There will also be an update to the BOM. (the new batch of pcbs have 1k trimmers instead of a fixed gain resistor) , and there is a pot range adjustment (thanks to @VanTa ) . r34, r35, r37, r38 are now 20k
The range of the Comparator pot could be improved too. (this changed when the 20k resistors are placed)
I’ll test it as soon as possible.
I PMmed most people who already have the pcb
I’ll post the updated build files soon, and also a resistor placement helper!
The BOMs and schematics on my site are updated.
note: the new pcbs have 2x 499r resistors instead of 1k trimpots,
for the gain of the noise transistor.
Sorry if this is a noob question or has been answered elsewhere, but does this module require NTSC or PAL sync or conversely is it HD/Chromagnon compatible?
Hi All
I’ve added a resistor & small cap placement document on my site.
This will make it much more easy to populate the board - as the resistor codes are pretty tiny.
Trimpot settings: The 2 trimpots (pcb version 2.2) set the gain amount of the Noise. The trimpot closest to the power header is for Noise1, the one above that for Noise2. Turn the screw clockwise for higher gain. To get the best setting, patch Filtered Noise1 to the RGB encoder and turn the volume Pot of that channel all the way up. Now turn the screw Clockwise until you see a nice noise image with lots of detail. If you set it too high, the noise signals clips too much and you will see no variation in the voltages. Do the same for the other channel (which looks different, because of the filter values. more stripes instead of dots).
Troubleshooting: If you see too little noise output, it is possible that your noise transistors (T1, T2) have a larger negative offset. To fix this, change r34 (Noise1) and/or r37 (Noise2) to a lower value, such as 10k or 1k. Alternatively, you can swap out the transistors.
I’ve got the boards!
I spent an embarrassingly long time wondering why the label said “MONS”
Question:
The bom says “Switch ON-ON Micro toggle” - “micro” in context of switches usually refers to bumper-style automation/embeddable momentary switches.
Am i missing something or will a standard sub-mini on-on toggle switch work?
I’ve updated the BOM, the word micro is indeed the wrong term.
You need a sub-miniature SPDT toggle switch that has two “ON” positions (on-on)
5mm shaft diameter . Thonk has them of the brand Dailywell, but any other will work too.
(I use TME’s TSSM1022A2, but those are out of stock now)
The switch sets the noise channel for the comparator. Noise1 or Noise2
