Water-logged HP-67 needs repair
Message #1 Posted by Brad Tritone on 8 Apr 2001, 9:57 p.m.
About 10-12 years ago I "lost" my HP-67 to an unfortunate accident at the office. I placed the 67 on top of its case in an office cabinet before going to lunch. When I shut the door, it must have pushed against something that punctured a pinhole in an aluminum can of Diet Sprite. It showered the 67 with the sticky liquid. The can was at the back of the cabinet and the 67 was at the front, but the mist obviously covered a broad area inside the cabinet. I don't think the 67 was plugged in, but upon my return I wiped the unit off and while still in shock turned it on to see if it would work. You can guess the answer.
At that time, I tried to see if HP would repair it, but the unit was no longer produced and they would not guarantee they would/could fix it. I think they wanted something like $90 to take a look, and offered a 30% discount on a new HP if they couldn't. I didn't want to risk being without the calculator, and since a new HP42s was not much more, I decided to stick it back in the box where it has been until last night.
I finally got up the nerve to open up the case. Over the years I have read about ways to clean circuit boards but I have forgotten most of the details. I'm hoping that I can get some good advice in this forum.
The keys were still noticebly sticky and "crunchy", but I assume they can be cleaned with water. The keyboard circuit was covered by a plastic sheet that I'm hoping protected the area underneath the metal key strips, but this is unknown. The area that looks the most "suspicious" is directly under the LEDs and where the power on/off and program "switch" is. It looks like there might be some mild corrosion there. I'm hoping that the "CPU board" that is underneath the calc was untouched by liquid, but I'm not sure that that matters. I haven't looked at the card reader or motor yet.
Can anyone offer me some advice about how I might proceed? Tonight I'm going to test the power adapter to see if it will still function. One of the battery contacts in the battery compartment is badly corroded, but I didn't notice any corrosion inside the battery pack itself (haven't opened it). Can I modify this plastic case and install new NiCad batteries? Any suggestions here?
Or am I just wasting my time on this project? Am I virtually guaranteed to have a competely DOA 67 because I turned it on back then? Or do you think it would be worth my time/effort to clean it up and see? Is there a service manual or some simple diagnostics I might perform to see if some of the parts are electrically damaged?
Thanx in advance for any help. Brad
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