01-11-2016, 09:05 AM
vk4adc Wrote:Replacement for YAESU VX-6R VX-7R Signal Crash 450F Filter 3 PCS Bundle
My ceramic filter problems in the VX-7R are now gone. The two new filters were fitted with small 100nF 0805 SMD-style DC blocking capacitors in series to each active signal point so now there is no DC on any of the filter pins. The PCB traces were not cut and I used mylar tape to provide insulation underneath so the filter pin leads could not contact the PCB holes directly. The sensitivity on 70cm seems normal although it has not been directly measured. The frequency display on 2m is flashing which (I think) means a PLL unlock state, but is normal on all other bands in the coverage. Maybe I disturbed something on the VHF section of the VCO submodule when I was working inside but I haven't yet pulled it apart again to check.
The three replacement filters were marked LTM 450FW on the case and since I only used two, that leaves me one spare.
Characteristics at http://pdf.eepw.com.cn/l20090915/7fd9c85...189c9c.pdf
Doug VK4ADC @ QG62LG51
http://www.vk4adc.com
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http://www.vk4adc.com
This Forum is only going to be as interesting as the posts it contains.
If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.