A new (to me) problem just showed up. On 30m, even into a dummy load, the
overdrive lamp flickers and the RF output is a tad down (just a tad from my
usual 400)
If I increase the drive from the Omni-V I can cause the overdrive trip to shut
the amp down. As this is specific to 30m (40m is OK) I guess it may be a
relay problem. The circuit indicates that some (but not all) unused low pass
filters are terminated thru resistors to ground by relay back contacts. If
one of those filters is not properly terminated and has a 30m resonance or
near resonance, then maybe thats whats upsetting the Herc.
This problem is additional to a tripping problem I have had for a while on 10m
and to a lesser extent on 12m . Now that one is very definitely intermittent;
sometimes the Herc delivers 500w on 10 and 12 without the slightest sign of a
an overdrive flicker. Then it quits at around 150w on 10 or 250w on 12.
But both problems look to me like being relay related .... unless you know
better !
Yes, I should take the thing apart and clean the relays. Yes, I have had (and
fixed by slightly bending relay contact blades) a similar relay problem in my
TT 253 auto-ATU, but it is very difficult to get at the Herc in my
sub-miniature shack ... I would prefer to dismantle the entire station only
after I have a better idea whats wrong.
John G3JAG.
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|