TROUBLESHOOTING AND REPAIR
A10 Premodulator PCA 6-12.
Adjustments: R51 and C7, AM Bandwidth adjust. See paragraph 6D-20.
A11 Modulation Control PCA 6-13.
Adjustments:
• R28, detector offset/linearity. See paragraph 6D-13.
• R20, RF Level adjust. See paragraph 6D-15.
• R10, AM Depth adjust. See paragraph 6D-14.
A12 Sum Loop PCA 6-14.
Adjustments: R116. See paragraph 6C-36.
A13 Controller PCA 6-15.
Adjustments: None.
To preserve the instrument calibration/compensation data, transfer the battery
backed RAM IC U8 and the EEPROM U9 from the old Controller PCA to the
replacement controller. If either U8 or U9 are bad, review "CALIBRATION/
COMPENSATION MEMORY" (Section 6B) then replace the faulty IC.
A14 FM Board PCA 6-16.
Adjustments:
• R107, FM deviation high-rate. See paragraph 6E-18, item 12.
• R39, HIDEV volts/steering. See paragraph 6E-20, item 8.
• R35, LOWDEV volt/steering. See paragraph 6E-20, item 9.
• R116 on Sum Loop PCA. See paragraph 6C-36.
A15 Power Supply PCA 6-17.
Adjustments: None..
A19 Switch PCA 6-18.
Adjustments: None.
A20 Attenuator/RPP Assembly (A7, A21, A30) 6-19.
Adjustments: R20, RF Level. See paragraph 6D-16 (Mod Control PCA).
A compensation data EPROM containing Attenuator/RPP level correction data is
included. See paragraph 6-21 for data transfer instruction.
A22 Delay Line Assembly (A25, A26, Delay Cable, Trim Cable) 6-20.
Adjustments: None.
6-6
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