Wiring gtm 25 tmc usb connectorHi, I like to put a new mini usb connector on the TMC / charger cable since the old one came of. I know that I need a 5...
回答“GPS Not working well at all”Update. When I broke my display again I used the opportunity and drilled a hole in the backcover, allowing me to attatch different antennas to the gps antenna connector. That brought no good results, but it ruined the backcover. So I used the old backcover again, but this time I took the PCB off as well and applied conducting silver to the point where the PCB touches the contact bridge in the display part, and after refitting the PCB I applied conducting silver to the point where the contact bridge touches the wire mesh in the backcover. Gps has been wonderful since then. So I dont think that the gps antenna in the backcover degrades, I guess that just the two contact points leading the signal from the antenna to the PCB are corroding.
回答“GPS Not working well at all”When GPS vanished I tried cleaning the copper mesh in the backcover, didn't help. I used a backcover from a broken phone, this having a metal contact plate instead of the copper mesh. Didn't help. I cleaned the contact plate and GPS reappeared. Then I applied some conducting silver (I took out a droplet of the silver sediment from the tube) to the contact plate and closed the phone immediately, hoping it would kind of "cold solder" the PCB contact to its counterpart in the back cover, making it a permanent fix. We will see how permanent this is. Funny to mention that when I tested, GPS worked without the backcover (battery held in place with a rubber band), though only with weak signals, but not with the backcover on.
回答“Wiring gtm 25 tmc usb connector”Since nobody knew, I borrowed a coworkers satnav, took the receiver apart and checked with a ohmmeter. Contact 4 on the mini USB plug is NOT connected to ground as I had read somewhere on the net. receiver-----------------mini USB plug on garmin Nuvi 1 ground black--------------- contact 5 2 n/c 3 data green------------------contact 3 4 data white------------------contact 2 5 n/c 6 n/c 7 +5volts red---------------contact 1 inside plug: contact 4--R27 Kiloohms--plugs enclosure The trick is to connect the metal shild part of the mini USB plug with the plugs contact 4 via a resistor 27 Kohm. When contact 4 is connected to ground, Nuvi expects a charger. When contact 4 is not connected at all, Nuvi expects a data connection. And when contact 4 is connected to the metal shield part of the plug via a 27 Kohms resistor, Nuvi expects the TMC receiver. If the receiver is recognized, the setting appears in the menu and the green button appears in the map. Manfred, Berlin