Notes on Titan II Linear

Placed in service in February of 2002, but did not operate that contest.

Used successfully until October 2002, when it failed the morning of the beginning of the CQWW SSB contest.

Repair suggestions from Paul Clinton, WD4EBR, service@tentec.com 865.428.0364 (John Maples can also advise.)

Disconnect power transformer
Check HV shorting bar
See if screen transformer smells burned
Lift fuses from the screen board -- if OK, then screen board is the problem
Ck 10 ohm 25 W resistor on screen board visually

They have a spare tube that generates fair (1500 W) output.

November 2002

W0NB replaced the screen board and the HV inrush board. (The inrush current limiting resistor had blown.) Likely problem was a dead short in the tube, grid to plate, which drew too much inrush current and fried the resistor. W4PA replaced the tube and the amp worked perfectly for all of CQWW CW 2002 at 20 meter position. We need to try to get replacement boards for the future, because this amp has been discontinued. (Failed resistor is R4 10 ohm 25 watt.)

October 2005

Installed one of the two new 4CX1600B tubes. Result was full output. Also cleaned the fan and interior case and set linear higher on the table.

October 27, 2006

Failed during CQWW SSB at about 2:30 AM local on Sunday morning. Amp is on and HV up and PTT keys, but no RF output. On 30 October K6AM and W4PA troubleshot and found P20 burned. This is a four conductor jumper from the screen grid board to the tube jumper board. Specifically, the filament lines were burned black and there was also no screen voltage making it to the tube. Put in a new jumper from the spares box and all worked 100% perfectly.

February 2007

Many complaints of very distorted and wide audio on SSB. Will investigate further prior to ARRL SSB contest.

7 March 2007

First attempt to fix bad audio was to install the old good tube. When HV was switched on, the HV board blew out two metering resistors and two bypass caps on the HV line. Installed the known good tube and a new HV board, this time blowing one electrolytic cap and possibly other HV components. Unable to find the source of the HV short. K8ND shipped the white box to W9JUV to arrive 13 March, and Joe will bring it to Curacao on 21 March. Amp to be returned to Ten-Tec for service. Amp taken to States by W0CG on 7 April 2007 and shipped to Ten-Tec.

9 June 2007

Repaired Titan II received at W0CG from Ten-Tec. Click here for the photo of the UPS delivery in the middle of a raging hailstorm. Click here for photo of the blown parts. The tube socket shorted, taking out many components on the HV board and throughout the amp. Click here for Page 1 of the repair invoice and here for Page 2. Tube socket, panel meter (Ip), many HV components, and some metering board components replaced.

4 July 2007

Returned to Curacao by W0CG. Installed transformer and tube. Linear is fully operational. Resting bias is 20 ma, and all tuneup settings have changed. Used amp in PJ2HQ IARU 2007 contest with total success. Paid duty to get amp back into Curacao. Click here for scan of that customs form. Amp seems to perform much better than ever before. Spare HV board is stored in Titan III boards bin, fully repaired.

22 November 2007

Titan II was arcing in the area of the bandswitch above about 1000 watts output on 20 meters. Investigation revealed that the middle wafer of the bandswitch was broken. W0NB and NP2L removed the bandswitch and took it to Iowa. Replacement parts obtained in U.S. in December from Ten-Tec. W0NB will reinstall in the amp in February 2008.

February 2008

W0NB, N0YY, N1ZZ replaced the bandswitch that contained the new wafer. Worked 100%.

25 November 2008

Turned on HV on a very, very humid day and had sparks and loud popping. On HV board, metering caps C11 and C13 exploded, R36, 37, 38 open, R39 good. All electrolytics and diodes good. Replaced with spare rebuilt HV board and amp worked fine except for no front panel metering function whatsoever. On 29 Nov W0NB removed the metering board and meters. Disassembly directions and front panel knob are in the amp as well as all hardware. Metering board and HV board sent to Ten-Tec via K8ND. We are requesting to buy a second metering board and meters.

January 2009

Boards returned to Curacao by K8ND following repair. Click here for repair invoice from Ten-Tec.

5 February 2009

Reinstalled meters and metering board after repair by Ten-Tec. (Did not put in the fourth screw in the Faraday shield to the tank compartment. 

Disassembly Procedure: (From W0NB.) Remove power transformer. On RF compartment vertical aluminum divider, remove three bottom screws and four on the side. Remove tank inductor ground lug. Disconnect all wires and plugs from metering board. Remove aluminum bar by removing its three screws and sliding it out sideways. Remove four screws holding metering board in place. Use Allen wrench stored in Titan II parts bin in radio closet to take off metering knob. Loosen three turns plug lug compression.

Reassembly Procedure: (From W0CG.) Align three red LEDs using a home made index card template then install plastic meter escutcheons from the front and meters from the back. Put in one top corner screw. Slide aluminum bar in through four slots, then install and tighten three screws in the bar. Check LED alignment. Connect all wires and plugs to metering panel using J-number legend on board. Reinstall aluminum divider, three bottom screws first, the two in rear and two into meter board corners. (Bottom one was omitted.) Reinstall power transformer and connect both HV and primary plugs. Check HV shorting bar position and install case top.

After reassembly powered up the amp without HV and the blower failed after about one second. Verified it was dead by removing it from the amp. Used an old Rotron blower and adapted the case by drilling mounting holes and installed fan. Made up new quiet muffin fan for top of amp. Ran amp for 45 minutes to dry out interior. Left two wires to HV board disconnected for initial HV turn on test. HV came up normally and amp easily produced full 1500 watts output on 40 CW. Powered down and connected the two-wire plug to the metering board. All worked OK except that HV metering is dead. Screen current metering seems OK. Output of amp is excellent. Time will tell how long it will hold up or whether this fan will cool the tube sufficiently.

15 March 2009

Amp worked fine for half of ARRL SSB, but then would not tune up on 10 meters. No output whatsoever. Today I verified that it was still bad, then compared schematic with band switch wiring and with photos from before the disassembly. Band switch appears to be 100% wired correctly.

26 October 2009

Repaired by K6AM, who found a leaf on the bandswitch not in contact with the wiper. (Need to but a set of all sizes of snap ring pliers.) Amp good on full power test, all bands. Put in all new brass cabinet screws from Ace Hardware in Idaho.

20 Nov 2009

Turned on HV. HV board blew again, just as last November. C111 and several components on HV board blown, plate current meter pegged again, one of two primary fuses blown. K8ND and I decided to retire the amp for whatever salvage value it would bring. Packed in white case. Removed two 1600 tubes and one GU-91B from Boxes 9 and 10 to return with amp.

1 December 2009

Returned to States with K8LEE. Transformer taken by N4RR. Tubes still awaiting transportation. RF deck and transformer donated to N9AG.