I bought an "as-is" big box clone theory off eBay. It's the earlier "edge" model. It has the end of the power cord chopped off. what's the risk of me putting a new end on the power cord and plugging it in to test?
(https://s30.postimg.org/5d93qsq3x/IMG_3490_1.jpg) (https://postimg.org/image/5d93qsq3x/)
(https://s1.postimg.org/l68z52p63/IMG_3491_1.jpg) (https://postimg.org/image/l68z52p63/)
Is it made for the mains voltage of your country?
Do you know how to make a current limiter with an incandescent light bulb?
Quote from: thermionix on June 07, 2017, 06:38:45 PM
Is it made for the mains voltage of your country?
Do you know how to make a current limiter with an incandescent light bulb?
Is that second one just a competency test, or are you being serious? :icon_razz:
It's 120v I'm in the US. I don't know how to make a limiter but is it easy to learn?
If you know for sure that it's made to run on US mains voltage you should be fine wiring on a new plug. May be worth future proofing it by completely installing a new cable as well.
You could instead put in a DC jack, a charge pump, and a 15V regulator....
you could do some basic meter tests on the transformer and diodes before doing anything else more dangerous.
having just looked at "the big picture", I wouldn't go near that box with that mains wire and the electrical tape. ymmv.
Do I see a "mysterious" partially resolder IC on the left..??
Quote from: EBK on June 07, 2017, 06:53:27 PM
Is that second one just a competency test, or are you being serious? :icon_razz:
It's real. If it were dead shorted for example, you'd just get a glowing light bulb instead of sparks, fire and smoke.
https://www.youtube.com/watch?v=wRFRwOnLsZI
Quote from: karbomusic on June 08, 2017, 12:24:42 PM
Quote from: EBK on June 07, 2017, 06:53:27 PM
Is that second one just a competency test, or are you being serious? :icon_razz:
It's real. If it were dead shorted for example, you'd just get a glowing light bulb instead of sparks, fire and smoke.
https://www.youtube.com/watch?v=wRFRwOnLsZI
Awesome! Thank you!
Quote from: karbomusic on June 08, 2017, 12:24:42 PM
Quote from: EBK on June 07, 2017, 06:53:27 PM
Is that second one just a competency test, or are you being serious? :icon_razz:
It's real. If it were dead shorted for example, you'd just get a glowing light bulb instead of sparks, fire and smoke.
https://www.youtube.com/watch?v=wRFRwOnLsZI
you sure??
(http://www.ideefesta.it/assets/images/halloween/costume-halloween-fester-addams.jpg)
I watched some YouTube vids on the dim bulb tester, will try and make one. Any recommendations for bulb wattage?
That video Kary linked to mentioned how to pick the wattage.
Quote from: EBK on June 07, 2017, 06:53:27 PM
Quote from: thermionix on June 07, 2017, 06:38:45 PM
Is it made for the mains voltage of your country?
Do you know how to make a current limiter with an incandescent light bulb?
Is that second one just a competency test, or are you being serious? :icon_razz:
One of my most-used tools. Anything questionable that plugs into wall juice goes through the current limiter. I do tube amp repair, and sometimes people bring me stuff that looks like it's been in a barn for the last 25 years. Also good when checking fresh work, and when forming new filter caps.
One situation it doesn't help with is a PT primary that's shorted to ground, but that's only happened to me once. Tripped the circuit breaker. "WTF?...Oh, I see..."
I used to always use a 100W bulb, but now those are hard to find so I'm using a 60W. Doesn't really matter.
Maybe measuring resistance from both sides of the primary to ground before plugging into mains would help? ;)
Hey, it happens.
Yup, light bulb's the way to go. Just cuz I'm like this, I'd also see what goes on when it's plugged in (no smoke, sizzle, fire? good)...then I'd measure what's coming OUT of the transformer (AC)...then I'd check for AC and DC on the input and output jacks...just because. I worry like that sometimes cuz it's mains...and only takes 30 seconds to look at all of that. I have found some odd things (not high level, but DC on jacks due to dead caps) before hitting my amp with it. Fingers far away from that line cord please.
Some day I hope to be around to see 120V on the input jack, but BEFORE I try to plug my axe or amp in to try the circuit out!!
Quote from: EBK on June 08, 2017, 04:11:30 PM
That video Kary linked to mentioned how to pick the wattage.
Ooops sorry... just search for lightbulb current limiter on YT there should be plenty there with sufficient explanation - the video I linked is my mistake of just linking the first video I thought was close but didn't confirm by watching it. At the end of the day, it's the same thing, you get a glowing bulb instead of more damaging results.
Do you know why the plug was chopped off?
Where I come from, that is usually done more as a message than anything else - i.e to prevent someone (often in the distant future/with no knowledge of the working device) from finding it and plugging it in due to fault and/or safety concern(s).
So I would work from the assumption that it isn't working (edit: and/or fundamentally unsafe), and test everything I can before applying any power.
Plz reflectors, do anything you like but OUT of that metal box...
If I was in your place, I should firstly desolder red wires from transformer (not from PCB 'cause loose secondary wires are prone to short-circuit) and check primary's resistance (black wires) then secondary's one (red wires) and of course any transformer's lug to GND..
(probably your secondary is center-tapped so resistance (and voltage) between center and any outer lug should be half of the one between outer lugs..)
Then some rectifier diode testing (forward & reverse voltage drop) and filter capacitor for possible short-circuited (or open)..
If you like to use a metal enclosure pedal with mains inside (safety is also a matter of taste.. :icon_cool:) throw away that mains cable and replace it with an appropriate 3 wire one and ground the enclosure via GND 3rd wire..
It should be a good idea to place a sealed FAST blow fuse - your transformer and filter cap size don't indicate any inrush current or shut-off inductive kick issues..
(although R.G. will come and slap my hand..) :icon_redface:
ANY mains wiring/joint should be insulated with heat-shrink tube..!!
Just noticed there is no grommet where the wire enters the enclosure. :icon_eek:
[Flashback]
....
It was my very first job. I was in charge of cooking burgers at a royally-named fast food restaurant. Thanks to the miracles of modern semi-automation, this involved taking raw frozen hamburger patties out of a freezer chest and placing them onto the right hand side of a conveyor belt and placing a bun on the left hand side of said conveyer belt.
Whenever the freezer chest needed refilled, I had to slide it out from under the conveyor system, lift the lid, and drop in a new box of frozen meat.
Here comes the relevant part.
One day, the electrical cord for the freezer chest was wrapped around a metal rung of a prep table, which eventually, through one part of the loop laying on top of the other, created a lot of friction and took away all the slack necessary to successfully pull out the chest. The lack of a grommet where the cord entered the metal chest had, over time, caused the metal edges of the chest to wear through most of the insulation on the wires.
After one pull too many, there was a loud POP, a bright flash, and before anyone knew what had happened, one of the main breakers tripped, shutting down 90% of the restaurant. :icon_eek:
My favorite part: when the fryers lost power, the timer clocks on them repeatedly flashed "HELP". :icon_lol:
I was not injured, by the way, nor was I fired.
....
[/Flashback]
With something like this pedal, it would just take one person tripping over the cord....