Scanner repair

[Fred Juire]

Hello to everybody. I got an old broken scanner and I wanted to repair. The job looks easy at the beginning but I get stuck and I need some help.
The scanner is an Mustek BearPaw 4800TA II. When I scan documents, in the direction of scanning appears some stripes from beginning to the end of document. I cleaned all the optics with clean cloth for glasses and liquid to clean glasses but I didn't see any improvements after that. I use the drivers from mustek and I download vuescan free edition to make a try. On the attached file it can be seen the stripes. If more pictures are needed, please let me know. Thank you in advance.

 

[4pyros]

I think you may to try some more aggressive cleaning.
Witch way is it scanning in reference to your picture?
If its top to bottom it could possibly be a speed issue. IE to slow in the beginning?

 

[granddad]

My guess would be the light tube , taking time to get up to full brightness . "old" would be the clue.

 

[atferrari]

If what we see at the top of the image is scanned first, it seems in agreement with what GD says.

Just by watching how my scanner works, the warming up time could be out of your control. In other words, you could not start the warming a little before than the actual scanning.

Any way to measure voltages? Maybe there is precisely one taking too long to take off. A tough one this. . .

No to derail this thread, I always wonder if when we say "old" we actually think of age or just "worn out by frequent use". (As you know, non-native here).

 

[granddad]

I always wonder if when we say "old" we actually think of age or just "worn out by frequent use". (As you know, non-native here).

Your right , some things get better for being "old" the word should not be used to mean clapped out..

re post, could be warm up timer needs a tweek.

 

[atferrari]

Your right , some things get better for being "old" the word should not be used to mean clapped out..

re post, could be warm up timer needs a tweek.

Hola GD

I am afraid that the tweak would be pure software. . . Not directly related to that scanner but the last time I met some office equipment where you could eventually tweak almost all (but timing) was the Epson LXF 850, IIRC the model.

 

[Fred Juire]

Yes it start from the top of the picture and I observe that on black and white option the stripes aren't so visible. It appears if I skip warm up or even if I double warm up cycle in software. The speed of motor looks ok but I don't know if I can find a new light tube. By the way, I mean old both, it was bought 10 years ago and it was use quite frequently. I'll try one more good cleaning and try to have a software calibration. If anyone has other ideas, please let me know. Thank you

 

[4pyros]

I don't know why I didn't think of it but I think the old lamp may be your most likely scenario. They are probably only good for so many hours.

 

[dumpsterdiver]

I have a Mustek parallel port scanner that's almost as old as yours. Did you clean the underside of the glass as well as the top? While you are inside the case do an inspection and dust removal. Accumulated dust and dirt might be messing with the scan head's movement

 

[Fred Juire]

I have a bad news and a not so bad one. I started to rub all the mirrors and lens, result, no more horizontally lines but I got a prize( I don't want it) vertical ones like in image
**broken link removed**

Unhappy after this I tried again but the result was worse, another line on the left. And this is not all, now when it start the motor make noise.

To clean I tried glass washing liquid and alcohol, last variant seems seems to be very bad. Thank you for any new idea.

 

[atferrari]

Some of those vertical in the first scan seem gone. Am I right?

 

[Fred Juire]

Atferrari, Is more like moving apart. Now I think the problem looks like is the optic system. The problem which I met is no matter how much I clean, on the mirror will remain some hues, is not dirt but something from liquid which dried. I clean with
cloth after but I see it just moved from one side to other.

 

[dumpsterdiver]

Atferrari, Is more like moving apart. Now I think the problem looks like is the optic system. The problem which I met is no matter how much I clean, on the mirror will remain some hues, is not dirt but something from liquid which dried. I clean with
cloth after but I see it just moved from one side to other.

Those mirrors are most likely first surface type where the reflective surface is on top of the glass instead of the underside like a bathroom mirror. You mave have scratched the reflective surface.

 

[Dr_Doggy]

just a guess, but those lines don't look like dirt as the first ones do, more like the top of my tv when i mess with v-synch and the top image folds over,
is it possible that something could have gotten misaligned? pushing gears alignment out of wack when rubbing?

 

[Fred Juire]

The only thing which can be misalign is all the head itself with optics and light tube source. When I cleaned it, I took out all an disassembled but I didn't make a sign on the conveyor belt and I mounted it just from eye. I assume that the logic will do the calibration itself, but looks like It didn't, or at least it didn't properly. My wrong assumption.

 

[mvs sarma]

Hi Fred Juire,
it has to do with the traction motor and the nylon gears used therein, the teeth get de-shaped or worn and the traction belt also get stuck at times you hear tic-tic sounds while tractor is moving
Once you could get and replace the wheels , the scanner works

Perhaps a timing belt changing should not be a problem.
all the best

 

[Fred Juire]

Thank you Mr. Sarma, the gears looks fine but the traction belt it is old. I tried to find parts but for the moment I didn't find. I even think if it worth to change if is too expensive. I'll have some more practice and hopefully find a solution.

 

[mvs sarma]

Thank you Mr. Sarma, the gears looks fine but the traction belt it is old. I tried to find parts but for the moment I didn't find. I even think if it worth to change if is too expensive. I'll have some more practice and hopefully find a solution.

you may see my case where little dented teeth (Marked) of the gear of the scanner

 

[atferrari]

you may see my case where little dented teeth (Marked) of the gear of the scanner

And so relevant...!

 

[Fred Juire]

I checked my gear but I didn't find anything but I thought I understand how it works, everything goes wrong. After that noise made by the gear on the belt I checked the optical sensor and I obstructed it to see if the motor stop, but nothing happen. I thought that the sensor it doesn't do its job, but after I assemble it again everything works fine, no more noise but the scanned document still have some shadows and just after some scanning a vertical stripe appeared again. By the way, I didn't tell that I don't have the original power adapter(12V/1.5A) and I use another adapter(12V/1A). I checked to see if get hot but looks to work fine.