Need Help: PrintrBot Plus 1303 Restoration for MRRF 2019

[moyerek]

I am the original owner of a 2012-era PrintrBot Plus and about two weeks ago I decided to get this machine running again for MRRF 2019. About 4 years ago I disassembled the printer since it was taking up room we didn't have at the time and I just wasn't using it since it required regular maintenance. Fast forward to today and in the last week I have taken what was a box of partially assembled wood piece into what is starting to look like a printer again.

As I mention at the very beginning I am under a bit of a time constraint as I am trying to get everything working for MRRF 2019 which is taking place in Goshen, Indiana starting this Friday 3/29. The information on this forum has already been a HUGE help to my build up unto this point however I am looking for some insight and recommendations on some steps moving forward.

I am planning on reusing as much of the original hardware/components as I can however I have already started a few upgrades which include Bondtech BMG and E3D V6. I would also like to figure out how to wire in an external MOSFET for the bed heater since I don't want to fry to RevD PrintrBoard.

Some information about my current machine. Other than the planned update to the extruder and hotend I am stock. I have PrintrBoard RevD with all the original steppers, heated bed and power supply (ATX 250W). I don't think I have ever updated the firmware on my Printrboard and when I pinged my board this is what I got:
FIRMWARE_NAME:Marlin V1; Sprinter/grbl mashup for gen6 FIRMWARE_URL:[Printrbot Site Here] PROTOCOL_VERSION:1.0 MACHINE_TYPE:Printrbot EXTRUDER_COUNT:3
echo:Active Extruder: 0

I have already done my best to search for the information in the forum (and elsewhere) and if there are post out there to address what I am looking for then please just post the link.

Here is what I am looking for help with:
1. Firmware Update? - I am trying to figure out if I have to update the firmware on my RevD board. As I mention above I do plan on updating my machine to a BMG and V6 so I know there will be updates to both the E step and thermistor type but I am hoping I can do that with my current board firmware. Do I need to update the firmware to properly work with current slicing programs? In the past I have used Repetier w/Slic3r with my Printrbot.

2. External Heated Bed Mosfet - If I want to use my stock 250W ATX and power the heated bed through an external MOSFET which wires from the ATX do I still need to connect to the PrinterBoard and which wires should I wire to the external MOSFET. I know I need to still power the board and provide enough for the hotend cartridge heater. I purchased the "BIQU Heat Bed Power Module Expansion" from Amazon (couldn't post link as a new user).

If any needs more information or pictures please let me know.

Thanks in advanced for any help you can provide.
Eric

[Mooselake]

I'd suggest switching the hot end thermistor to the ones sold by ubishotends.com, although this won't happen by the weekend. Some have had success by adjusting print temps, supposedly the strange thermistor chosen by E3D will work but you'll get erroneous but consistent temps. Or you could just run what you brung for now and use the original Ubis for MRRF. Like the old maps, when mucking with the firmware there be dragons.

The Amazon description of the mosfet board has decent directions for power hookups. The supplied push in connector for the control signals will need a little research or experimentation but should be straightforward. RJ can comment if connecting them wrong will let out the magic smoke and if you might want to order a spare or two on your Bezos Prime account

Kirk

[RetireeJay]

Regarding the thermistor, what Mooselake said. Both the Ubis and the E3D thermistors are "negative temperature coefficient" thermistors that are 100k ohms at 25C, but they differ by several percent at operating temperature for extruders. However, as Mooselake said, the E3D will be repeatable. So you may find that you need to tell the extruder to be 20 degrees hotter or colder than what you would expect, but the temperature will go there and it will work just fine (Temperature is only a number. Consider degrees C, degrees K, Degrees F, etc. So your magic number for getting good prints is different from mine - so what?). It's not possible to change the "thermistor table" in use without re-compiling and flashing the firmware. Using a Ubis - supplied thermistor will make your numbers calibrated correctly.

The old firmware in your machine will probably work OK. Most of the recent revisions make it work more smoothly or add features; there were very few bothersome bugs (if any) in the original issue firmware. I'm with you; I like using Repetier and Slic3r. The G-code produced by Slic3r is compatible, and Repetier talks to the Rev D Printrboard just fine (as well as lots of other boards).

You can update the E step calibration (and you should) using G-code. Just do a little searching and you'll find plenty of explanations. Personally, I like burning the correct calibration into EEPROM. See viewtopic.php?f=18&t=2763

Regarding the hookup, the video that's accessible on the Amazon site does a fairly decent job of explaining how to hook it up. To recap the video:
1) Polarity of the Power Supply to the board DOES matter. A lot. Get it right.
2) Polarity of the Heated Bed connection to the board probably does not matter unless your heated bed has an indicator LED. But the bed itself will heat just fine regardless of polarity.
3) Polarity of the connection from the Rev D board to the auxiliary board DOES matter. They aren't showing you a Printrboard. On a Rev D Printrboard, looking at the heated bed connector, the two pins closest to the incoming power connector are plus, and the two pins closest to the edge of the board (and the USB connector) are minus. It seems that they don't provide you with a mate for the kind of connector on a Rev D board, so you'll have to improvise; anything you can do that will make a secure connection is fine, for example soldering to the outer pins. The voltage is only 12V, so there's not a personnel safety problem.

[moyerek]

Big thank you to the quick response by Mooselake and RetireeJay.

Probably not enough time to get a Ubis thermistor by the weekend but I sent them an email to see what my options are (maybe someone from Ubis is attending MRRF). Great comment RetireeJay that temperature is just a number and if I have to print at "180" or "240" it doesn't really matter in the end.

Can either of you please review my plan for what ATX wires I should be using. I am starting with the assumption that my stock heated bed has (2) 20awg red wires and (2) 20awg black wires from the Printrboard so I figured I would just just connect the same number (and size) of wires from my ATX to my MOSFET.

[moyerek]

One more thing I forget to ask. Rather than run another 12V line from my ATX for my "always on" V6 hotend fan is there a 12V pin on a "EXP" slot I can just tap off?

[RetireeJay]

Regarding the "always on" +12V - you can get that from one of the two +12V pins on the Heated Bed connector (while you are using the other +12V pin for feeding the MOSFET expansion board). There are no +12V pins on the Expansions headers.

I'm not quite sure what to make of the ATX connections you show in the Powerpoint. The ATX power supply that came with my Plus had several more plugs. One 4-pin plug fit directly into the power receptacle on the Rev D board. But there were other plugs with yellow and black wires. If you have other plugs, use them.

If you have to cut wires to add in your MOSFET expansion board, I'd say to pick up two independent yellow wires (and two independent blacks) that lead back to the ATX. From your picture, it looks like you might be just taking two wires that come out of a connector but ultimately those wires come from only a single wire coming from the ATX.