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Dangerous and hard to believe or am I overreacting

buickguy62

buickguy62

Active Member
On the large auction site is a Harman Kardon A700 amplifier for sale. In the description the seller notes that one of the can capacitors has a red X on it "not because it's bad but as a warning against touching it while the amp is in operation." It is a replacement for one of the voltage doubler caps and is not the proper insulated can, so yes you should not touch it--the voltage on the can is over 200 VDC!! I emailed him and explained the problem, that contact could be lethal, and it should be replaced with a proper cap (could mount a replacement under the chassis), or else cut off the power plug and sell it as non-functioning. He replied that in the description he states that you should not touch the cap, and added that he plans to put a piece of plastic pipe over the cap. Am I overreacting--I can imagine someone new to tubes buying this with possible tragic consequences. If you look for the listing there are 2 Harman Kardon A700's for sale, this one has 'fully working' in the title.
 
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You are overreacting. 250V ( or more ) is to be expected inside stuff like this.
One might expect a cover however, keeping both hot objects ( tubes) and dangerous voltages
away from children pets or curious bystanders.
 
Not uncommon to have a hot cap, even on the deck, though they usually have a cardboard sleeve or other insulation. High voltages are part of tubes, and deserve respect!
 
Any modifications done to a piece of gear should be documented and supplied upon the sale of the unit.

This is particularly important when the modification involves safety.

Although there is no certainty that the documentation would be included in any subsequent sales of the unit.

The new owner may have the service manual, but if the modification exposes high voltage where it is not expected, then that is a safety issue.

It is to the credit of the seller that this is mentioned and that it appears that he will take steps to reduce the risk.

For the experienced among us this may not be an issue, but for the less experienced it could well be somewhat dangerous, for they may have no idea of the voltage levels involved or the risks associated with high voltage.

The learning (from experience) curve for high voltage can be very steep.
 
JBL GUY said:
The learning (from experience) curve for high voltage can be very steep.
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The 28,000dc I got working on a tube color tv in school hurt. Though it is low in amps, it was an extended shock.

I have been bare foot in water on concrete at 110ac and a few times at high current 220ac but that color tv from 34 years ago stands above them all.
 
jaymanaa said:
Normally a hot can will be encased in a black cardboard insulator. Are you still into Buicks btw??
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Yes, still into Buicks, I've had my '62 Skylark for 18 years now, and this fall bought a '90 Reatta Convertible, great travel car, AC, cruise and all. Also just had to replace my wife's Terraza van, was totaled while she waited at a red light, now she has a '11 Enclave, that's a real nice SUV. Buick is now selling more cars in China than in the US. I guess Chinese folks insisted on GM selling Buicks there based on there reputation -probably from the 1950's or so.
 
I think the seller is doing the responsible thing by pointing out the risks, for those who wouldn't know. Prospective purchasers have been warned, and should be careful.

I've been seriously zapped years ago by a TV discharge tube and by a (240? 320?) high voltage supply to big central air-con motor that later knocked a big man unconscious for 45 minutes, nearly killing him. That was the worst shock I've ever had; it glued me for a few seconds of shaking, before throwing me clear. I was just lucky to survive it. Also got zapped earlier this year by some kind of lightning "bleed" when I was taking a shower during a storm.
 
Shocking

Yes those old TV,s with with those Shunt regulators or those old Philco,s with the tube high voltage regulators in those cans would surely give you a jolt even if you discharge them!
 
IMO, stuff needs to be safe, if just for the liability aspect. You can get shrink tubing in all sorts of large sizes. I'd cut a mylar disk for the top, then put a big piece of shrink around the whole thing and shrink it, just like a commercial unit.
 
What every one else said. One should never tinker with something one knows nothing about. Respect voltages/current should be a fist rule one learns. Ditto on HV when working on CRTs or other equipment like radars, radios, damm near everything. I have personally seen a dead body hung up on a HV device. Something no one should ever have to see. Electronics is a "hobby" not suited for those who have a touch of the "jinks" in them.
 
buickguy62 said:
Yes, still into Buicks, I've had my '62 Skylark for 18 years now, and this fall bought a '90 Reatta Convertible, great travel car, AC, cruise and all. Also just had to replace my wife's Terraza van, was totaled while she waited at a red light, now she has a '11 Enclave, that's a real nice SUV. Buick is now selling more cars in China than in the US. I guess Chinese folks insisted on GM selling Buicks there based on there reputation -probably from the 1950's or so.
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I had a '62 Skylark convertible in light blue and white interior. It has a 215 aluminum V8 with a 4 barrel carb.

I built the Reatta plant in Lansing, MI. Also in charge of the process equipment. Also a consultant to HP & Rockwell International with regard to process equipment design and final approval. The plant used automated gilded vehicles (Portec) vs in floor conveyers. The Reatta plant QC was capable of measuring every surface of the body to less than 20 millionths of an inch. The hood is so long that until the interior bracing was installed, only robots could handle it without damage. It may still be the most sophisticated auto plant in the world.

BTW- The car is out of production, thus I can talk about the plant now.
 
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As a general rule in electronics safety, ANY "HOT" (Voltage or temperature) component should be insulated and marked with a symbol or text that it is dangerous to touch.

Any electrolytic cap. that is "above ground" (Not connected to the chassis) SHOULD have an insulated covering applied to it, both the can AND the top.

Mark T.
 
sony6060 said:
I had a '62 Skylark convertible in light blue and white interior. It has a 215 aluminum V8 with a 4 barrel carb.

I built the Reatta plant in Lansing, MI. Also in charge of the process equipment. Also a consultant to HP & Rockwell International with regard to process equipment design and final approval. The plant used automated gilded vehicles (Portec) vs in floor conveyers. The Reatta plant QC was capable of measuring every surface of the body to less than 20 millionths of an inch. The hood is so long that until the interior bracing was installed, only robots could handle it without damage. It may still be the most sophisticated auto plant in the world.

BTW- The car is out of production, thus I can talk about the plant now.
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When I was at Chevy in Flint, I worked with the fellow who later became the first Plant Manager at the Reatta Craft Center (later renamed Lansing Craft Center), great plant and it seemed to me, had a very dedicated workforce.
 
This is another that has be shaking my head. From experience with my own, this is unecessary but then again, mine is upgraded with White Oak Audio components and top quality control board. Everthing dangerous that made these "Flame Linears" has been replaced and upgraded. She now puts out over 250wpc

http://www.ebay.com/itm/Phase-Linear-400-Energy-Storage-Unit-RARE/321256185214?_trksid=p2047675.m1850&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%26asc%3D19051%26meid%3D2939689834349256612%26pid%3D100011%26prg%3D8643%26rk%3D1%26rkt%3D5%26sd%3D300995760057%26#ht_291wt_988
 
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Buickguy - I am in agreement with you. HK amps rarely have covers, and they came from the factory with cardboard enclosed caps for that side. I am sure it was for safety reasons as the other 2 caps are not insulated above chassis. Just my two cents.
 
I remember My uncle got zapped by the metal back on an old black and white tv picture tube,he remembered it for 40 years.
 
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