"Cold Extrusion Prevented" mid print

I have a Prusa i3 clone that I recently upgraded to a dual head block and aluminum print bed. Standard Arduino w/ Ramps 1.4 + the latest Marlin.

I have suddenly run into an issue as I started a longer print after the upgrades where it will stop extruding randomly in the middle of the print.
If I pause the print and try to extrude, it will echo a "Cold Extrusion Prevented" message even though the temperature is reporting normal.
I read that the probe might be dropping out for a second in the middle of the print. I looked at my log and it was inconclusive.
The only way to reset the low temperature condition is to cancel the print.
I have tried unplugging the main power (arduino still powered), disable the motors, turn the print head heater on/off. No beans.
I have swapped to the other print head and get the same issue.
Tried wiggling the probe wires everywhere and didn't see anything happen.

I need some help figuring this out. Why doesn't the extrusion resume after the temperature "returns to normal" during the print??? Baffling.

Edited 1 time(s). Last edit at 08/19/2018 08:58PM by naps1saps.

Its either a broken cable or the hot end is unable to maintain the temperature (to much part cooling fan hitting hotend

Do you have a silicon sock? This helps keep hot end hot even with stray fan air

Print head is being heated to 240 and the low cutoff is 190. Variation is a few degrees so cooling isn't an issue.
I've tried both heads and both have their own thermistor. I really doubt both have a broken wire but that's the only thing I can think of at the moment.

Honestly why does it trigger and then not reset. Is that a Repetier issue or Marlin issue?

I'm not sure what I'm looking at. It appears something resets? From what I can tell it is not a temperature issue unless it's randomly looking at the other cold nozzle for some stupid reason.

Please help.

Here is the log:
< 21:39:27.327 : N119181 G1 X74.96 Y104.988 E2009.142*111
> 21:39:27.686 : ok
< 21:39:27.686 : N119182 G1 X75.583 Y105.439 E2009.189*93
> 21:39:27.765 : ok
< 21:39:27.765 : N119183 G1 X76.901 Y106.502 E2009.292*90
> 21:39:27.795 : ok
< 21:39:27.795 : N119184 G1 X77.489 Y106.997 E2009.339*81
> 21:39:27.811 : T:239.79 /240.00 (53.75) B:130.07 /130.00 (382.13) T0:239.79 /240.00 (53.75) T1:48.00 /0.00 (875.00) @:44 B@:0 @0:44 @1:0
> 21:39:28.343 : echo:Active Extruder: 1
> 21:39:28.343 : ok
< 21:39:28.343 : N119185 G1 X78.726 Y108.154 E2009.443*90
> 21:39:28.358 : Error:Line Number is not Last Line Number+1, Last Line: 119183
> 21:39:28.358 : Resend: 119184
> 21:39:28.374 : ok
< 21:39:28.374 : Resend: N119184 G1 X77.489 Y106.997 E2009.339*81
< 21:39:28.374 : Resend: N119185 G1 X78.726 Y108.154 E2009.443*90
> 21:39:28.374 : echo: cold extrusion prevented
> 21:39:28.374 : echo: cold extrusion prevented
> 21:39:28.374 : echo: cold extrusion prevented

Edited 1 time(s). Last edit at 08/23/2018 12:45AM by naps1saps.

This is a serial communication issue

line N119184 was not received correctly by the controller
then line N119185 was sent and the controller said hey what happened to N119184 and requests N119184 gets re sent

try a better usb cable or shorter, and move usb cable away from any possible sources of electrical noise... like stepper motors

Edited 1 time(s). Last edit at 08/23/2018 01:56AM by Dust.

the line

> 21:39:27.811 : T:239.79 /240.00 (53.75) B:130.07 /130.00 (382.13) T0:239.79 /240.00 (53.75) T1:48.00 /0.00 (875.00) @:44 B@:0 @0:44 @1:0

is most interesting,
T:239.79 /240.00 (53.75)
B:130.07 /130.00 (382.13)
T0:239.79 /240.00 (53.75)
T1:48.00 /0.00 (875.00)

so t1 is reading 48 degrees, but is set to zero this is to cold to extrude and thus you get "cold extrusion prevented"

I had a feeling.
I've got the baud rate as high as it will go 2.5Mbps so I'll reduce it. That's probably what's going on. I'll update tonight if that resolved the issue.

@Dust
I'm not using T1/E1, only using T0/E0.

When it says "Active extruder: 1" is it referring to the ID such as E1 opposed to E0? When I read it, I'm assuming it means only one extruder is active.

Edited 1 time(s). Last edit at 08/23/2018 11:16AM by naps1saps.

Quote
Dust
This is a serial communication issue

line N119184 was not received correctly by the controller
then line N119185 was sent and the controller said hey what happened to N119184 and requests N119184 gets re sent

try a better usb cable or shorter, and move usb cable away from any possible sources of electrical noise... like stepper motors

Reducing my baud rate back to the default 115200 resolved the issue. I think what was happening was when it lost a line, it would default back to the other print head that was not in use which is a bug IMO. I'll submit a bug to Repetier.