AMERITRON AL-80A Manuel d'instruction - Page 2

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VEI.iTILATION

-l-he

AL-804 ventilation system has been designed and tested

to maintain tube seal temperatures safeiy below the tube

m a n u f a c t u r e r ' s

r a t i n g w h e n o p e r a t e d w i t h i n o u r g u i d e l i n e s .

To insure proper ventilation in your installation, observe the

following:

1. Do not block or restrict the ventilation holes in the

cover.

2. The exhaust air llow is over 50 CFM. Do not "assist" the

air flow unless the fan used exceeds the AL-B0A blower

C F M b y a f a c t o r o l 2 : 1 .

3. Do not mount additional fans on the AL-BOA cabinet.

4. The exhaust air will become quite warm at high

power levels. Do not place any heat sensitive objects

in the exhaust air stream.

P O W E R C C N N E C T I O N S

The AL-BOA is supptied with a NEMA 5-i 5p ptug for 1 17 VAC

operation. The AL-80A can be modified tor 234 VAC opera-

tion. lf you desire to make this modification, two jumper wires

must be moved to new locations on the terminal block. (see

rllustration below) The terminal block is located on the left

s t d e o f t h e r e a r p a n e l .

The rviring between the fuse box and the amplifier A.C. outlet

m u s t b e N o . 1 2 g a u g e o r l a r g e r i n o r d e r t o s u p p l y t h e c u r -

r e n t r e q u i r e d ( 1 5 a m p e r e s ) w i t h o u t a s i g n i f i c a n t d r o p i n l i n e

v o l t a g e . T h e 1 1 7 V o u t l e t s h o u l d b e f u s e d f o r 2 0 a m p e r e s .

A L C

Use a shielded audio-type cable to connect the 0-20 volt

n e g a t i v e A L C v o l t a g e t o t h e t r a n s m i t t e r A L C i n p u t . C o n s u l t

t h e t r a n s m i t t e r m a n u a l f o r p r o p e r c o n n e c t i o n d e t a i l s . T h e

amplifier must be properly tuned on CW before adjusting the

Proper adjustment is achreved as follows:

1 . S e t t h e M U L T I M E T E R s w i t c h t o t h e P O p o s i t i o n .

2. Set the transmitter audio control about 200/o hiqher

than normal.

3. Speak into the microphone in a normal tone ol

voice and observe the reading on the 0-2000 R.F.

Watts scale.

4. Adjust the ALC ADJ control on the rear panel until the

amplifier is not clipping on an RF scope.

5. lf an RF scope is not available, adlust the ALC control so

the audio peaks do not exceed the single tone output of

1000 watts.

M E T E R I N G F U N C T I O N S

The AL-BOA has two illuminated panel meters. The Grrd Cur_

rent meter provides a continous reading of grid current. This

is an exclusive feature of Ameritron amplifiers. Grid current

will indicate proper operation of the amplifier better than any

other parameter. Do not exceed 200 mA on this meter dur_

Ing operation of the amplifier. The other meter reads plate

Voltage (HV), Plate Current (lp), peak R.F. Watts (pO) and

ALC. The functions are explained as foJlows:

PLATE VOLTAGE (HV): Read D C. ptare Vottage on rhe

0-3500 Volt scale. This scale is 100 volts per division. lrlor-

m a l v o l t a g e s a r e 3 1 0 0 v o l t s n o l o a d , 2 7 0 0 v c i l s f u l l l o a d .

PLATE CURRENT (lp): Read ptate Current on the 0-700 mA

scale. This scale is 20 mA per division. The average

operating current rating of the 3-5002 is 400 mA maximum.

PEAK R.F. WATTS (PO): Read peak R.F, Wats on the

0-2000 scale. The scale has 50 watt divisions below i0O0

watts and 100 watt divisions above 1000 watts.

ALC: In this position the meter indicates the ALC detector

voltage. lt provides a relative drive level indication of 200

watts full scale. The approximate drive level (average, not

PEP) can be estimated by dividing the peak R.F. Watts scale

b y 1 0 .

2 3 4 V O L T O P E R A T I O N

I M P O R T A N T

D o n o t m a k e a n y m o d i f i c a t i o n s t o t h e A L - B 0 A c i r -

c u i t b e f o r e c h e c k i n g w i t h o u r e n g i n e e r i n g s t a f f .

lmproper changes may damage the AL-B0A and void

t h e w a r r a n t y .

I I 7 V O L T O P E R A T I O N