AMERITRON Al-800H Instruction Manual Download Page 15

AL-800H Instruction Manual

 

11 

 

Installation Guidelines and Suggestions

 

Location Of  The Amplifier 

Do not install the amplifier in excessively warm locations or near heating vents or radiators.  Be sure air can 
circulate freely around and through the amplifier cabinet.  Provide an unobstructed cold air inlet for the 
amplifier.  

DO

 

NOT

 place any books, magazines or equipment that will impede the free flow of air near or 

on the cabinet ventilation holes. 
 

Ventilation 

The AL-800H ventilation system has been designed and tested to maintain tube seal temperatures safely 
below the tube manufacturer's rating at 1200 watts of continuous two tone test SSB PEP output, or 1500 
watts of continuous two-tone or CW power output when the amplifier is properly tuned. The blower in the 
AL-800H is a permanently lubricated type that requires no maintenance in normal operation.  To insure 
adequate cooling in your installation, please observe the following: 
 

1.

    Do not block or unduly restrict the ventilation holes in the cover.  Be sure that the amplifier is located 

in an area so the ventilation holes have open air circulation.  It is particularly important to avoid 
restricting the air inlet. 

 

2.

    The exhaust airflow is over 30 CFM.  Do not "assist" the exhaust airflow with cabinet mounted fans. 

 

3.

    The most efficient way to improve airflow is to pressurize the air 

inlet

 area.  Be sure that any fan used 

to assist the inlet airflow has 

at least

 a 60 CFM rating. 

 

4.

    The exhaust air will become quite warm at high power levels.  Do not place any heat sensitive objects 

in the exhaust air stream. 

 

Power Connections 

The AL-800H is supplied with a NEMA 6-15P plug for 240 Vac operation.  Full duty cycle operation with 
ac supply voltages below 200 volts is not recommended.  The 

 

TRANSFORMER CONNECTIONS section 

on page 13 show the correct wiring for various supply voltages. 
 
This amplifier has a current demand of approximately 14 amperes at 240 Vac with 1500 watts of RF carrier 
output.  The average power line current during voice peaks on SSB will be approximately 9 amperes at 
1500 watts PEP output.  Most normal residential power lines and house-wiring should meet this demand for 
current. 
 
If the power mains have excessive resistance, the high voltage may sag to less than 2200 volts under load.  
Voltage sag will not hurt the amplifier if the fully loaded high voltage remains above 2000 volts.  
 

CAUTION:  

Never allow the high voltage to exceed 2700 volts under any condition. 

 
For 240 volt operation, the wiring between the fuse box and the amplifier ac outlet must be number 14 
gauge (or larger) in order to supply the current required (14 A) without a significant drop in the line voltage.  
The 240 volt outlet should be fused 20 amperes. 

Summary of Contents for Al-800H

Page 1: ...H THE VOLTAGES INSIDE THIS AMPLIFIER CAN BE FATAL PLEASE READ THIS MANUAL BEFORE ATTEMPING TO OPERATE EQUIPMENT Improper or abusive operation of this amplifier can damage the tubes or other components...

Page 2: ...s Install the rubber chimneys over the tubes The seam of the chimneys must face the fiber panel The bottom of the chimney has notches that must fit over the grid connectors near the base of the tube R...

Page 3: ...Envelope Power vs Average Power 8 Tube Life 8 Export Modifications 9 Technical Assistance 10 Installation Guidelines and Suggestions 11 Location Of The Amplifier 11 Ventilation 11 Power Connections 11...

Page 4: ...Operation 23 Periodic Maintenance 24 Parts List 25 Power Supply SWR Board 50 0800H 1 25 Tuned Input Board 50 0800H 2 26 AL 800H Tuned Input Chart 26 Meter Board 50 0800H 3 26 Timer Overload Board 50...

Page 5: ...ves for smooth tuning Logging scales allow quick and repeatable control adjustment for rapid band changes The AL 800H has two illuminated cross needle panel meters the left meter provides a continuous...

Page 6: ...oltage 2250 V Full load current 1 2 A Regulation 15 Transformer 32 lb E I lamination grain oriented Capacitors 63 mFd total computer grade Normal line current at rated CW output 14A at 240 Vac Normal...

Page 7: ...the primary circuit of the power transformer The interlock will open and de energize the transformer primary if the top cover is removed WARNING High voltage can kill Accidental contact with the volta...

Page 8: ...ith large signal levels The AL 800H contains an exclusive bias circuit that reduces the idling quiescent current very close to the tube s cut off region The power amplifier tube in the AL 800H has a f...

Page 9: ...will latch on and remove the voltage from terminal 3 and relay RLY101 power supply board Thermal Overload The transformer in this amplifier contains an internal temperature sensor This sensor disables...

Page 10: ...F101 during start up If F101 or the 10 ohm resistor R27 fails the amplifier will not start If F101 fails from a momentary HV to ground fault meter protection diode D117 may also fail See the METERS se...

Page 11: ...is marked every 10 watts below 100 watts and every 100 watts from 100 to 500 watts NOTE The SWR of the load can be measured when the MULTIMETER switch is in the REF position by observing the different...

