At 15:48 2/25/99 -0800, Brad Loomis wrote:
>I've been trying to install a new HP 4C to my system. What is happening,
>is most of the time it is not recognized at boot up. I do turn it on first.
>It gives a bit of a whir, then is quite until I have been Win95 for about
>two minutes. then it makes some more noise, I can go to device manager and
>refresh. Lo and behold there it is. However if I try to run the HP scan
>test, it says communication problem, then that program freezes. Or if I
>try to use HP desk scan, (just to test) it will whir for a moment, pause
>for a while and then return a "scanner problem" message. So did i get a
>non-functioning scanner? this is running off my 2940UW using a 50pin mini
>to 50centronic cable. I had no luck using the included card, IRQ problems,
>and i'd rather not anyway. Any suggestions appreciated.

Hi Brad

A few points/questions to consider...not in any special order...

Isn't the external connector on the 2940UW a *68* pin mini connector?
I assume you meant 68 pin. (Unless you are using a ribbon cable that
leads to outside your case.) Remember that you can't use all three
connectors on the 2940UW simultaneously. That would create a "Y" shaped
SCSI bus which may or may not work. (This configuration is against the
rules and if it does work, it is probably not going to perform well.)

How are you terminating the 2940UW? You are hanging a narrow device off
a wide connector. It is quite possible that the "high byte" [see ** below]
is not being terminated. (Most external cables do not provide this
termination.)

There have reportedly been problems when "automatic termination" is
enabled in the Adaptec "SCSI Select" untility (entered via hitting
<Ctrl><A> when you see the Adaptec Banner at boot). Try the setting
"High Byte On, Low Byte Off" in SCSI Select. (I have even heard of cases
where setting HIGH ON, LOW OFF, does not work properly...maybe it depends
on what version BIOS your 2940UW uses.) If your 2940UW is not recognizing
the HP 4C at boot, this could be confusing the controller's termination
settings. By the way, I would make sure that the scanner is turned on
(say) 30 seconds before the computer...to make sure that it is detected
properly. (This shouldn't be necessary, but...)

If this doesn't work, you may need to purchase an external "68-to-50
*terminating* converter" which plugs into the back of the 2940UW. You
plug your 50 pin cable into the far end of this converter. By the way,
how good is the external cable that you are using? A cheap (say $10 to $20
SCSI cable may not work really well. Besides offering poor shielding, some
cheap cables do not have all the wires connected...you may not be
supplying termination power to the terminator at the end of the SCSI bus.

Another factor is the quality of the terminator that is built into the
HP 4C. I suspect that it is a passive terminator and as such would be
unsuitable for terminating the SCSI bus if any faster devices (like a
SCSI2 or better hard drive or even a fast SCSI CDROM drive) are present.

If you are using an Ultra speed hard drive, your cable lengths
should total less than 5 feet. I don't see how you could do this with
an external device connected unless the external cable is only 3 feet
long and only one internal cable that's less than 2 feet long is used.

If the scanner is not detected at boot by the controller's bus scan
and is not reported on screen, I would suspect a termination or
cable problem.

I am currently running an HP 4C using an Adaptec 2940UW. I bought a
high quality 68to50 terminating converter, a 50 pin MicroD to 25 pin
Apple external cable, and a 50 pin centronics active terminator from
Granite Digital at <http://www.scsipro.com/>. Their prices are high...
I can provide a half dozen other places that sell less expensive SCSI
cables and converters...just ask.

I also use the latest drivers from Hewlett Packard. You can download
them from <http://www.hp.com/cposupport/swindexes/sj4cpc_swen.html>.
Be sure that you reload the aspi layer (run the following updater
<ftp://ftp.adaptec.com/pub/BBS/win95/aspi32.exe>) after installing
the HP software. (When you install the HP drivers, you must specify
that you have an "other" SCSI controller controlling the scanner.)
By the way, if your scanner came with a triangular shaped ISA SCSI
controller, it should work with Win98. (If you have the rectangular
shaped HP SCSI card, it doesn't.) But I can understand why you want
to use the Adaptec controller...it's much faster with the scanner.

[**] The WIDE SCSI bus is composed of the LOW BYTE (carried by the
50 lines that compose the NARROW SCSI bus) and the HIGH BYTE (carried
by the other 18 lines). Both HIGH and LOW bytes must be terminated at
both ends of these respective buses...which are not always at the same
locations.

Regards,
Bill

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