Kücke KS T-22

Data

General

• Manufacturer: Kücke
• Model: T22
• Year of manufacture: 80s
• Made in: West Germany
• Color:
  • Front: chanpage (brown keys); gold, chrome, black (black keys).
  • Case: Brown for front: chanpage; Black for front: gold, chrome, black
• Remote control:
• Power consumption: 30VA
• Dimensions: 445 x 60 x 365 mm (WxHxD)
• Weight: 7.2 kg
• New price approx:

Connections

• Number of outputs
  • 1 x Stereo Chinch outputs
  • 1 x remote out
  • 1 x X, Y output for oscilloscope to analyse the RF signal with regard to multipath reception
• Number of inputs
  • 1 x antenna 75 Ohm
  • 1 x remote in

Technical data

• Reception: (VHF)
• Frequencies:
  • VHF: 87.5 to 108.0 MHz
• Frequency response: 20Hz to 15kHz (-3dB)
• Input sensitivity: 30uV stereo 46dB S/N
• Distortion factor: 0.08% in stereo (measuring method L=R, represents the best value, against L, R or L-R with 0.7%)

Signal-to-noise ratio: Mono 72 dB Stereo 65dB

• Channel separation: > 45 dB (1kHz)
• selectivity: (+/- 300kHz) > 80dB
• Common mode selection: < 1,5 dB
• Nebenwellenselektion:
• Spiegelfrequenzdämpfung: >100 dB
• IF attenuation: > 100 dB
• AM suppression: n.b.
• Output level: 775 mV
• RDS: no
• Station memory: 10

Special Features

• Quartz PLL frequency generation with 10 kHz tuning increment
• Microcontroller and PLL control shielded by its own housing

HF front-end (HF input module) Valvo FD12

• IF filters consist of series connection of:
  • 2 x SAF (surface acoustic filter)
  • 2 x 6-pole LC (resonant circuit) IF filters (manufacturer Toko) with constant group delay
• Quadrature demodulator
• Coilless stereo decoder in PLL switch technology TCA4500A
• Logarithmic field strength display
• Muting function to avoid inter-transmitter noise
• Ratio center weighting

Signal-to-noise ratio weighting

• Digital direct frequency input via input keys
• Manual tuning wheel with optical direction decoding (with flywheel mass)

Remarks

The KS T22 was produced by the Wuppertal company KS Electronic (Kücke & Co) and marketed in parallel by ASC under the name AS3100. From 1985 on ASC took over the production of the components and released a revised version AS 2T. Compared to the AS3100 (T22), the AS 2T has an improved separator shaft due to modified IF filter characteristics (LC TOYO IF filter).

• Compared to the ReVox B 760 poorer selectivity with strong local transmitters
• Increased pilot tone distortion

Possible error symptoms of the aging electronics:

• Defective components in the power supply, preferably short-circuited input charging capacitor.

--> leads to a defect of the corresponding bridge rectifier Cold solder joints in the area of the bridge rectifier due to the high thermal load (recommended: glue on a heat sink)

• Cracked electrolytic capacitors with capacity loss in the power supply, output capacitors voltage regulator
• Infrequent and short sound interruption, later with jumping or fluttering signal strength indication (input part power supply 15V;

 --> bridge rectifier shows brief breakdown of a diode, this leads to discharge of the charging capacitor
     via the DC resistor of the transformer winding and change of the PLL control voltage

• Bouncing jog keys
• When tuning manually by means of a rotary wheel, the display jumps temporarily by 10kHz in the opposite direction to the direction of rotation (up/down). (Re-tuning of the discrete direction encoder necessary)

No reception from transmitter only intermediate station noise, PLL did not look, tuning voltage FD12 faulty

 --> Error in input of PLL control loop

Crosstalk audible in stereo mode during speech peaks and sibilants, PLL frequency of stereo decoder out of alignment.

• Running out of memory battery
• Low holding time of stored station frequencies
• Deep-discharged battery after long standstill without operation of the device

 Attention: If the battery is exchanged or if the battery is deeply discharged, the alignment information in the memory will be lost
     and the device reports with three - - - in the display, or with wrong frequency range MW 520..1600. 

Recommendation: Have the battery replaced by a specialist/workshop!

Often more is broken than repaired by the intervention (repair attempt) and ends up in the worst case in the online auction house. Burned traces, misaligned trimmers (you should know what you're doing if you mess around with trimmers for no reason without knowing their function) etc. are the result.

If in doubt, contact the competent repair service of Kücke see link on the company profile!

Links

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