Harris SX-5 blows wall breaker.

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Jim Sofonia
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Harris SX-5 blows wall breaker.

Post by Jim Sofonia » Thu Apr 21, 2016 5:11 pm

I've read the advice in here before. Opening the door of your transmitter building can cause blowouts on your SX-5.
It started with a 3rd harmonic complaint from a ham operator that we were checking. ( I'll post another thread on this) We cut over to the SX-5 in standby status. Hasn't been on the air in several months. Ran just fine for about 15 minutes, then when we switched back to the DX-15 the SX-5 blew the main breaker during power down. A re-start immediately trips the main service breaker. A slight burnt smell is noticed. The smell did not have the usual burnt PC board, or mica caps in the output. More of a slight hint of gun power. We found one of the six rectifiers in the main supply shorted. All of the main P.S. filter capacitors were checked, all ok. I'm going to order a new power diode tomorrow but I wonder if I have other trouble. Never found the burnt smell component. Any ideas for me to look for when I go back out there?

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Re: Harris SX-5 blows wall breaker.

Post by ChuckG » Thu Apr 21, 2016 8:32 pm

I'm not familiar enough with the SX5 to offer anything useful, other than you might want to repeat the gunpowder smell. 5-6 times, depending on caliber :lol:
Can you disconnect the PS output from the caps and see if the breaker holds?
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Jim Sofonia
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Re: Harris SX-5 blows wall breaker.

Post by Jim Sofonia » Fri Apr 22, 2016 12:36 pm

ChuckG wrote:I'm not familiar enough with the SX5 to offer anything useful, other than you might want to repeat the gunpowder smell. 5-6 times, depending on caliber :lol:
Can you disconnect the PS output from the caps and see if the breaker holds?
Are you suggesting we shoot the transmitter 5-6 times? :wink: Probably good advice.
I'm waiting for a replacement power diode before I test it further.

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Re: Harris SX-5 blows wall breaker.

Post by ChuckG » Sat Apr 23, 2016 12:53 am

WTCM wrote: Are you suggesting we shoot the transmitter 5-6 times?
What was I thinking. It's a SX series. Make that 7-8. :lol:
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Shane
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Re: Harris SX-5 blows

Post by Shane » Mon Apr 25, 2016 12:42 am

The topic could be reduced to:
'"Harris SX-5 blows"
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Re: Harris SX-5 blows wall breaker.

Post by RGORJANCE » Mon Apr 25, 2016 7:44 am

Ok, so I'm the "odd ball" here. As a former seller of those "infamous xmttrs", I will try to defend the SX series. :lol:

I sold several, but never a straight 5. I sold a single SX-2.5, and a pair of SX-2.5's combined into a 5kw combo. Maybe a couple others I forgot about.

The single SX 2.5 was very reliable over about 20-25 years with pretty much only capacitors going bad. I think we might have lost 3, or 4 RF transistors due to lightning over that time span with it living in a pretty harsh environment. Pretty much the same story on the combo, although that pair spent it's life in the lap of luxury-----air conditioned, nicely heated office type environment.

Now on the other side of the fence.........after about 20-25 years, things really got nasty and these rigs have been replaced due to lack of parts, complexity, etc. I have to say that over that span of time, they were pretty good boxes, but when they went bad, they were very, very bad. :twisted:

That design was due to overzealous "college boys" that never worked in the "mud, the blood and the beer", real world of broadcasting. There wasn't a great understanding of the various environments they would end up in.

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Re: Harris SX-5 blows wall breaker.

Post by kcbooboo » Mon Apr 25, 2016 10:57 am

"...design was due to overzealous "college boys" that never worked in the "mud, the blood and the beer", real world of broadcasting. There wasn't a great understanding of the various environments they would end up in."

Funny how a lot of companies seem to have that problem with college graduates who are full of life's little experiences. I felt much better about going back to college after working for 10 years to get the experience college can't and doesn't teach.

Bob M.

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Re: Harris SX-5 blows wall breaker.

Post by Shane » Mon Apr 25, 2016 11:39 am

RGORJANCE wrote:....and a pair of SX-2.5's combined into a 5kw combo....

...Pretty much the same story on the combo, although that pair spent it's life in the lap of luxury-----air conditioned, nicely heated office type environment.
So YOU'RE the one! :?

I was told that there were only 8 of those combos in the world. That piece of info didn't exactly fill me with confidence. But if they got 20-25 years out of it, that's decent.

Wonder how many of the digital indicators on the front were still working by then. They had a pretty good start on becoming unreadable by 1998.

