Some interesting suggestions there .. your talk of the ground for example, the 14 pin cable would have had huge ground plane from the shielding and now if course I am just the 14 pins 3 + 7 are hooked up to grounds on the 34pin cable.. but yes. only 2.. so I will increase that. The cable was not as short as possible so that I could reach where I need to put the external, and the PSU is a fairly new 165w I pulled from a pc I no long use (ACER) and now use as my bench psu. SO on the power cable I just put a 4700uf between a ground and the +5 ? as close to the drive end as possible right?exxos wrote: ↑Sun Dec 03, 2017 11:45 pmIt might be the old DMA type screwy issues as a side thought. Where the DMA databus needs some pull ups.. That's caused me issues with older drives on my ste machines. Similar circuit on mste.
Or you might simply not have enough gnd wires from your external drive to the mste. Try at least 4 gnd wires from drive to mste.
If you have drives working as internal and intermittent for external.. Then its probably not the drive at fault.
Longer the cable is the more chance of noise and issues. Keep cable short as possible.
Also make sure you use a good regulated PSU for external drive power. You should add some caps on the 5v drive end to be sure. 4700uf low ESR etc.
On an internal cable.. there is no shielding ground.. but I assume all odd pins from the schematic are tied together to ground.. so I will try that first, as one of the most logical issues. I have had this same issue with my boat wiring, motorcycle wiring.. good grounds are #1 - complete the path man!