Advice Appreciated! Furman Voltage Regulator

mellowgerman

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Hello all, I was hoping that maybe someone who has experience with this kind of device (possibly having worked on some before?) might have a suggestion for trouble-shooting. About 3 years ago I picked up a Furman M-8x AR voltage regulator, with the intention of protecting my valuable bass rig, from the presumably iffy old wiring of the house we lived in at the time.

New, these units were around $650, but there was a B-stock model available for around $380 if I recall correctly. It was from a well-reputed retailer, so I decided to go for it. Once it arrived, I mounted it in the rack-case with my amp, plugged everything in, and it seemed to work just as designed and intended. In terms of set-up it's no different than a power strip. There is only an on/off switch, a series of outlets, and the power cable that plugs into the wall.

Anyway, about 6 months down the line, something went wrong. During that whole time it was only used at my house, responsibly, safely, gently, etc. It was never dropped, abused, sunken in a bathtub, etc. That day, I was using it in my music room and everything was working perfectly. It was plugged into the same circuit that my phone, lap-top, lamp, etc were plugged into. No issues. All good. Then when my band-mates arrived for rehearsal, I turned off the amp, moved it into the living room where we set up for rehearsal as always. Once again, there were plenty of other devices plugged into the same circuit. This time the guitarist's amp, my TV, our digital clock, another lamp, etc. When I flipped the power switch to turn on my rig this time though, the green "Protection OK" light came on, the little voltage meter portion was not lighting up. None of my gear was getting power. Again though, there was no indication what-so-ever that any issue had occurred. The lights didn't flicker, none of the other devices acted weird in any way, there was no hiss, hum, pop, boom, zip, nothing. Just that this supposedly SUPER RUGGED, ULTIMATE PROTECTOR AND INVINCIBLE TAMER OF ELECTRICITY was not letting power pass, nor was it indicating that anything was wrong via it's multiple warning lights. I tried different outlets throughout the house, every now and again, but the same result. I did notice that the "High EV" warning indicator super faintly blips right as I flip the switch, but it's so quick and faint that you can hardly catch it. This happens right as the green "Protection OK" light turns on. Again though, absolutely none of the other devices that were plugged in throughout my house took any damage or gave any indication of electrical issues. I would think if there was a problem at that moment with the electrical, bad enough to kill this 25 lbs behemoth, designed to be the ultimate protector of electrical equipment, it would have fried at least one other of the dinky cheap devices, right? Like the digital wall clock maybe? Or the computer speakers? Or the crappy desk lamp? Nope, everything was fine.

Both attempts to reached out to Furman, went completely unanswered and ignored. I was very polite in my email, humbly requesting any insight, suggestions, or referrals to any potential solution or somebody who could help. I would even have been happy to pay a repair service. Nothin but nothin... just like the Voltage Regulator. Like father, like son apparently.

So today when I was rearranging one of our storage closets, I came across the ol' power regulator, neatly tucked away in it's original packaging and stashed in the closet. I tried it out again, but of course, same result.

Now, I don't really have much of a need for this device these days since the power at this house, that we bought 2 years ago, is pretty good as far as I can tell. That said, before I throw this hunk of metal away, I figured I'd ask here and maybe over at talkbass as well, if any experienced folks might have a suggestion. I figure this can't be a super complicated device, right? I'm not saying I want to open it up and attempt to fix it myself, but do you guys think this could be worth taking to an electrician or an amp shop maybe? Since I don't really have a use for it, I'd hate to stick another $80+ of hourly expert pay into it, just for somebody to tell me that it's dead. That said, if the general consensus was that it shouldn't be hard to fix, I'd rather not just send it off into a land-fill.

So again, any advice, thoughts, ideas, or even good electrical failure puns would be greatly appreciated!

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GAD

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Have you tried calling them?

The “schematic” online is just a block diagram and has “computation” as one of the blocks, so it could be more than just electrical.
 

Nuuska

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There is a chance that there is just one bad connection inside - like bad soldering on one component on pc or loose wire in the harness.

It might have been making contact for years - but when you moved the unit - that was enough.

I had similar problem w one of my digital mixers - one night it was located on side of a stage made of raisers - so it reacted to some bumps on the stage. Luckily the gig was ok - after show I unpowered all amps and gave the mixer few bumps to see that all meters jumped to max. At home I opened it and started to study PSU. Indeed there was one coil that had a questionable soldering. I removed old solder - made sure that the wire comes good thru the pc-board - resoldered. Has been fine ever since.

A quick search showed an YouTube video presenting the unit - - and here is a screenshot of that video


Näyttökuva 2022-7-11 kello 10.21.30.png

On the left is input side w switching regulator - the transformer is for output.

What you could do - UNPLUGGED - open the unit - study all connections - try wackle the components to see if any of them are loose - see if there are any fried components - you could take a photo of the pc and share with us.

With good luck it is just something easy .

As long you don't plug it in while it is open - you'll be safe.
 

mellowgerman

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Thanks for taking the time to chime in, GAD and Nuuska!

I did not call them, as the issue arose right around the time that COVID was leveling company offices around the world, extended wait times on customer service calls, etc. I figured that email would be the more courteous way to approach it, giving them time to respond. After waiting for a few months, I sent another. Again, politely, just asking for guidance. I never expected that multiple emails would go unanswered. That said, not too long after the second email, I had already stashed the unit away, then life got pretty hectic, revolving around the stressful house buying process during a crazy market and the eventual move, and a bunch of other situational turmoil. By the time this unit crossed my mind again, it had been so long since the it's failure and my attempts to get help, that I just let it go. Until I came across it again yesterday!

When I get a chance, I will open up the unit (unplugged of course) and take a look, along with some internal photos.

Again, I appreciate the contributions here!
 

mellowgerman

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Sorry for the delay, but I finally got around to snapping some internal photos. This has been an absolutely crazy week... between my wife and I both getting COVID, me having to get up at 3am for work on Wednesday & Thursday, AND a leaking pipe taking out part of our kitchen ceiling!

In any case, everything looks fine to me. Please let me know if I'm missing anything!

Also, I tapped at everything with my trusty chopstick but nothing seemed loose either.

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Nuuska

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Hello

Next - wiggle all those wire connectors to make sure they have good contact.

But that one power transistor - 3:rd from face plate - looks like it has been hot - may be that is the culprit - not forgetting there is the surrounding circuit.

At least - have a hard and close look at soldering connections at that area.
 

mellowgerman

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Hello

Next - wiggle all those wire connectors to make sure they have good contact.

But that one power transistor - 3:rd from face plate - looks like it has been hot - may be that is the culprit - not forgetting there is the surrounding circuit.

At least - have a hard and close look at soldering connections at that area.

You're absolutely right! I don't know how I missed the goopy stuff on that transistor. Okay, will check the connectors too. Thanks again!
 

Nuuska

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Goopy stuff ? Like greasy powder or sumpting ?

That would be heatsink paste to improve contact. If it wipes off and you can read the text on that transistor - then it is not what I thought.
 
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