Microelectronics | Adaptec AHA-1542CF SCSI Controller

Synopsis

I bought this SCSI controller back in 2000-2001 for about $1 at the time. Virtually for nothing. I have used it extensively with many different computers alongside different peripherals connected. Probably the strangest SCSI device that I used was an old Tandberg tape drive. I retired it in 2006 or so after years of heavy usage. Since then, it has stayed in the drawer. Well, actually, in many drawers. These days I plan to use it again in one of my vintage retrocomputing projects.

Disclaimer
This article is not to be treated as a do-it-yourself tutorial on how to fix, restore, rebuild, or improve this unit. This was not my initial intention. But you can consider this whole content as a general guideline, should you decide to attempt any service procedure on an identical or similar unit.

The entire documentation is just a reflection of my work and I cannot be held responsible if you damage your unit, or even harm yourself in the process.

Maintenance

But I have noticed that it has a couple of electrolytic capacitors that I'd better replace as a precaution. I wouldn't risk destroying any of my DIY ISA cards due to a cheap failing part. Most electrolytic capacitors will go open when their lifetime ends. But some decide to go short. That would spell disaster. I replaced both 10 uF / 25 V and 22 uF / 25 V parts with single-ended conductive polymer aluminum solid capacitors. Everything went straightforwardly.

Pictures

Here are some pictures that I took during this operation.

New capacitors installed.

Some of the pins were pretty close to the serial number label, but not close enough to damage the label in the process.

I never had any external SCSI peripheral that would employ the 50-pin Centronics connector. Maybe, at some point, I will find a use for that bulky external connector.