HP Designjet 4500 Scanner-after a while starts only scanning center one-third only

[pbrooks259]

Help. HP Designjet 4500 Scanner-after a while, several to many minutes, starts only scanning center one-third only (scan image attached), only between the 2 stitch wires apparently. (Maybe I inadvertently set something to the wrong setting; I don't know. The scan seems to be centered about the dome whereas in the drawing the dome IS NOT in the center, so I don't think it is just scanning what is between the stitch wires.)

I have restarted the scanner and that corrected it for about 12 or so minutes, then it started doing it again--only scanning the middle one-third, between the 2 stitch wires.

However, this last scanner restart (3rd time), it has been scanning OK for about 45 minutes.

Bad circuit board? I don't know.

There is a dome in the drawing I am scanning, and it appears towards the top in the middle one-third of the scan.

Thanks.

[pbrooks259]

Hindsight: It seems that the scanner senses the top part of the drawing--the dome--as being the image to be scanned, so it simply scans the width of the dome plus a margin--the dome seems to be the center of the scan whereas it is NOT the center of the drawing being scanned. I don't know why it does this from time to time. Seemingly after it has been "on" for several to many minutes. But presently it has not done it again--"knock on wood".

Height auto-size method = Paper

Limit auto-detect scan length (is selected) = 5"

Another tech told me maybe it is "heat" or "interconnect" related and sounds like a processing problem. Told me to reseat cables to main pca, if the fans are working clean air filters if dirty, clean dust from main pca if any, etc.

Thanks,
Paul

[GIUBOSS]

before replacing the board try to perform the firmware update and repeat the calibration procedure. Calibration will not work well if the scan area is not clean. The Maintenance Wizard guides step by step through the procedures of camera alignment, stitching, and calibration. Maintenance Sheet that came with the scanner is required. I think you will have done all of this.

[pbrooks259]

OK, thanks. ....I tried calibrating. During vertical alignment Got 55-203. I guess a camera is not moving--bad motor or jammed or something. Dang!

I'll run the scantests 6, 9, or 11. Boy, these things seem like a PITA. (I need to run these tests and get back. It might tell me Camera A or B motor is bad.)

(I ran them: SCANtest 6--the stepper motor seemed OK,
SCANtest 9--I couldn't tell much; I pressed forward and reverse buttons when I should not have--dang it!, SCANtest 11--was "black screen" in the window during "vertical alignment" and then I got, at some point, 55-608 "The camera signals in the scanner is not stitched" and 51-22 "The operation failed".)

Well, I checked the resistance of each motor. The left motor as you face the scanner is ABOUT 102 ohms. The right motor as you face the scanner is all over the place--anywhere from 200 to 1000 or more ohms.

I'm thinking the right motor is bad. Is that the camera C motor? Whichever it is that is a high resistance reading. I've heard 55-203 is indicative of something up with camera C, but I'm not sure about that.

I have an old HP DJ 4200 Scanner that has been kicking my butt.

Is the motor on the 4200 interchangeable with the 4500 camera motors? I'll open it up and check them out. I assume they are not interchangeable.

I checked; it is the same motor but different gearing?: 4500 is direct drive. 4200 is belt drive. I assume I could interchange them with some effort.

And that 4200 camera motor too has a high resistance reading similar to above--I think it was giving me a stitching error 50-195, maybe could be caused by a bad motor; I posted it in here about 3 years ago I think. Maybe the 102 ohms is out of the ordinary but I don't think so. I think the 4500 right camera motor and the 4200 camera motor are BOTH bad. But I'm not 100% sure. I would think a 102 ohm reading would be most likely indicative of a good motor, not 200 and way higher ohms--those may be about burned out, maybe that's the problem.

Well, the high ohms readings could possibly be due to the relative positions of brushes and commutators or whatever these motors have. I didn't think of that earlier. But they are not open or infinite, just very high.

Thanks again.
Paul

[Kiran Otter]

The motors won't affect it scanning the entire width of the page, only the calibration. If the motors failed you would see a disjointed image because they can't align the cameras together.

If that PDF is exactly what it saved, then it would appear you have some kind of page width setting wrong. Why this would change after a certain time passes, I don't know. I don't remember the touch-screen software but I believe there's basically two settings that would affect the size of the scanned area, the actual document size, and the output size. They should both be set to auto. I believe if you told it it's a D-size sheet (24x36) you should get a PDF that's 24x36 no matter what the image size is on the paper. If it's set to auto detect the page width, and it isn't, I think that is caused by a dirty or damaged reference strip in the top cover (that white strip that slides into the cover. Service manual calls it the white background assembly.)

The only thing I can think of that changes over time, is the lamp. As it heats up it gets brighter. If it's old, stick a new one in there. (These used a lamp cartridge, but with some diligence you can just replace the bulb in the cartridge.) Make sure you let it warm up for a good hour before running the calibration.

