Scanner SCSI Inteface Problem

Early last summer I replaced an HP 6250cse scanner with a much faster HP 7450c. I have opted to use the SCSI interface, in lieu of the USB port, because the SCSI connection allows for faster scans. I am using an Apaptec 2930cu SCSI card on an ABIT IC7-MAX3. The slower 6250cse worked without problem. However, the 7450c, will not scan a high resolution color image at anything greater than 100 dpi without crashing the computer (a reboot is necessary).

The 7450c will start scanning but after a second or so the scanner will stop and the scanning software (HP Precision Scan Pro V3) appears to lock up. The Windows Task Manager indicates that the scanning software is still running even though it is obviously unresponsive. I get the impression something is waiting for something else. That is, the software has not crashed, it is just waiting for something to proceed. A reboot is required to recover.

The scanner works fine if I switch to the USB interface. It also works fine using the SCSI interface as long as I do not make a color scan with anything greater than about a 200 dpi resolution. This makes me believe the problem has something to do with the very high data transfer rates associated with fast high resolution scans and the inability of the SCSI card to transfer this data to memory somewhere. I do not know if this is an accurate perception but it certainly seems to describe what is happening.

The Windows XP virtual memory paging file is set to "System managed size". I also have a 3.2 Gig P4 with 512 MB memory Mushkin PC3500 BLII) so there should be sufficient horsepower to handle whatever the the scanner sends to the computer. The Adaptec 2930 is rated for 20 MB/sec. In case the computer is choking on a too high data transfer rate I slowed the speed to a max 5 MB/sec using the Adaptec bios setup utility but this had no effect.

I much prefer the SCSI interface because the scanner scans so much faster. The problem occurs even if Precision Scan is run as a stand alone program (in lieu of from Paper Port).

I contacted HP but they are clueless. HP suggested I talk to Adaptec but Adaptec refuses to help because I purchased the 2930 two years ago (it is still a current product).

Help in resolving this problem would be appreciated because I cannot take full advantage of the faster 7450c. Upgrading to the 7450c was driven solely by the fact of it being so much faster than the old 6250cse. Much of this speed advantage is lost with the USB connection. I cannot help but feel the problem has something to do with the Adaptec SCSI card having a problem transfering the data it receives from the scanner to memory. This makes me believe there is probably some setting somewhere that will resolve this problem.

Do you have problems when using the winxp scanner program? Just click on the scanner in the scanner and cameras section of the control panel. you can test the resolution rates also to see if it is a program problem or not.

If you have another computer, you could throw it in there and see if it has the same problem.

Termination? Your problem sounds like noise on the bus. Is there anything else on the scsi card? Is the cable hanging near a power line?

I have the 6250cse and it works fine on a really old scsi card (sc200). My USB didn't work though.

kusojiji, thanks for some good ideas. I had forgotten about the Windows scanner & camera app. I tried it and it too responded exactly like the HP Precision Scan Pro does. This was a good diagnostic test because it now eliminates the HP software as contributing to the problem.

The scanner is the only device attached to the SCSI card. I am using a 6 foot HP supplied cable. However, there is a dual in-line internal connector on the card for devices internal to the computer. I am thinking that maybe this connector needs a terminator but since it is directly on the card I wouldn't otherwise think so.

We had two 6250cse scanners. We still have one but it is collecting dust because it will not communicate with the computer. I tried to buy a new circuit board for it but HP would not sell the part and wanted too much to send it to them for repair. I gave the other away when I bought the 7450c. The 7450c is much faster, even with the USB port. However, even the USB port is noticeably slower than the SCSI connection. One annoying problem with the 7450c is that the document feeder does not do as good a job as the 6250 in keeping individual pages aligned and straight. Paperport, will electronically straighten the skewed pages but one would think that the problem should not occur in the first place. I also think the Precision Scan Pro software sucks. It certainly has a lot of capability but there is no good reason it cannot handle repetitive scanning of identically sized papers without reloading the settings for each page (much too many mouse clicks and time required to set up each identical scan). They could also have made the button bar much more useful.

Thanks again.