Hey Gang, Just picked up an DX400 off eBay, its an old Bi-Lateral with 4 - SRF2072 trannies and has 3 symptoms. The good, the power output seems fine, driving it with 1.5w's with AM button in out's 100w carrier and 400'ish with swing, just like it should. That's where the good ends. - When amp is on and tx'ign its normal power, the SWR is off the charts, like a 5, other amps I throw in line are fine, 1.2 - 1.5. I have the meter immediately following the amp, then into a Bencher LP filter. Meter is an MFJ-870, never any issues with the meter. - The preamp is not working, just goes deaf, doesn't affect the Xmit power. - When the SSB/delay button is pushed, its as if the output transistors/amp are taken out of line and I get stock power. When tx'ing no delay can be heard kicking the relay in and out, again like the amp is off. Honestly I could care less about the Preamp working, I've never used them anyway on every amp I've ever had, but obviously all the either issues are the real issues, but sure its connected. I'm sure just a couple of simple components, but not a super troubleshooter kinda guy. Any help would be welcome, thanks in advance!