Re: Mandatory Job Log

Barry,

Thanks for the chuckle.


On Wed, Jan 11, 2012 at 4:58 PM, Barry L. Kline <blkline@xxxxxxxxxxxxx>wrote:

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On 01/10/2012 04:44 PM, rob@xxxxxxxxx wrote:

Seriously you have a 5251-11 still in use? Only thing cool about
that was it's ability to blow raspberries at users.

Heavens no Rob. I was talking about a System/34 package from 25 years
ago.

One story I have to pass along though concerns a 5251-11 that had been
put into a closet, having been supplanted by a 5291. One of our
employees wanted a terminal at his desk but there was no budget for
it. So I hauled the '51 out of storage and set it up.

A few weeks later the employee calls and said that the screen was
"wavy". Looking at it he was right; the image was moving around. I'd
experienced that problem before. The cooling fan had locked up and
the unit was overheating. Those who ever opened the clam-shell 5251
know that the fan was mounted on a bulkhead and a pair of heat sinks
were bolted on to it, forming a tunnel. The heat sink tunnel came
almost to the edge of the terminal where the vents were.

Obviously, the terminal was no longer under IBM maintenance and I
didn't have an exact replacement so I pressed into service a
physically identical fan that I had laying around -- one that was
meant to be used for moving high volumes of air. When everything was
reassembled and turned on the thing sounded as though there was a
Shop-Vac in his office; a rather large one. In fact, an 8.5x11 sheet
of paper would get sucked against the terminal should it be dropped
next to it.

I looked in my parts bin and found a thermal switch, which I mounted
to the heat sink and put in series with the fan's power line.
Success! The terminal would run quietly for about five minutes, the
Shop-Vac would kick in for about a minute until things cooled, and
quiet would resume.

Now for the best part --

The IBM district sales manager gave me a call and said that he had a
couple of the IBM higher echelon visiting and they wanted to tour his
territory and visit some of his customers. He asked if they might
drop in. During the course of our visit one of them asked what
terminals I used, and I gave the list of the various models,
concluding with "... and a 5251-11A." He bit: "I've never heard of
that. What is it?" I told him that is was a model that IBM had
released that was the predecessor to the 5291 and it had been designed
to be fan-less and thus quiet. So he asked if he and his colleagues
could see it.

Fortunately, the other employee wasn't around so I took them into his
office and turned on the terminal. They oohed and awed about the
thing, remarking amongst themselves about how they'd never seen one
nor had they been aware that there was ever such beast. Sure
enough... the fan kicked on almost on queue, startling the one guy.
He jumped then exclaimed "Holy hell!!! What is that?"

I said simply: "That's the reason the model was never successful."

Regards,

Barry
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