IIvx & BlueSCSI issue

[corytryan80]

I seem to be having some sort of technical issue with a IIvx someone recently gave me and trying to install a BlueSCSI. I have a one gigabyte hard drive image on an SD card that I’m trying to use with the computer. The issue is when I use a BlueSCSI connected to the back of the machine. I have no problem with the computer, recognizing the image and booting from it. When I try to use the same SD card in an internal BlueSCSI nothing… The activity light just flashes. I’ve tried unplugging the internal CD, I’ve tried changing cables, nothing seems to work. I even swapped out the internal BlueSCSI for a Zulu - same result. Any advice would be greatly appreciated. I’ve used a dozen of these units in the past and have never had this issue before.

 

[daanvdl]

I don’t have a IIvx myself; It’s hard to say for sure just from photos, but it looks like there may be a buffer IC involved — though I can’t immediately tell whether it sits between both the internal and external SCSI ports, or just one of them. Have you checked the schematic yet?

Given that the external BlueSCSI works flawlessly while the internal one doesn’t (even after swapping devices and cables), it really points toward a hardware issue on the internal SCSI path. It could be something as simple as a bad buffer, or even board damage caused by leaking capacitors — especially considering the distance between the controller and the internal connector.

If you haven’t already, I’d recommend tracing the SCSI signals on the board to see if there’s continuity or distortion. Scoping the signals at both the controller and internal connector could also give you some insight into where things might be going wrong.

 

[zigzagjoe]

If it's blinking in a steady pattern, the number of flashes describes the error; most common is 5 flashes then repeat for no SD card detected or an issue with the card. An issue on the host side wouldn't cause that.

Could be weak termination power. Try giving the zuluscsi power via USB. You can also open the USB serial port in PuTTY or similar to view the log.

 

[corytryan80]

If it's blinking in a steady pattern, the number of flashes describes the error; most common is 5 flashes then repeat for no SD card detected or an issue with the card. An issue on the host side wouldn't cause that.

Could be weak termination power. Try giving the zuluscsi power via USB. You can also open the USB serial port in PuTTY or similar to view the log.

I actually have power directly connected to it using a Molex adaptor - I've had that issue before in the past and now I make sure to supply power to all of them now.

 

[corytryan80]

I don’t have a IIvx myself; It’s hard to say for sure just from photos, but it looks like there may be a buffer IC involved — though I can’t immediately tell whether it sits between both the internal and external SCSI ports, or just one of them. Have you checked the schematic yet?

Given that the external BlueSCSI works flawlessly while the internal one doesn’t (even after swapping devices and cables), it really points toward a hardware issue on the internal SCSI path. It could be something as simple as a bad buffer, or even board damage caused by leaking capacitors — especially considering the distance between the controller and the internal connector.

If you haven’t already, I’d recommend tracing the SCSI signals on the board to see if there’s continuity or distortion. Scoping the signals at both the controller and internal connector could also give you some insight into where things might be going wrong.

There are quite a few surface mount caps and with the board being ~32 years old I suppose I should recap it anyway...

 

[corytryan80]

If it's blinking in a steady pattern, the number of flashes describes the error; most common is 5 flashes then repeat for no SD card detected or an issue with the card. An issue on the host side wouldn't cause that.

Could be weak termination power. Try giving the zuluscsi power via USB. You can also open the USB serial port in PuTTY or similar to view the log.

From what I've seen in the past this isn't an error code pulse - it's just a momentary flash as if the SCSI bus is being pinged. I'm really curious about what could possibly be causing this because if I connect the internal caddy CDR, I am able to boot off disk which makes me think the SCSI bus is working as it should.

 

[finkmac]

There are quite a few surface mount caps and with the board being ~32 years old I suppose I should recap it anyway...

that should have been done before using it. iivx caps are very leaky. in fact, there's a pair near the internal SCSI port.

check here for a cap reference

there's no schematic sheet available so you'll have to manually figure out connections.