Performa 6200 — ADB power-on works but no keyboard/mouse input

[mndeaves]

Might be how I was counting the pins or setting up my meter. Fresh eyes this morning show me it is the pin highlighted with continuity to pin 1. Multimeter set to the the speaker icon/200 Ohm settings with speaker enable. Just to check I'm not losing the plot, picture of the jumper wire I have in port 1.

 

[Phipli]

Might be how I was counting the pins or setting up my meter. Fresh eyes this morning show me it is the pin highlighted with continuity to pin 1. Multimeter set to the the speaker icon/200 Ohm settings with speaker enable. Just to check I'm not losing the plot, picture of the jumper wire I have in port 1.
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That's pin 20 that makes more sense

 

[mndeaves]

Realise now the Cuda chip is actually programmable by the sound of it, so just swapping it in with one that hasn't got the same firmware on it is not going to work. I guess at least we have connectivity to pin 20 and as you say, the soft power works so the chip firmware should be ok. I re-flowed R85 and it now sits flatter on the board but still.. same symptoms.

 

[Phipli]

Realise now the Cuda chip is actually programmable by the sound of it, so just swapping it in with one that hasn't got the same firmware on it is not going to work. I guess at least we have connectivity to pin 20 and as you say, the soft power works so the chip firmware should be ok. I re-flowed R85 and it now sits flatter on the board but still.. same symptoms.

You want to trace out from pin 19 next - check if it goes to the resistor, then the transistor, and then the other resistor. Perhaps reflow each (don't put too much heat in the transistor, some are super heat sensitive, perhaps leave it until last)

 

[mndeaves]

I've found R227 and one meter lead on either side of that gives no continuity to any pins on the cuda.. the hunt for R241 continues with the magnifier

I think R227 is ok as with the meter leads either side of it and the meter set to 2k Ohm setting it reads 0.22.. which I think means its ok

 

[Phipli]

I've found R227 and one meter lead on either side of that gives no continuity to any pins on the cuda.. the hunt for R241 continues with the magnifier

I think R227 is ok as with the meter leads either side of it and the meter set to 2k Ohm setting it reads 0.22.. which I think means its ok

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Careful, you mis-understand. As I've previously mentioned, the two schematics are from different models. The labels are completely different. R227 is not the same on your board, nor is R241. You're looking for resistors that are wired the same, not the same label.

Also, someone has crudely reworked U32.