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NeXT
April 27th, 2015, 08:15 PM
Panic is setting in.
Printing worked when I got the machine in 2010. It's worked ever since and it worked before I put it in storage last year.
Now that I have a PRM-85 I pulled it out again and it no longer works. :|
I pulled up the diagnostics program and ran the printer test. The print head swishes back and fourth and it properly line feeds but nothing gets printed. Pulled it apart and inspected the ribbon cable between the head and the PCB. no signs of tears or breakage. reseated the connector while I was in there. Still no dice. Also checked for my own sanity that I did not somehow turn the print darkness all the way down but it's still sitting at "5". Pulled out a scope and probed to see if anything was coming out of the connector while printing and yes, all the lines are doing something with a nice 0/12v rise and fall. Not promising..... :(

Any immediate ideas? I find it extremely unlikely that all the elements on the head just croaked all at once.

http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8971.jpg


Edited:

So it turns out that the substrate on the print head before the actual elements is conductive so I can confirm that the ribbon cable and the bonded connections between the cable and the head itself are okay. Resistance between ground and each print head line is 55 ohms so no at least, it isn't like the heads have all blown open or something. Something is travelling to the elements but either the elements aren't doing their job, or the signals are improperly formed.

Edited:


.....I'm an idiot.
While I was cleaning the head some overspray from the cleaner landed ont he paper which reacted and turned blue. Curiously I tested on another piece and realized I was trying to print to the wrong side of the thermal paper. Flipping the roll around )it must of fallen out at some point) fixed the problem.

http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8973.jpg

modem7
April 27th, 2015, 11:58 PM
.....I'm an idiot.
Ah, we've all said that to ourselves more than a few times.

DaveH
April 29th, 2015, 02:09 PM
Ah, we've all said that to ourselves more than a few times.

Very very true, but ive learned to not complain when its an easy fix as there's sure to be a hard one coming soon , like when I get round to powering up my HP85 for the first time in 15 years :)
DaveH