TS850modifications: Difference between revisions
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[http:// | [http://tigerfire.ca/assets/ts850/tcxo_kenwood_so2.htm VCTXCO upgraded, for higher PLL-reference stability. This small PCB can work in many synthesized Kenwoods, in addition to my '850] | ||
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[http:// | [http://tigerfire.ca/assets/ts850/ts850noiseblanker.htm Kenwood TS-850 Noise Blanker Modification - stiffens the bias-voltage, raises the threshold, alters time-constants] | ||
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[http:// | [http://tigerfire.ca/assets/ts850/850BAT.html TS-850 volatile-memory backup battery relocation (mine's under the DRU-2 top-cover hatch, for easy replacement - I have no DRU-2)] | ||
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[http:// | [http://tigerfire.ca/assets/ts850/cw_sidetone_adj_850.html Make the CW sidetone level adjustable, via the front-panel MONI control (just like SSB)] | ||
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[http:// | [http://tigerfire.ca/assets/ts850/alc.htm Stablize the Transmit-ALC reference-voltage, by broadening the operating range of the multivibrator/invertor] | ||
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[http:// | [http://tigerfire.ca/assets/ts850/ts850_mf_sensitivity.htm TS-850 Low Band (MF: 0.5MHz to 1.6MHz) Sensitivity Improvement, by disabling/bypassing the broadcast-band attenuator] | ||
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I have also replaced all my carrier-board aluminum electrolytics with 25V-rated solid tantalum caps. No leakage was present in my '850, but while it was open I thought it best to ensure continuing operation. These solid tantalums have no liquid to leak, and maintain their capacitance to well-below freezing. They were physically a bit larger than the aluminum cap carriers, so I had to gently scrape solder-mask from nearby traces, to accommodate the negative contact of the larger tantalums. | I have also replaced all my carrier-board aluminum electrolytics with 25V-rated solid tantalum caps. No leakage was present in my '850, but while it was open I thought it best to ensure continuing operation. These solid tantalums have no liquid to leak, and maintain their capacitance to well-below freezing. They were physically a bit larger than the aluminum cap carriers, so I had to gently scrape solder-mask from nearby traces, to accommodate the negative contact of the larger tantalums. | ||
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There are reports that C18 on the display-PCB can also leak. I replaced this 470uF with a higher-voltage-rated tantalum capacitor also. This bulk/filter cap is not present in the schematics, but is present on the display board nonetheless. When it leaks, it can etch and open-circuit one of the supply-traces to the display (resulting in no display). | There are reports that C18 on the display-PCB can also leak. I replaced this 470uF with a higher-voltage-rated tantalum capacitor also. This bulk/filter cap is not present in the schematics, but is present on the display board nonetheless. When it leaks, it can etch and open-circuit one of the supply-traces to the display (resulting in no display). | ||
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[http:// | [http://tigerfire.ca/assets/ts850/ts850_inrad_filters.pdf Installing my #528 Inrad filter (500Hz / 455kHz IF)] | ||
[[File:Ts850_underside_view.jpeg|500px|thumb|center]] | |||
[[File:Ts850_underside_RFboard_view.jpeg|500px|thumb|center]] | |||
[[File:ts850_underside_IFboard_view.jpeg|500px|thumb|center]] | |||
Latest revision as of 16:48, 16 July 2020
VCTXCO upgraded, for higher PLL-reference stability. This small PCB can work in many synthesized Kenwoods, in addition to my '850
Kenwood TS-850 Noise Blanker Modification - stiffens the bias-voltage, raises the threshold, alters time-constants
TS-850 volatile-memory backup battery relocation (mine's under the DRU-2 top-cover hatch, for easy replacement - I have no DRU-2)
Make the CW sidetone level adjustable, via the front-panel MONI control (just like SSB)
Stablize the Transmit-ALC reference-voltage, by broadening the operating range of the multivibrator/invertor
TS-850 Low Band (MF: 0.5MHz to 1.6MHz) Sensitivity Improvement, by disabling/bypassing the broadcast-band attenuator
I have also replaced all my carrier-board aluminum electrolytics with 25V-rated solid tantalum caps. No leakage was present in my '850, but while it was open I thought it best to ensure continuing operation. These solid tantalums have no liquid to leak, and maintain their capacitance to well-below freezing. They were physically a bit larger than the aluminum cap carriers, so I had to gently scrape solder-mask from nearby traces, to accommodate the negative contact of the larger tantalums.
There are reports that C18 on the display-PCB can also leak. I replaced this 470uF with a higher-voltage-rated tantalum capacitor also. This bulk/filter cap is not present in the schematics, but is present on the display board nonetheless. When it leaks, it can etch and open-circuit one of the supply-traces to the display (resulting in no display).
Installing my #528 Inrad filter (500Hz / 455kHz IF)
