Picked up a Metal Muff with Top Boost on CL listed as broken for $5. Won't power up. Figured it was a blown voltage protection diode. Opened it up and it is SMD! Should have known. What's a rough estimate in terms of money investment for equipment for getting started on SMD?
After some searching, it seems possible that a regular soldering iron might suffice in removing the diode and replacing it. Anyone with any experience in this area?
Investment about $3 - a pair of smd tweezers. Cut the old leads off the part and solder another in there. A smd hot air tool is nice but you can just use your ref iron. If you want to unload the muff I'd be interested.
Thanks Rullywowr. The diode seems to lay flat against the board. Not sure how you would cut the lead. Would you use an exacto knife or something?
I'll let you know if I decide to be rid of it. It seems to be in good condition mechanically and cosmetically.
No problem. Since the diode is fried anyway just cut it right in the middle. Use your iron and some wick to clean the pads and install a new one ;)
Here is a pic. I'm assuming D2 would be the correct diode given it's proximity to the power jack. Need to verify with a schematic.
(http://img.tapatalk.com/d/14/05/30/6ypybezu.jpg)
It would appear so. Can you test it with a dmm?
I can later tonight. I'm just learning but if it were that diode, I would find voltage on one side and not the other?
If the diode was to blame yes you would find 9v on one side but not the other when plugged in. Try both ways. Most likely was used with wrong adapter and burnt out.
That's my hope:)
Im a little new to SMD parts but....
That component marked D2 in your pic looks like a transistor to me. Do they make diodes in that packaging?
Also, as an alternative... could you peel up the D2 part and replace it with a through hole diode using the solder pads right next to it?
EDIT: Looking up the code 104H tells me that it is a 100uH INDUCTOR. Might want to research it before you go pulling parts ;)
Guess I need to find a schematic. Did a quick search on my phone an came up with nothing.
Quote from: Govmnt_Lacky on May 29, 2014, 05:29:46 PM
Im a little new to SMD parts but....
That component marked D2 in your pic looks like a transistor to me. Do they make diodes in that packaging?
Also, as an alternative... could you peel up the D2 part and replace it with a through hole diode using the solder pads right next to it?
EDIT: Looking up the code 104H tells me that it is a 100uH INDUCTOR. Might want to research it before you go pulling parts ;)
Diodes often come in sot23 and melf packages for smd. You could be correct but I don't think an inductor would be in a metal muff. Def smart to check before pulling parts.
Yes, if you wanted to you could solder in a 4001 to the pads but it would look pretty redneck.
I do love in Memphis;)
Quote from: rullywowr on May 29, 2014, 05:35:20 PM
Yes, if you wanted to you could solder in a 4001 to the pads but it would look pretty redneck.
Only to Superman..... who could see through the aluminum enclosure ;D 8)
I have had a few EHX pedals (a couple small stones) come by me with the FB (which I assume to mean ferrite bead???) located nearest the power jack doing weird things. I can't remember if they were failing open or closed, but they were the problem. I assumed they were just for rf filtering, pulled them, and everything was great after that.
I think that's a diode. The SMD parts don't make any sense with their codes. You have to look them up in a chart that also makes no sense. Fun! But, it looks like the board has both the part number and values for the parts on it. Is that the diode's value above it on the edge of the PCB above the diode?
If I remember right, it was a string of letters and numbers starting with 'M'. It had no meaning to me last night when I looked at it. Then again, I've never worked with SMD
I once fixed an SMD pedal by top soldering a through hole electro ::) The guy I did the fix for has been gigging with it for over a year now without any trouble, to my surprise.
Quote from: PhiloB on May 29, 2014, 09:22:06 PM
If I remember right, it was a string of letters and numbers starting with 'M'. It had no meaning to me last night when I looked at it. Then again, I've never worked with SMD
If it's something like MMB at the start of the string, I'd guess that was your diode value and try putting it in Mouser or Digi-Key or one of the other suppliers.
I'd guess you could use your diode tester with the diode in-circuit in addition to testing the voltage at the diode.
It's a diode, ref designators don't change thruhole vs smd.
You can heat each lead one at a time and once solder melts you can pry each lead upwards out of the solder. Then wick off the extra solder on the pads and solder on a new part. Should take about 2 min.
If its a diode, then why does it have 3-4 legs on it ???
The D2 component looks just like the Q3 component.
Uggg.... SMD :-\
Quote from: Govmnt_Lacky on May 29, 2014, 10:19:42 PM
If its a diode, then why does it have 3-4 legs on it ???
The D2 component looks just like the Q3 component.
Uggg.... SMD :-\
To help orient it for automatic placers. One leg isn't connected.
I have seen 2 switching diodes in one package in smd that have 3 legs before just like Q2 in the photo. I guess they could be using something like that? (not sure what they would need the second 1n4001 for though).
Edit: one leg is not connected! Yeah my votes for 2 rectifiers in the one package
Or dual Zeners
Looks like I don't have to worry about the diode. Looks like the DC jack doesn't work. I put a battery in and the pedal works. I get no voltage on the jack pin when plugged in.
Side note, the LED for the Top Boost is a little dimmer and occasionally cuts out but doesn't affect the signal.