Cobra 200 GTL DX Radio Service Manuals for access to repair and align the Cobra 200 GTL DX Mobile Radio.

Have my brothers Cobra 200 GTL DX in for repairs and it has a some strange issues in transmit power cutting out on both  HIGH/LOW setting.

The problem is NOT the Finals (2SC’s) as momentary full power is displayed on the B&K TX Test rig on 100W scale.

Adhering to the Service Manuals as included as downloadable .pdf files below.

Section 2.1 is alignment of the PLL. 

This diagram shows TP 1 & TP 2 on the TOP Printed Circuit Board (PCB) on LHS Front,

BUT these Test Points are sealed in a Metal Can soldered all round to the PCB earth.

SO the best way to access them is from removing the Bottom Cover and find these noted solder pads plated through from the Top PCB. Question Marks are before I confirmed that these ARE the correct TP1 & TP2 locations. There is a metal Can also screwed to the side frame that I initially removed to ensure I located them correctly but you dont need to remove the can as the Points are just outside the bottom edge and accessible. Rest the radio on the RHS Edge with both covers removed and the Points are then easy located at the top with your Left handed Probe and the tune-able slugs can be aligned with your Right Hand.

Done and confirmed STEP 1& 2, STEP 3, the Frequency checked at 17.3058MHz.

BUT it is difficult to get past Section 2.2

2.2 Alignment of the Carrier

3 Toko Inductor Coil IFT slugs..

Located on Diagram below at center near front of pcb in radioshown as Boxes – 1 Red 2 & 3 Green

1. STEP 1=AM /T716 to 10.6950
2. STEP 2=LSB /T714 to 10.6975
3. STEP 3=USB /T715 to 10.6925

Closest possible with slug near all way out AND near jammed at bottom is 10.3/4/5 (approximate)

SO, what are the possible causes of this situation where very close alignment is NOT possible?

My first thought, permeability of the slugs is wrong or faded? ??  CAN YOU THINK OF ANY OTHER REASON?

DO YOU HAVE A COBRA 200GTL DX WITH A SIMILAR PROBLEM AND CAN HELP

– PLEASE POST on CQDX11dotcom FB Group link below..

2024/JUNE/ This is an ongoing project that requires more thought and input from people on our FaceBook Group

https://www.facebook.com/groups/CQDX11dotcom/

To download the below .pdf Document Files

HOVER OVER & RIGHT CLICK Mouse and scroll down to 

“Save Linked Content as”  AND CLICK!

A new SAVE AS BOX will open with the .pdf File name in the box at the bottom Left.

CLICK the “SAVE” Button on the Right Hand Side Bottom to save to your selected location on your computer.

200gtl_dx 

Service_Manual_Cobra_200GTL_DX_ENG

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