[TenTec] Low (to no) Power Out Omni D--han'nt given up yet

scottsheppard at videotron.ca scottsheppard at videotron.ca
Wed Feb 15 17:52:14 PST 2012


Well, the saga continues...in addition to the previous work I have replaced the diodes on the SWR board as well as the TX mixer board no diff.

Present condition:

PA bypassed from circuit altogether with output from Low Level Driver to Low Pass Filter and out to the SO-239.

I have checked the Control Board and the voltages are OK..although a bit lower...my T voltage is about 9.7 volts but the RX is 0 during tx and tx is 0 during RX...otherwise the control board is behaving as it should...

For fun I removed the low level driver board and transmitted into the dummy load...I could just hear the tone in my newer omni...

put the LLD back in and it was considerably louder but still very low under 100mw or so (estimate)...I do note that the mrf 476 on the LLD was getting warm, however.=, regardless of the low output (which should be about 10w?)

When the final  PA gets hooked up I can get about 2 watts out or so depending how much I tweak its bias...so each stage seems to be helping a bit...my sense is the LLD is either not getting enough drive to it or the LLD itself is still N/S...I have replaced most all of the components--1n4001's. 2n3866's etc  with the exception of maybe a few  resistors and a zenor...

Anyway, still plugging away. Perhaps dear Paul at Ten-Tec will have some further thoughts.

I think I need another OMNI D so I can plug and play with complete board replacements...oh, one other thing...this rig has no antenuator board...the previous owner seems to have just bypassed the board with a wire between the in ans out...I do not think it is significant...

kind regards
scott  va3ied





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