Slush's pool is reporting 9.435MHz

while cgminer is showing:
AMU 0: | 290.4M/364.9Mh/s | DA:20 DR:0 HW:106 WU:2.33/m

I'm going to buy an 85°C working temp crystal and replace what's on there and take that out of the equation.

[2013-07-17 17:14:40] USB: AMU0 read1 buffering 4 extra bytes
 [2013-07-17 17:15:13] Stratum from pool 0 detected new block
 [2013-07-17 17:15:21] USB: AMU0 read1 buffering 4 extra bytes

Have lapped the complex heatsink for better contact with the CP2102 and ASIC tops.  Using thermal compound between the chips and heatsink.  Pre-chilling in AC.  Will shut down bfgminer on the laptop, it having the -S all switch, plug-in the B.E., start bfgminer, plug in fan.  Have an alligator clip to the top of the crystal tho if the heat from the CP2102 is effecting it, this might not improve the situation but instead cause additional heating of the crystal. ...  No joy.  Trying RPi. ... Okay, hashing on RPi via a USB2.0 hub.  Must wait tho as it warms.

First try after repair attempt on the crystal was a bust.  Into hub, short blink of the LED and nothing.  I had used an iron to solder in the crystal.  Now I put the custom protective alligator clip heatsinks in place and while  holding down with the dental pick, heated with hot air.  Cooled in the chill of the AC and tried the hub plug-in test again and got the standard flashings of the LED!  Didn't try to get it hashing yet but looked at the laptops std out and see 'device descriptor read/64, error -71' four time then an instance of 'device not accepting address 40, error -71' then and instance of 'device not accepting address 41, error -71, then finally 'unable to enumerate USB device on port 2'.   So, essentially it's the original failure messages - there's no topside heatsink of any kind.  Replacing the CP2102 is out of the question so I'm left with replacing the crystal.  Meanwhile experience has showed me it will run like this if tucked into the AC outlet.  Will try the two heatsinks and fan.

Made a complex heatsink that made contact with both the CP2102 and the ASIC. Also, the heatsink was mounted to two standoffs atop which sat a small 12v fan.  I was undecided whether to power the fan with a wall wart or step-up module powered from the USB 5v. I went with a 9 volt wall wart then changed up to that thru the step-up module for high fan speed.  It was only a little more capable of communicating with the RPi or a laptop via a USB2.0 hub than when it only had a TO-220 heatsink and chilled.  A few mods to the heatsink then it stopped hashing and couldn't get brought back to life.  I looked into what an 11.0592MHz crystal would be used for.  One application online said the frequency was right for the interrupt for multiple processes at some common frequency another said it related to baud rate in communication processes.  So, since it was positioned in what looked like a funky fashion, I decided to remove it and replace it.  Taking two large alligator clips I trimmed them down with a Dremel until each could clamp either side of the crystal protecting the adjacent chips from heat as well as some caps.  I applied light pressure with a dental pick to the top of the crystal while heating with a hot air desoldering tool.  The top pair of pads freed first but the lower pad pair ripped off the device.  Too much pressure, too little heating time.  So, looking up replacement crystals I find only one brand in a Digikey catalog 2010 that was the correct package dimensions and had an operating temperature of 125°C as it was for automotive applications.  Unfortunately not available in 11.0592MHz.   Searching Digikey online couldn't find the frequency at 125°C.  Other brands offered the frequency but with a max of 85°C.  I recall I found the temperature in the area of the CP2102 and 11.0592MHz crystal to be around 250°F with an IR meter.  That's 121°C in the neighborhood of a crystal who's max working temp is likely 85° and that is involved in com baud rate.  So, the heat from the CP2102 is perhaps destabilizing the crystal.  Before buying another crystal I'm trying to repair the present.  Curiously only pins 1 and 3 of the 4 pad crystal have any function.  This might explain the funky positioning, getting max access to the only 2 functional pins.

Lastly went back to the TO-220 heatsink mounted atop the B.E.  Anodized so it doesn't conduct, a reduced Teflon washer as a spacer off the board so it lays flat, heatsink compound, in free air in a 75° room without a fan, it lasted 5 minutes.  This was using the CyberPower USB2.0 hub rather than the new USB3.0.  I don't think the USB3.0 hub feels the signal is good enough to pass.  I'll try it again tomorrow.

