I just blew up a millenium bypass!!!

[intricatecode]

I accidently plugged an active mixer box i made to my 18v adapter and blam a cloud of smoke arose from it. 

I plugged the 9v adapter to see if it still worked and it did, the only thing that stopped working was the millenium bypass, the led always stayed on,  so the first thing i did was to check if the problem was the bs170, i swapped the one in the socket for a fresh one and the led still stayed on at all times. I guess the problem must be one or both of the 1n1418 diodes and i'll be checking to see if it is them later.

My question is, I'll eventually want to use a millennium bypass in a pedal powered by 18v power supply, how can i prevent this from happening again? whas it the voltage? the current (it's a 1A 18v power supply)? that blew the diodes up? I'm guessing the current since i'm looking at banzai's website and it says (75V 150mA).

What should i use instead of the 1n4148 if i want to use a millennium bypass on a 18v 1A powered pedal?

[R.G.]

I plugged the 9v adapter to see if it still worked and it did, the only thing that stopped working was the millenium bypass, the led always stayed on,  so the first thing i did was to check if the problem was the bs170, i swapped the one in the socket for a fresh one and the led still stayed on at all times. I guess the problem must be one or both of the 1n1418 diodes and i'll be checking to see if it is them later.

1N4148 diodes can conduct 100ma and block 100V. Unless you got the polarity backwards and had no other polarity protection (like a reverse biased rectifier across the power supply) there's no reason to suspect the diodes. If you didn't have any other polarity protection and got it backwards, yes, then the 4148s could die.

It's more likely to be the current/power spent in the MOSFET.

My question is, I'll eventually want to use a millennium bypass in a pedal powered by 18v power supply, how can i prevent this from happening again? whas it the voltage? the current (it's a 1A 18v power supply)? that blew the diodes up? I'm guessing the current since i'm looking at banzai's website and it says (75V 150mA).

The problem is that those diodes are reverse biased in normal operation. 18V is not enough to break over two 100V diodes in series. So the voltage wasn't it. The current could be if and only if the power supply was reversed.

I think what happened is that the additional current in the LED caused by the doubling of the power supply caused the MOSFET to burn out. I suspect that if you use your ohmmeter to check the diodes and MOSFETs you'll find the MOSFET is shorted.

What should i use instead of the 1n4148 if i want to use a millennium bypass on a 18v 1A powered pedal?

Find out what really happened first.

[StereoKills]

^^I agree with RG here. In my experience, MOSFETs are pretty prone to shorting out. Sometimes even for no apparent reason.

[intricatecode]

I've got to stop working on my projects with only 3 hours sleep that's for sure  .

I don't think the power supply had the polarities switched and of course you guys are right, the diodes should take the voltage without any problems. Still, when i tried another bs170 it still stayed on at all times. After getting a good night's sleep I'll debug the circuit and find out what happened and I'll report back what I find.

Thanks for the help guys 

[Renegadrian]

intricate, did you manage to solve your problem???

Got a Q here...or better a (probably stupid) doubt...

Will the Millenium 2 work the same at 12V?! I have built one at 9V and works good, obviously, but what if I put one in a Valvecaster, so with a 12V regulated supply?! Should I increase/decrease some values?!

[R.G.]

It'll be fine if you calculate and limit the LED current to be within the limits of both the MOSFET and the LED. The turn on/off stuff works the same.

[Renegadrian]

Let's say I use this layout there
http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=37764&g2_serialNumber=2
So I should raise the res. value on the board, and add a LED res.?!

[intricatecode]

Sorry Renegadrian I've been busy working on my altered version of the valvecaster and trying to work out a compressor based on it too and i haven't bothered to check out the millenium's problem. But i would trust R.G. on this...

I will definitely get around to trying the millenium bypass using 18v and see that everything works fine, i will post my findings here.

[jmwreck]

as im reading the post, ive remembered my problem, regarding millenium 2, it was built for BSIAB2 and PROCOrat DIY pedals, ive done everything all right, coz ive done millenium 2 many times, but now, the problem was, the LED wont turn off, all i know is that i use only 9V power supply, ive checked everything, changed the MOSFETS, and found out, that the LED is still ON, what could possibly be the problem?