Page 12: ...rid A fraction of a second of incorrect tuning can cause control grid damage This is especially true in amplifiers that use fuses or resistors to protect the grids Fuses and resistors are much too slo...

Page 13: ...y manifest itself as a loud pop when the amplifier is first turned on or during conditions of high anode voltage A gas arc will often damage diode D117 on the negative rail of the filter capacitor ban...

Page 14: ...For service or written correspondence use the following address AMERITRON 116 Willow Rd Starkville MS 39759 Telephone 662 323 8211 FAX 662 323 6551 NOTE Service history has clearly shown that most pr...

Page 15: ...th cabinet mounted fans 3 The most efficient way to improve airflow is to pressurize the air inlet area Be sure that any fan used to assist the inlet airflow has at least a 60 CFM rating 4 The exhaust...

Page 16: ...sing braided or woven conductors they have very high resistance to both RF and lightning currents RF and lightning flows along the surface of conductors almost no current flows in the center of the co...

Page 17: ...240 C B 1 2 15 245 C B 2 3 15 250 C B 1 3 15 90 B A D C 3 1 20 100 B A D C 3 2 20 110 B A D C 2 1 20 115 B A D C F E 20 125 B A D C 1 2 20 130 B A D C 2 3 20 140 B A D C 1 3 20 Factory wired WARNING T...

Page 18: ...ments vary with different manufacturers The ALC section describes adjustment of this circuit in detail Operating Instructions And Guidelines Front Panel Controls MULTIMETER Switch This four position s...

Page 19: ...oading control properly can result in excessive tank circuit voltages and damage to components The PLATE control should always be checked after the LOAD control is adjusted by more than one number For...

Page 20: ...especially if the heavy ALC levels are used in conjunction with other speech processing In these situations operating in a quiet room and close talking the microphone will minimize objectionable backg...

Page 21: ...wly advancing this control clockwise The ALC LIMIT ADJUSTMENT section that follows gives adjustment details An external 1 000 to 5 000 ohm potentiometer can be added from the ALC output line to ground...

Page 22: ...while the plate current and output power increase slowly The amplifier LOAD control needs to be advanced to a higher number if this condition occurs Non linear operation splatter and excessive grid c...

Page 23: ...nerate high level RF pulses when first keyed These short duration pulses may greatly exceed the exciter s steady state operating output power Unexplained activation of the grid overload circuit may in...

Page 24: ...ht and the plate current Ip on the left meter should be close to zero 0 8 With the exciter in the transmit mode apply a very low amount of RF drive power about 100 mW The plate current Ip should sudde...

Page 25: ...be allowed to go above 100 mA at this stage The plate current should not be allowed to exceed 1 5 ampere during brief periods of tuning 30 seconds 11b Increase the exciter drive power if the ALC is n...

Page 26: ...e flat topping and splatter with only a few hundred watts of RF output NOTE Always remember that the LOAD control setting is much more important than any other parameter for good linearity To maintain...

Page 27: ...eration Commonly available vacuum relays are specified at 5 to 7 milliseconds of switching time Even expensive vacuum relays are less than ideal for high speed QSK operation At 60 WPM less than 50 of...

Page 28: ...plifier 6 ALWAYS be cautious of heat Many components inside the amplifier operate at high temperatures 7 NEVER make any unauthorized component or circuit modifications to this product The only accepta...

Page 29: ...22 C133 2200 uF 25 V 203 0207 C134 220 uF 25 V 203 0565 R101 4 7k mox 1 W 103 1747 R102 470k 1 4 W 100 0188 R103 104 121 10k 1 4 W 100 4100 R105 10 ohm 1 2 W 100 0727 R106 3 ohm 2 W 1 103 3400 R107 13...

Page 30: ...5440 5 75 405 1057 270 208 5775 15 17 220 208 5175 3 75 405 1037 150 208 5175 10 12 220 208 5175 4 75 405 1047 180 208 5396 Ameritron part numbers parenthesized Meter Board 50 0800 3 Designator Descr...

Page 31: ...l op amp 311 0724 Q501 NPN transistor MJF3055 305 3055 Q502 504 PNP transistor 2N3906 307 0722 Q503 505 NPN transistor 2N3904 305 0645 R501 503 10k 1 2 W 101 0643 R504 505 3 3k 1 4 W 100 0729 R506 508...

Page 32: ...oard Assembly 50 0800 3 50 0080 4 RF Tank Board Assembly 50 0800 4 50 0117 2 Timer Overload Board Assembly 50 0117 2 L1 L Coil 10 13800 LC L2 LF Coil 10 13800 LF L3 HF Coil 10 13108 M1 Meter current g...

Page 33: ...z 20 meters 10 1 15 5 MHz 15 meters 16 5 21 5 MHz 15 meters 16 5 21 5 MHz 10 meters 24 29 MHz Operation on 11 13 MHz 15 5 16 5 MHz and 25 27 9 MHz will damage components Amplifier Tuning Log Band LOAD...

Page 34: ...AL 800H Instruction Manual 30 Notes...

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