+InsaneMultitasker Posted September 2 Author Share Posted September 2 Sometimes, damage happens when and where you least expect it. I was testing two MFM hard drives this afternoon. The first one checked out OK. The second drive did not spin up, so I picked it up and gave it a few quick 90-degree rapid rotations; the motor slowly started to turn and eventually, came up to speed. I rested the hard drive on a non-metallic surface and waited for the Geneve OS to start. A few seconds later, I caught the unmistakable smell of hot, burning circuitry and saw a few whisps of smoke escape from the PC case where the cards and drives are installed. I quickly unplugged everything. My first thought was that I had pulled the HFDC from its slot when I picked up the hard drive, but it and all other cards were firmly in place. It was then that I spotted a SCSI2SD "hiding" in the drive bay, its solder side resting on a metal surface. This device has no plastic short protection on the solder side. The last time I used this particular system, I never remounted the device. Visually, the SCS2SD did not show any signs of damage. This led me to inspect the SCSI Card. Alas, the underside of one regulator was all that I needed to see... and smell. With the SCSI card removed and all drives disconnected, I removed all cards and checked them for shorts between input/ground and output/ground. Finding none, I powered up the system one card at a time. The Geneve, HFDC, and various other cards were seemingly unaffected. And I'm hopeful that after replacing the SCSI card's regulator and capacitors, the SCSI card will be OK. This was a cautionary tale and reminder to (1) inspect your system before using it, especially if it's been months or years since the last powerup and (2) be wary of drives connected to cards like the SCSI and IDE that provide power via the cable or on-board connector. 3 1 Quote Link to comment Share on other sites More sharing options...
RickyDean Posted September 2 Share Posted September 2 23 minutes ago, InsaneMultitasker said: Sometimes, damage happens when and where you least expect it. I was testing two MFM hard drives this afternoon. The first one checked out OK. The second drive did not spin up, so I picked it up and gave it a few quick 90-degree rapid rotations; the motor slowly started to turn and eventually, came up to speed. I rested the hard drive on a non-metallic surface and waited for the Geneve OS to start. A few seconds later, I caught the unmistakable smell of hot, burning circuitry and saw a few whisps of smoke escape from the PC case where the cards and drives are installed. I quickly unplugged everything. My first thought was that I had pulled the HFDC from its slot when I picked up the hard drive, but it and all other cards were firmly in place. It was then that I spotted a SCSI2SD "hiding" in the drive bay, its solder side resting on a metal surface. This device has no plastic short protection on the solder side. The last time I used this particular system, I never remounted the device. Visually, the SCS2SD did not show any signs of damage. This led me to inspect the SCSI Card. Alas, the underside of one regulator was all that I needed to see... and smell. With the SCSI card removed and all drives disconnected, I removed all cards and checked them for shorts between input/ground and output/ground. Finding none, I powered up the system one card at a time. The Geneve, HFDC, and various other cards were seemingly unaffected. And I'm hopeful that after replacing the SCSI card's regulator and capacitors, the SCSI card will be OK. This was a cautionary tale and reminder to (1) inspect your system before using it, especially if it's been months or years since the last powerup and (2) be wary of drives connected to cards like the SCSI and IDE that provide power via the cable or on-board connector. I will say that if you blew the PAL's that you now have the ability to replace them with GAL's. I rebuilt my 1st SCSI and it works fine. So at least everthing can be replaced on the SCSI card now. 1 Quote Link to comment Share on other sites More sharing options...
+InsaneMultitasker Posted September 2 Author Share Posted September 2 35 minutes ago, RickyDean said: I will say that if you blew the PAL's that you now have the ability to replace them with GAL's. I rebuilt my 1st SCSI and it works fine. So at least everthing can be replaced on the SCSI card now. Does this apply to the cards with the Michael Becker mod (daughter board)? The damaged card is a Rev F with daughterboard. The regulator that caused the scorch mark is dedicated to powering the SCSI bus connector. I'm hoping the short did not affect the chips via the IO lines or ground. The good news is that I'm not reading any low resistance (or shorts) on the card. Quote Link to comment Share on other sites More sharing options...
RickyDean Posted September 2 Share Posted September 2 (edited) 23 minutes ago, InsaneMultitasker said: Does this apply to the cards with the Michael Becker mod (daughter board)? The damaged card is a Rev F with daughterboard. The regulator that caused the scorch mark is dedicated to powering the SCSI bus connector. I'm hoping the short did not affect the chips via the IO lines or ground. The good news is that I'm not reading any low resistance (or shorts) on the card. The one that was blown on my original REV E board was the U2 CRU PAL. But I though in the SCSI thread that we had all the PAL's now. I have a REV E witht the becker Mod, but it's not got any problems. I can't say about the Becker Mod, though Shift838 may have that one as he built those new boards, based on the Rev F design. Maybe these Edited September 2 by RickyDean added content Quote Link to comment Share on other sites More sharing options...
+InsaneMultitasker Posted September 2 Author Share Posted September 2 I replaced the scorched regulator this afternoon. The SCSI card powered up and was visible on the bus. I attached an EZ135 to the SCSI card but was unable to read the drive. I then remembered that the SCSI2SD device was at the end of the chain supplying termination, so I checked for shorts on that device (there were none) and re-attached it to the cable. The EZ135 now seemed to be working but I got no response from the SCSI2SD. When I unplugged (or plugged?) the device, I inadvertently depressed the micro SD card, so it had unmounted itself. With fingers crossed I pushed the SD card into the slot and turned on the system. Both the EZ135 and SCSI2SD seem to have come through unscathed! Whew. 5 Quote Link to comment Share on other sites More sharing options...
RickyDean Posted September 2 Share Posted September 2 17 minutes ago, InsaneMultitasker said: I replaced the scorched regulator this afternoon. The SCSI card powered up and was visible on the bus. I attached an EZ135 to the SCSI card but was unable to read the drive. I then remembered that the SCSI2SD device was at the end of the chain supplying termination, so I checked for shorts on that device (there were none) and re-attached it to the cable. The EZ135 now seemed to be working but I got no response from the SCSI2SD. When I unplugged (or plugged?) the device, I inadvertently depressed the micro SD card, so it had unmounted itself. With fingers crossed I pushed the SD card into the slot and turned on the system. Both the EZ135 and SCSI2SD seem to have come through unscathed! Whew. Sounds like one of my episodes, only mine usually damages the components and I have to fix.....fix....fix... 2 Quote Link to comment Share on other sites More sharing options...
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