900 volts, 1 finger ,and a trip to the emergency room

[W1RKW]

AMFone has the Handbook Section and other sub-features but we don't have a section on the importance of safety. Most, if not all of the people here are dealing with older rigs that have big volts and deadly volts at that. Some of us are newbies blazing new trails down a path with old rigs and homebrew rigs wielding HV.  I know I am and I'm a newbie.  We should have a Safety First section on AMFone.  As common sense as it might seem to protect oneself, putting some safety measures in some valuable words of wisdom might be a good idea.  There might be some safety tidbits some of us could use or are not aware of as apparent as they may be.  I'd like to think of myself as a pretty common sense person but I find myself doing something stupid occasionally and reprimanding myself for being so stupid. With HV that chance is very narrow.

[K1JJ]

Glad you ok Gary, that's scary..

The worst shock I got was with my Valliant. I was using an external 811 modulator
which was getting the B+ off the vaillant through the accessory plug. I forgot to connect the
ground from the valliant to the ground (chassis)of the modulator. I was touching the Modulator chassis
with one hand and flipped the PTT switch on the valliant with the other. I then became ground connection.
between the two. I immediately got thrown back on my butt, saw stars for a second. No damage, but I
never forget that lesson....

Becareful folks...  Chuck

Chuck,

You have brought up a good point that is worth repeating and expanding upon.

For the longest time in my early years, it didn't dawn on me (with separate units) that when there is a standard (ground referenced) power supply and transmitter connected together with a (+) HV lead, that there is full HV voltage potential sitting between the two chassis if they are not bonded together.  For some reason I thought, "ground is ground" and neutral is neutral - no shock risk there.  But think about it - when the final tube's filaments are on with HV and is keyed on, there is little resistance across the tube. This causes almost the full HV to drop across the infinite and open path between the two chassis, if they are not bonded together.

This is a deadly error and easily overlooked, especially when we are first testing our modules outside of the metal bonded rack.  Many times we are saved by coax cable connections, but power supplies don't use coax connectors.

To prove this to yourself, take a 9V battery (power supply) and clip lead a 1K resistor (load) to the (+) terminal.   Then measure between the other side of the resistor (ungrounded) and the (-) terminal on the battery (ungrounded). You will measure the full (+) 9 volts.

Bottom line is always run a ground strap between the power supply and unit and also a SECOND wire as backup. This is in addition to the normal bonding that takes place IF the units are installed in a common metal rack cabinet.

These precautions are especially important if the remote unit sits on the table and the power supply is on the floor. The worst scenario imaginable is to lose the ground connection - then rest your feet on the power supply cabinet while tuning the RF deck with your hand... OUCH!

Floating the power supply circuitry above chassis will help solve the chassis risk problem, but still requires a good negative chassis connection between units... cuz what if a power supply component shorts to ground like in the case of Don's mod transformer and D-104 event?


Bottom line is, you can lose your HV + lead connection and be QRT for 15 minutes - but lose the chassis ground connection and maybe SK forever.

T

[W2INR]

Don

I have been doing just what you are doing. The doctors are throwing all these terms at me and I spend time home using Google to learn what they are talking about.

I can say this, besides feeling sore I don't feel like any of the other stuff they are saying they think happened.

I guess that is a good thing.

G

[KF1Z]

Adds a whole new meaning to the term..."Pulling an INR.."
 


Seriously though Gary...

Hope a hurt finger, and scorched pride is all you end up with out of it!

[w3jn]

Thankfully, I've never been zapped by an xmitter.  My two worst shocks involved receivers.

When I was a young JN someone gave me a Hammarlund SP-400.  While a FB receiver it has all kinds of safety hazards - 300V on the standby terminals, 365/300/120VAC on the power supply terminals, etc.  What got me was one humid summer day I decided to do an IF alignment.  Put one sweaty mitt on the front panel and gripped the metal shaft of the screwdriver (for better "feel", I guess).  What I didn't know was the IF trimmers are hot with B+.  Got 300V right across the chest; I felt like crap for a week.

