ZeroPhone after-assembly fixes (Gamma)
When finishing ZeroPhone assembly, it's good to have a checklist of things that need to be done. Currently, this list only has small things that need to be done after most of the main components have already been assembled (most of steps described here also belong on the "ZeroPhone manufacturing steps that are hard to automate and will have to be solved" list)
Contents
- 1 Covering front board display header holes with Kapton tape
- 2 Make sure display solder jumpers on the front board are connected the right way before turning the phone on
- 3 Soldering microUSB charging port to the back board
- 4 Adding Velcro to hold back board and 18650 holder together
- 5 Isolating the battery board traces&wires
- 6 Connecting DC-DC output to the back board
Covering front board display header holes with Kapton tape
On Gamma front boards, in order to connect a display breakout (a 6-pin one), you need to make solder jumpers on the lower display header. In process of doing that, you're also likely to fill the lower display header holes with solder, which is OK by itself, but sometimes solder bubbles up on the other side - which, if coupled with a lack of case on the phone, can short out the OLED panel flex cable pins to those bubbles. In order to avoid the contact between the jumper header and the OLED flex cable pins, before adding solder to the jumper, cover the holes with Kapton from the other side.
Make sure display solder jumpers on the front board are connected the right way before turning the phone on
Different OLED breakouts can have different pinouts. ZeroPhone can accomodate different pinouts for displays, but you need to wire the header in a proper way. Here are solder jumper examples for two popular OLED display types:
Warning: make sure you have the VCC and GND pins wired correctly! Wiring them incorrectly will destroy the display the instant you power the phone on.
Soldering microUSB charging port to the back board
This is done for (somewhat) better mechanical stability of the microUSB port. Soldering has to be done with something, like a MicroUSB cable or a microUSB male connector, inserted in the port - otherwise, solder will flow into the port (through the holes in the port) and make inserting a cable into it impossible, or just really hard.
Adding Velcro to hold back board and 18650 holder together
Currently, there's nothing that holds the battery holder and back board together, apart from the battery cable. An easy non-permanent solution is Velcro (you need to get the kind that has glue on both sides). Just cut the Velcro pieces into approx. 30mm*10mm pieces and attach them to battery and back boards.
Isolating the battery board traces&wires
This is a Gamma board revision-specific fix that won't have to be applied on subsequent revisions
Gamma 18650 holder board has traces and exposed pads on the backside, which, as it seems, made it possible for the battery to short onto various metal pins on the back board. To prevent that, apply two layers of Kapton tape over all the traces and metal on the exposed side of the 18650 holder PCB. It's also advised to apply a blob of hot glue on the place where battery wires are soldered to the 18650 board.
Connecting DC-DC output to the back board
As of now, ZeroPhone uses a 5V DC-DC module that's initially designed with a USB socket. As a result, it's hard to connect its output to the ZeroPhone back board. To do that, you need to either use short wires or 2.54 male connector pins to bridge the distance from the DC-DC board to ZeroPhone, and apply liberal amounts of solder.
