Level 1

28 points

Vintage PowerBook display & PRAM issues post-HDD replacement

i have a vintage Powerbook question…

I was switching out the hard drive recently. When I powered up the screen was lit but then dimmed automatically (the screen had been working fine) had random horizontal lines and I can’t see the desktop in the background.

So I got the Apple video adapter cable to connect to the external port and a 10 dip switch adapter to connect my HP1907 vga monitor.

When powering up I get a desktop pattern but no desktop icons. I can’t select mirroring settings because I have no internal screen.

Tried to zap the PRAM but the computer doesn’t give me the second chime. This is odd. I’ve never had this happen on any of my macs.

Looking for a solution. Thanks!

Posted on Jul 6, 2026 7:29 AM

39 replies

beigebox Author

Level 1

28 points

Jul 8, 2026 12:38 PM in response to beigebox

I’m about ready to conclude the HP1907 monitor is just not compatible with the 640x400 (?) resolution for the PB180.

I’ve tried all relative adjustments on the monitor itself to no avail. The blank desktop pattern is magnified so i think it’s blowing the HD icon off the edge so it’s hidden.

I would still like to try and get the PB HD mounted on the Powermac 7600 desktop via Localtalk and file sharing. I have it shared but haven’t figured out how to mount it. Again, the limitation here is that I have no internal video on the PB.

Jan Hedlund

Level 7

24,815 points

Jul 8, 2026 4:14 PM in response to beigebox

It used to be here:

download.info.apple.com/Apple_Support_Area/Apple_Software_Updates/English-North_American/Macintosh/Utilities/Network_Access_Disk_7.5.sea.bin

download.info.apple.com/Apple_Support_Area/Apple_Software_Updates/English-North_American/Macintosh/Utilities/Network_Access_Disk_7.5.txt

You should be able to find the necessary PowerBook Display control panel on the existing PB 180 hard disk. Could be copied to the 7.5.5 Power Macintosh 7600 via SCSI disk mode.

beigebox Author

Level 1

28 points

Jul 29, 2026 5:03 AM in response to Jan Hedlund

Jan, the PowerBook 180 has bedn working flawlessly. Thanks again

I want to connect an external scsi hard drive (Apple formatted IBM 320MB 2.5 drive) to this computer via the HDI-30 SCSI connector with Centronics-50 port.

The case that I have looks like this:

https://ebay.io/m/qFAjoV

I I have a DB25 adapter to use with the Centronics 50. I have the ID set to 2. There are no other scsi devices daisy-chained.

Should I use the other port on the scsi case for termination or should this work “out of the box”?

Attaching the user manual

https://i.ebayimg.com/images/g/FXEAAeSwlOZqaKm3/s-l1600.jpg

https://i.ebayimg.com/images/g/QtYAAeSw5eRqaKm3/s-l1600.jpg

https://i.ebayimg.com/images/g/OFcAAeSwDCFqaKm4/s-l1600.jpg

beigebox Author

Level 1

28 points

Aug 9, 2026 11:44 AM in response to beigebox

100% 2.5' SCSI I drive compatible
Daisy chainable, up to 7
Quick rotary SCSI ID Switch
Designed and built by aftermarket Apple service provider
Apple II SCSI, DB-25 external enclosure, 2.5" SCSI case, vintage Macintosh external drive, NOS SCSI case

Acceptable power sources (not included):

ABD cable (mini-din connector)
AC/DC adapter +5V/1A (3-mm jack)

Jan Hedlund

Level 7

24,815 points

Aug 10, 2026 7:43 AM in response to beigebox

An external power adapter capable of 5 V DC (1.0 A) output should be OK for the pictured IBM drive (which requires 0.5 A). Alternatively, a special ADB power cable may be used. Make sure that the tip polarity (centre positive) is correct for the hard drive storage case. Can the hard disk be heard spinning?

Termination can be tricky and may require a few extra experiments.

Jan Hedlund

Level 7

24,815 points

Aug 10, 2026 8:31 AM in response to Jan Hedlund

Jan Hedlund wrote:

/.../

Alternatively, a special ADB power cable may be used.

/.../

Correction:

The maximum current draw for all Apple Desktop Bus (ADB) devices connected to a PowerBook 180 is 200 mA (0.2 A), so power supplied via a special ADB cable from the PB 180 ADB port would not be suitable in this very case. Use a separate power adapter instead.

beigebox Author

Level 1

28 points

Aug 10, 2026 8:57 AM in response to beigebox

I have not tested the adapter. Footnote- it’s new and has a led light on it which is very bright when plugged in. I notice it dims and flickers when powering up the external. Not sure what that means?

I may try a couple of extra adapters to see if that makes any difference

Jan Hedlund

Level 7

24,815 points

Aug 11, 2026 8:28 AM in response to beigebox

Important:

I have a 2.5" hard drive storage case that looks VERY much like the one in your pictures. Similar case, similar connection board with the ID switch, one DB-25M, one DB-25F, a hard drive connector, and a power inlet.

I have not used this case for a long time, and I am not sure about which power adapter once was used. However, a quick inspection of the case connection board (including a comparison with an IBM H2xxx Sx pinout) appears to indicate that my device has a centre negative (!) power inlet. That is, not centre positive.

I know that all your documentation says centre positive. It is quite possible that this really is correct for your device, but in order to avoid damage to the drive, please try to verify this.

Does the power adapter label have a polarity icon?

Did you receive an ADB power cable with the case? If so, you could check the 5 V output polarity with a multimeter at the barrel-type DC plug when the ADB power cable is connected to the ADB port of a Macintosh computer (make sure that the computer is off when connecting/disconnecting anything to the ADB port).