Fritzed the output touching machine head to rack mount!!

Started by Smash, February 24, 2018, 03:52:45 AM

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Smash

Well that was weird! Was recording with Vax 700 and accidentally touched a machine head to underside of the tray in my 19" rack - slight static noise and no more Vax!!

There are only 2 things with chassis touching the rack - a W audio dmx5 mixer and the VG99....

admin

Quote from: Smash on February 24, 2018, 03:52:45 AM
Well that was weird! Was recording with Vax 700 and accidentally touched a machine head to underside of the tray in my 19" rack - slight static noise and no more Vax!!

There are only 2 things with chassis touching the rack - a W audio dmx5 mixer and the VG99....

ESD ( Electro static Discharge)  The achilles heel of on board CPU electronics

Smash

Well totally fritzed.

Stuck on eBay as spares or repair. Gutted.

Smash

Indeed. The VG99 is mounted on it as is a small DMX mixer but there is no actual earth as such - none of this kit has earth to the power plug. Also ground loop isolator on vg99 output.

admin

#4
Quote from: Smash on March 04, 2018, 11:27:40 PM
Indeed. The VG99 is mounted on it as is a small DMX mixer but there is no actual earth as such - none of this kit has earth to the power plug. Also ground loop isolator on vg99 output.


If nothing has a reference to earth ground from an AC power plug - then its very likely the surface area can become electrostatically charged, with resulting damage during the instanataneous ESD discharge event

ESD is real and most folks lack understanding of how it can occur and how to prevent it.
https://www.allaboutcircuits.com/textbook/semiconductors/chpt-9/electrostatic-discharge/

https://www.minicircuits.com/app/AN40-005.pdf

https://www.esda.org/about-esd/esd-fundamentals/part-1-an-introduction-to-esd/

chrish

Grounding is definitely a confusing subject.

I understand the need to provide a path to earth ground for your body when working on sensitive circuits, however aren't guitar pedals and rack gear designed so ESD is not a factor for frying internal circuits during normal use?

Especially when you consider that wall wart power supplies do not ground to earth the pedal chassis.

I've been doing some reading on this subject and came across a circuit element called a zener diode which supposedly provides outside ESD protection to the circuit.

And some more research found a guitar pedal where the zener diode protection was left off the circuit, in earlier model, and a guy fried his pedal.

Maybe there's a warranty claim here.

I was doing some searches online and I found this appropriately named (to this thread) "Electrosmash" website.



https://www.electrosmash.com/boss-ds1-analysis

"The Boss DS-1 is a distortion guitar pedal released in 1978 by Boss. ... series will protect the base of the transistor from surge currents ( electrostatic discharges from the guitar jack tip  .."

gumtown

The key is to creating an 'equipotential step-touch voltage zone' around you and with your equipment.
Simply meaning having all equipment around you bonded (guitar, amps, floor pedals, desk, racks), and if you go the extra mile, and anti static floor mat bonded to the same equipment.
All this may or may not be bonded to 'ground', but you are within your own "Faraday cage' area.

Randomly placed equipment on nylon carpet would be possibly the worst situation for static discharge.

Here is some reading on static discharge
https://physics.stackexchange.com/questions/177961/what-is-the-voltage-of-an-average-carpet-static-shock-can-you-make-it-lethal

Info on types of Transient protective devices
http://www.littelfuse.com/~/media/electronics_technical/application_notes/varistors/littelfuse_transient_suppression_devices_and_principles_application_note.pdf


So far, we all know that the active ingredient in electronics is 'smoke',
because when it escapes, the device stops working.

Here is an option to put smoke back into your device to get it working again  ;D
I hope this helps.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

vtgearhead

On analog op-amp input stages you'll often see a pair of fast switching diodes intended to prevent the input pin from being pulled more than one junction drop above or below the +/- rails.  Unfortunately, back in my repair bench days I saw many cases where the op-amp was blown out despite the protection.  Better than nothing, but not foolproof.  In a dry climate (such as here in Vermont during the winter) you can build up a hellacious charge just walking across a rug.  No FET gate in the world can stand up to something like that.

Smash

So....I sold the VAX for spares or repairs on eBay and was amazed to see a bidding war ensure and it selling for  £300!

Apparently the buyer had discovered that although the analogy out is fritzed , the VDI out is working fine! Good for him - smart cookie and I'm happy with what it achieved.

I'm going to buy a JTV59 for acoustic sounds in conjunction with HD500x and FTP.

