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ScottC
Copper Member
USA
20 Posts |
 Posted - 02/04/2009 : 04:56:04
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I've got 4 2N7000's that I bought to have for the "Stormchaser" mod once I get this thing working. Will those work? I believe they have S - G - D pinout -- see attachment.
Download Attachment:  2n7000.jpg
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Edited by - ScottC on 02/04/2009 05:00:33 |
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cctsim
Silver Member
United Kingdom
418 Posts |
Posted - 02/04/2009 : 05:14:28
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The 2N7000s are MOSFET types and are not suited for this application due to their additional body diode between drain and source.
I would put the original jfets back first and see if the new opamps solve the problems.
Were the original jfets 2SK30ATM ?
They have usually the Gate electrode in the middle. |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 02/04/2009 : 06:00:35
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Completely missed the "is a 2N5458 OK - I didn't have 2N5457" question... good pickup cctsim!!
Yes, please put the originals back in and try it. The key to repairs is to try one thing at a time 
Q3 and Q9 should be 2SK118 (or Boss may have used an equivalent) |
Edited by - Laurie on 02/04/2009 06:05:21 |
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ScottC
Copper Member
USA
20 Posts |
Posted - 02/04/2009 : 14:07:00
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Thanks. Will put the old ones back in and try. The old ones are labeled:
K118
Y7D |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 02/04/2009 : 14:41:52
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Awesome! They usually drop the "2S" at the start, so "K118" is a 2SK118.
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ScottC
Copper Member
USA
20 Posts |
Posted - 02/05/2009 : 00:36:36
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Took out the wrong transistors, put the old ones back in, tried it out (not mounted in the enclosure), and everything seems to work as it's supposed to .
Then my son and I quickly put it back in the enclosure and he ran off to church with it tonight for practice, so hopefully it will work there.
I'll double check it later tonight to make sure everything is OK.
As I was probing it on the wooden board I had it mounted on, I was getting some erratic results, but hopefully that was just sloppy probing on my part. I'm keeping my fingers crossed.
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 02/05/2009 : 00:39:24
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| Awesome! Will await your report with interest! |
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ScottC
Copper Member
USA
20 Posts |
Posted - 02/05/2009 : 04:45:01
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Well, my son said the Metalzone worked fine in practice but when he played on stage he said it "wasn't loud at all". But afterwords, and now at home, it seems to be working fine. So... I think it's fully functional, we'll just keep an eye on it for a while before I declare total victory. I guess I'm still a bit leary of Q2, Q3, Q9 that were mentioned earlier, and not totally confident in my de-soldering and soldering skills.
Thanks everyone for your help, especially Laurie, it is very much appreciated.
By the way, I did buy two 16 pin DIP sockets and cut them down to get four 8 pin SIP sockets that I put the ICs into. The ICs near the in and out jacks didn't have enough clearance, so I had to bend the ICs down at about a 45 degree angle to get the PCB back into the enclosure. Just an FYI for anyone interested in socketing the ICs.
Thanks again all.
Once I'm comfortable that the Metalzone is working consistently, I'll probably pursue the Stormchaser mod. |
Edited by - ScottC on 02/05/2009 04:46:15 |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 02/05/2009 : 05:17:35
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One of the problems the metalzone has is the "nasally" mids - they kind of get lost in the general mix. Nearly all of the MT-2 mods (Stormchaser included) remove the parts of the circuit that cause that - makeing it "cut" a little better.
Of course, there are no certainties - your mileage may vary 
Anyway, glad to hear it's up and running!
If it works at all, then the transistors are almost certainly OK. They will generally fail completely.
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MT-2 Metalzone Problems - Help Please
2n7000.jpg