The Defpom Superstar 3900 Alignment Page

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SuperStar 3900
Alan 87 Alan 8001 Cobra 148GTL-DX Eagle 2000 Galaxy DX99V Mirage 88 Sommerkamp TS-790DX SuperStar 390FM (New)
I make a special EPROM expansion board that will add 4 more bands to many radios that use either Binary or BCD programming, it also adds a 10KHz shift function as well, click here to find out more. It will give 1 band down, 1 band up, UK 40 (up 64 channels without Alpha ch hops), NZ 40 (down 63 channels) and 10KHZ shift. On a 40 channel radio it will give coverage from 26.335 to 28.005 (including the normal low,mid and high bands of 26.515-27.855), that is a total of 167 channels ! I can also make a custom board upon request which will give whatever frequency range you want (within the limits of the radio).

Circuit Theory

PLL Circuitry. PLL is an abbreviation of the phase-locked loop which is fundamentary composed of a closed loop feedback citcuit. The feedback component is the balance of frequency drift and the PLL circuit acts to cancel it out. To detect out the frcquency drift of the PLL output, a fixed reference ocillator (10 kHz, 1/1024 divided down from 10.240 MHz) is compared constantly with the input frequency (10 kHz). The input frequency is obtained by dividing the VCO frequency. A functionalI block diagram is provided below under "PLL Circuit" for the easier understanding. Off-Set frequency oscillator IC10. The off-set-frequency oscillator IC10 oscillates at 14.460 MHz for all band. Switching between these oscillating frequencies is made by biasing the diodes D34 to D36. The off-set frequency signal is obtained at IC10 Oscillator and flows into IC10 Mixer where it is beat with the VCO signal. The VCO signal is obtained from the following: f vco = foff-set + Nfr Where, f vco = VCO frequency, N = programming code for divider output, and fr = referency frequency step (10kHz). i.e.: At channel #1 in band A, and band corresponding N code is 91: f vco = 14.010 + 91 x 0.01 = 14.920MHz.
http://www.radiomods.co.nz/superstar3900align.html

2008-05-08

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Since the mixer output determined by two factors the off-set frequency output (dependent on band selector switch) and the VCO output, the mixer output contains the subtracted frequency of 0.91 to 2.25 MHz. These frequencies appears in pin #2 of IC5, and divided by the programmable divider in IC5 down to 10 kHz which is compared with another 10kHz signal obtained from the reference oscillator TR24 (10.240MHz). The VCO output is mixed with the off-set frequency signal and applied to the TX mixer IC9 through band-pass filters. i.e. At channel 1 in band A, and AM band, the TX mixer IC9 accepts 14.920 + 10.695MHz = 25.615MHz is TX frequency. When receiving channe 1 in band A (26.065MHz), the 1st RX mixer TR18 accepts 15.370 local ignal at its base, and converts down it down to 10.695MHz IF (for AM/FM mode, this is the 1st intermediate frequency). TR18 off-sets the 10.695MHz signal so that TR30 can oscillate at 10.6975MHz for LSB.

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Adjustment

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Test equipment required: Power Supply: 13,8 V
Frequency Counter DC Amperemeter

Dummy Load 50 ohm RF SSG

Oscilloscope AF SSG
Preparation alignment: Clarifier SQ GAIN AF GAIN RF GAIN MIC GAIN MOD, S/RF NB/ANL Band Channel Reading Point PLL Condition
Mid. Max. Max. Max. Max. S/RF Off D 19 Adjustment Procedure

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IC5 Pin 3 TP2 TP3 OSCILLATOR IC10 Pin 9 IC10 Pin 9 IC10 Pin 9 IC10 Pin 9 TP5 TP6 TP6 TP5 RECEIVER
Band:D, Ch.:40 AM USB LSB TX AM TX AM RX USB RX LSB TX USB RX AM RX AM RX AM RX FM
Check L17 L18 L19 L20 L21 VR21 L26 L27 L28 VR7 L6 L7 L8 L10 L11 L12 L3 L4 L5 L1 L2 VR3 VR4 VR1 VR2 VR11 VR10 VR20 L42 L43 L44 L40 L42 L33 VR13 VR12 VR14 VR5 VR16
10.2400MHz 5,0 Volt Maximum on Oscilloscope 16.9400MHz 16.9425MHz 16.9375MHz 16.9400MHz (TX-Frequency) 10.6950MHz 10.6925MHz 10.6975MHz SSB Modulator Balance RF Input AM/FM/SSB IF AM/FM IF Discriminator Coil (FM Demodulator) Noise Blanker IF SSB Squelch AM/FM Squelch

RX USB

RX USB RX AM AM/FM S- Meter RX AM SSB S- Meter RX SSB TRANSMITTER TP9 (+) TP8 (-) Bias Driver TP9 (+) TP7 (-) Bias Finale TP9 (+) TP7 (-) Bias Finale TX AM TX AM TX AM TX AM TX AM TX AM TX USB TX AM TX FM TX CW
10mA 100mA 100mA Maximum Mixer Coil (VCO-frequency input) Mixer Coil (TX-carrier 10.695MHz input) Maximum RF output Minimum Harmonic 15 Watt (30 Watt with Dual Finale output) AM/FM 20 Watt (40 Watt with Dual Finale output) SSB (ALC) 90% AM-Modulation (AMC) 2 kHz FM-Deviation CW Tone (Not in all model`s)

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Power Meter

Microphone Connection

Pin Ground Microphone TX Key (Connect to Ground) Speaker (Connect to Ground) Description
This counter shows the number of hits since the 7th November 1999
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