If you can calibrate it and it succeeds then I'd avoid tinkering with anything inside the scanner. These things are a nightmare to get right if you start messing with the cameras, and can require special calibration tools that you'll probably never find.

Kiran

[pbrooks259]

I was trying to get it to calibrate but again only got to 55-203 & 55-608. Well, now even before that it states that the calibration sheet is not recognized. It had worked a few months ago; and does not seem to be any worse for wear since then.

I tried a spare lamp that I know to be good. I scanned a drawing. It scans totally black in the preview. I think it would have scanned black with the original lamp too. The previous time I had that happen the lamp was burned out. But I'm sure both of these lamps are not burned out.

I put the original lamp in and I get the same thing--a total black scan in the preview.

I do notice on the main board that LED D04 is continually flashing amber for what that is worth.

Gosh, this is getting worse and worse. Perhaps something is just continually degrading. The main board???? I don't really know.

Seems that possibly whatever was going on to make it only scan the mid-section of the drawing has possibly further degraded to where it now does not scan at all--results in black.

Thanks.

[Kiran Otter]

This might sound like a dumb question, but is the lamp lighting?? If it's like every one of these scanners I've seen, the power supply is bad, and/or the driver board. And note you can have a bad power supply that won't power the lamp circuit on the driver board, but will power everything else. If the lamp is not lighting, I would replace the power supply first, then the driver board if it continues to not light.

That LED blinking is normal. There are two LEDs on the driver board that indicate if the lamp driver voltage is in the correct range. This is adjustable and should be adjusted if you replace the driver board or the lamp sensor. I've attached the instructions. I believe this still applies to the 4500; it did to the 4200.

Lamp driver adjustment.pdf

Kiran

[pbrooks259]

Thanks, Kiran. Both lamps that I tried are lit, so they are getting power. Is the driver board just for driving the lamp? I don't know.

Do you think this scanning to BLACK is a BAD driver board? ....or possibly a BAD main logic board? Or what do you think?

It's like the problem I first saw--only scanning a center portion of a drawing--morphed into scanning to BLACK. But I'm not sure at all.

I CONFESS: I did while in Test 9 with the software oscilloscope, press the "reverse" and "forward" buttons briefly a time or 2 for cameras A & C. I shouldn't have but I did. I thought perhaps such would "unstick" the vertical alignment screw or something in that drive train. As I stated earlier, I think I did, it would throw up 55-203 while trying to do the vertical alignment. It seemed like the motor just could not vertically align the camera--it would not quite align the horizontal bars--it would attempt like 7 or 8 or so times and then throw up 55-203.

I don't know whether 2 problems or 1: 1. Scanning BLACK & 2. 55-203. I don't know whether there is 1 cause or 2 or, heck, maybe more.

(The flashing amber LED is on the main logic board. And I assume that is normal as well, but I don't know for sure.)

Thanks a heap,
Paul

[Kiran Otter]

Well I've never seen one that scanned black that didn't have a bad bulb/driver board/power supply.. causing the lamp not to be lit. So I don't know what your issue is. The 55-203 means it can't move the camera(s) so that's not related to the black images. I'd say if you have black images, and motors not being driven, it all stems from the main logic board that the cameras plug into. I'll assume you've re-seated all the cables.

If it's any help for finding parts, the HP 4500 scanner is the same as the Calcomp Chroma G600 and Vidar Specta 600e.

I do have a new driver board for the 4500, and a new driver and main PCA for the 4200. I don't think the 4200 & 4500 are interchangeable; otherwise HP would give the boards the same part number.

Kiran

[pbrooks259]

Thanks Kiran. Yes, I reseated all 3 camera cables to the main logic board, but that's all. I should reseat everything.

So, you would start with a main logic board replacement? (But so far as 55-203, I think the Camera C vertical adjustment? motor is bad, given that I measured resistance at each lead and got wild numbers--approx. 200 ohms and up to over 1,000 ohms, but again maybe that had to do with the relative position of brushes and commutators, if that's what they have. I assume they do. I can't believe that is normal. Camera A motor read about 102 ohms between leads. They are identical motors. I'm going to doublecheck Camera C motor, so I may revise this.)

I was thinking kinda similarly: The camera cables all run to the main board, so maybe main board--and maybe a failing main board was causing the partial one-third middle scan; don't really know about that for sure. But the lamp is lit and I even tried another lamp and it lit. I got black scans with both.

Now in Test 9. Camera Adjustment?, software oscilloscope, that pulled up seemingly fine. Does that mean anything in ruling out the main logic board? Seems that would all have to pass through the main board as a scanned image would have to pass through the main board. But maybe what I am saying is nonsensical.

Thanks for the info. on Calcomp Chroma G600 and Vida Specta 600e being the same.

What are you asking for 4500 new driver board?

Thanks again.
Paul