WCTV Analog transmitter tube change Part 2

[MadManMarkAu]

@douro20 I don't mind solid state. I like the fault tolerant nature of the PAs, but dislike their lifespan. On the Rohde-Schwarz DVB-T TXs I've seen, with 10 PAs, you lose one PA and your 10kW becomes ~8kW. Not optimal, but still not a dire emergency. Real handy for an unattended site. However, the PAs start dying after only a year.

Still, the old tube girls are still going strong after many years. Changed the tube in an FM radio TX about 6-7 years ago, haven't heard a peep from it since. :)

[jrcstudios]

I miss the NEC...If you can't watch eyewitness news, you can listen to us at 87.7 on the FM dial.

[jrcstudios]

I miss the NEC...If you can't watch eyewitness news, you can listen to us at 87.7 on the FM dial.

[douro20]

Better to spend an extra thousand on a new tube than to buy a recon'd one.

[drradio2003]

wow, you should see what happens when you have an hv overload on a acrodine IOT transmitter going into crowbar! woo hoo. harris platinum is a piece of shit ar 15%eff in the digital domaine at 14% effy its a piece of junk. had to install a nothrt 15 tun a-c unit to keep it cool in thr transmitter building. acrodyne acceria, even the good ol pineaple tech transmitters are way better than anything thet ever came from quncy .. I know , I have both.

[contrapezist]

The efficency of a platinum does stink but it will run and run and run. Harris has really gone to hell the last 10 years they would rather buy and slap their name on it than design and build. Case in point the harris sigma hands down the most reliable and clean IOT TX built, designed by phillips. Accrodyne is decent if you dont mind regular unscheduled replacement of some exotic single sorced outragously expensive tube order it with the EEV IOTS.

[douro20]

@drradio2003

I hate solid-state. In my opinion anything higher than 5kW ERP shouldn't be solid-state.

[BamBamFun]

I guess you're glad to be going digital soon.

[douro20]

I guess you don't have access to a "megger" to test these tubes with...

[Erzahler]

Looks like time to find another tube supplier if you can, especially if you have two tube failures in short order like that. Apparently the manufacturer isn't testing the tubes properly or something. Probably a mute point anyway, I think you said in another video you were going to replace both transmitters? I'd hate to think what you'd have to deal with if this were an all-tube transmitter.

[contrapezist]

In my early TV days (late 90's) I had care of a GE TT6-D at the studio, back up to the all solid state harris platinum at a remote site. 40+ years old all tube complete with mercury vapor rectifiers and went on air weekly after a 35 minute warm up. The harris took up less than half the space, put out 10 times the power, took less than 30 seconds to come on air and didnt have to have a babysitter.

[panaflex]

what happened at the end "not good....." ?

[contrapezist]

The tube arced internally plate to cathode, tripping the 350 Amp main breaker and damaging the bias supply. Time was running out and I was scrounging for parts pretty heavy to get it back on the air by 5 AM so no vid of putting the old tube back in and fixing the supply. The replacement tube that arrived 3 months later from Econco also failed after 300 hours wrecking the filament supply and ruining my labor day holiday.

[douro20]

What kind of tube is it?

[contrapezist]

4CX25000A

[norom117]

right on with the tetrode! lol