TOOL SUGGESTION: I just tried the Ideal grip-n-strip #45-227 wire strippers. They are great!! Friend of mine who used to work at Bell Aerospace suggested them.
Just finished with installing the VRM module into my SIIIv6
First an apology, no pictures
one of these days I'm going to have to break down and get a digital camera
Next: manditory safety warning
Make sure the caps are safely discharged and you know what you are doing !! Leathal voltages and all that!!
Second: TAKE YOUR TIME!! The space inside the SIIIv6 chassis with the tube select and boost switch is getting tight!
The module came in a cushioned package with a cardboard protector over the anti-static bag. Be careful, the mica insulator shim is in there too!! Nice packaging job Stephen.
I chose to use a standard pot (Ratshack 1M linear) and located the pot / control knob on the back of the amp.
Going this route requires that 3 holes be drilled into the chassis
No heat transfer grease yet, the shack didn't have any and what they have is $13 plus shipping for web sales.
My method for drilling the chassis is to securely tape the rear plexi plate (if you have an older kit, Stephens newer ones are screen printed) to the chassis to help prevent the plexi from grabbing the drill and breaking.
Use a sharp drill and use a drill stop. My drill stop is two 1/4" wide strips of duct tape wound around the drill bit about 3/8" from the end to help prevent "overdrilling". My biggest fear was the drill breaking through the chassis and wiping out the board, or wiring or something important
Remember to deburr all of the drilled holes
Take it SLOW and don't push too hard!! The nice thing about the duct tape is that it holds onto some of the chips.
The most difficult part of the install was relocating the tube select switch.
Because of space limitationsand to keep the wiring short the VRM pot needs to go where the tube select switch is located and the mounting hole needs to be enlarged to accept the pot.
The tube select switch is relocated between the impedance selector and the speaker out jack. This needs to be a .250" diameter hole for the supplied Trinity switch.
The rewiring of the tube select switch will require that some of the connecting wires be shortened and others lengthened. It's pretty obvious what wires need what done to them
To "streach" the wires that required it I just spliced them and covered the joint with heat shrink.
The old tube select hole now needs to be enlarged to about a .264" (has to be larger than 1/4") for the control pot. Mount the control pot fasten it down.
Next is to locate where the VRM module will be located on the chassis. For me it was between the 6v6 tube socket and the gounding lug next the power transformer. I wound up putting it in "upside down" from how it is shown on the layout.
Mark the location and drill a .125" hole for mounting the VRM module.
Next I scuffed the chassis aluminum up a bit with a scotchbrite pad to remove surface oxidation and hopefully get some better heat transfer.
Carefully mount the VRM module with the mica shim between the module and the chassis and tighten the mounting screw.
If you have heat transfer grease, a thin layer between the mica and the chassis and between the mica and the VRM is required.
Now just follow the layout for the hookup
viewtopic.php?t=1176
Remember to braid the wires from the VRM to the control pot (I didn't
)
I did all the above and got a functioning VRM.
Now I'm going to give it a workout and will report back
Hope this helps!!
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