HP/Agilent 16702A won't boot from SCSI CD-ROM drive - Page 1
Forum section: electronics / repair

author: ZaneKaminski
author_rank: Contributor
timestamp: April 04, 2017, 05:18:24 pm
content: Hopefully someone can enlighten me as to what I'm doing wrong... I have a 16702A and it works, but I would like to upgrade it to the latest version of the software. I got the Plextor Ultraplex 40max drive, HPDB50-to-IDC50 cable, terminator, the drive, set the "block" jumper (for 2048-bytes/block, right?), hooked it all up, and I got this error message when trying to boot:I have since tried two different Plextor drives, two different HPDB50-to-IDC50 cables, internal and external termination, with and without the "block" jumper set, with different power supplies, using a CD from Agilent, using a CD I burned myself (from the apparently working image hosted in Glen Slick's Google Drive)... I get the same error message every time.Both drives I have make some strange sounds. They both play audio CDs fine through the integrated headphone jack, but fail to spin up when I try to read a data CD. Both seem to try to get up to speed, maybe draw 0.3A for a brief moment, and then quickly fall back down. They get stuck in a loop doing this and after a while, the error message I posted shows up. I can even successfully "cat" or "dd" an audio cd in HP-UX, but the system gets hung up for a while if I try it with a data CD in the drive.I have the Molex connector for the drive hooked up to two lab power supplies. The supplies are the isolated type, so I have connected the negatives for the +5V and +12V supplies together and to the "GND" terminal of the power supply. This is correct, right?What am I doing wrong?Zane Kaminski

author: MarkL
author_rank: Unknown
timestamp: April 04, 2017, 06:39:37 pm
content: Can you mount the CD on another computer?Are you using a CD-RW? Maybe try a CD-R?Is the SCSI bus properly terminated? (Probably, since you can read the music CD's.)

author: PaulAm
author_rank: Frequent Contributor
timestamp: April 04, 2017, 09:27:13 pm
content: I had the most awful time getting that to work.I ended up with several drives. Once things started working, drives that had failed worked fine. However, in most cases it didn't even find the drive.The one that worked for me was a quad speed IBM drive 73h1609 manufactured in 1996. I didn't have any luck with the Plextor drives I tried.BTW, are you using an Agilent CD or one made from a downloaded image. One of the images floating around, and I think it was one hosted by Keysight, is actually corrupt.

author: CJay
author_rank: Super Contributor
timestamp: April 04, 2017, 10:09:43 pm
content: Seconded on bus termination, it has to be terminated at the ends of the bus, one end is usually the controller and the other is the last device on the bus but is often built into the cable itself so none of the intermediate devices have terminators fitted/enabled.IIRC a lot of CD-ROM drives of that era would play audio CDs when one was inserted and some drives even had play/pause controls on the front so just because the drive plays one does not mean the drive is being controlled by the bus correctly, indeed, you could use one of those drives as a standalone CD audio player with the only 'peripheral' required being a suitable PSU.SCSI CD-ROM drives were an odd beast on occasion, I had a pile of Toshiba drives from Sun equipmnent that would just not work in anything unless flashed with a generic version of the firmaware and even then you had to fiddle with jumpers to get them to work, Parity needed to be set for instance.I'd consider using the Seagate HDD as a reference for setting up the CD-ROM drive, the datasheet for the HDD will have jumper settings and that will tell you how the CD needs to be configured.

author: MarkL
author_rank: Unknown
timestamp: April 04, 2017, 10:43:57 pm
content: Quote from: PaulAm on April 04, 2017, 09:27:13 pmIf the image came from the drive referenced in this post:https://www.eevblog.com/forum/testgear/hdd-dead-on-a-hp-16702a-logic-analyzer/msg814598/#msg814598then I can confirm the B3760_14243-16700-A.02.90.00.ZIP image is ok. I compared it against my original CD which I used a couple of months ago to install on a 16702B..To make sure you have a good version, you can check the md5sum of the .zip file or the .iso within. Here's both:190bd96d7facfad0f7117c9a2fa25ff4 B3760_14243-16700-A.02.90.00.ZIPb9ebcb2855e2c6b9ea3a30ba95bd12d2 B3760_14243-16700-A.02.90.00.ISO

author: ZaneKaminski
author_rank: Contributor
timestamp: April 04, 2017, 10:49:48 pm
content: I'm too young to have used SCSI (at least knowingly, I did take apart a lot of computers in my childhood), so I can't say that I'm 100% sure that I have it right, but I am within the length constraints, I have an active terminator at the far end of the IDC50 cable, and then the drive is in the middle. I've got the drive set to ID 4, and I have set the "block" jumper as recommended in this thread:https://www.eevblog.com/forum/testgear/hdd-dead-on-a-hp-16702a-logic-analyzer/?allI have the "parity" jumper set and the "test" and "eject" jumpers unset on the Plextor drive.The thread I linked has a picture of a 16702A booting from a drive of the same model as mine:He's booting a Debian for PA-RISC disc though. I'll try with that ISO as well. I think my image for the 16702A software is the right one though. I'll buy the IBM drive if I have to, but it's frustrating to throw even more money at the problem.

author: helius
author_rank: Super Contributor
timestamp: April 04, 2017, 11:21:17 pm
content: From reading your description of the symptoms, you can clearly rule out termination or the format as problems. I think the power supply is causing the drive to crash/hiccup when it recognizes a disc as data and tries to spin up to "40x" (actually the angular velocity in these drives is about 24x). You may be hitting the current limit of the power supply.

author: MarkL
author_rank: Unknown
timestamp: April 04, 2017, 11:26:05 pm
content: I looked at the built-in CDROM in a 16702B.It's a Plextor PlexWriter 40/12/40S (PX-W4012TS). Keeping in mind this is a different model than yours, the jumpers are set to:SCSI ID: ON OFF OFF (unit #1)Parity: ONTerm: OFFTest: OFFBlock size: OFFOFF = no jumperON = jumper installedSCSI busses need termination just at the ends, so you should not have termination set on the drive if it is not at the end of the chain. One thing you could try is to remove your terminator and end the chain right at the drive. In which case you'd turn on the internal termination.You haven't said if you can mount the CD you made on another computer. You should be able to see the directory structure and files on it.

author: ZaneKaminski
author_rank: Contributor
timestamp: April 07, 2017, 12:03:38 am
content: Aha. Helius, you are right. It was the power supply. I tried with multiple lab supplies capable of at least 3A each, and the drive supposedly draws 1.2A at most from the +12V. Swapping the lab supplies for a cheap PC PSU I picked up for $15 fixed the problem.I tried with multiple lab supplies, so that's odd. Maybe they didn't have enough capacitance on their outputs? None of the lab supplies were of great quality, honestly. No-name Chinese brands and and Elenco.

author: MarkL
author_rank: Unknown
timestamp: April 07, 2017, 12:48:23 am
content: Wow, nice call Helius!