Products > Test Equipment
Miniware MDP-XP Digital Power Supply Set
herczegzsolt:
I did some digging with USB-C devices, and I have also took apart my P905 to take a look at why it does not work from USB-C capable chargers.
Fun fact: the Miniware P905 would work, even from 5V USB.
It turns out that the USB-C port is actually wired incorrectly on the P905. The CC pin is left floating, which indicates "unplugged" state for a USB-C cable. Therefore, any USB-C power supply would not provide any voltage, not even 5V volt.
If a device wants to operate in legacy mode, a 5.1k pulldown resistor should be present on the CC pin.
The reason the P905 works at all is that you're probably using it with a USB-A to USB-C cable. Since a USB-A connector does not have a CC pin, the floating pin on the miniware does not cause an issue.
If you want to use the miniware form. USB-C brick, you can use two adapters to trick the powerbrick into legacy mode: a USB-C -> USB-A -> USB-C double conversion will make things work. (It'll use 5V if there's no QC capability on the powerbrick and 12V if there is. QC does not use the CC pin to negotiate.)
It would be theoretically easy to fix the P905 by just putting two 5.1k resistors inside (there are two CC pins in USB-C). I did make it work with a 5.1k resistor on a USB-C breakout board in series with the miniware, but the connector pins and the free space inside was way too small for me to succesfully fit that inside the housing. Maybe someone with am extremly steady hand and razor sharp soldering iron could pull it off.
For Miniware, it should be easy to add those two 5.1k resistors to the PCB layout, at least until PD support arrives. Please do so!
Seems like mishandled CC lines in peripherals are a common cause of USB-C compatibility issues. For example the Raspberry Pi 4 had a similar but slightly different problem with them as well.
ploxiln:
The updated MDP-P906 seems to now be available on AliExpress for $160 - $173 USD. USB-C PD, 30V 10A 300W (up to 14A input ?!), a bit thicker with a fan. I was shopping around about a month ago, and found the MDP-P906 manual had recently been published by Miniware, but couldn't find it for sale anywhere, so I ordered an MDP-P905 (with shipping and NY taxes $123), it should be quite sufficient for my needs.
Even though I had already read about it in this thread ... when I was first trying out the MDP-P905, I powered it up with a 19V barrel jack laptop charger, looked through the menus, unplugged it then connected it to my laptop with a usb-c to usb-a cable ... and the laptop zapped right off from having 19v injected into its 5v usb port. Luckily the laptop was fine after a power cycle. Measuring with a multimeter, the charge in the input capacitors can remain for a surprisingly long time.
In addition to my 19V 65W barrel plug laptop power adapter, I have an 87W USB-C Macbook charger, so I got a little USB-C 20V PD trigger to barrel plug dongle for $11 on Amazon. Given I was already aware of the handful of hardware design issues with the MDP-P905: (no USB-C PD not even 5V, need to ensure discharged before connecting to PC, non-standard banana jack spacing), and my primary constraint these days is space/size, I'm happy with this thing.
kloetpatra:
--- Quote from: herczegzsolt on January 24, 2022, 01:20:29 am ---It would be theoretically easy to fix the P905 by just putting two 5.1k resistors inside (there are two CC pins in USB-C). I did make it work with a 5.1k resistor on a USB-C breakout board in series with the miniware, but the connector pins and the free space inside was way too small for me to succesfully fit that inside the housing.
--- End quote ---
I had some P905 laying around. I can confirm that after adding 5.1k pull down resistors at CC1 and CC2 the device works up to 18W @ 12V. 0201 resistors seem to be the perfect size for the job.
I also bought some small PD-trigger boards, maybe it's possible to stuff them inside to get 60W/100W USB-C PD.
negativ3:
Hi all,
Can anyone share the firmware for the MDP-P905 and the MDP-M01?
My MDP-P905 can only enter DFU mode as turning on normally displays "Demo Mode" then switches off.
If in DFU mode, it opens a folder on windows and remains on.
Many thanks in advance.
Andy
negativ3:
Found them.
Now available on
https://www.morningtools.com/list/13.html
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