Tait Limited TEL0024 用户手册

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Refer to the synthesiser circuit diagram (sheet 7) in Section 6 and the VCO circuit dia-
gram in Part E.

N

   A 

   B

Check biasing

resistors, Q4 & Q5.

N

Y

N

8.3V present

at VCO?

DC V present

at Q4 & Q5?

9V present at
VCO Q4/Q5?

No VCO RF output.

Y

DC V present at

VCO, Q1, Q2 & Q3?

Check biasing

resistors, Q1,

Q2 & Q3.

Y

N

Capacitors OK?

Check for cracks,

shorts, etc.

N

Y

Replace VCO.

Replace

if faulty.

Y

N

Y

N

N

N

Y

Y

DC V present

on Q795 emitter?

Check 9V supply.

9V present on

Q795 divider buffer?

20V inverter

supply faulty.

20V present

on IC750 pin 8?

Check 5V reg. &

supply resistor

to each IC.

+5V present at

IC700, IC710,

IC740, IC720

& IC730?

VCO out of lock.

Y

Y

Y

Continued on the next page

Y

VCO freq. correct?

Synthesiser OK.

VCO trimmer

freq. range OK?

Check VCO tuning

caps & trimmer.

VCO OK.

N

N

N

N

N

Y

Y

Recheck

programming

via PGM800Win.

Check Q5 C

multiplier

(synth).

Check biasing

resistors & Q795.

Check Tx reg.,

Q610 & 9V reg.

Does VCO trimmer

adjust for stable

control line

between 3 & 16V?

Does VCO trimmer

adjust for required

frequency range

between 3 & 16V?

Check #C1, #C7, #C8,

C6 & D1-D2 in VCO.

Is 8MHz VCO range

achieved between

3 & 16V?