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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: stevee617 on January 23, 2011, 05:06:39 AM

Title: A3000 Rev 7.3 mobo SCSI problems
Post by: stevee617 on January 23, 2011, 05:06:39 AM

Did the A3000 Rev 7.0/7.3 motherboard have the backward diode issue?

I have an Apple CD-600e connected & terminated and the computer just sits there with the HD light on and does nothing.

I shut down, turn it off and turn off the CD-Rom, switch the computer back on and it boots right up.

Any ideas?

Title: Re: A3000 Rev 7.3 mobo SCSI problems
Post by: lost_loven on January 23, 2011, 06:56:45 AM

scsi id conflict maybe?
I had that problem with a hard drive but used scsi prefs (i think that is what its called) and set the boot timing to wait for hd spin up. but i think check you scsi id's.
lost

Title: Re: A3000 Rev 7.3 mobo SCSI problems
Post by: Amiduffer on January 23, 2011, 07:35:17 AM

I think you're confusing the problems with some of the C= 3640 accelerators which had the problem with reversed caps.

Make sure that the CD and HD have different unit numbers and that your HD isn't terminated.

Title: Re: A3000 Rev 7.3 mobo SCSI problems
Post by: VingtTrois on January 23, 2011, 09:03:20 AM

First, check if you have the bugged SCSI CONTROLLER: WD33C93A-PL 00-04 or 00-06

Title: Re: A3000 Rev 7.3 mobo SCSI problems
Post by: stevee617 on January 23, 2011, 04:17:57 PM

Yep, It has the -04 SCSI controller chip in it. Guess I need a -08 SCSI chip.

Title: Re: A3000 Rev 7.3 mobo SCSI problems
Post by: stevee617 on January 23, 2011, 04:24:12 PM

Amiduffer stated:

"Re: A3000 Rev 7.3 mobo SCSI problems
I think you're confusing the problems with some of the C= 3640 accelerators which had the problem with reversed caps.

Make sure that the CD and HD have different unit numbers and that your HD isn't terminated.
__________________
Amiga 3000D UP and running! Hear that clicking. 8)
Amiga 3000D & 4000D in storage sadly. "


No, there was an issue with some motherboards with the SCSI termination diode, which supplies 5 volts on Pin 25 of the external SCSI port. The diode is installed backward. To make matters worse, the silk screen on the motherboard was even print incorrectly.

I am unsure which motherboards were affected by this.

Title: Re: A3000 Rev 7.3 mobo SCSI problems
Post by: Zac67 on January 23, 2011, 08:53:46 PM

Quote from: Amiduffer;608412

Make sure that the CD and HD have different unit numbers and that your HD isn't terminated.

Err....

Make sure you've removed the onboard terminators if an external unit is connected. And terminate the devices on the cable ends (internal and external). SCSI requires exactly two terminators sitting on the bus ends.

Title: Re: A3000 Rev 7.3 mobo SCSI problems
Post by: stevee617 on January 23, 2011, 09:11:38 PM

All the on board terminators are removed. The CD-ROm is terminated as well.

I just verified that the CD-ROM is bad, so I think that solves my problem.

Title: Re: A3000 Rev 7.3 mobo SCSI problems
Post by: Darrin on January 23, 2011, 09:18:15 PM

Ah, the "fun" of A3000 SCSI...

I installed a Buddha.  :D

Title: Re: A3000 Rev 7.3 mobo SCSI problems
Post by: Matt_H on January 23, 2011, 09:57:09 PM

I was having external SCSI problems on my 3000, too, and it turned out to be a weird jumper on the (EDIT: internal) hard drive itself that had to be removed.