Kenwood TS-830 Survival Manual

Also see for TS-830: Instruction manual

Contents

126.9 Lack of crispness in transmit audioCause: The RF-bypass capacitor, at the collector of the 1st audio amplifier, is so large that itbypasses the higher audio frequencies along with the RF. {The amount of treble-rolloff in astock radio is about 4.5db at 2800Hz.}Fix: On the IF Unit, at Q19, change C106 from .015μF to approx. 0.001μF. Q19 can be founddirectly behind the filter space for the larger of the two, optional CW-filters.6.10 No power output on most bandsCause: This is usually due to the final unit bandswitch being out-of-sync with the bandswitchshaft. This problem is caused by a cracked, plastic shaft-coupling between the RF unit and thefinal unit. Trio-Kenwood did not use Locktite, or a similar thread-locking compound, so thesetscrews in the coupling had to be over-tightened, by the assembler, to prevent the setscrewsfrom loosening during operation. The constant stress on the plastic, caused by the combinationof ordinary use and the over-tightened the setscrews, eventually causes the plastic couplings tocrack.Fix: Remove the cracked plastic coupling and either epoxy it together, buy a replacementcoupling from Trio-Kenwood, or find a replacement shaft coupling made from metal. UseLocktite in the setscrew threads during re-assembly so that the set-screws will not need to beovertightened. Plastic shaft couplings can be cracked by overtightening the setscrews. Allow theLocktite to set 2 minutes before operating the switch.6.11 Noisy or intermittent front panel control potentiometers [pots]Cause: The grease, that is used to lubricate these pots, oxidizes and becomes gummy with age,causes an intermittent connection between the rotating wiper-arm and the resistance-film in thepot.Fix: Stand the radio up on its back, on the original rear packing cushion. Pull-off the knobs ofthe offending pots. Using a syringe and small-gauge needle, inject TCE degreaser down into theclearance spaces next to the concentric shafts of these pots, rotating the shafts back and forth toloosen the gummy grease. When the pot is no longer intermittent, inject GC Electronics Co."De-Ox-Id" . This material should be thinned with about 50% TCE to help fluid penetrate downinto the pot.Note: TCE is carcinogenic and should be used with good ventilation.6.12 On the AF-AVR Unit, the 4-pole relay contacts which switch the biasto the finals may fail after extensive use.This relay is neither cheap nor easy to replace. The failure is caused by th.00000 repeatedshorting to ground of a charged capacitor in the bias circuit by one set of the relay contactsduring T/R transition.Fix: On the circuit diagram, find the leftmost set of contacts. The arm [movable contact] of thisset of contacts is grounded.Fix: cut the trace from the arm to ground in 2 places about 5mm apart. Remove the foil betweenthe cuts. Solder a approx.100 Ohm, 0.25 W resistor across the gap. The resistor will limit thepeak discharge current during T/R-R/T switching to a value that will not burn the relay contacts.