VOGONS

Can you help me ID and configure LED MHz display

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First post, by p6889k

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This LED display is currently set to 2 MHz and I'm trying to change it. I think I figured out the scheme, but still would be nice if anyone could actually ID the model so that I can look up any official documentaion.

I'm also trying to figure out how to make it change its value when Turbo button is toggled. Right now it's only connected to power so it doesn't have any way to get triggered.

Power cable is connected to the 2pin horizontal header on the left side. I'm not sure what is the purpose of the 2 pin vertical header to right of the 2pin horizontal header. I also don't know what is the purpose of the 1pin header on the right side - to the top right of the chip.

The case has both a turbo button and turbo led light. The turbo led light is connected to the motherboard's 2pin turbo led connector. The turbo button is connected to the motherboard's 2 pin turbo connector. Both work correctly. How should I wire things to trigger the MHz display when turbo is changed?

Thank you.

Sinclair ZX Spectrum 48k, 48k+, 128k, +2
Amiga 1200, 68030/40mhz
386DX/33, ET4000, SBPro2, MT32
Dual PPro/200, Millennium II, Voodoo 2, AWE32, SC-55
etc.

Reply 1 of 3, by p6889k

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I did some more experimentation and connected the motherboard 2pin turbo led connector to all combinations of the 3 available pins on the led display - 2pin vertical and 1 pin standalone. Neither permutation triggered any change on the led display. I did change the configuration jumpers to a position where the display should change based on turbo on/off.

Sinclair ZX Spectrum 48k, 48k+, 128k, +2
Amiga 1200, 68030/40mhz
386DX/33, ET4000, SBPro2, MT32
Dual PPro/200, Millennium II, Voodoo 2, AWE32, SC-55
etc.

Reply 2 of 3, by p6889k

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I figured it out. I need to connect only the +5V Turbo LED output from the Motherboard to the single pin connector on the LED display (right side on my picture) and leaving the 2nd pin on the motherboard empty. The LED display then correctly changes based on turbo position. I guess the LED display is triggered by the 5V voltage coming from the motherboard. Additionally I then also connected Turbo light from the case to the 2 pin vertical connector on the LED display board, this then provides power to the Turbo light so that it can light up when turbo is engaged. The turbo light is little bit more dim than when connected directly to the motherboard's turbo LED output, but I guess that's because of some voltage loss by passing through the LED display.

Sinclair ZX Spectrum 48k, 48k+, 128k, +2
Amiga 1200, 68030/40mhz
386DX/33, ET4000, SBPro2, MT32
Dual PPro/200, Millennium II, Voodoo 2, AWE32, SC-55
etc.

Reply 3 of 3, by p6889k

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And here's a picture in case someone in the future is using the same LED display.

Sinclair ZX Spectrum 48k, 48k+, 128k, +2
Amiga 1200, 68030/40mhz
386DX/33, ET4000, SBPro2, MT32
Dual PPro/200, Millennium II, Voodoo 2, AWE32, SC-55
etc.

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