The new USB3.0 hub with the room temperature B.E. was plugged into the booted Inspiron 5150 which was at a linux root command prompt.  The new hub was turned on and immediately there scrolled on the screen 'unable to enumerate device' messages and this with the TO-220 heatsink still strapped to the B.E to the surface of the CP2012.  I unplugged the B.E. and the scrolling stopped.  Will try and measure the voltages on Vdd and REGIN (USB voltage in) and will attempt a reset pulling 9 low.

So, the CP2102 among other things takes the USB 5 volts and generates 3.3 volts that it can source to other components.  250°F is hot.  the datasheet says its temp range is -40° - +85°C (185°F) although under absolute maximum ratings, ambient temperature under bias max is 125°C (257°F).

When the AC went to fan only last night as the home cooled for the night, the green LED came on as it stopped hashing.  I took a TO-220 heatsink, put on a dab of heatsink compound, and strapped it to the CP2102 on the B.E. board and returned it to the AC air duct.  It's been running ever since - 11  hours.

So, its heat might be due to high USB voltage that needs to be knocked down to 3.3 volts by the CP2102 or internal switching supply inefficiency or excessive load on the 3.3 volts.  I looked at the poor positioning of the crystal next to the CP2102 and what looks like excessive solder - if it's shorting to the metal case that would load it down.

The new USB3.0 hub is sitting at the post office.  Must get it now and check if it improves the heating problem.

Just looked at the cp2102 datasheet and it's a USB 2.0 device.  Must look tomorrow if there's a suffix.

If it is the CP2012 heating due to incoming slew rate of the data, since this type of failure is apparently common in the USB3.0 world, somebody can make a good buck selling a small signal conditioner to be placed between a USB port and a USB3.0 device.

Took it out of the AC and it failed in 60 seconds.  I wonder if the problem may be the USB2.0 rise time.  Lower slew rate causing heat as occurs in poorly designed switching supplies.  Popped it back in the AC and restarted - running okay.  Wondering if the input to the USB3.0 hub will be too fast for my USB2.0 machines.

I suppose Schmitt triggers would be asking too much.

So, when it's running properly the green LED is off except for when sending a burst of data.

 cgminer version 3.3.1 - Started: [1969-12-31 19:00:26]
--------------------------------------------------------------------------------
 (5s):503.9M (avg):291.9Mh/s | DA:34  DR:2  HW:0  WU:4.5/m
 ST: 2  SS: 0  NB: 3  LW: 87  GF: 0  RF: 0

Too bad it will go wrong when I shut down the AC for the night.

............
 [P]ool management ettings [D]isplay options [Q]uit
 AMU 0:                | 334.8M/333.7Mh/s | DA:47 DR:2 HW:0 WU:5.74/m

Okay, with the B.E. tucked into the air conditioner outlet and the RPi on top of the AC and the net a nearby switch for my WDTV, it's running:



 cgminer version 3.3.1 - Started: [1969-12-31 19:00:26]
--------------------------------------------------------------------------------
 (5s):133.4M (avg):138.3Mh/s | DA:4  DR:0  HW:0  WU:2.0/m
 ST: 2  SS: 0  NB: 1  LW: 14  GF: 0  RF: 0
 Connected to xxxxxxxxxxxxx diff 1 with stratum as user xxxxxxxxx
 Block: 00966e42400b20a1...  Diff:26.2M  Started: [19:00:26]  Best share: 10
--------------------------------------------------------------------------------
 [P]ool management ettings [D]isplay options [Q]uit
 AMU 0:                | 300.9M/279.5Mh/s | DA:4 DR:0 HW:0 WU:4.03/m
--------------------------------------------------------------------------------
 [1969-12-31 19:00:25] Loaded configuration file /opt/minepeon/etc/miner.conf
 [1969-12-31 19:00:25] Loaded configuration file /opt/minepeon/etc/miner.conf
 [1969-12-31 19:00:25] No devices detected!
 [1969-12-31 19:00:25] Waiting for USB hotplug devices or press q to quit
 [1969-12-31 19:00:25] Probing for an alive pool
 [1969-12-31 19:00:26] Switching to pool 2 xxxxxxxxxxx- firs
t alive pool
 [1969-12-31 19:00:26] Pool 1 http://xxxxxxxxxxxxx:3333 alive
 [1969-12-31 19:00:26] Switching to pool 1 http://xxxxxxxxxxxxxxxxxx:3333
 [1969-12-31 19:00:26] Pool 0 http://api-stratum.bitcoin.cz:3333 alive
 [1969-12-31 19:00:26] Switching to pool 0 http://xxxxxxxxxxxxxxx3333
 [1969-12-31 19:00:26] Network diff set to 26.2M
 [1969-12-31 19:00:31] API running in IP access mode on port 4028 (12)
 [1969-12-31 19:02:08] Accepted 1895e4cb Diff 10/1 AMU 0 pool 0
 [1969-12-31 19:02:15] Accepted 195fa067 Diff 10/1 AMU 0 pool 0
 [1969-12-31 19:02:15] Accepted fe3f5bb0 Diff 1/1 AMU 0 pool 0
 [1969-12-31 19:02:16] Accepted 1b280425 Diff 9/1 AMU 0 pool 0

