Mark wrote:
Hi ..
Over the last two or three weeks i have noticed my TS 870 is taking
less current than usual.. maybe 13 amps, maybe 14 as far as i can tell ,
but never more .. .. so i and another local amateur tested the RF output
with a nice power meter / dummy load
The results were even across the board, 160 right up to 10m (my usual
haunt) any mode, except for AM of course, -
about 65w - 70w. everywhere.

I was doing research before i bought an '870 and a couple of people
mentioned the 870's generally dont give 100w,
but ck, its less than 3dB difference, but we tested the 870 2 years ago
when i bought it, and it was giving more RF out then,
it was drawing nearly 18A, and correspondingly more RF too, except that
it seems the PA is getting weaker.

My main use for the radio is local chatting on 10m FM 90% of the time at
lowest power, strangely when on full power i got occasional fuse blows..
though i know not to waffle on 100w FM, though the 870 spec and users
report its ok to do so for about a hour.

Have you tried resetting all the PA bias levels on the pots inside? You
might have an oxidized connection somewhere, possibly inside a pot, on a
connector pin or a crimp, even a cracked solder joint that causes the
lower levels and the occasional burst of full power. I've seen similar
symptoms in other radios that went away after exercising (turn all the
way one direction, then all the way the other direction a few times with
the power off) related adjustment pots or finding a bad crimp or cracked
solder joint.