I leave my PowerMacs running all the time. Every now and then, I open the case and blow out the dust. No problem. The ability to easily open the case (without tools) and to keep running is a nice feature.
'Bug' in custom chip
on
Pet Bugs?
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· Score: 5, Funny
I was trying to debug a CMOS standard-cell chip that I designed in the late 80's. The bug was elusive, only showing up occasionally and I'd written various test routines to ferret it out. I started to suspect it was something to do with the PCB layout, so I was cutting and pasting tracks. Suddenly all the test routines worked perfectly and I thought GOTCHA! My mind was almost blown when I realized that I had inadvertently cut the power trace to the chip - it was working perfectly when Vcc wasn't connected!
Of course, I eventually figured out that the original problem was ground bounce and that with Vcc disconnected, the chip was getting power through the protection diodes on the control lines and bus. The lower voltage was slowing down the edges and reducing the ground bounce so that it worked correctly. I eventually solved the problem with PCB layout changes and the chip started working with Vcc connected!
I always thought of homebrew as (dating self) wire-wrapping your own bit-slice machine or porting FORTH as an OS to a hand-built Z80 board or designing a new processor in a FPGA.
Somehow buying a bunch of components, screwing and plugging them together, and then installing Windows or Linux doesn't seem the same.
>but several die each year because someone's power went out and their generator/UPS/alternative power system was back feeding the utility company when the grid was down
I seriously doubt this. Even if your inverter doesn't have automatic line failure disconnection and/or you were dumb enough to directly wire your generator to the grid, there not much chance your 1-50kW power source can bring up the grid - even in the case of islanding. Moreover, as you say, linemen treat downed lines as live and dangerous.
The urban legend of the guy with the 5hp generator backfeeding the neighborhood and electrocuting the lineman is just that. And it makes it hard for those of us who want to supply power to the grid to get net-metering (etc.) approved by the bureaucrats.
I live out in rural Montana, halfway up a mountain, so getting shipments of anything is iffy. e.g. the Post Office and UPS disagree on our address - as I understand it, the Post Office assigns these things and UPS should just deal with it - but they always put shipments on the wrong truck and I've had shippers back-charged for an "address correction". Multiple phone calls to UPS still haven't resolved this problem. And UPS is better than Airborne Express - these guys won't accept a PO Box as an address, but don't deliver out here, so they consign all shipments to the Post office. Since the Post Office won't deliver to our house, the shipments need to go to the PO Box! Luckily, the local postmistron knows us and we no longer have a problem (in the past, we had a couple of shipments returned). I won't even get into Fedex.
Montana's a beautiful place to live, but don't count on infrastructure (when we first moved here 6 years ago, I called the local phone cooperative and asked if I could get ISDN service - the rep put me on hold for about 10 minutes and then informed me "we now have call waiting"!)
Slashdot Mirror
Now if they'd also offer domain hosting (for a small fee of course), I'd jump on it.
I leave my PowerMacs running all the time. Every now and then, I open the case and blow out the dust. No problem. The ability to easily open the case (without tools) and to keep running is a nice feature.
I was trying to debug a CMOS standard-cell chip that I designed in the late 80's. The bug was elusive, only showing up occasionally and I'd written various test routines to ferret it out. I started to suspect it was something to do with the PCB layout, so I was cutting and pasting tracks. Suddenly all the test routines worked perfectly and I thought GOTCHA! My mind was almost blown when I realized that I had inadvertently cut the power trace to the chip - it was working perfectly when Vcc wasn't connected!
Of course, I eventually figured out that the original problem was ground bounce and that with Vcc disconnected, the chip was getting power through the protection diodes on the control lines and bus. The lower voltage was slowing down the edges and reducing the ground bounce so that it worked correctly. I eventually solved the problem with PCB layout changes and the chip started working with Vcc connected!
I always thought of homebrew as (dating self) wire-wrapping your own bit-slice machine or porting FORTH as an OS to a hand-built Z80 board or designing a new processor in a FPGA.
Somehow buying a bunch of components, screwing and plugging them together, and then installing Windows or Linux doesn't seem the same.
>but several die each year because someone's power went out and their generator/UPS/alternative power system was back feeding the utility company when the grid was down
I seriously doubt this. Even if your inverter doesn't have automatic line failure disconnection and/or you were dumb enough to directly wire your generator to the grid, there not much chance your 1-50kW power source can bring up the grid - even in the case of islanding. Moreover, as you say, linemen treat downed lines as live and dangerous.
The urban legend of the guy with the 5hp generator backfeeding the neighborhood and electrocuting the lineman is just that. And it makes it hard for those of us who want to supply power to the grid to get net-metering (etc.) approved by the bureaucrats.
I always liked the NED (Noise Emitting Diode) ... it only worked once
And there was the quad DONT gate
> i have had a lot of stuff delivered to me with just a name..
Yep, a name and the ZIP is all you need!
> just curious, what part of rural montana?
Stillwater County in South Central
I live out in rural Montana, halfway up a mountain, so getting shipments of anything is iffy. e.g. the Post Office and UPS disagree on our address - as I understand it, the Post Office assigns these things and UPS should just deal with it - but they always put shipments on the wrong truck and I've had shippers back-charged for an "address correction". Multiple phone calls to UPS still haven't resolved this problem.
And UPS is better than Airborne Express - these guys won't accept a PO Box as an address, but don't deliver out here, so they consign all shipments to the Post office. Since the Post Office won't deliver to our house, the shipments need to go to the PO Box! Luckily, the local postmistron knows us and we no longer have a problem (in the past, we had a couple of shipments returned).
I won't even get into Fedex.
Montana's a beautiful place to live, but don't count on infrastructure (when we first moved here 6 years ago, I called the local phone cooperative and asked if I could get ISDN service - the rep put me on hold for about 10 minutes and then informed me "we now have call waiting"!)
Moose Drool is good, but try a manly Montana brew: Black Widow from Yellowstone Valley Brewing