K4NYW's AN/FRT-17 Transmitter Project - Page 5
     Page 1 - Acquisition & Disassembly
     Page 2 - Frame & p/s reassembly
     Page 3 - Module Restoration
     Page 4 - Master Oscillator and FSK Keyer Restoration
     Page 5 - Back to Life

10/17/13 - 230vac - first power-on
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Start checking out the interlocks and relays after wiring up the harnesses to the drawers....

1) found/corrected my rewiring error in the tune-operate switch 

2) the AM-CW HV relay was chattering - readjusted contacts & seems OK
    (whew - this sucker is really buried in the bottom)

3) brought up the bias/fil supply and adjusted the overload trip relays - found/corrected my rewiring error

4) brought up MV (600vdc & 1200vdc) supply to 1/2 voltage on a 115v variac, then full bore on 230 vac

5) couldn't get any AF in to speech amp - fixed a wire I had pulled loose on  the 10-section mode switch - see below

6) hooked up TMC transmitting balun to convert FRT-17 600 ohm balanced output to 50 ohms coax to Bird dummy load

7) checked out the HV supply (up to 1kv) with the 115v variac

The 10-section mode switch way back inside there
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It's alive!...alive!

11/24/13 - with help for my buddy K4OZY, we started to tune up in CW mode with full B+....

4-125 modulators
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4-65 driver
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4-400 final
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TUNE mode - 250ma final cathode current
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TUNE mode - 280 watts output
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TUNE mode - B+ about 2.4 kv

Screen voltage set to 640v per manual

OPERATE mode - 350 ma
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OPERATE mode --about 600w output
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OPERATE mode - B+ about 3.1 kv

Screen voltage creeps up to 700-720v
...but I don't like that change - needs investigation

AM Troubleshooting - I see HV arcing on the scope at both pos & neg modulation peaks.
Shows up on both modulator plates, modulated B+, and modulated RF. Fastest rise times appear on modulator plates.
Can't get above 30% modulation or so before this happens.
I have gradually tried to isolate it.
> Listened - mod xfmr buzzes a little when arcing appears on scope. Is this a direct or secondary symptom?
> Turned out the lights - can't see any blue glows anywhere.
> Disconnected leads to shorting relay for CW operation - no change
> Replaced modulator plate to mod xfmr wiring - no change.
>Disconnected PA screen winding on mod xfmr - no change.
>Disconnected PA plate/screen and connected 10K 300w resistive load to mod xfmr
   AHA - no arcing with B+ disconnected from load, but arcing returns if B+ is connected.
>So I tried switching the mod xfmr secondary terminals
  (hypothesizing that there is arcing from one modulator plate winding to the nearest (modulated) end of the secondary)
>And got no arcing! See scope photo .
>So next move is to wire the PA, etc. back up and keep my fingers crossed.
Modulator drawer
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temporary replacement modulator plate leads
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substitute resistive load 10k/300w
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Temporary mod xfmr connections
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HV scope probe on resistive load
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Oh yeah! - 1KV/division
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And finally - with the PA hooked back up..... We Have AM!

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