ICD host adapter with extremelly strong pull-up !?

[BigSteve]

I have an 'unmolested' ICD SCSI controller and can confirm that R4 is 100R.

To my knowledge this device was never daisy chained - so would not know the behaviour - however I have (faulty) SH205 that once repaired, I could chain and test!!

[exxos]

To my knowledge this device was never daisy chained - so would not know the behaviour - however I have (faulty) SH205 that once repaired, I could chain and test!!

Would be interesting to see what happens :) Also if you have a scope You could measure pin 19 and see what its switching is actually like.

[ijor]

Also mA ratings are guarantees. I had a long talk to maxim once about such things. Where they may well aim for 50mA for example, but in real world production it's likely more like half that value. So all chips could drive 25mA for example without problem. But it's out of guarantees....

All very valid points, Exxos, I agree. But if the current generated is too high, even if it still works, it might reduce the lifetime of the chip, right? At least I will be very cautious if I need to daisy chain to an ICD adapter.