Rf sampler smoked out my radio

[mb91w126]

how about one step at a time.
1) radio>coax jumper>dummy load
2) radio> coax jumper>sampler>dummy load NB: no connections to scope from sampler
3)radio>coax jumper>sampler>dummy load NB: connect scope to sampler but scope powered off
4) same as 3 but scope powered on

that should give you an idea of componet causing issue

 

[Captain Kilowatt]

Something is not right with the wiring. There should not be any significant voltage between the radio chassis and ground or the scope chassis and ground. That 36 volts is suspect to me. Man I hate giving advise to someone regarding AC wiring. I am very comfortable tearing into an outlet to check the wiring but others may not be. I guess once you worked on 5000 volt DC supplies a little 120 ac outlet is a piece of cake. LOL All I can say is in the AC outlet the white wire (neutral) should go to the longer hole, the black wire (hot) should go to the shorter hole and the bare wire (ground) should connect to the outlet box itself or to the green terminal screw on the outlet itself. If the CB power supply has a two prong cord and the prongs are the same width, reverse the way it plugs into the outlet and measure again. If there is still no difference you may need to run a simple wire connecting the radio chassis, power supply chassis, and scope chassis together and tie it to ground. Then stand back and turn everything on. LOL No seriously sometimes you can have a phantom voltage floating around on the chassis and a common ground solves the issue however it is always better to solve the source of the issue first. I did have to install a common ground on a piece of tube type test gear one time to eliminate a similar issue.

 

[Robb]

These are cheap and available just about everywhere. My dad rewired our old house electrical system and didn't get every socket wired correctly. Went thru the house and used this tool to make sure that all of the wires were phased correctly and the ground was working. Any hardware store has them for about +/-$5.

Amazon product ASIN B002Q3R7HI

 

[Captain Kilowatt]

You mean one of these?

Amazon product ASIN B002LZTKIA

 

[805 california]

Something is not right with the wiring. There should not be any significant voltage between the radio chassis and ground or the scope chassis and ground. That 36 volts is suspect to me. Man I hate giving advise to someone regarding AC wiring. I am very comfortable tearing into an outlet to check the wiring but others may not be. I guess once you worked on 5000 volt DC supplies a little 120 ac outlet is a piece of cake. LOL All I can say is in the AC outlet the white wire (neutral) should go to the longer hole, the black wire (hot) should go to the shorter hole and the bare wire (ground) should connect to the outlet box itself or to the green terminal screw on the outlet itself. If the CB power supply has a two prong cord and the prongs are the same width, reverse the way it plugs into the outlet and measure again. If there is still no difference you may need to run a simple wire connecting the radio chassis, power supply chassis, and scope chassis together and tie it to ground. Then stand back and turn everything on. LOL No seriously sometimes you can have a phantom voltage floating around on the chassis and a common ground solves the issue however it is always better to solve the source of the issue first. I did have to install a common ground on a piece of tube type test gear one time to eliminate a similar issue.

Yeah I tested the sock and I'm getting 60 Volts ac on ground to ground. Any idea how to fix this?

 

[Tallman]

Where are you getting these voltages? from radio ground to scope or scope to ground.
It's like I said earlier defective wiring or equipment.

 

[805 california]

Where are you getting these voltages? from radio ground to scope or scope to ground.
It's like I said earlier defective wiring or equipment.

I got 60 volts from ground to neutral on Wall socket. Might be phantom volts. Getting wall tester now.

 

[805 california]

If I had my scope on the wrong
Settings could that smoke my radio?

 

[Tallman]

If I had my scope on the wrong
Settings could that smoke my radio?

NO! scope setting could not hurt your radio.
Sixty Volts can't be just stray voltage. Some thing is dangerously wrong.

 

[805 california]

NO! scope setting could not hurt your radio.
Sixty Volts can't be just stray voltage. Some thing is dangerously wrong.

I tested the wall outlets in my garage and all of them except one tested open ground. So did the open ground Fry my radio?????

 

[Tallman]

An open ground would not cause a radio melt down. Voltage on the wrong pins would.

 

[805 california]

An open ground would not cause a radio melt down. Voltage on the wrong pins would.

So I have concluded it has to be the scope. I have an old tektronix 465b. I hooked up to good wall supply. Fixed the burnt out radio it was running and lights working. Hooked up to scope through rf sampler and guess what????? Smoke starting billowing out. Something is seriously f-ed up with the scope is my conclusion.

 

[Tallman]

Sounds like a defect in the AC wiring in the scope.

 

[Captain Kilowatt]

Sounds like a defect in the AC wiring in the scope.

Wondering if the AC input has shunt capacitors across the leads to ground for RFI filtering and if one of those has developed a short or if the power cord was rewired at any time with the hot and neutral reversed. There is DEFINITELY something wrong with the AC power configuration in his setup somewhere. I wish I lived next door. I could probably find the issue in five minutes but it is so hard to coach someone how to deal with an AC power problem over the internet if they don't have a clue about AC power. No offense meant by that BTW.

 

[Tallman]

There is DEFINITELY something wrong with the AC power configuration in his setup somewhere. I wish I lived next door.

Agreed! One company I worked for back in the late 70's and early 80's required me to assist customers in trouble shooting (Over the Telephone) very complex computerized equipment. I was dealing with high level engineers and that was very hard to do.
Most of the equipment was D. O. D. and considered secret. Some very nasty technology came out of there.