TS440S.50

I've seen a lot of bulletins from people experiencing problems with PLL5
being unlocked do to VCO5 problems. There is a service bulletin from
Kenwood on this problem. It is SB-973 and you can get it by calling
their customer service line. It's not posted on their computer BBS
because it contains a diagram.

Basically, the VCO5 problem is caused by the synthetic rubber that's
spread around the circuit for mechanical stability. The stuff loses it's
insulating properties over several years. In effect, it becomes
somewhat conductive... not good! Kenwood recommends removing Q34, Q35
and D14, then removing the rubber around them by picking it off with
tweezers or whatever. They also recommend replacing Q34, Q35 and D14
with new parts.

I went a step furthur and removed all the rubber from the circuit and
the parts. In my judgement, replacing Q34, Q35 and D14 really isn't
neccessary if you get the rubber off the leads. I also replaced some of
the 1/8-watt resistors because it was nearly impossible to get the
rubber off them without damaging them in the proccess.

To finish, Kenwood recommends sealing the VCO with a hot glue gun and
using a hot air gun to make the glue flow around the components, being
careful not to overheat the parts. After the rig has warmed up for about
30-minutes, set the frequency to 14.200-MHz and adjust T20 for 5VDC at
TP11 with a DVM or VTVM.

I hope this information helps. It seems to be a very common problem with
the TS-440's with some age on them. You should obtain the bulletin
(SB-973) and have the service manual before attempting this fix.

73, Mike N1ENA @ K1RQG.ME.USA.NA