Cobra Electronics (Chicago USA) manufactured the COBRA 200GTL-DX in the Philippines from Summer 2003 until Winter 2007 and was the first Cobra multimode transceiver utilising "NightWatch" technology.
The Cobra 200GTL-DX was incidentilaly, the first multimode transceiver Cobra Electronics had produced since the 148 in the early 1980's. (see Cobra 148GTL-DX) Expectations were extremely high for Cobra's latest transceiver and early pictures of the 200GTL-DX looked, .....simply stunning.....
NightWatch Electroluminescent Technology, (above and below picture) enables the Face Plate to illuminate, especially useful for night-time or low light-level use.
The first 200's Cobra produced had NightWatch Face Plates and High Voltage units, that could "light a room" due to the brightness of their Electroluminescent Panel & Face Plates. Later revisions of 200 the Face Plate brightness was toned down.
Shown below is a as supplied brand new COBRA 200GTL-DX Summer 2003 Revision 1 (REV1) (PFM-0090A-BA Chassis) (see the Cobra "mail-in" rebate card..)
Cobra 200 GTL-DX
During production from 2003-2007, Cobra Electronics produced Three (3) Revisions and Six (6) different Chassis of the 200 GTL-DX.
On this webpage, Cobraworxshopz show how to recognise the different revisions of Cobra 200GTL-DX and share specifics.
CHASSIS NUMBERS #'s
With the Top Case of the 200 removed, look on the left-hand side of the main Printed Circuit Board (position arrowed) for the PCB CHASSIS REVISION number.
Shown below is a Revision 1 PCB number # (PFM-0090A-BA) SUMMER 2003.
Shown below is a Revision 1 PCB number # (PFM-0090A-BB)
Shown below is a Revision 2 PCB number # (PFM-0090A-BD)
Shown below is a Revision 2 (Late) PCB number # (PFM-0090A-BE)
Shown below is a Revision 3 (NEW) PCB number # (PFM-0090A-BF)
The Six (6) Cobra 200 GTL-DX Chassis start at 0090A-BA through to 0090A-BF (-BA.B.C.D.E.F)
COBRA 200GTL-DX CHASSIS
Visual differences of the Chassis are shown below between the 200's REV1 and REV2 / REV3.
The REV1 PCB shown below with Transistor legs "Through-PCB" (centre of picture) rectangle-hole in PCB.
The REV2 PCB below, with the Transistor legs soldered in the normal hole-through way, (no hole cut in PCB) AKA-REV1.
Next difference, the output stage...
Devices for early REV1 (HF50-12F devices x 2)
note: Some late REV1's (0090A-BB) also used 2SC2290...!!
Devices for REV2 & REV3 (2SC2290 devices x 2)
Shown below is the REV2 & REV3 output stage with the Toshiba 2SC2290 x 2 devices
Another visible difference between REV1 and REV2 / REV3 is the TX/RX switching relay.
REV1 uses HAN KUK HR90 Shown below.
The REV2 & REV3 later chassis PFM-0090A-BE/BF uses a SANYOU DSY2Y
TX/RX Switching relay, below.
The Cobra 200 GTL-DX REV2 & REV3 was shipped with Factory switchable Talkback, using the Echo On/Off control. The below picture shows the speaker side bottom cover removed. The NightWatch High-Voltage unit (metal box) with multiple wires can be seen, attached to the side of the 200 (bottom of picture).
Inside the "Metal Box" (seen above) is the Electroluninescent High-Voltage circuit / PCB.
A Top-down view of the High Voltage Unit below.
Another view of the NightWatch High Voltage circuit below, Check out the 105 degree Centigrade Electrolitic Capacitors and HV823 4-pin dil "driver" integrated circuit. The 5-Volt Regulator transistor and HUGE "Tesla-Style" coil can be viewed at the top and middle of picture.
Shown below is the Cobra 200 GTL-DX Channel Selector Control Unlike the Cobra 148 GTL-DX Channel Selector the 200's Selector is a "Digital Encoder". The unit is physically about a third the size of the 148's and is PCB mounted. A three wire connector located on the PCB transfers encoder signals to the main Chassis of the 200 then on to the CPU. The wires are different colours depending on revision of the Chassis.
An exploded view of the Cobra 200 GTL-DX Channel Selector's internal components is shown below. Notice the PCB and three pin connectors attached. The Channel Selector can be un-plugged and removed as a complete part.
The Volume / Squelch / Power On/Off, Microphone Gain / RF Gain, Clarifier Fine / Coarse and Echo On/Off / Volume & SWR Calibrate Controls are shown below. The controls are all soldered to a PCB in a similar fashion to the Channel Selector. The PCB also has x3 mulit-wire connectors soldered and various Surface Mount components. See below.
