Superstar SS3900 (By CRT & Dirland)

Superstar SS3900 EFT (1st with Channel Frequency)
Black Version, Dirland SS3900 (Last one, Black)

CiBi
Frequency Range: 26.965 - 27.405 MHz
Channels: 40
Modes: AM/FM/LSB/USB/CW
with NO Frequency Steps
4 Watts

Export
Frequency Range: 25.615 - 28.305 Mhz
Channels: 240
Modes: AM/FM/LSB/USB/CW
with 10Khz Frequency Steps
10 Watts (and 20 Watts for USB)

TS

More infos, http://www.cbradio.nl/superstar/superstar_3900.htm

Improved receive gain

Quieting of AM reception and improving gain of incoming signals is a common request from radio operators. In the first stages of the HF input 2SC1674 transistor can be found. This transistor is responsible for the amplification of a small detected signals. A problems exist if the transistor itself is noisy as is such the case of the 2SC1674 when compared to other low noise packages. Along with the amplification of the incoming signals is transistor noise. Replacement of this transistor with a higher gain, lower noise transistor greatly improves the signal to noise ratio of your receiver.
We will use an 2SC2999 transistor that has higher gain lower noise characteristic. Replace the 2SC1674 (TR17) with an 2SC2999 (or similar low noise and high gain transistor) to achieve this improved signal to noise ratio.
Re-Adjust L6 and L7
The gain will improved with more than 6dB with the same signal to noise ratio.





PLL Circuit. 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.

Off-Set frequency oscillator IC10. The off-set-frequency oscillator IC10 oscillates at 14.460MHz 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.

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 channel 1 in band A (26.065MHz), the 1st RX mixer TR18 accepts 15.370 localsignal 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.

http://malzev.tripod.com/cb-funk/ept3600.htm

PLL and CPU PCB
In some model`s the PLL-circuit on Main PCB is replaced by a separate CPU and PLL board.

Decoder Board
In some model`s the decoders (MC14008) on Main PCB is replaced by a separate EPT004410Z board.

http://malzev.tripod.com/cb-funk/ept3600.htm

SuperStar 3900 finale output



http://malzev.tripod.com/cb-funk/power.htm