The other shock is one that could get any of us with old buzzard receivers and plays into TOm's dissertation above.  My Hallicrafters SX-11 standby switches the B+ (I shoulda changed it to a AVC cutoff arrangement but I was too lazy).  One day the ground wire broke off the radio and I hit the keying switch for the xmitter (which also was wired to the SX-11 standby) and adjusted something on the receiver.  Whammo, 365V right across the heart again.  Thankfully it wasn't hot/humid and only momentary.

Either incident could have turned out very differently.  BE CAREFUL when working on these old buzzard rigs, you can get killed by receiver voltage just as easily as from an xmitter.  And if your old receiver uses a switched B+ as the standby, change it over to something that opens the ground in the RF gain circuit.  Easy to do, just don't let the Collins Collectors mafia find out.  It could save your life!

[Bill, KD0HG]

A really interesting poll for this group might be, "What boatanchor fan *hasn't* gotten zorched at least once.."

I got snapped once when I had a recently-installed 1,500" Vee beam on my dad's farm in Illinois.
A big summer storm was rolling in and I started hearing explosions from the  ham shack. The antenna's feeders were arcing several inches to a water pipe. Not piss-ant sparks, but real lightning. I ran downstairs, grabbed some auto jumper cables and went to ground the feeders with it, but I got in the way of one discharge...No damage, but knocked on my arse.

BTW, that was a hell of a DX antenna. Average height was maybe 100' out to some old cottonwoods. Aimed around 45 degrees, NNE. Mid-afternoon, during daylight, I was able to work UK2BBB on 40 meter phone.

[WA1HZK]

What doesn't Kill Us makes us stronger.....
Have you noticed any new super powers?

[Bill, KD0HG]

Ah..That last shock I got is why my wife sticks around.

 

[N3DRB The Derb]

i got across the b+ of a viking 2 years before i got my ticket when (I literally knew nothing bout HV) I remember waking up on the floor, and the rig being on the floor smoking away ( all the tubes had broken)

I'm deathly concerned about having a seizure while working on a live radio. I have about 30 seconds to a minute warning  so I can get away as long as I'm smart and do it. I had a pretty bad one last night, but it didn't happen in the shack. was able to down some valium
and Glo got me on the bed so I didn't fall down and go boom.

When I feel like that, I dont even go in there. I've got to be 100% to go into the shack and work on things.

HV is just one of the things we deal with.

[Opcom]

I am also glad you are OK. Fair Radio has a slogan "God is only a prayer away". I like to think I have been original and not blasphemous, and added to that "and a couple hundred volts is all it takes to meet Him".

Having been nailed by a variety of voltages (highest B+ was 2500V), I am a bit scared when working a high voltage rig "hot", and I think that keeps me from making too many mistakes. When I sit on the stool behind the rig with the doors open and the interlock bypassed, Every action is deliberate.

When I got the "Tucker", I found the only bleeder to be the 5-meg HV meter multiplier. With 40uF capacitance sitting there and plenty of reserve mA available, I soon added a 100mA bleed so when I turn it off, it is OFF. Also picked up a mil-spec shorting stick and I USE it.

[Vortex Joe - N3IBX]

Thankfully, I've never been zapped by an xmitter.  My two worst shocks involved receivers.

When I was a young JN someone gave me a Hammarlund SP-400.  While a FB receiver it has all kinds of safety hazards - 300V on the standby terminals, 365/300/120VAC on the power supply terminals, etc.  What got me was one humid summer day I decided to do an IF alignment.  Put one sweaty mitt on the front panel and gripped the metal shaft of the screwdriver (for better "feel", I guess).  What I didn't know was the IF trimmers are hot with B+.  Got 300V right across the chest; I felt like crap for a week.

