#95 National NCX 3 Repair Part 1 Blooper to follow

[Radio Tech]

This is part one of the National NCX-3 repair. We replace some capacitors and check out the receiver.
At the end of the video I share a major blooper with the group.

[voltz]

That was interesting. Thanks for posting! re:queston, thinking its because the two contact metals are different (bi-metal) so causes corrosion. Must admit, i dont know exactly why its only on the negative. Electrons flowing from negative to positive right? So i assume its some kind of electrolysis taking place.
Great blooper fail, you get a gold star for that one 

[GreyWoolfe]

  for the repair job and, of course, a for the blooper!  A few years back, I was given 2 old Tek tube scopes, 1 without the cover on it.  Not having either a variac or a dim bulb tester, I still decided to plug them in.  The one without the cover powered up fine with traces, the other didn't power up at all.  I decided to check the plug-ins from that scope in the original one since the plug-ins were the same.  The first went fine but when I powered up the scope with the 2nd plug-in,  .  I actually had a small flame coming out of the top of the scope until I pulled the plug out of the wall.  Needless to say, I didn't have the door to my office closed so the smell made its' way into the house and lingered for a couple of days.  SWMBO wasn't happy with me and made me put the scopes out for trash.  Unfortunately, the trash pickup is early so she waited until she saw the scopes go into the garbage truck before she went to work because she didn't trust me.  I now have both a dim bulb tester and a variac  .

[Radio Tech]

That was interesting. Thanks for posting! re:queston, thinking its because the two contact metals are different (bi-metal) so causes corrosion. Must admit, i dont know exactly why its only on the negative. Electrons flowing from negative to positive right? So i assume its some kind of electrolysis taking place.

Correct. There is a difference in the two metals.  And also correct in the flow of electrons. 

Great blooper fail, you get a gold star for that one 

Thanks again. I will wear the gold star proudly 
Most of the time I edit out the fails but let this one stay.

[Radio Tech]

for the repair job and, of course, a for the blooper!  A few years back, I was given 2 old Tek tube scopes, 1 without the cover on it.  Not having either a variac or a dim bulb tester, I still decided to plug them in.  The one without the cover powered up fine with traces, the other didn't power up at all.  I decided to check the plug-ins from that scope in the original one since the plug-ins were the same.  The first went fine but when I powered up the scope with the 2nd plug-in,  .  I actually had a small flame coming out of the top of the scope until I pulled the plug out of the wall.  Needless to say, I didn't have the door to my office closed so the smell made its' way into the house and lingered for a couple of days.  SWMBO wasn't happy with me and made me put the scopes out for trash.  Unfortunately, the trash pickup is early so she waited until she saw the scopes go into the garbage truck before she went to work because she didn't trust me.  I now have both a dim bulb tester and a variac  .

Thanks, guess it happens to us all.
Thanks for sharing that story.  A exploding capacitor can stink up a place for a long time.  Wife will not let me have a lab in the house for the last 30 years.  We had a sun room where my lab was and was working on a tube amp.  Like you no protection devices.  I powered it up and next thing I know, the 6 220 uF and 500 volt capacitors went into melt down.  Then a huge BANG. Took a week to get the smell out of the house.  Month later I was still finding bits of paper and foil around the room.