Inside of the Cobra 200's Standard supplied Microphone is shown below
The Cobra 200GTL-DX's Face Plate was supplied as a spare part in two seperate pieces. The "NightWatch" Electroluminescent Panel (the part that Glows) and the Face Plate Sticker.
Face Plate sticker shown below.
Face Plate and "NightWatch" Electroluminescent Panel shown below in original manufacturer packaging
The Cobra 200 GTL-DX "NightWatch" Electroluminescent Panel electrical connection, two-pin "ribbon-wire" can be seen protruding into the S/RF Meter cut-out on the Face Plate. (above and below pics)
The Cobra 200 GTL-DX Chrome Bezel, Face Plate and "NightWatch" Electoluminescent Panel (backed with SEKISUI #5760 thermal adhesive tape) are shown below. The process for application is first to peel off the backing from the "NightWatch" Electroluminescent Panel and attach it to the new Bezel, making sure the two-pin "ribbon-wire" is fed through the cut-out next to the S/RF Meter. Next remove the backing from the Face Plate and attach it over the top of the "NightWatch" Electroluminescent Panel.
The Chrome Bezel from the Cobra 200 GTL-DX is pictured below. Notice the small rectangular hole next to the location of the S/RF Meter, where the "NightWatch" Electroluminescent panel's "ribbon-wire" passes through for connectivity inside the transceiver.
The 3-Bar type, square shaped Signal / RF Power / SWR Meter from the Cobra 200 GTL-DX is pictured below. The meter has excellent response time and easy readability. Measuring to a maximum of +30dB of RF receive signal, in excess of 7:1:1 for SWR reading and can reflect 200 Watts !! of RF output power with ease.
Shown below are the underside and rear views of the 200 GTL-DX Chassis with the Heatsink removed. Notice the two 2SC2290 RF output transistors and RF driver RD16HHFC1 (right hand side)
Rear view with Heatsink removed below.
The Cobra 200 GTL-DX's Heatsink is without doubt the L A R G E S T installed any 10 meter Mobile radio ever Manufactured and very capable of dissipating the 100 Watts of RF output power produced.
MICROPROCESSOR CPU CONTROL
Low-Res picture seen below of the CPU "Main-Brain" of the Cobra 200 GTL-DX
The same SMD 80-pin CPU device is used in the Cobra 150 and 200 GTL-DX
Made in JAPAN (0515 HAL) the CPU device number is:
COBRA 200 GTL-DX MODIFICATIONS
1: Receiver audio distorted and Transmit audio warble modification
Does your 200 receiver overload when receiving a strong signal, resulting in distorted audio.??
Do you ever get reports of a warble on your modulation when transmitting.??
The latter due to RF bleeding into the front-end.
This mod cures both the Receiver audio distortion and Transmit warble.
2: Frequency Calibration
We correctly adjust the VCO to within Cobra Factory specification.
3: Adjacent Channel NB (Noise Blanker) modification
This superb mod reduces the adjacent channel rejection when the Noise Blanker is switched on, a must for all REV1's.
4: Echo Delay Speed modification
This modification effects the digital delay to “Speed-up” the echo effect (add reverb).
5: Talkback - Fixed and Variable level modifications available
This mod adds adjustable-volume talkback or fixed-volume talkback.
Talkback allows you to monitor your Transmit audio from the Speaker.
6: Low Audio modification (noise cancelling mics)
The 200 Modulation may be low with some noise canceling microphones.
This mod increases Transmit audio level.
If your Squelch chops in and out or sounds 'feathered' this mod will make the Squelch threashold more precise.
Cobraworxshopz.com Technicians offer the following modifications for
Cobra 200 GTL-DX REV2 & REV3 Transceivers
8: Expand the Clarifier range from 5Khz to 11Khz Swing
Developed for REV2 Transceivers this mod Expands the Clarifier range from 5Khz to 11Khz giving more 'Swing' to the Clarifier.
Cobraworxshopz.com Technicians offer the following mod for Cobra 200 GTL-DX REV1 and REV2 Transceivers
9: Unlock the Fine clarifier for RX ONLY!! - same as Cobra 148 GTL-DX
This mod unlocks the 'Fine' clarifier to make it RX receive ONLY, just like the 148 GTL-DX.
This mod transforms SSB operation on the 200 and keeps your Transmit frequency locked when you tune Stations in using the Fine control. The Coarse control changes Transmit and Receive frequency as standard.