Disk II troubleshooting guide

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Joined: Oct 8 2021 - 13:45
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Disk II troubleshooting guide

Does anyone know of working links to Disk II drive troubleshooting guides?

I found links in some forums here but they don't work for me.

My first Disk II drive is working great, I can create bootable disks with AdtPRO (great tool!).

The issue is with my 2nd Disk II drive which I recently bought on ebay:

1. When connected as the first drive, it will not read any disk. It powers on and just keeps spinning forever. I cleaned the drive head but it did not help. Worse, it seems to be erasing disks :-(

Any disk I try on this drive is no longer recognizable by my good drive. I need to reformat and re-write on those disks.

2. Connected as a 2nd drive, I tried Locksmith on it. Disk speed test makes it spin but does not show any lines/measurements. Erase option with Locksmit shows the EEE.... status.

If you know of working guide links, please let me know. Thanks.

 

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Last seen: 2 hours 49 min ago
Joined: Feb 27 2021 - 18:59
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If the drive is erasing disks
If the drive is erasing disks it must have a shorted transitor in the write gate circuit.

Check the '3906 at Q2, the 'LS215 at B4, the ULN2003 at D4, and the CA3146 at A3.

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Thanks Robespierre, the LS125

Thanks Robespierre, the LS125 seems to be the issue. It looks fried and leaked upon close inspection.

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Joined: Jul 5 2018 - 09:44
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The 74LS125 is the most

The 74LS125 is the most common chip to blow on the Disk ][ Analog Card.  It also often causes the disk erasure issue.

 

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