The other shock is one that could get any of us with old buzzard receivers and plays into TOm's dissertation above.  My Hallicrafters SX-11 standby switches the B+ (I shoulda changed it to a AVC cutoff arrangement but I was too lazy).  One day the ground wire broke off the radio and I hit the keying switch for the xmitter (which also was wired to the SX-11 standby) and adjusted something on the receiver.  Whammo, 365V right across the heart again.  Thankfully it wasn't hot/humid and only momentary.

Either incident could have turned out very differently.  BE CAREFUL when working on these old buzzard rigs, you can get killed by receiver voltage just as easily as from an xmitter.  And if your old receiver uses a switched B+ as the standby, change it over to something that opens the ground in the RF gain circuit.  Easy to do, just don't let the Collins Collectors mafia find out.  It could save your life!

John,
      Good point! Some OB receivers like the AR-88 I believe, has as much as 500V on them when in the standby position. I think the same may be true for HRO's, etc.

[steve_qix]

No fair getting killed with a "measley" 900 Volts.  Seriously, I'm glad you're ok.  I've had some zaps in my life, but nothing over the past 30 years which were that bad.  Before that, definitely had some bad ones.

See you at Deerfield, in any event.

Regards,

Steve

[WBear2GCR]

!!!

yikes!

whoooo...


      friggin rice boxes! 






                   _-_-Wooly Bully Two Gross Creepy Roaches

[k4kyv]

I forget his callsign, but sometime in the 80's a well-known AM'er, a W2, got across the HV in an amplifier...

I think that was Ralph, W2WME.   I remember his voice well. I heard that he met his fate only several years after the fact. I think he had a BC-610.

Yes, that's who it was.  Not sure of the exact rig he was working on.

But this shouldn't make us shy about working around high voltage. 

Loaded guns can be deadly, but many people like to go shooting and hunt for game all their lives with never a mishap, and remember all the howls and screams you hear at any mention of restricting gun ownership. 

One minor little lapse of attention can be fatal if you are driving a car.

The list could go on and on. We don't need safety police outlawing the possession of devices that contain high voltage. One just has to be careful and use common sense.

[WA1GFZ]

I thought it was a SB200

[K1JJ]

I thought it was a SB200

Yes, I think so too. The story goes that his wife walked in after hearing some noise and he told her that he just electrocuted himself... and then passed out and died or something like that. Pretty dramatic.

I wonder if anyone remembers the famous NJ ham who moved to Belize, SA and became V31BB, back around 1989-1991?   He became a full time DXer ham receiving "green stamps" for his rare QSL cards. Anyway, he had an ongoing feud with MFJ about their crappy amplifier and even held MFJ Junk nets. He was world-wide on 20 M daily. They wouldn't take the amp back, no how. I'm sure the nets drove MFJ crazy.  Anyway, they found him slumped over his open (and still running) MFJ amplifier one day, fried. I had met him in Dayton in '90... nice guy.

My point is, have you ever thought about the risk to family members or any rescuer who comes upon you IF you ever get fried and the circuit is still live?  Many times they, too, can get it. It's probably a good idea to instruct family members that they should never directly touch you in this situation.  They should also know how to turn off the main breaker and give CPR too.... 

Back to the real world - I'm sure this information would go over like a lead balloon with the average XYL - to say the least... but should be done... :-)


T

[Pete, WA2CWA]

I thought it was a SB200

From what I remember of the story, it was a Heath SB-1000, which was a kit version of an Ameritron amp. Dave, W3NP, was bit (damaged a finger or two) by an SB-200 several years ago.

[W2INR]

I use to visit Ralph a few times a year. He had a nice place just east of me.

He was working on a SB 220 amplifier and he took the B+. He fell to the floor and his wife heard the noise and came into the room and Ralph told her he had just been electrocuted just before he passed away. He was pronounced dead at the scene.

Good old Buzzard radio guy.

[WA1GFZ]

Gary,
I seem to remember Armstrong having that rig and you showing it to Tom and I when we visited

[David, K3TUE]

Gary,  Sorry you had a hard lesson/reminder.  Glad to hear you are alright.  Stay safe.

