YTO Leveling Loop (334)

 

This error often requires troubleshooting the Al4 Frequency Control

 

assembly or A7 LODA (Synthesizer Section) or the ADC circuits.

334 LO AMPL

1ST LO Distribution Amplifier is unleveled. This error is usually

 

accompanied by error codes 300 or 301. ERR 301 YTO UNLK is

 

cleared once ERR 334 has been cleared. Check the output of the

 

All YTO with the jumper on A14J23 in the TEST position. The

 

YTO power output should be between +9 and +13 dBm. If the

 

YTO is working properly, refer to “A7 LODA Drive” in Chapter

 

10. The LODA AGC voltage is monitored by the ADC. ERR 334 is

 

set if LODA AGC is outside of its prescribed limits. Refer to “A7

 

LODA Drive” in Chapter 11. Error 334 may also be displayed if the

 

front-panel LO OUTPUT is not terminated into 50 ohms.

Sampling Oscillator (335)

This error indicates an unlocked Sampling oscillator (also known as the offset Lock Loop).

335 SMP UNLK Sampling oscillator PLL is unlocked. ERR 335 is set if OFL_ERR is outside its prescribed limits.

Automatic IF Errors (400 to 599)

These error codes are generated when the automatic IF adjustment routine detects a fault. This routine first adjusts amplitude parameters, then resolution bandwidths in this sequence: 300 kHz, 1 MHz, 100 kHz, 30 kHz, 10 kHz, 3 kHz, 1 kHz, 300 Hz, 100 Hz, 30 Hz, 10 Hz, and 2 MHz. The routine restarts from the beginning if a fault is detected. Parameters adjusted after the routine begins but before the fault is detected are correct; parameters adjusted later in the sequence are suspect. Refer to “Automatic IF Adjustment” in Chapter 8.

The IF Section relies on the ADC and video circuitry to perform its continuous IF adjustments. IF-related errors occur if the ADC, video circuitry, or A4 assembly linear path is faulty.

400

AMPL

100

Unable

to

adjust

amplitude

of

100

Hz Resolution Bandwidth.

401

AMPL

300

Unable

to

adjust

amplitude

of

300

Hz Resolution

Bandwidth.

402 AMPL 1K

Unable

to

adjust

amplitude of 1

kHz

Resolution

Bandwidth.

403

AMPL

3K

Unable to adjust amplitude of 3

kHz

Resolution

Bandwidth.

404

AMPL IOK

Unable

to

adjust

amplitude of 10 kHz Resolution

Bandwidth.

Errors 405 to 416:When these10K resolution bandwidth (RBW) error messages appear, use the following steps to check for errors 581 or 582.

1.Set the spectrum analyzer (LINE) switch OFF.

2.Set the spectrum analyzer m switch ON and observe the lower right-hand corner of the display for 10 seconds.

6-22 General Troubleshooting