[Amps] Viewstar PT 1000a

[K4elv@bellsouth,net]

Good day to the group. I am new to the group and was hoping that someone out there may have an idea to help me with a problem I am having with this PT 1000a.  

I purchased this unit new at Dayton in 1983.  I haven't used it very often but never had any problems with it until recently.  Previously I only used it on the major bands 160 -10.  With about 50 - 60 watts in I could get 400- 500 watts out depending upon the band.  Now I have been getting active on the WARC bands and this has been my problem.  30 meters was no problem, but 18 and 24 Mhz are another story.  Besides having difficulty tuning up (very critical final dip) I was getting some arcing at the band switch on both bands, and no amplification on 18 mhz.. i.e., 50 watts in - 50 watts out!  Also, the arcing was more pronounced on 18 mhz.. I thought of VHF parasitics and recalled I had a parasitic kit I had bought years ago from AG6K.  I installed the kit in both the anode and cathode of the 3-500. By the way I have tried 2 different tubes.  I have stopped the arcing on all bands but 18 (if I try to tune up on that band).  Still no amplification on 18.  I am having problems with the resistors in the anode parasitic choke over heating on 24 and 28 mhz, so I still have some adjusting to do with the coil length on the choke.  I've followed the schematic and the unit appears to be wired correctly for 18 mhz.   SWR on the input doesn't appear to be a problem except on 18, where it'll hit 3:1 with 50 watts of drive even tuning into a dummy load. By the way, all efforts at tuning have been into a dummy load.  I have cleaned the carbon path on the band switch, but that doesn't effect the arcing the next time Itry to tune up.  The arcing is between the switch contact closest to the wafer mounting screw.

Any thoughtswouldbe appreciated.
73 Mike K4ELV