[W1RKW]

I just acquired a mushroom switch with the intent of disabling the entire station via contactor in the event of an emergency. I don't want someone coming into the station finding me slumped over a piece of equipment and try to move me only to find themselves energized and dead too. Whether it's 100 volts or 5KV, it's nothing to sneeze at. Under the right circumstances the right amount of V and return path it will nail someone.  Think of the others who don't understand your setup/station and take action to rescue you.  No point in taking others out.

Again, I stipulate this website should have a safety section to drill it home and a disclaimer. If you're worried about libelous and slanderous messages worry about safety (or lack thereof) messages too if you're telling people how to do things on a piece of equipment with HV. Hopefully someone won't tell someone to do something with a probe on a HV power supply (incorrectly) and end up dead and you're on the end of a lawsuit based on information posted here.

Just my nickel (inflation).

I thought it was a SB200

Yes, I think so too. The story goes that his wife walked in after hearing some noise and he told her that he just electrocuted himself... and then passed out and died or something like that. Pretty dramatic.

I wonder if anyone remembers the famous NJ ham who moved to Belize, SA and became V31BB, back around 1989-1991?   He became a full time DXer ham receiving "green stamps" for his rare QSL cards. Anyway, he had an ongoing feud with MFJ about their crappy amplifier and even held MFJ Junk nets. He was world-wide on 20 M daily. They wouldn't take the amp back, no how. I'm sure the nets drove MFJ crazy.  Anyway, they found him slumped over his open (and still running) MFJ amplifier one day, fried. I had met him in Dayton in '90... nice guy.

My point is, have you ever thought about the risk to family members or any rescuer who comes upon you IF you ever get fried and the circuit is still live?  Many times they, too, can get it. It's probably a good idea to instruct family members that they should never directly touch you in this situation.  They should also know how to turn off the main breaker and give CPR too.... 

Back to the real world - I'm sure this information would go over like a lead balloon with the average XYL - to say the least... but should be done... :-)


T

[w1vtp]

I use to visit Ralph a few times a year. He had a nice place just east of me.

He was working on a SB 220 amplifier and he took the B+. He fell to the floor and his wife heard the noise and came into the room and Ralph told her he had just been electrocuted just before he passed away. He was pronounced dead at the scene.

Good old Buzzard radio guy.

Emphasis mine.  I recall a "dead short" interlock on my SB-220 - it being an insulated rod that held a shorting tab away from the HV.  Lesson to learn -- DON'T BYPASS INTERLOCKS! Unplug lines and short out B+ before venturing inside HV type rigs.  I've made a practice of just walking away from a HV project for a few minutes just to clear my head during troubleshooting.  Oh yeah, DON'T TRUST BLEEDERS!

Al

[w3jn]

Another do not trust:  Panel meters!

I scored a SB-200 for $20 or 30 at a hamfest.  It had been dropped, and the cabinet bottom was torn.  Fixed that and a few busted things inside, powered it up and the HV meter read barely off the peg.  Went at it with my Fluke 77 and promptly fried it due to the 1500V plate supply being alive and kicking.

Problem was the meter multiplier resistors were all bad (5 10 meg resistors in series, IIRC).  Had I been a little less careful I coulda killed myself, as I figured the PS was only putting out 50 volts or so (according to the front panel meter).

[ka3zlr]

Agreed:

 Something should be set up to address what is being said by Bobby and the rest...I"m for that.

Main thing G is recuperating and Still with us ....Thank God...


That one time i went off on Ricks Amp for the Eye Sight Glass it wasn't to put Rick down it was to address exactly what is being said... hell I got Glass on some of my stuff that should be shielded..I know better But i like it too...LOL...

But it being broadcast on here is well different...i dunno...I'm Not trying to tell anybody what to do here..But ya know...Murphy's law man...

[k7yoo]

YO
JN

ya need an SB220 cabinet ? or is this ancient history?
I have on the someone started building a 6 tube sweep amp in. The coil looks suspiciously resonant on 11m
Cabinet is OK though

k7yoo@yahoo.com