[R.G.]

We get lots of posts similar to this one.

"I've built an Xxyyzz pedal. I know I've done everything right because I checked it N times. what could possibly be wrong?"

We had a saying back where I used to work - Mother Nature waits for you at the end of the assembly line. No matter what you convince yourself and your bosses of, if it isn't right, Mother Nature will tell you; but that happens at a very unopportune time. 

The answer to "what could possibly be the problem?" is - the same stuff that could have been a problem on any of them.
- MOSFET pinout (different makers do make different pinouts, especially on the BS170 if you used that one)
- solder short
- PCB, perfboard, or stripboard flaw
- wiring error
- many more things
- (last in list) bad new component

Having done a circuit before, even many times, is no guarantee that it was done right this time. I know this from my own work.   

[jmwreck]

We get lots of posts similar to this one.

"I've built an Xxyyzz pedal. I know I've done everything right because I checked it N times. what could possibly be wrong?"

We had a saying back where I used to work - Mother Nature waits for you at the end of the assembly line. No matter what you convince yourself and your bosses of, if it isn't right, Mother Nature will tell you; but that happens at a very unopportune time. 

The answer to "what could possibly be the problem?" is - the same stuff that could have been a problem on any of them.
- MOSFET pinout (different makers do make different pinouts, especially on the BS170 if you used that one)
- solder short
- PCB, perfboard, or stripboard flaw
- wiring error
- many more things
- (last in list) bad new component

Having done a circuit before, even many times, is no guarantee that it was done right this time. I know this from my own work.   

I have a great respect with regards to your skills, and thankful, that you have come up to a certain answer..
I'm pretty much discouraged on building it, with regards to cost, and availability, DPDT switches are more of a comfort in my country, anyway, here are the components that i've used in particular:

1n4001
1n4148
1k-4k resistor
100k resistor
2n7000

since these are fairly available...

thank you so much, i hope, i can find a better way to the millenium 2 build 

[Renegadrian]

Sorry Renegadrian I've been busy working on my altered version of the valvecaster...

Well, thanks for the answer, but it's ok man! Haven't tried a M2 at 12v still, but shoulda work...
Tell me more (here or better in its topic) about the "altered" Valvy...You know I'm curious!!!

[R.G.]

I have a great respect with regards to your skills, and thankful, that you have come up to a certain answer..
I'm pretty much discouraged on building it, with regards to cost, and availability, DPDT switches are more of a comfort in my country, anyway, here are the components that i've used in particular:
1n4001
1n4148
1k-4k resistor
100k resistor
2n7000

Take out that 1N4001 if you're using it for a low-leakage diode. It's a rectifier type and its leakage is not all that well controlled.

[jmwreck]

I have a great respect with regards to your skills, and thankful, that you have come up to a certain answer..
I'm pretty much discouraged on building it, with regards to cost, and availability, DPDT switches are more of a comfort in my country, anyway, here are the components that i've used in particular:
1n4001
1n4148
1k-4k resistor
100k resistor
2n7000

Take out that 1N4001 if you're using it for a low-leakage diode. It's a rectifier type and its leakage is not all that well controlled.

i know its a wrong component, but as what ive found out, i cant have any 2n3904, can i use a 2n7000, coz i've read this --------"A good example is 2N3904, 2N4124, 2N4401, 2N5088, etc. If you can't get 2N transistors, use what you can find. Any BCxxx series NPN will work, as will any 2SCxxxx series small signal device. Get yourself the easiest to find  NPN small signal device (TO-92 package is ideal), cut off the emitter lead at the plastic, and use the resulting C-B junction for your low leakage diode." -------- and obviously, 2N7000 is 2N, i hope what i think is not stupid... 

[DougH]

I just blew up a millenium bypass!!!

OH MY GOD!!! Did you get hurt???

















Sorry.... Just reacting to the dramatic sounding thread title...