Howtek D4000 vertical streaks

[IanMazursky]

The rotational encoder is located on the back of the drum spindle and it is sealed.
Do not try to open it or you will probably kill it. They are almost never the problem and last a long time.

The linear encoder on the other hand is open and as i mentioned in my last post, you can clean it.
But be very careful, a strong blast of air can damage the metal encoder wheel.
Its most likely the carriage motor and or the linear encoder that is attached to it.

Aztek may have the replacement parts. I would give them a call, they are amazing people to work with.
Evan might have more insight on the problem, he is Azteks service and support guru.

[onnect17]

The image shows the problem I had. It's like a shifting of the line.

The movement of the carriage in the D4000 is different than other howtek scanners.
Quoting Phil from Aztek,
...The D4000 and 4500 are more likely to vibrate because they
capture one raster line move the lead screw and then capture the next.
The Premier and HR8000 to synchronous capture thus moving and capturing
in on motion...
Unfortunately the drum drive pulley receives too much pressure from the drum in one of the sides, getting the pulley out of alignment and affecting the traction of the belt (it changes from the center to the sides, changing the transmission rate). The vibration associated with moving the drum to the next raster line does not help. The only way I'm able to reduce the problem is with a softer rubber belt.

[eric black]

I had a similar problem with my HR8000 which I sent to Evan at Aztek for diagnosis and fixing. Evan spent quite a bit of time troubleshooting and I dont recall all of the details but the verdict was new Mother Board needed- an expensive repair at over $5K but worth it for me as I now have essentially a new scanner and hope to get many years more of use out of it. Good luck with your troubleshooting and diagnosis- I hope your problem isnt as severe as mine.

[IanMazursky]

I could be wrong but i think the 7500, 4500 and 4000 use the same scan then move system.
At least thats how it sounds when my carriage on my 7500 moves.
My Premier sounds much different, its more fluid and doesn’t have move/stop sounds when its scanning like my 7500 does.

But it sounds like something is wrong with your scanner, i would try to let the scanner warm up for 4 or 5 hours and see if anything changes.
There is a lot of metal in these scanners and it takes a long time for them to warm up if its really cold.
You can also try reseating the main boards (turn the scanner off first), cleaning out the scanner of dust bunnies and reloading the firmware.
You never know what might help. Evan at Aztek might be able to tell you more.

[onnect17]

Ian,
Glad you mentioned the firmware. This one of the first things George should check.
I think the latest is the 535. Because my investment on the scanner was low I was free to almost totally dismantle it, and got familiar with it.

Check the 7500. Perhaps the drum has two dents or orifice. The 4000 has only one dent and the drum puts too much pressure in one side of the drum drive pulley. Also, every time the screw moves to the next raster line the momentum of the drum affects the match between pin and dent (I think they fixed the design later using orifices instead of dents and two pins instead of one).

[IanMazursky]

The firmware is always a good thing to re flash every now and then.
I have no idea why or how it gets corrupted but it does and will produce the strangest errors that will drive you crazy.

My 7500 drums have an through hole for the center hub to go into and another one off to the side for the pin.
I think this is a much more stable design then the 4000.
Also the clamping pressure of the 7500 is high, it could take your finger off!
I think my Premier is also designed roughly the same way.

[onnect17]

Ian, I sent you a PM. Thanks.

[georgl]

I've tried to install the new firmware but Trident says the scanner doesn't accept it and the scanner gives the error-code F717 ?
Since Trident doesnt start the scanner, either, I guess I have install WIN98? Does Win2000 also work?

I've tried some very flexible rubber bands - it seemed to help in the very first scan when I compared it to the scan made the day before with the new belt. But it introduced new artifacts, then the rubber band felt apart and spread all around the scanner! After close inspection of the scans, they showed the same streaks... It drives me mad!

[aluncrockford]

I have had exactly that problem,it was caused by a lose connection to the bulb causing the slightest of flicker, though having a unstable base might also not help

I also would recommend Pete, he serviced my Howtek and I have not had a problem since, If you have not tried it then Silverfast scanning software has made my life a lot easier.

The only problem I have got is trying to wet mount 10X8 negs, and the least said about that the better

[IanMazursky]

Speaking of the bulb, use the front panel and access the testing functions.
Turn on the transmissive lamp, open the lamp access door.
Look at the light coming out of the bulb and see where it collimates onto the fiber bundle.
The center brightest part should hit the middle of the fiber bundle, if not unscrew the lamp assembly and adjust it.
Just be careful they get hot!

Onto the base, i have placed all of my scanners on rubber vibration isolation pads.
This has helped tremendously with shaking. Even though our tables are stable the vibration from the scanner would still it to shake lot.
The pads are really necessary to reduce it to a manageable level. I bought some from McMaster Carr.