Periodic Maintenance; Troubleshooting Chart - QRO Technologies HF-2500DX Instruction Manual

feature after your Amplifier has been properly tuned.
Make sure the Amplifier has been disconnected for the AC power source and the high
voltage filter capacitors have bleed down to zero.
Remove the top cover from the Amplifier at least once a year and remove the dust. Dust
accumulation can help cause the variable capacitors to arc between plates. Use the blower
connection on a vacuum cleaner or a soft bristle brush. Also, remove the tubes from their sockets
and check to see if any tarnish buildup has developed on the tube socket contacts. If so, use a
Q Tip and Tarn-X solution, and clean each of the socket contacts.
The following charts lists specific difficulties that could occur in your Linear Amplifier. Several
possible causes may be listed for each difficulty. Refer to the Printed Circuit Board diagrams
(PCB) and the Schematic Diagrams to locate and identify the parts listed in this chart. If a
particular part is mentioned as a possible cause, check that part and other components
connected to it to see if they are defective. AS ALWAYS, BE SURE THE AMPLIFIER POWER
CORD HAS BEEN REMOVED FROM THE AC LINE RECEPTACLE AND THE HIGH VOLTAGE
FILTER CAPACITORS HAVE BLED DOWN TO ZERO VOLTS BEFORE REMOVING THE TOP
COVER FOR YOUR INSPECTION.
DIFFICULTY
No AC power
Multimeter inoperative in High Voltage
Function

PERIODIC MAINTENANCE

TROUBLESHOOTING CHART

POSSIBLE CAUSE
1. Fuse F1 or F2 rear panel
2. Jumpers missing on Terminal Block TB1
3. Transformer T1
4. On/Off Switch SW2A or SW2B
5. Interlock Safety Switch SW1
6. Solid State Relays SR! or SR2 or related
circuitry
1. Resistors R210, R211, R212, R213 High
2. Multimeter Switch SW501A or SW01B Meter
3. M-1 Multimeter
4. Transformer T-1 Secondary
5. Component failure on HV Diode or HV
Voltage Diode PCB
Switch PCB
Capacitor PCB
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