's tip at various points along the RF signal path, including mixer and IF stages, to see if the signal is getting that far. You should hear the station that the radio under test is tune to.
:::
:::Not sure about you police scanner experiment. Best to start with a tube-type AM broadcast-band radio that is working.
:::Doug
:::
:::
::::Hello, I just purchased an EICO 147A signal tracer that did not come with any probes. I converted the RF connector to a BNC type. I made a probe out of a 1N34A diode and a 470K resistor. These components were soldered in series with the center wire of the RF cable and I solder a test lead with an alligator clip to the outside wire mesh. When using the probe if I do not ground the probe it buzzes when I touch anything including myself. If I ground the probe it goes quiet when I touch anything. I connected a antenna from a radio shack police scanner and using a EICO signal generator when bring the RF wire near the antenna on the signal tracer the tracer buzzes and the angle on the eye tube come together so not ever using one of these I don't have any idea how it should work. When I soldered the BNC connector in I did an OHMS test from the inside pin to the outside of the connector and it show continuity but then again I don't know if that is correct. Can someone educate me on how this signal tracer work and what I am supposed to hear when tracing a signal?
::::Thank you for your help. Terry N.
::::