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To read DC + Voltage

CAUTION

When making voltage checks in the unit, be ve is touched as 110V AC voltage is present also

ry careful where the probe .

1. The first test is to check the DC voltage pass transistor Q8. If any deficiencies are must be corrected before proceeding on.

s for the power supply and found in this area, they

2. The most important section in the keyer i Dash Divider, this will be checked as follows

s the Dot Generator and :

With the keyer shut off, connect a jump to ground. With the keyer set up in this man and dash divider can be checked at the same t paddles. Turn the keyer on. Connect the gro chassis of the keyer.

er wire from pin 8 of IC1D ner, both the dot generator ime without pushing the und lead of the VTVM to the

A. Set the VTVM to a 1.5VDC range and of IC2D. The meter should read about .16 an oscillating slightly. If these results are n C3, D1 and speed control.

touch the probe to pin 10

d the needle

should

be

ot obtained,

check

Q1,

Q2,

B. of IC4A.

Check

D3

Set the

VTVM read +5VDC range and

Reading should be

and

R12,

if

proper

.16VDC

with

results

are

nee not

touch meter probe to pin 5 dle oscillating slightly. obtained.

C. oscillate obtained,

Touch meter probe to pin 8 of IC4A.

rapidly between first check pin

1.5 and 2.5VDC.

2

of

IC4A.

Meter

If

n

Meter needle should proper results are not eedle should oscillate

between 3.6 to 4VDC at half the rate of pin 8. necessary.

Replace IC-4, if

D.

Touch meter probe to pin 13 of IC4B.

Meter needle should

oscillate between . proper results are Replace IC-4, if ne

5 and 3.5VDC at 1/2 the not obtained, check pins cessary.

rate of test

C above.

If

14 and 3 of

IC-4 for

5VDC.

E. Touch the oscillate from 1.6 pin 13 of IC3C for

meter probe to pin 12 o

to 3.4VDC.

If

5VDC.

Replace

proper re IC3C, if

f IC3C. Meter needle should sults are not obtained, check necessary.

3. Output circuitr generator and dashe for checking the ou

y: Since the jumper is s are being produced, we tput circuitry.

already installed in the bit 'll use this same approach

A. Touch the swing between .2VDC check resistor R24.

meter probe to the [C] and 2.8VDC. If proper Replace Q4.

of Q4. Meter needle should results are not obtained,

B. Touch the oscillate between . check R25. Replace

meter probe to the [C] 3VDC and .8VDC. If prop Q5.

of Q5. Meter needle should er results are not obtained,

C. Touch met needle should oscil obtained, check or

er probe to point [J] or late from .3VDC to .8VDC replace D4.

.

keyer output jack. Meter If proper results are not

D.

Repeat

th

e same procedure for Q6,

Q7 and D5.

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