Alignments
Cobra 148GTL (PC-412)
The PCB in this radio is almost identical to the Grant (PC-409) and the Madison (PC-411) and it can be used for comparisons
Alignment
| Reading Point | Adjustment | Description | Value |
|---|
| OSCILLATOR | | | |
| TP9 | L19 | VCO Coil | |
| TP1 | | AM | |
| TP1 | | USB | |
| TP1 | | LSB | |
| TP1 | L20 | AM | Maximum |
| TR20 Emitter | L21 | AM | Maximum |
| TP3 | CT2 | Carrier frequency | 7.800MHz |
| L48 | Carrier frequency | Maximum |
| L47 | TX Mixer frequency | Maximum |
| TP10 | | | |
| RECEIVER | | | |
| L4 L5 L6 | RF | |
| L7 L8 L9 L10 | 1st. IF | |
| L12 L13 L14 L15 | SSB IF | |
| L3 | AM IF | |
| L1 L2 | NB/ANL IF | |
| | | |
| Internal S-Meter | VR1 | AM | |
| Internal S-meter | VR2 | SSB | |
| TRANSMITTER | | | |
| TP8 | VR9 | Driver Bias | 10mA |
| TP7 | VR8 | Finale Bias | 100mA |
| L46 L45 L44 L38 | | |
| VR4 | Modulator Balance | |
| | | |
| | | |
| VR10 | AM Power | 15 Watt |
| VR11 | SSB Power | 20 watt |
| Internal Power Meter | VR6 | | |
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Cobra SERVICE PDF Files - CLICK to OPEN
cobra_140gtl_142gtl_148gtl_tb1226.pdf
cobra_148_gtl_sm_pg01_pg15.pdf
cobra_148_gtl_sm_pg16_pg30.pdf
cobra_148_gtl_sm_pg31_pg47.pdf
cobra_148_gtl_sm_pg48_pg63.pdf
cobra_148gtl_om.pdf
cobra_148gtl_sch_a_size.pdf
cobra_148gtl_sch_b_size.pdf
cobra_148gtl_sch_redraw.pdf
cobra_148gtl_sch_redraw.pdf
TDA6131-Replacement-Schem.pdfTHE COBRA 148GTL-B 02A PLL CYBERNET PCB.
