Any standard failure modes in old TI calculators?

Swallens would buy overstock from distributors. The Timex/Sinclair ZX-81 was still for sale for another six months before they were dumped for $10. You had to be careful what you bought there. They were known to find a couple hundred 10 year old color TVs still in the crates, and not tell people that there was no factory warranty. They would also sell tube type TVs as solid state. By the time they needed repaired, it was too late to take it back.

Those magazine ads were usually two months or more behind in the current prices, due to the time required to hand set the pages, print & assemble the magazines, and distribute them.

I guess that you've never heard of a 'Loss Leader'? SS Kresgie's 'Five & Dime' was started that way. Sell some cheap items at a loss to get people in the store. Today they are called Kmart.

Reply to
Michael A. Terrell
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Well, I was in college and the university had a few. I got the job for two reasons. I was a local (my father was a prof), so I was around in the summer and on breaks, when all the maintenance was done. And the second reason, well, is there in the first. ;-)

Supply and demand is a good thing.

I rode my bike to school and work, though it wasn't all that far (3-4 miles). My wife took the car, since I couldn't park on campus. In bad weather she'd drop me off at 6:00AM and I'd catch a few Zs, sitting in the chair at work before everyone else showed up.

I had a nice receiver (Heathkit SB-301) when I was in high school. I sold it when I was in college because I didn't have the time (or space) for such things. I needed the money, too. Never wanted to go back to it, though.

Reply to
krw

Those are NiCd cells, they can develop internal shorts due to whisker growth. Take the dead cell and pop it in parallel with a 22,000 uF cap charged to 12 V or so. The whisker ceases to be and the terminal voltage comes back. Do take care to use normal polarity.

?-)

Reply to
josephkk

Nope. For my HP41cx, I only use the cheapest alkaline N batteries that I can find in the half off bin at the supermarket. Not a joke. That's where I've been getting N batteries. They're not used in much equipment, so I just wait until the current stock reaches near expiration data, and buy the collection. Any excess gets stored in the fridge. Of course, I voltage check all the batteries to remove any lemons. None found so far.

See bottom photo for the HP41 type battery "pack".

The problem is that the HP41 battery connectors are gold plated, while the N battery contacts are either tin or stainless steel. Mine build up some black crud that needs cleaning or it eventually breaks the connection. How to repair the battery contacts with copper sheet (near bottom of page):

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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

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