I think a USB jack on a board with nice beefy power rails and a big capacitor close by, such as you would find on a hub, is better than 1 meter of pretty much any wire. Especially when you're asking it to feed current to a switching regulator. Long wires carry inductance, and inductance opposes current changes; switching regulators have really rapid input current changes. Long wires carry resistance, and resistance means voltage drops at high currets, which mean your regulator could be bottoming out and turning off.

I'm pretty sure this has been covered in the thread already. I know you're not a native English speaker, so I'll try and be nice, but I also get kinda annoyed easily.

Long or short wires? Heavy or thin wires? Capacitor bypass for high current nearby? Providing the same information a third time is, oddly enough, not nearly as helpful as providing new information.

Sounds like all of this question should be addressed (or likely has already been addressed) in the hardware thrad.

The question does not make sense. There is no hot/cold default for either; the hot/cold switchup is something I implemented specifically to have a higher voltage for startup stability at low running voltages. "Default hot/cold" does not exist.

The default voltage for an S7 is higher than the S7LN since it's designed to run at higher frequency. At least all the ones I've played with.

And you're using the right version of cgminer and the right command line flags?

Shouldn't be an honor. I'm just some dude on the internet.

Also, if you're looking at the oscillator, it's different because the part I originally used on the first batch went out of stock. I provided bitshopper with a different compatible part number, and then started using it myself on later batches. It's a standard 25MHz 1.8V oscillator and has no bearing on your problem.

Most questions that aren't a result of dead or damaged hardware are addressed in the first post of this thread. Like how the potentiometer in the bottom corner of the stick is there to adjust core voltage, which allows you to run a higher frequency. AT NO TIME SHOULD YOU EVER put more than 5.5VDC into the USB jack. Since the buck driver is 5.5V rated and the caps are 6.3V rated, I'm surprised it didn't just explode when you hooked it to 8.5VDC. A regulator's output voltage should not change from a change in input voltage unless something is seriously wrong with the circuit, so that you could get a higher voltage from it with a higher input voltage is a very bad thing. Unless the problem was input power limits from input impedance, where the voltage was bottoming out due to "high" load currents. 350MHz is going to want to pull about 8W which means 5V 1.6A so if your input lines can't handle it you'll see performance issues.

All of this has been addressed, probably repeatedly, in this thread. This thread has been here for a year and is over a hundred pages long. Very few problems by now haven't already been addressed. Do a bit of searching.

And if you try something that destroys the miner, you are doing something very very wrong.

I don't know how to interpret that question. All my "work on the S7" is the same as my work on the S7LN, which is all already laid out in the S7 hacking thread in Hardware.

Was that before or after you destroyed the buck circuit by feeding the 6V-rated parts with 8.5V?

Also, this is not a tech support thread. If you have questions, take them to the tech support thread.

Where'd a USB to UART enter the picture?

Signals in Antminers go uphill, so the first chip would be on the lowest-volt node and the last is at the highest. I'm not sure offhand where those are but it  shouldn't be too hard to tell.

That's about exactly what you should be seeing, so it means the power circuit is functional. Next thing would be to poke reset, TX, RX and clock lines at the 18-pin and see if those signals make it all the way to the last chip in the chain. This should be done while the board is powered up, of course.

I'd watch for a HW percentage below 0.01 - that's when I started noticing the effective hashrate dropping out. Make sure to keep fans low too; these boards really like to be kept above about 45C to run stable and at low powers it takes almost no fan to do that, especially with the oversized heatsinks in the LN.

I've got one on my shelf (ordered an extra) that's probably decent enough to sell. I forget the numbers exactly; it wasn't super so about 450W at 2TH. If someone wants me to work one up, you can always just have it shipped here and I'll make it as stably efficient as possible for a given hashrate and reship for a nominal fee.

I'm going to work on a couple of proper 3-board S7 machines in the next couple days, probably optimized for 600MHz or so and have them for sale - 4TH at between 900 and 1000W is what I'm shooting for if anyone's interested. I might shoot for 550MHz and get 3.7TH around 800W.

I did work up a test Compac with BM1385 but could never get it to work. The friggin' 0.4mm pitch ASICs are a bear to work with, plus that they're impossible to reliably acquire thanks to the chipside heatsinks, got the whole project scrapped in prototype.

I haven't looked over an S7 board specifically for chip stuff in a while (been focused more on power) but I believe there are test pads between chips if you can get to them around the heatsinks. You could at least verify where signals are going.

If the DC-DC is at about 8V, there's something wrong. It should start out around 9.3V and if you provide 3.3V to the 3.3V pin on the 18-pin header (or just plug the cable into a powered controller board) you should see that jump to 10.2V or so unless there's something very wrong with the PIC/DPOT parts of the power circuit. There's already a couple threads on that subject though.

I know 610 and 600 are specifically labeled "unstable" in the chart, but it's also noted in places that 620 isn't always reliable either. A lot of the group-buy miners weren't stable until 630 or 640. I did each of those on a per-board basis. I've got an S7 right now that has been dropping one board at like 670 for 550MHz so it really depends on the hardware. If a board runs unstable or drops out, the voltage is too low.

Know that the S7LN restarts cgminer. It runs for about a minute to warm up the chips (during which time you'll see hundreds of errors) and after that it should kill and restart clean. The firmware shifts to cold running about 30 seconds into the restarted process. At least that's how it should work - sometimes cgminer doesn't restart and you're left with the jillion errors.

Bugger anyone who'd have a requirement like that for gear to work properly.

This thread contains all the answers to those questions.

It's a good thing you provided enough information to discover the mistake, because paying for a 0.98W/GH miner is actually pretty stupid.

Also, paying more than probably about $1000 for an S9 is a bad decision. I know the going price is twice that, but the going price is stupid.

Only idiots are buying, so it's a good way to designate idiots from the rest. At those prices they aren't selling much, so it won't murder the diff. Except if it does murder the diff it's because they're self-mining on the most profitable farm on the planet.

There are also philosophical reasons to not GPU mine despite the potential for profits.

If compac-freq is an unrecognized option or the stick enumerates as an AU3, you're not actually using cgminer-gekko. I'm assuming you paid some attention to my last post?

Also, one good thing to do when you have a problem is search within this thread. It's been around for a year and it's over a hundred pages long so it's very very likely that your problems have already been seen and resolved. Multiple times.