It's amazing, Bob. I almost spent more time having coffee with you a few years ago, than I did working up there and, whaddya know*, in that short time I got rather intensely familiar with the inside of the left side of that very pair, it would seem. Can't recall if our wide-ranging discussion ever fell upon that. If "fuses" rings a bell then we probably did. Don't remember you saying you sold it to them, but I've slept since then. :roll:

*This may serve as an oblique hint to a geographic location. If that's what the reader suspects, the reader is right! :!:
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Re: Harris SX-5 blows wall breaker.

Post by Deep Thought » Mon Apr 25, 2016 1:18 pm

RGORJANCE wrote:There wasn't a great understanding of the various environments they would end up in.
Those SXs are about to have company in that wing of the hall of shame...Nautel seems to be hell-bent to jump head-first into the cesspool of designs that don't really work in the field. Several of their transmitters now steadfastly refuse to come on if the temp in the room dips below freezing due to the third-party computers they use going stupid. If you have to heat the room to keep the transmitter on then there goes all of that vaunted savings on the electric bill... :roll:
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Re: Harris SX-5 blows wall breaker.

Post by RFWarrior » Mon Apr 25, 2016 1:29 pm

Deep Thought wrote:Several of their transmitters now steadfastly refuse to come on if the temp in the room dips below freezing due to the third-party computers they use going stupid.
Below freezing being less than zero degrees Celsius - the bottom end of the operating temperature range for everything we've built for 47 years...
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Re: Harris SX-5 blows wall breaker.

Post by TPT » Mon Apr 25, 2016 3:43 pm

I live a mile from the Ohio river--and have several sites in and out of the valley. In the fall we get these nasty fogs in the morning. Now with tube transmitters there is enough heat to keep condensation away. At my big transmitter building (40X60, two heated 15X25 rooms & the 35X40 garage) the ECO-4 is kept happy with a heat pump, while the waste heat from the transmitter exhausts into the garage. I keep it at 50 in the transmitter room & the garage stays reasonably warm and dry from the heat coming off that inefficient Energy-Onix.

But the solid state rigs (at my stations a Nautel 2.5 and Nautel NV-10LT), while real easy on electric, just don't generate enough heat to keep the transmitter buildings warm enough. I keep heat on in both locations in the winter--the 10 has a nice through-the-wall combination air and heat unit (like what you find in your local motel room), at the other site I leave a little 1500 watt space heater on. Not only to protect the transmitters (which may not necessarily need the heat until it gets real cold) but also to prevent condensation from those river fogs messing up other equipment such as STL receivers, processors, etc. that don't generate much internal heat.

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Re: Harris SX-5 blows wall breaker.

Post by kcbooboo » Tue Apr 26, 2016 3:21 am

It's not that the electronics needs the heat, it's the computers and hard drives that must be kept above freezing (0C).

I know of one 1kw site running a DAX-1 that generates maybe 200 watts of heat. The building is poorly insulated, so when the temps get down to 10F outside, the building would be that cold inside, and those DAX fans aim the blast right at you.

They added a pair of 1200-1500w oil-filled radiator-style heaters just to keep the room at 50 so the computers and hard drives would continue to function. The audio processors didn't care. The monitors didn't care. The TX didn't care. The remote control cared. The desktop computer cared. The DeathStar cared but it didn't last too long anyway. So that's almost 3kw additional power wasted at a 1kw station. Rather poor efficiency I'd say.

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Re: to prevent condensation from those river fogs

Post by RGORJANCE » Tue Apr 26, 2016 6:07 am

I had forgotten the condensation bit. I work a 4 twr DA that uses a solid state 2.5kw rig. I had condensation going on inside the phasor a few years back that really messed up two coils. I did a full replacement on three coils just to be safe, and was able to clean up the messed up coils to the point that they really look good. I now have some good spares, one of which will probably be put in soon to replace a sticky input R coil.

The DOE was able to get a good air handling system installed that fixed the condensation problem.....and we are pretty much far away from lakes/rivers, swamps, etc.

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Re: Harris SX-5 blows wall breaker.

Post by ChuckG » Tue Apr 26, 2016 2:00 pm

There have been a few days where one AM site here has gone below zero (F) when it's gotten really cold outside. Solid state Omnitronix, doesn't seem to bother it.
It bothers ME though, so I started running the old Collins into the dummy load to keep the building warm. "Energy savings" indeed. Baseboard heaters are on the agenda for this summer.
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Re: Harris SX-5 blows wall breaker.

Post by davek » Tue Apr 26, 2016 3:35 pm

RFWarrior wrote:
Deep Thought wrote:Several of their transmitters now steadfastly refuse to come on if the temp in the room dips below freezing due to the third-party computers they use going stupid.
Below freezing being less than zero degrees Celsius - the bottom end of the operating temperature range for everything we've built for 47 years...
Oh, I've seen them go stupid in perfectly comfortable temperatures as well. There is a NV at a site I regularly visit, which spends most of it's time stuck in a reboot loop!

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