how to repair this circuit board?

My prior post inquired as to a cheap ink and paper that could be used to test out my recently acquired barograph from an estate sale.

After some trial and error and with the group's help, I have managed to get some accurate traces:

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However, at least one issue still remains: the large ink spot you see occurs within an hour of me refilling the tiny ink well on the device arm. Once all that ink "hemorrhages", the trace then proceeds as you see with no more spots. Any idea what could be causing this? Am I adding too much ink each time?

One other thing I'd like to ask about is paper. For the chart, I had printed them out on a piece of Georgia Pacific standard 20 lb weight

8.5x11 multipurpose paper and backed it with a couple of strips of packing tape in the event a bleed-through occurred (and good thing I did!). Suggestions for maybe a thicker paper I could try would be welcome, with the idea to increase absorbency and still keep cost low. In a pinch, I've been thinking of just doubling up the sheets I have except the new thickness would not be uniform and glue would decrease absorbency.

Thanks in advance.

JJ

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J-J
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Was the drum moving when the blob appeared, or was it stopped? If the clock mechanism had stopped, I could see why there was a blob. However, if it was moving, as in the visible trace in the photo, I would ask what is different between when the blob formed and when it did not? Other than a stalled or erratic clock mechanism, it could be a "bubble" in the paper, where it was warped or curled, some defect in the paper itself, or one of the problems mentioned in the article at: "The two halves of the nib bucket should be of even length..." If only one point is touching the paper, I think you might get a blob.

Dunno. I was wrong about the paper needing to be absorbent (see above Metcheck URL). I suggest you try a variety of paper types and see which works best. Coated, not coated, 22 lb, vellum, photo paper (glossy or matt), butcher paper, wax paper, premium clay coated plotter paper, etc. Visit an art store and see what they have to offer. Also look for "pen plotter paper": The pen is critical because most "plotter paper" is for inkjet plotters.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Jeff Liebermann

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