Treo 650 2.5 mm to 3.5 mm Audio Jack Swap
This is not really a How-To guide but more of a Proof-of-Concept. Palm could have made the Treo 650 with a more media friendly 3.5 mm jack, but they chose not to. A correctly designed connector would have worked great.
If you want to do this mod, there is enough information here for any competent electrical hobbyist to perform the upgrade. I would not recommend doing this upgrade and don't ask me if I can do it because I will not. I have been repairing broken jacks for a nominal fee but this is way different. If you really want a 3.5 mm jack, look at my Audio Jack Hack. I also do those for a fee.
This jack swap uses the same jack as the one used in the Audio Jack hack mentioned above. Let me start by showing a board with the original 2.5 mm jack removed.
You will need to bridge MIC and GROUND where the 2 white arrows indicate "BRIDGE" this is so you can have internal mic functionality with the 3.5 mm stereo headset. The 2 pads labeled "TIP or LEFT" also need to be bridged together. The round pad labeled "MIDDLE or RIGHT' will be used to solder to the connector and the square pads need to also be bridged together. There is no need for a switch since the Treo has an electrical switch that senses when there is a Stereo headset pluged in.
After performing the above modifications to the board, you can now prepare the connector. I used a Kycon P/N ST-3500-3N. The connector needs to be shortened by 2 mm and a placement pin removed. The pin removal weakens the connector bond to the board, so you may want to use a non-conductive epoxy afterwards to secure the connector to the board. A before and after picture of the connector is shown below. Notice the edge of the connector is cut away to the metal contact. That metal contact will need to be soldered to the board since the tab had to be cut away.
Afere the connector modification, you can then place it to the board and solder it in place. Solder as shown below, making sure the solder point on the right is soldered to the contact deep in the connector. The other solder tab on the opposite side of the connector gets soldered to the round solder pad previously shown.
Once the connector is soldered in place. place the rear plastic on the board. Notice you will need to cut some plastic to get the board to sit flush. You will also need to trim more of the connector if it protrudes out like pictured below. It need to be flush with the plastic so that it does not interfere witht the battery. a normal OEM battery should be ok, but high-capacity batteries barely fit. Notice the jack tip in the pcture, it fits but any longer ant it would hit the battery.
below is a picture of two plastic shells joined together, notice they do not join correctly. You will need to cut the half circles on each plastic halve to make room for the bigger connector.
Well, that is enough info I think. Please let me know if anyone else was brave enough to do this mod. I did it just to prove that it would work on a spare board.... It works!!! the board is now sitting in a box of treo junk...