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Home › Forums › Vintage EHX › Vintage Electric Mistress Help
Hi Folks and Thanks in advance!
I am working on a vintage Electric Mistress for a friend, I have found it is most likely V2 though I can find no exact schematic match.
The first thing I thought of was a reverse polarity burn. I pulled the 10uF cap and LM741 and tested them, they were toast. Before I was going to put it back together I noticed the transistors for the voltage regulation and VCO are the same part number, 2N5087, almost all of the schematics I have found use 2 different transistors. Before I put it together and fire it up I wanted to make sure that this set up is correct and not a previous repair gone bad.
I would really like to rebuild the entire board with better resistors(metal) and capacitors(stacked poly) to be honest. I have already put IC sockets in where there were none.
I have linked a schematic that suggests 2N5037(which I believe is wrong as those are NPN transistors) and the schematic from Ralf Metzgers site.
Top of board: http://tinypic.com/r/qrakh1/8
Bottom of board: http://tinypic.com/r/1zpjy9f/8
Schematic using 2N5037: http://tinypic.com/r/2n994ed/8
Ralf Metzger schematic: http://tinypic.com/r/2h3c2s8/8
It’s all together now.
Getting 5.19V at pin 2 of the 741
Getting 18.75 @ pin 7 (using 9v batteries)
Nothing on pin 8 of 4558
I am really hating this 4 transistor set up. I am contemplating cutting a version 2 board from the schematic @ Ralf Mtezgers site. Especially since I am getting no love here.
Can you please tell the more specifications about the your gadget? What type of gadget it is and what it contains?
Is it sensitive to frequency changes? Also what tools are you using or the measuring?
Can you please specify the more details about the surrounding components of your effective area of fault?
I got it working! Now, I will tell everyone I know do NOT purchase ANYTHING Electro-Harmonix, because the admins at the EHX site have issues with noob questions.
P.s. Nice trolling there with a new member and one post.