User's Manual

ALPHA 9500 Interim OPERATING MANUAL

www.alpharadioproducts.com

One of four situations will typically result in a fault:

• Incorrect gain. Output too low or too high for the input power supplied.

• High reﬂected power (SWR).

• Incorrect plate voltage (too high).

• RF arc in output circuit including antenna.

If the 9500 encounters unsafe operating conditions, it enters a protective “Fault” mode. When this

happens, the tube is biased off and the relays are placed in the bypass mode, so that RF from the

radio goes directly to the antenna. The FLT (Fault) switch below the seven segment display will be

lit and the fault number will be displayed.

1 Gain below 10 dB

2 Mains board unable to ﬁnd a valid tap in auto mode

3 “Soft” plate current trip (Ip>1.6A)

4 “Hard” plate current trip (Ip>2.5A)

5 Plate voltage did not come up to spec in 2 seconds

6 Output relay did not close in speciﬁed time

7 Output relay closed with no relay drive

8 Bandswitch failed to reach target setting

9 Tune cap could not locate zero

10 Load cap could not locate zero

11 Temperature fault

12 Reﬂected power trip

13 Temperature Fault Cleared

14 Plate voltage too high

15 Grid current trip

16 Auto-tune failed to resolve

If the tube current exceeds about 2.5 amps, the ampliﬁer is switched to the ON1 condition. At this

point the amp should be turned off and the power disonnected for at least 20 seconds before

attempting to put the ampliﬁer back on line. If the ampliﬁer trips again immediately, investigate

and cure the problem before attempting to turn the ampliﬁer on again.

Repeatedly hitting the ON switch when the ampliﬁer trips out is likely to result in severe damage

to components in the ampliﬁer.

If a hard fault trips the ampliﬁer all the way OFF, wait at least 20 seconds before turning the

ampliﬁer power on again.