First thing we will need to do is print the PCB trace page to use with the toner transfer method print the artwork from page 4 of the PDF file:
(you can use any method you wish to transfer the pattern)
ForumVibe.pdf
4.7MB Download
The page is already scaled exactly, so you will need to tell your printer not to adjust it's size at all, the following selections should be made in the print dialog box:
There are some really great turorials on using the Toner Transfer method on the net, a particularly good one done by a friend of mine John Lyons can be found here: How to make Printed Circuit Boards.
Download the tutorial in Windows helpfile format: FYI: Windows (Xp/Vista) may try to block you from viewing the helpfile, how to unblock the helpfile.
How-to-make-PCBs Helpfile 519Kb Download
I've printed two ForumVibe PCB patterns onto some photopaper, ironed them onto a single piece of copper-clad board, then rinsed/removed the photopaper and residue off the board, here the board(s) are ready to drop into the etch tank:
after etching, it is now ready to cut and drill:
Here is a cut and trimmed board after drilling, you can also see through the PCB to the Flat Black area painted on the component side:
This is the area to be painted flat-Black, while not mandatory doing this helps isolate the LDR's under the light sheild from ambient light that can even go through the FR4 board material:
(it doesn't matter if you paint first, or drill first)
Quick story: once I installed a board into a crybaby shell, the gig'ing user soon complained that sometimes while playing the vibe seemed to change it's depth setting by itself. I took the unit back to my shop and found nothing wrong with it, so I returned the unit to the owner and he brought it back again saying it changes by itself sometimes on stage in the middle of a song. Attending the next gig, listening and observing the player and stage setup it dawned on me what was happening.
If you look at a crybaby wah shell there is a big square hole in the box right under the pedal where the potentiometer is mounted, well when the player was soloing the lightman's (stationary) spolight was on him, and his pedalboard, and was actually shining right through that hole under the pedal and lighting up the FR4 circuit board which changes the LDR's "resting" spot, the user was right, the 'vibe was changing depth without him touching it, while he was playing. I then added this flat black painted circle under the light sheild to fix this random issue. If you box-up your vibe in a tight box you may not need the flat black painted area, I just do it anyway on all my builds now.
You can see in this picture that the build is a Modern/Redhouse build (on page-13 in ForumVibe.pdf) the nice 1uF stacked polyester caps are visible (the tall white square caps), the MPS-A13 darlington transistors are clearly seen in the LFO section along with the appropriate jumpers.
Note: ...about lamp bulbs and R47/TR2
When using 8v-15v bulbs you can reduce (and sometimes omit) R47 to a lower value (50-76Ohm), it's only when using lower voltage bulbs like Radio Shack 272-1139A (a 1.5V/25mA bulb) you need to be concerned with the value of R47 which should be in the range of 86 to 150 Ohm.
If you use the Radio Shack bulb note there are two different sizes sold under the part number 272-1139, the one on the left marked 272-1139A is a bit easier to handle for soldering:
272-1139A 272-1139
Next is a close-up of the trimpots I pre-marked at their default setting, a step I highly recommend (page-24 in ForumVibe.pdf) and you will be very glad you did this later on during dial-in and tweaking time.
The solder side (bottom):
© 2002 - Brad Burt