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Disassembly of Motorola Iridium Telephone.

 

After it was announced by the media that the Motorola Iridium system would be de-orbited I obtained an Iridium phone (very cheap, less than 1/100th of original cost) and proceeded to pull it apart. Now that the system is back going again I wish that the phone was still in one piece :-( However I thought that others might learn from my disassembly of the phone...thus this web page.

To pull the phone apart four screws need to be undone.  Two are easily visible on the top back of the case (near the antenna).  Two are to be found beneath the plastic ITU badge on the rear of the phone.  Peel away the ITU badge to get to the screws

 

Disassembly of the antenna

·        The antenna is removed from the main body of the phone by pressing the antenna release latch and rotating the antenna

·        I snapped the connector off the base of the antenna.

·        There is a circular end cap (disk) which is held in by the two black plastic halves of the cylinder

·        To pull the antenna apart I simply placed a screwdriver in the gap of the plastic casing and prised it apart.  The end closest to the phone is the place to start otherwise the antenna insides may be damaged. The antenna unit is a clear plastic cylinder with "silver tracks" on it.  The coax is coupled to the plastic cylinder.

 

What I found when I disassembled the antenna:

·        The antenna is coupled to the coax using capacitive coupling?

·        The antenna is a quadrifilar antenna, constructed using a clear plastic cylinder and plated on "elements"

·        Blue semi rigid coax connects the capacitive coupling to the antenna socket

·         The "elements" on the quadrifilar appear to be plated on silver. It looks like the silver has partly oxidized.

·         There is no preamp built into the antenna.

 

Above picture shows an end view of the antenna coupler. This is inserted into the end of the plastic tube. The coupler

is soldered onto the blue coax. It may be hard to see from the picture but the coupler is comprised of two “halves”. There

is an air gap between them. The coax seems to have shield soldered on one side,core on the other.

 

Above picture is quadrifilar antenna. The Iridium phone antenna looks similar to the Qualcomm GSP-1600 (used by Globalstar)  antenna. I wouldn’t be surprised if the antennas are very similar in Globalstar units.

 

 

Battery Compartment and Back Case of phone

·        The batteries I received with the phone are Lithium Ion batteries. The battery pack is a small “box”. Batteries are 3.? Volt.

·        They batteries wrapping has lots of security holograms on them to state that they are Motorola original products.

·        The battery charger appears to be a switch mode device (very light). Can take 110 or 240V. Novel design means that it can take use straight or angled pins in mains voltage socket via a small slide on adaptor.

·        The battery charger plug  on the low voltage side is a unique design. It has a huge number of contacts

·         The cover for the battery compartment is constructed from thin plastic???mm. It can be easily flexed between two fingers.

·         Inside the back of the phone is a main wiring harness made from (Flat Plastic Cable) FPC.

·         A small PCB is found behind the antenna connector. It has several SMT components.

 

 

The PCB at the LHS of this photo is mounted on the back of the antenna connector. The coax originally  went to the main board.

 

Keypad

·        Thick “silicone” type rubber keypad presses onto “bubble” type switches on PCB.

·        Illuminated by SMT LED

 

SIM Card and IMEI

·        The SIM card is a full size ISO "credit card" sized card. The phone accepts the full sized cards.

·        When I acquired the phone it was missing the actual 'smartcard' portion of the simcard.

·        Appear to be a lot that can be done when the phone is powered up without the simcard. I tested it however when the system was in "bankrupt" mode.

·        The IMEI number is displayed inside the battery compartment.

·         The card I have has an Australian address etc printed on it.

 

Main PCB

 

·        VERY physically large capacitor (approx 60mm x 50mm x 10mm )  Has marked on it 48300 MFD 8.5 Volts.

·        Almost all circuits well RF shielded with metal covers

·         Two interesting looking "cans" made by Raytheon (Part number RMPA-1620A-121) and RMLA1620C122. I haven't been able to find product info sheets on these. Can anyone
help?
From looking at the Raytheon RF components web page it seems obvious that the RMPA component is the RF Power Amplifier. The RMLA is the RF low noise amplifier. The frequency that these devices are centred on is likely to be 1620Mhz. The RMPA-1620A-121 appears to have a LARGE number of pins. There are shielded cans on the back of the PCB behind the PA module.

 Large Metal Cover
The large metal cover with the gold clips is the only one easy to remove.  A soldering iron, screwdriver and desolder braid can be used to free this cover.  Underneath are a load of chips made by various manufacturers Atmel, Temic, AD, Maxim etc. There is also a very odd shiny silicon chip. Instead of being made with a plastic or ceramic case the “lid” looks like it is made of glass!

·         These chips appear to be the "brains" of the phone.
I guess that the AD7342XST is the DSP that handles the IMBE codec??
An Temic TSS4550-1A (Temic make speech recognition???)
An Atmel AT28BV4 64K EEPROM
An MAX3238 RS232 Driver
There are various Motorola SC.. chips that I cannot identify..

 The photo on the left shows the The RMPA-1620A-121 module.

 

 View of a portion of the main board. It looks like this is the main processing area of the phone.

 

 

Manual

An excellent spiral bound manual came with the phone. Interesting points from the manual are:

·        GSM cassette is available as optional extra

·        ????????

 

What I would like to know:

·        Are any service manuals for this phone available? If so what are the part numbers and where can they be obtained?

·        Are any service manuals for the Iridium pager available? If so what are the part numbers and where can they be obtained?

·        Is there anything interesting that can be accomplished by having an Iridium phone or pager without a subscription? Eg receive status reports from visible satellites etc?

 

Any feedback on my assumptions etc would be much appreciated. Please e-mail

 

mailto:radioencryption@hotmail.com