I await the ebay bargains...

sixeight

QuoteI'm going to buy a JTV59 for acoustic sounds in conjunction with HD500x and FTP.

Now that you discovered the value of good amp sounds, why not try and get a Helix LT. It is night and day in vomparison to the HD500...

admin

#10
Quote from: sixeight on March 15, 2018, 10:37:35 AM
Now that you discovered the value of good amp sounds, why not try and get a Helix LT. It is night and day in vomparison to the HD500...

Agreed!


Id rather use a Cube Street than a HD500

https://shop.line6.com/promotions/factory-refurbished-and-closeouts/

gumtown

Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

Smash

I've been pretty impressed by the hd500x tones on YouTube plus it's less than half the price of Helix LT. I only want one for the link to the Variax and it would be very much the heart of an acoustic/synth rig. Not for the Vigier - I'm thinking Katana with speaker swap for that. I want something I get less tied up with chasing my tail making presets and is a bit more stomp box.

I suppose I could get Helix LT and run it through my dxr10s...

Elantric

#13
Quote from: gumtown on March 15, 2018, 12:47:14 PM
I'm a technician in the High Voltage Industry, it's an everyday phrase we use.
https://en.wikipedia.org/wiki/Earth_potential_rise


Yikes!
https://en.wikipedia.org/wiki/Single-wire_earth_return
QuoteSWER is a viable choice for a distribution system when conventional return current wiring would cost more than SWER's isolation transformers and small power losses. Power engineers experienced with both SWER and conventional power lines rate SWER as equally safe, more reliable, less costly, but with slightly lower efficiency than conventional lines.[3] SWER can cause fires when maintenance is poor, and bushfire is a risk.[4]


https://www.mercurynews.com/2017/10/10/pge-power-lines-linked-to-wine-country-fires/
Quote"The historic wind event that swept across PG&E service area late Sunday and early Monday packed hurricane-strength winds in excess of 75 mph in some cases," said PG&E spokesman Matt Nauman.
"These destructive winds, along with millions of trees weakened by years of drought and recent renewed vegetation growth from winter storms, all contributed to some trees, branches and debris impacting our electric lines across the North Bay," he added. "In some cases, we have found instances of wires down, broken poles and impacted infrastructure. Where those have occurred, we have reported them to the CPUC and CalFire. Our thoughts are with all those individuals who were impacted by these devastating wildfires."

When your homes neutral ac power Ground return connection (including the metal conduit in your wood frame home becomes a hot 22kV AC connection ( as may occur after a fire damaged substation's large transformers  "short out", or high power lines go down from falling tree limbs  )  this raises a credible explanation  for what occurred in Coffey Park near Santa Rosa California last year.



http://www.pressdemocrat.com/news/7833312-181/pge-reports-detail-proximity-of
QuoteDamaged PG&E equipment found near origins of North Bay fires
         
KEVIN MCCALLUM
THE PRESS DEMOCRAT | January 3, 2018

Read all of the PD's fire coverage here

State regulators have released previously withheld details in reports filed by Pacific Gas & Electric Co. revealing the exact location of damaged transmission equipment found near the ignition points of the wildfires that ravaged Sonoma and Napa counties in October.

The documents — including the precise address and specific types of damaged equipment — provide new information about the proximity of PG&E equipment to the origins of the deadly Oct. 8 fires.


Cal Fire officials say their investigation is not complete, and PG&E officials stressed no causes of the fires have been identified. Nevertheless, dozens of lawsuits have been filed against PG&E alleging the fires were sparked when gale force winds sent overgrown tree limbs crashing into powerlines.

Redacted versions of the reports were released by the state Public Utilities Commission late last year, with specific address and equipment details withheld to preserve the integrity of the Cal Fire investigation. The PUC has now posted unredacted versions of the reports online.

The news Wednesday that his address on Nuns Canyon Road in Glen Ellen was listed as the location of a PG&E equipment failure didn't surprise Tim Korn one bit.

The former owner of Relais du Soleil guest ranch, most of which burned to the ground, said the events of that night left little question in his mind about what sparked the blaze, which would eventually grow to become the largest of the North Coast fires, burning 54,300 acres, destroying 1,355 homes and killing three people.

"The fire did start at Nuns Canyon when a tree fell on a power pole and a transformer exploded," Korn said. "I know because it woke me up."

Korn, 75, ran the guest ranch for 22 years on the property at 1210 Nuns Canyon Road. The ranch had a separate PG&E metered line running to the well pump, he said, and there was a large tree with limbs overhanging the wire, he said. He said he believed the limbs of that tree caused the transformer explosion and the resulting power outage.


