[Amps] Amplitec UG:2-20/350 question

[Kees - pa7two]

Dear all,

Recently I purchased a VHF Amplitec amplifier, model UG:2-20/350, based on one single GI7B.

I noticed immediately the bad condition of the bleeding resistoirs (many of these were blown), so I replaced both the HV capacitors, diodes and bleeder resistors. During a quick test the result was a 50 watt more output, isn't that nice :-)

Now that I did some serious testing, I noticed a pretty high input SWR (SWR is 1:2.5), which my Kenwood TS790E does not like at all. Transceiver pushes a maximum of 25 watts when the ampifier is on TX. This 25 watt results by the way in a pretty decent 350 watt RF output.

I wrote HA8UG several emails for support (mainly a digital copy (or payed copy even!) of the service manual), still waiting for reply.

What could have cause the excessive input SWR? What is more likely, a misalignment internally in the amp or is it the tube that is (a bit) worn out? 

Who can help me obtaining a copy of the user-manual, the service-manual and some guidance to get this amp back to operational 'life'?


Vy 73, de Kees. 

AmateurRadio : PA7TWO
 - M5TWO Locator: JO22jp.