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Twiggy Analog Board Damage

Started by ried, September 12, 2026, 06:59:49 PM

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ried

I recently picked up a loose Twiggy Analog Board and found that it has a damaged inductor at L6. The board appears to have had a rough life, with a piece of the PCB broken off at the corner. Photos are attached. Is this inductor something that can easy be procured at i.e. DigiKey or Mouser and, if so, can anyone confirm the exact replacement part that I need?

TorZidan

The RRAuction buyer's identity has been revealed  :o !

The schematics show that L6 is a 470uh inductor. I have not tried to color-decode the rings from the photo, you could do that.

A google search for "470uh inductor axial" shows plenty of components.




ried

#2
Yeah, I've picked up a few lots from them over the years  ;)  Gemini is giving me some conflicting info during a Google search. It says:

Based on the standard multiplier color coding for military or commercial axial inductors, this component is a 100 µH inductor. Here is how the color bands break down from top to bottom (reading away from the wider silver identification band at the very top):

  • 1st Band (Digit 1): Brown = 1
  • 2nd Band (Digit 2): Black = 0
  • 3rd Band (Multiplier): Brown = ×10 (or 1 zero)
  • 4th Band (Tolerance): Silver or Gold (Denotes tolerance percentage)

Combining these digits (1 and 0 multiplied by 10) gives 100 µH. A 470 µH inductor would instead feature a yellow band (4) and a violet band (7) at the top.

sigma7

The Twiggy Analog Board Rev. F schematic is here (Rev F is the final version, early versions are very different):
https://lisalist2.com/index.php/topic,797.0.html

That suggests it is 100 µH, but does not specify a current rating; perhaps the size can be used to determine that.

For completeness, Twiggy Digital Board Rev. H schematic is here:
https://lisalist2.com/index.php/topic,524.msg3712.html#msg3712
Warning: Memory errors found. ECC non-functional. Verify comments if accuracy is important to you.