Frankly I'd put it into a dummy load thru a watt meter to see if the metering circuit is at fault instead of power actually fluctuating.
There are a myriad of points of failure on those units, before going to the trouble of sending it out for repairs find out if you really have a problem with it, or just a meter malfunction.
FYI - YMMV
Jim "Turbo" Turvaville
SBE Certified Radio Engineer
Turbo Technical Services
From: Bill Hurne <email@example.com>
To: CRTech <firstname.lastname@example.org>
Sent: Monday, April 16, 2018 4:46 PM
Subject: [CRTech] TFT 5290 STL Transmitter
Before sending off for repair, anyone have rapidly fluctuating RF output from an analog 950 MHz TFT transmitter?
The UNLOCKED light on the front panel is not coming on, and it sounds really nice and clear on the air in spite of fluctuating output.
I just replaced both RF module cooling fans, one had died. But it is running nice and cool and the RF output is fluctuating between 3 and 6 watts. Long before a fan died I have seen the RF fluctuate between 5 and 6 watts. Reflected is zero.
I know TFT went out of business but support is still available.
The Pilgrim Radio Network
Western Inspirational Broadcasters, Inc