[Amps] Ten-Tec Titan 425 - input SWR high

[Prem]

Friends, for a long time now, the input SWR on my friend's Ten-Tec Titan
425 is very high (average > 2 on all bands) - when measured with a MFJ
analyzer at the input - with a 50R dummy-load at the AMP output.

So long, he's used an ATU between the exciter and the 425, but I'd like to
find out if there's way to fix this SWR problem (no slug-tuning. fixed L
and C in the i/p LPF).

I've already checked/assessed the following:
1- Amp gives full o/p of 1500W pep on a DL with an ATU between the exciter
and the amp (so, tubes should be OK ?)
2 - The vacuum relay contacts test 100% OK with a multi-meter continuity
test.
3 - No visual or smell indication of any burns/arcing/toast - in the I/P
LPF or in any other circuit elements.
4 - Band switch contacts look good. Cleaned with De-Oxit - just to be on
the safer side.
5 - Ig and Ip are as per specs

Any help/lead is appreciated.

73,
Prem
VA3UMA
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