Recovering at the time from heart surgery, Korn initially decided to go back to sleep, he said. But his family members, including grandchildren, were sleeping in one of the cottages on the property, spotted the fire and tried to evacuate, he said.

"I was the first one to report the fire," Korn said. "We saw exactly where it came from."

But the fire grew quickly and blocked their retreat toward Highway 12, forcing them to flee farther up the narrow rural road where he and his family spent seven hours in a meadow surrounding by an inferno before they were able to escape, he said.

Korn, who lost most of his possessions in the fire but isn't expecting a big insurance payout because he leased the property, said "PG&E has been out a bazillion times" to the property, and a guard was posted at Nuns Canyon Road for weeks after the fire.

PG&E spokeswoman Deanna Contreras said the utility is fully cooperating with the investigation and is focused on helping its customers rebuild.

"We'll let Cal Fire and CPUC investigators do their work, and we're not going to speculate on the causes of the fires while the investigation is ongoing," Contreras said

In its report, PG&E notes that during winds up to 58 mph, the top of an alder tree "broke and fell on an open wire secondary service" at Korn's address. The report notes that Cal Fire had taken possession of the "overhead secondary distribution conductors" in question.

In addition to the Nuns fire, three other fires appear to have started in locations at or near the addresses where damaged PG&E equipment was discovered. These include:


— 4011 Atlas Peak Road, north of Napa, near the suspected start of the 51,642-acre Atlas fire;

— 1721 Partrick Road, west of Napa, near where the Partrick fire, which merged with the Nuns fire, is believed to have started; and

— 1128 Bennett Lane, Calistoga, near where the 36,807-acre Tubbs fire, the most destructive in state history, is believed to have begun.

Jim Frantz, principal of Frantz Law Group, said the new details support his suspicion the fires were caused by the utility's failure to maintain trees and brush around its equipment. Frantz said he is representing hundreds of clients pursuing litigation against PG&E, including five wrongful death cases.

"We think their wires came down onto the ground and started the fires," he said.



Sonoma County explores potential lawsuit against PG&E

State utilities board adopts stricter fire regulations in wake of wildfires

What caused the Northern California fires?

PG&E has raised the possibility that power equipment "owned, installed and maintained by a third party" in Calistoga might be responsible for the Tubbs fire. An Oct. 26 report lists the 1128 Bennett Lane property as the location where Cal Fire investigators took possession of "fused cutouts" and a "secondary service line" that "served multiple pieces of customer-owned equipment on the property."

"No damage to PG&E equipment was readily apparent," the report notes.

Frantz said the utility's "private wire theory," was "bogus."

Cal Fire spokesman Scott McLean said he didn't know what led the California Public Utilities Commission to remove redactions in the reports.

The evidence-gathering phase of Cal Fire's investigations into the cause of the October fires is done, but that doesn't mean investigators won't return to fire origin sites for follow-up, McLean said.

Cal Fire has not publicized a cause for any of the fires, and will do so on a rolling basis as each investigation is finalized. McLean said there's no standard time frame for how long fire investigations take. He noted the cause of the 2015 Valley fire — electrical wiring of a hot tub — was made public "one day less than a year" after the fire started.

"Each fire is different," McLean said.

Separate teams of Cal Fire investigators have been assigned to each fire. The teams start large and grow smaller as aspects of the investigation are completed.

Some of the locations where damaged equipment was discovered, such as Chateau St. Jean Winery in Kenwood, were enveloped by larger fires.

Another, on Sullivan Way in Santa Rosa, is near the spot of a small fire that destroyed a few homes and burned into the northern edge of Howarth Park before being extinguished. That fire, however, is not considered part of the larger wildfires.

Staff Writers Julie Johnson and Paul Payne contributed to this report. You can reach Staff Writer Kevin McCallum at 707-521-5207 or kevin.mccallum@pressdemocrat.com. On Twitter @srcitybeat.


http://www.latimes.com/local/lanow/la-me-fire-cause-creek-fire-20171213-story.html

gumbo

..if you can do that with 110, think what we can achieve with 240..    ;D
Read slower!!!   ....I'm typing as fast as I can...

vtgearhead

Quote from: gumtown on March 15, 2018, 12:47:14 PM
I'm a technician in the High Voltage Industry, it's an everyday phrase we use.

Does anyone think it's an odd coincidence that Gumtown, Codesmart and I all work in the energy field? Maybe those voltage gradients are influencing our brainwaves in some manner...