Howtek drum scanner DIY thread: maintenance, troubleshooting, mods

... and it's back to normal (the banding is gone). Didn't do anything.

Lately the scanner wouldn't cold boot. If I leave it on for a minute, turn it off and on again it boots fine. Before it just complained about checksum error (I attributed that to a bad battery) but still booted fine in first try. Maybe my battery has degraded even further or this cold boot trouble could be a separate issue.

I removed the black electric cover to see how much stuff would need to be removed to get to the motherboard... Gulp! And there's sooo much dust!! I need to clean all this dust, change the battery and hope this fixes my cold boot issue...
 
Hmm, wish I could say I've learned something through my process of pulling all the boards, cleaning connectors under the back panel but I'm still getting that same electronic jitter.

What does your banding look like?
 
Red channel:



Now the scanner is back to normal with no banding. Today it even booted on first try.

Are you still getting the totally useless preview or just jitter with 4000dpi?
 
Hm, interesting that it corrected itself. Was it like that the whole session or intermittent between scans?

It's still going between half of the preview (always the left side on screen) and the whole thing. Seems to be intermittent, sometimes stable where I can preview 5x in a row and have the same amount of preview jitter and then it will start changing again.

I haven't been able to narrow it down (by wiggling) to any single connector/board contact with the back off. I'm wondering if I need to further strip it down. Need to read through the service manual again.

Another thought I had is it might be in my Adaptec card. I need to order another, and another SCSI cable so I can eliminate those as potentials. It still happens when I switch the card between the Mac on OSX and HP tower with XP.
 
The banding started at some point in the session and was more or less pronounced from that point.

I would definitely look into getting a different SCSI card and cable in your case. Even though I can't see how SCSI would be the cause for the banding in my case, I still went into SCSI bios settings and changed some parameters. Not really sure what all the settings do, but I disabled anything that seemed related to SCSI disks only and the hi-speed transfer options needed for SCSI disks...
 
Thanks for your thoughts. I'll get those ordered and report back.

Edit: Ordered an Adaptec 2930CU as it seems those are well regarded in working with the Howteks.

Any recommendations on cables? Doesn't seem like there is an established "best" for those like the 2930 or 2940 cards.

2nd edit: went with one on sold by ebay user: partsparadiseinc.


For you regular Howtek users, do you have backup/spare cables and cards at the ready, or are they pretty long lasting and stable once a good setup is found? This is my first foray into SCSI gear.
 
Got the Adaptec 2930CU card in, it's a PC version (they had a dedicated MAC version), bought new cable on ebay as above.

Took a few tries to get it to load the driver in XP, lots of restarts and pulling the card but as it sits it is loaded correctly. Seems like that is stable now.

Now the scanner is booting into "Restart scanner" mode and neither the Mac with the 2906 nor the PC with the 2930 card will talk to it.

Booting off the FST floppy, when I connect the scanner to the computer, it locks up any other input device.

Any thoughts on how/why it is locking up the other inputs (mouse, keyboard)?

tl;dr = Thought buying a new SCSI card & cable would solve my intermittent jitter issues but somehow have caused more problems.
 
Fixcinater said:
Now the scanner is booting into "Restart scanner" mode and neither the Mac with the 2906 nor the PC with the 2930 card will talk to it.
Click to expand...

Sometimes this scanner has a life of it's own. I once got into a situation that after manual focusing it just wouldn't return the drum into start position (it just wouldn't register "Offline" command after "Exit Focus"). Restarting scanner/computer wouldn't help. I let it rest for an hour and all was good after that. I've found out that if I turn on the scanner and wait a long time before I boot the computer and start scanning, it can do weird things. So far I attributed that to my bad motherboard battery...

Fixcinater said:
Booting off the FST floppy, when I connect the scanner to the computer, it locks up any other input device.

Any thoughts on how/why it is locking up the other inputs (mouse, keyboard)?
Click to expand...

On the machine that I otherwise use for scanning I can't boot into FST drive. The machine locks immediately after loading aspi8dos.sys driver (doesn't matter whether scanner is on or off). If I transfer the SCSI card to another computer I can boot from the same FST floppy/USB drive and run FST with no problem.
 
Thanks once again for sharing your thoughts and experiences.

I've been diagnosing stuff, it still won't boot 100% but by reading the service manual, I have narrowed it down to the SSC board at fault, or the flex cables, I suppose.

Not much else to update on my end unfortunately.
 
Another non-update, but I have reached out via email to Evan at Aztek to see if he has any next steps to getting this thing working again.

It's still throwing a "Scanner Restart" with an S in the lower right hand corner, which corresponds to the SSC board failure, but it doesn't get any more specific than that. I'm no EE, so I can't trouble-shoot it blind. If I had a schematic, or test points, I may be able to find a fault but until then...I may try new cabling if Aztek comes back with big money solutions or nothing definitive. I don't have $2500 laying around to ship it to them for a service, although that would likely be the best thing for it and my sanity.

Only mention I see elsewhere on the web is Link to GrossFormatFotografie.de but with no real resolution there.
 
Anyone know what size drum this looks to be? What sizes drums this Howtek mounting station will take for those who have seen it before.

24742498028_a5e7c38202.jpg


36871180600_80c90b8c0a_z.jpg
 
Shakedown, did you ever get that mounting station figured out? Looks bigger than my D4000 mounting station (logically: every Howtek station would be), but I couldn't say which model it is for.
 
Small update, I'll be moving back to SoCal in a few weeks time, will be dropping off the scanner for service at Aztek once settled into the new groove so I can get back to using it.
 
I hope they can fix your scanner and that there will be one more drum scanner rolling out there!

After we are finished with renovation in our apartment I will need to disassemble, change the motherboard battery and clean my H4500 (probably change the PMTs, too). I hope the scanner will still work when I'm finished 😉
 
Best of luck with the renovations! Where did you get the PMTs? From the previous scans I have been able to complete, I don't think mine need changing but would be nice to have spares.
 
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