Note | YTO unlock errors may occur if the power delivered to the A15A2 Sampler is | |
| less than | |
| external mixing modes if the output power is low or unlevelled. | |
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Caution | Connecting or disconnecting the A7 LODA’s bias with the HP 8560A IuNE] | |
| switch on will destroy the A7 LODA. Always set the HP 8560A (LINE switch | |
| off before removing or reinstalling W12 to either the A7 LODA or A14JlO. | |
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Note | Error 334 may be displayed if the LO OUTPUT connector on the front panel | |
| is not properly terminated into a 50R termination. | |
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1.Set the HP 8560A’s (LINE) switch to off. Disconnect W12 from A14JlO.
2.Connect a jumper between A14JlO pin 5 and A14J19 pin 6. Connect a jumper between A14J18 pin 13 and A14J18 pin 1.
3.Connect a DVM’s positive lead to A14J18 pin 14 and the negative lead to A14J18 pin 6.
4.Set the HP HP 8560A’s m switch to on.
5.The voltage measured on the DVM should be more negative than
6.Move the jumper from A14J18 pin 1 to A14J18 pin 2. The voltage measured on the DVM should be more positive than t12.3 Vdc.
7.If the voltages do not meet the limits listed in steps 4 and 5, troubleshoot the Al4 Frequency Control assembly.
8.Connect the positive DVM lead to A14JlO pin 1.
9.The measured voltage should be approximately +5 Vdc. If the voltage is not +5 Vdc, troubleshoot the Al4 Frequency Control Assembly.
10.Connect the DVM’s positive lead to A14J18 pin 1. The voltage should measure within 5% of the GATE BIAS voltage listed on A7 LODA’s label.
11.If this voltage is not within this range, rotate A14R628 GATE BIAS through its range while monitoring the DVM.
12.If the voltage varies between 0 Vdc and
13.Disconnect the jumper from A14J19 to A14JlO. Set the luNE] switch off. Reconnect W12 to A14JlO. Set the (LINE) switch on.
14.If the DVM reading changes significantly, the A7 LODA is probably defective.