digitech xc0348 or fine offset equivalent

[tintin007]

Hi,

I have one of these with the solar panel. Unfortunately the plastic transmitter broke at the bottom and was out in the wet too long. now corroded i need to replace it. I tried another brands transmitter with solar panel but this wont link to the base unit, It pysically looks the same. does anyone know anything about compatibility issues on these. are they limited to particular brands by way of coding or something. local retailer wont supply or help, so i am having to find out as i go along what works or not.

Whats the difference internally between the solar and non solar transmitters ??

Any help advice appreciated

cheers
mark

[AllyCat]

Hi Mark,

Does your solar panel (pod) just charge the batteries or does it also provide data (UV/Lux)?

I don't know about the solar-charging (only) units, but the solar data transmitters appear to use a completely different wireless protocol. Monitoring the transmitter current, the non-solar (and perhaps solar-charging) versions transmit for about 50ms (each 48 second period) whilst the solar data versions transmit for up to one second, apparently using amplitude modulation.

Another significant factor is that the transmitters may use one of three different carrier frequencies. 915 MHz in North America, 868 MHz in Europe and the UK and 434 MHz in UK and Australia appear to be the more common.

There are photographs of the internal construction of some different Transmitter units in the sticky thread "Photos of the insides..." at the top of this section.

Cheers, Alan.

[tintin007]

Hi Alan,

This one has a solar panel only. provides around 3v dc to the board (transmitter) via the 4 wires. + from the solar panel goes to the black wire and - from the panel goes to the yellow wire. this then goes off to the transmitter. the other 2 wires coming from that assembly are the green which goes to the re-set switch and rj11 and the red which goes to the rj11 only. There is a small component i am trying to identify ( see attached photo) sits in behind the battery connector next to the 4mhz crystal. Small silver item. possibly a cap. this feed into the main Ic. In the photo the rj11 sockets are removed as these will need replacing.

This one is a 433.9 mhz transmitter. would these be generic items or are they specific to manufacturers. The scientific scales solar transmitter i got wont work with this digitech one. I guess the coding must be different somewhere.
cheers

mark

[ejay]

The XC0348 is equivalent to the WS1081 - 433Mhz, no RCC, with solar charging (but not Lux & UV).

There is a seller on ebay selling replacement transmitters. You'd be best to ask if it is compatible before buying.
Search for "Transmitter for Wireless Weather Station WH1081".

[AllyCat]

There is a small component i am trying to identify ( see attached photo) sits in behind the battery connector next to the 4mhz crystal.

Hi Mark,

I'm fairly certain that that is a 32.768 kHz "Watch" crystal (divide by 2^15 gives one "tick" per second). They're ridiculously cheap so the main problem is finding a supplier with low shipping costs. It's almost certainly used to accurately time the 48 seconds between transmissions (which AFAIK is the only method that the receiver uses to discriminate between signals from more than one transmitter).

Their unusually low operating frequency (for a crystal) means that they have a very high impedance, so much so that even the leakage current across the surface of a "dirty" PCB can stop oscillation. Therefore you might find that just thoroughly cleaning the PCB around the relevant tracks with alcohol (or similar) may be sufficient to get it working again.

Incidentally, the "Solar Data" models use a 6 core cable with a RJ12 ("6p6c") plug and socket which may help to identify those particular Transmitter models.

Most of the components seem to be generic "off the shelf" types (but often available only to manufacturers from China), but the program code (in the microcontroller under the black "blob") determines the transmitted data protocol and that will be specific to Fine Offset and all the brand names which are put on its products.

Cheers, Alan.

[ejay]

You might even be able to salvage a 32.768 kHz crystal from a junked desk/wall clock. They're very common as AllyCat mentioned.
If you don't have any donor clocks lying around, maybe you could buy a cheap desk clock from a $2 shop or something.

edit: from the photos, I think I can only see one leg on the crystal. They should have two. The second leg could have fallen off from the corrosion, owing to its proximity to the battery terminals (electricity+water=bad corrosion).