The CP2101 gets hotest, in the neighborhood of 250°F according to my IR meter.  Don't want to give up until after I test it on a USB3.0 hub however and its tracking number isn't registering on the USPO tracking yet.

Tried it again.  First I put the B.E. at the output of my air conditioning for a minute until it was well cooled.  Then reinserted into the hub.  All was well for just about 60 seconds then the 'device descriptor read/64, read -32' messages appeared, then the 'unable to enumerate device' messages started.  Next to find out if it's the hub or the B.E. that changes.

With an air conditioner that looks like a Dr. Who darlek and the B.E. on a USB cable, the B.E. inserted into the AC output, the hub some distance, there are no error messages after 5 minutes.  Will now remove the B.E. from the AC and insert the hub.  Sixty-four seconds later the error messages started.  So, the problem starts after the B.E. heats.

Well, the other day I had replaced caps in a supply for an old Dell Inspiron 5150.  Power hungry laptop but fast.  I just gave the hub and B.E a try on that and no connections difficulties and correctly identified.  I'll have to fight with it to install mining software tho.  --nope, just looked back and now there's connect-debounce port error messages.  Perhaps after the B.E. warmed up?

What I've been trying to use while awaiting the 7 port Plugable (I see is unverified and some report problems) is a CyberPower CP-HA420 with a 2.6 amp 5 volt supply it came with.  Waking them all up at once I was getting connect-debounce errors.  I just tried waking up the RPi with the hub but not the B.E, then plugged in the B.E.

[   65.763973] usbcore: registered new interface driver usbserial_generic
[   65.764083] USB Serial support registered for generic
[   65.764110] usbserial: USB Serial Driver core
[   65.858437] usbcore: registered new interface driver cp210x
[   65.858635] USB Serial support registered for cp210x
[   65.858781] cp210x 1-1.2.2:1.0: cp210x converter detected
[   65.956346] usb 1-1.2.2: reset full-speed USB device number 5 using dwc_otg
[   66.060840] usb 1-1.2.2: cp210x converter now attached to ttyUSB0
[   66.795443] cp210x ttyUSB0: cp210x converter now disconnected from ttyUSB0
[   66.795590] cp210x 1-1.2.2:1.0: device disconnected

added the B.E.

[root@minepeon minepeon]# dmesg | tail
[   72.506354] usb 1-1.2.2: device descriptor read/64, error -32
[   72.696266] usb 1-1.2.2: device descriptor read/64, error -32
[   72.886272] usb 1-1.2.2: new full-speed USB device number 7 using dwc_otg
[   72.966416] usb 1-1.2.2: device descriptor read/64, error -32
[   73.156318] usb 1-1.2.2: device descriptor read/64, error -32
[   73.346341] usb 1-1.2.2: new full-speed USB device number 8 using dwc_otg
[   73.766120] usb 1-1.2.2: device not accepting address 8, error -32
[   73.846295] usb 1-1.2.2: new full-speed USB device number 9 using dwc_otg
[   74.266224] usb 1-1.2.2: device not accepting address 9, error -32
[   74.266471] hub 1-1.2:1.0: unable to enumerate USB device on port 2

I went into  /sys/module/usbcore/parameters/ and changed old_scheme_first to Y and increased initial_descriptor_timeout from 5000 to 15000.

I rebooted and no joy.  I stopped cgminer and restarted getting this:

 [1969-12-31 19:06:05] Started cgminer 3.3.1
 [1969-12-31 19:06:05] Loaded configuration file /opt/minepeon/etc/miner.conf
 [1969-12-31 19:06:05] No devices detected!
 [1969-12-31 19:06:05] Waiting for USB hotplug devices or press q to quit

Seeing the hotplug notice, I tried disconnecting the B.E. and reconnecting.  No change.