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viviridian

Color Classic / SCSI2SD v5.5 not terminated

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I recently got a SCSI2SD v5.5 to use with a Color Classic I recapped and have been getting running again.

For some reason, my CC is unable to boot from either the SCSI2SD or the internal hard drive when the SCSI2SD is attached, I get a floppy disk icon with flashing question mark. I then put together a boot floppy with SCSIProbe, which says that the bus is not terminated. I'm not sure how this is possible -- the v5.5 is always terminated and I have a 5v power supply connected (tried a couple combinations of wall adapter / microusb cable, but nothing seems to help.)

 

In scsi2sd-util, I'm setting my target IDs to >0. I also double-checked that it only has one drive without the SCSI2SD attached, and that drive has ID 0.

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Is your v5.5 the one that plugs into the external SCSI port or an internal style set up in an external enclosure?

 

When you run scsiprobe, are you seeing the drives at two different IDs? Are you setting the entire SCSI2SD to appear as one physical drive with multiple partitions? Or is it set to appear as multiple physical drives?

 

Also, generally the SCSI2SD should be able to be bus powered except for a few exceptions. But I’m pretty sure the CC can bus power it.

 

For kicks, have you tried removing the internal hard drive and having the SCSI2SD being the only device on the scsi bus?

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My v5.5 plugs into the external port.

When I run scsiprobe with it attached, I see no devices listed (photo attached)

I've tried configuring it to appear as both one physical drive and multiple physical drives, but there's no change in behavior.

 

I'll try unplugging the internal hard drive later and reply with the result.

scsiprobe.png

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I recapped it, some of the solder joints are a little suspect but I think everything's ok. I didn't see any obvious damaged traces on the board, do you have any ideas for areas to take a closer look at? I attached a pic of the logic board.

I haven't tried with the internal drive unplugged yet.

IMG_0578.jpg

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The chip U7 looks like it picked up some corrosion from C6. Not sure if that has anything to do with SCSI, but I’d definitely try to get that part cleaned up. Any remnants of old leaking capacitor fluid can cause electrical issues, and later corrosion. Scrubbing that off may help. If you didn’t do a deep cleaning during recapping this could

potentially be a side effect. How’s the startup chime? Nice, loud and clear?

 

I guess another question is, can you boot with internal drive attached, no SCSI2SD, with your boot floppy and see the hard drive in SCSIprobe? If it’s the factory drive it will likely be set to ID 0. Even if the drive is trashed, seals turned to sludge, heads crashed, SCSIprobe should still be able to report back it’s ID if the SCSI circuits on the logic board are in working condition.

 

Last side note which I’m sure you already know, but SCSI is not hot-pluggable. Computer must be shut down to plug and unplug scsi devices (internal and external).

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I have the same issue with my Classic II. If I have both the SCSI2SD (v6) and the internal drive plugged in it won't boot. Either of them on their own and it boots just fine. Was kinda wondering if it was my recap job or something else but haven't done enough troubleshooting.

 

So it's worth trying each on their own.

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Well, not necessarily.  As someone smarter than me has said, what causes “SCSI voodoo” is usually not that things don’t work when they should ... it’s that often, misconfigured things just happen to work when they shouldn’t, then suddenly stop working and people are surprised...  but anyway.

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Good point. If it's not on there is a bug in the firmware.

 

When both devices are on the bus the activity light for the SCSI2SD stays on 100% of the time.

 

If the SCSI termination is like other multiaccess busses in electronics the resistors are there to prevent reflection of signals on the bus lines caused by the unterminated ends. So no termination would create erratic noisy behavior on the bus line. On that note, though the problem may be the Mac not turning off its internal termination when two devices are connected. With the Classic II its a single SCSI bus inside and out. I assume its the same on the Color Classic II.

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On 8/1/2020 at 2:09 PM, just.in.time said:

The chip U7 looks like it picked up some corrosion from C6. Not sure if that has anything to do with SCSI, but I’d definitely try to get that part cleaned up. Any remnants of old leaking capacitor fluid can cause electrical issues, and later corrosion. Scrubbing that off may help. If you didn’t do a deep cleaning during recapping this could

potentially be a side effect. How’s the startup chime? Nice, loud and clear?

I didn't do a deep cleaning, just superficial cleaning with isopropyl wipes. The startup chime is loud and clear.

 

On 8/1/2020 at 2:09 PM, just.in.time said:

I guess another question is, can you boot with internal drive attached, no SCSI2SD, with your boot floppy and see the hard drive in SCSIprobe? If it’s the factory drive it will likely be set to ID 0. Even if the drive is trashed, seals turned to sludge, heads crashed, SCSIprobe should still be able to report back it’s ID if the SCSI circuits on the logic board are in working condition.

Yes, the factory drive is still fine, bootable, and reports ID 0.

 

On 8/1/2020 at 2:09 PM, just.in.time said:

Last side note which I’m sure you already know, but SCSI is not hot-pluggable. Computer must be shut down to plug and unplug scsi devices (internal and external).

Yep

 

On 8/1/2020 at 2:28 PM, karrots said:

I have the same issue with my Classic II. If I have both the SCSI2SD (v6) and the internal drive plugged in it won't boot. Either of them on their own and it boots just fine. Was kinda wondering if it was my recap job or something else but haven't done enough troubleshooting.

 

So it's worth trying each on their own.

I tried with the internal drive disconnected, and the scsi2sd connected to the external port. I still get the same result in SCSIProbe: "Bus Not Terminated" and no devices show (other than the CC itself).

SCSIProbe also reports that if I boot with *neither* the scsi2sd or internal drive attached. Is that normal...?

 

20 hours ago, karrots said:

When both devices are on the bus the activity light for the SCSI2SD stays on 100% of the time.

For me, the light on the scsi2sd has never stayed on. Actually, the only times I've seen the LED light up are:

1. Very briefly when the CC powers on.

2. When configuring it over USB

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10 hours ago, viviridian said:

I didn't do a deep cleaning, just superficial cleaning with isopropyl wipes. The startup chime is loud and clear.

Well the chime is good news. However, I always make sure to do a good deep cleaning after removing old capacitors but before installing the new capacitors. There are many different ways to do a deep cleaning. As long as all the old electrolyte is removed is all that matters. Any remaining electrolyte is both conductive and corrosive. Based on proximity, I'm guessing that U7 is involved with ADB somehow (assuming those are ADB ports right there, I'm not near my CC to check). Having that chip corrode away would not be good. Or any other areas on the logic board for that matter.

 

10 hours ago, viviridian said:

Yes, the factory drive is still fine, bootable, and reports ID 0.

That's promising news, at least the SCSI controller is working! :)

 

Aside from the logic board not being cleaned, I'm out of solid ideas...

 

Just for thoroughness, have you tried setting the termination on the SCSI2SD to "off"? If that's possible on the v5.5 board (mine is the 5.0 internal version IIRC, might be different). Theoretically, "on" should be correct but who knows. SCSI is definitely very sensitive.

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