https://github.com/jbilander/a1200_ide_led_fix_board
A small PCB that fixes the IDE Activity LED always lit problem on the A1200.
https://github.com/jbilander/a1200_ide_led_fix_board
Last synced: 4 months ago
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A small PCB that fixes the IDE Activity LED always lit problem on the A1200.
- Host: GitHub
- URL: https://github.com/jbilander/a1200_ide_led_fix_board
- Owner: jbilander
- License: cc-by-sa-4.0
- Created: 2022-03-11T12:00:04.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2022-04-26T18:06:06.000Z (about 4 years ago)
- Last Synced: 2025-02-06T16:05:36.386Z (over 1 year ago)
- Size: 2.34 MB
- Stars: 2
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# A1200_IDE_LED_fix_board
A small PCB that fixes the IDE Activity LED always being lit problem on the A1200.
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Video:
https://drive.google.com/file/d/1M3btw3f4qckySm2AM4Yh1fa0WKVMcq9z/view?usp=sharing
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Symptom:
When using the Sintechi (*) SD2IDE-adapter in an A1200 the H.Drive LED is always on.
Apart from this, these adapters works perfectly.
[* SD2IDE](https://goughlui.com/2019/02/03/tested-generic-sintechi-fc1307a-based-sd-to-ide-adapter-sd35vc0/)
Cause:
The motherboard should turn on the HD LED when the IDE /ACTIVE input is low.
However, the transistor on the motherboard controlling the HD LED will switch it on
whenever it sees more than ~0.6V difference from 5V on /ACTIVE.
As the more recent version of these SD card adapter outputs 3.3V when there is no activity,
the LED will never be switched off.
Solution:
Using a 74HCT14 IC in-between the pin 39 /Active signal will bump the 3.3V
up to 5V since HCT has TTL-level inputs. 2V is enough to detect a High,
which will then be shifted up to 5V on the output.
Description taken from [here](http://megaburken.net/~patrik/Amiga%20SD%20Adapter%20HD%20LED%20Fix/fix.txt)
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BOM Rev. A
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Position | Name/Value | Package | Notes
-|-|-|-|
U1 | 74HCT2G14 | TSOP-6 | Dual inverting Schmitt trigger
C1 | 0.1uF = 100nF | 0805 | Decoupling capacitor
J1 | PinSocket_2x22_P2.00mm_EdgeMount_SMD | |
J2 | PinHeader_2x22_P2.00mm_EdgeMount_SMD | |
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[Creative Commons Attribution-ShareAlike 4.0 International License][cc-by-sa].
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