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http://www.muffwiggler.com/forum/viewtopic.php?p=1566660#1566660
pics of all locations: ttsh-leds.zip
Solution:
Fixing the dimmer to dim all LEDs uniform requires some effort:
- the longest chain with 5 LED must be split. (Two traces to cut, two wires to solder. Resulting in two chains with four LEDs instead of one 5 and one 3. )
- all chains shorter than 4 LEDs get one or two additional orange LEDs in row to the resistor, so all are 4 LEDs long.
- all resistors get the same value (200 to 240 Ohms)
Replace the 1kOhm base resistors (LED-R3, LEDR6) with 100 Ohms. (They are not needed (straight wire would be ok), but having a resistor enables you to measure the base current and gives some fault protection. 1k gives nearly 1V drop, too much for proper current setting with resistors. )
So now all rows have the same current, at *all* dimmer setting (not just at one).
The current can be adjusted to nearly full brightness of the LEDs. (16mA or so. )
The dimmer can be set to all LEDs off.
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