Kenwood TS-830 Survival Manual

Also see for TS-830: Instruction manual

Contents

26removing the VFO from the radio, {see section 6.17, page 14, Fix 2} the VFO drive system'sgears and bearing surfaces should be lubricated with Tri-Flow, Break-Free or a similar, non-gumming lubricant, applied with a small watercolor brush. This procedure should be done oncewhen the radio is new and once every approx. 5 years thereafter.Note 1: WD-40 and LPS are not non-gumming products.Note 2: It is easier to lubricate the bushing-bearings on the main tuning shaft if the VFO isstood-up, face down, on its tuning-knob, so that the lubricant will run down into the concentricbushing-bearings. Put one of the original foam packing cushions between the front of the radioand the table so that the knob can not touch the table.8.2 Fan LubricationThe fan should be lubricated yearly with a few drops of 10W or 20W oil, placed on each of thetwo, felt oil-wicks which are accessible through the oil-holes on the fan-motor. Mobil-1synthetic, engine oil or Hoppe's #1003 oil works well for this purpose. Ordinary, SF / SG-gradeengine oil will also do the job. The fan is accessed by removing the 4, round-head sheet metalscrews. The dust that accumulates inside the Final Unit should be blown-out with an air-hosewhile the fan is removed. When replacing the fan, tuck-in the fan-motor wires so that they willnot touch the hot, rear-most 6146B.8.3 VBT [Variable {selectivity} Bandwidth Tuning] Oscillator Alignment[approx. 8375 KHz]The reason for performing this alignment is that the VBT-oscillator aligns the cascaded SSB-filters so that the 455 KHz, 2nd-IF filter's passband-"window" will align perfectly with the8830 KHz filter's passband-"window". Correct alignment makes the radio sound good onreceive and transmit, like it was designed to. It also allows the VBT-control to functionproperly.Someone may ask: Why not set the VBT oscillator to 8375.0 KHz and forget it?. If the two,filters' center-frequencies were exactly on-frequency, setting the VBT oscillator to 8375.0 KHzwould work well in all cases. However, since the combined, center-frequency error-difference ofthe two filters can be as much as 300 Hz off, the VBT oscillator's frequency should be custom-set to match the particular filters that are in each radio. The potentially excellent selectivityperformance of the 830 hinges on this alignment. It requires an external frequency-counter, a10:1 probe and some patience.Alignment Procedure Theory: When the VBT-oscillator adjustment [TC2 in the left-rearcorner of IF Unit] is set correctly, the combined filter-bandwidth of the two, SSB-filters will bemaximum when measured at the approx. minus 4S-unit rolloff-points. In other words, the filtersare working in perfect concert and they are optimally reinforcing each other's selectivity skirts.The minus 4S-unit points are found by tuning the receiver to the high and low edges of thepassband-window. If a spectrum-analyzer and a sweep-oscillator are available, the alignment iseasy and fast. Since most of us do not have access to such costly test equipment, the alignmentprocedure described uses the trial and error method of setting the VBT-oscillator. The end-resultis the same with either method: The VBT front-panel control will function perfectly.Alignment Procedure: Set the TS-830S to LSB, Calibrator to on, RF-gain to maximum, AGCto fast, VBT to normal , Audio Gain to 2, and IF-Shift to "0". Plug the external-counter into theheadphone jack. Tune the TS-830S to a 25 KHz calibrator frequency plus 1 KHz, until theexternal-counter shows approx. 1000 Hz. The S-meter should indicate S8 to S9. Tune thereceiver higher in frequency until the S-meter indicates S4. This is the upper-frequency, approx.4S-unit rolloff-point. Write down the frequency reading on the external-counter. This frequency