OK here's one for ya...

A case of PEBKAC (Problem Exists Between Keyboard and Chair)? Tell us about your war stories!
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Deep Thought
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OK here's one for ya...

Post by Deep Thought »

The weather in the Chicago area the last few days has definitely lived up to the "windy city" meme...my office power was out for almost two hours Wednesday afternoon due to the wind. It was still blowing pretty good this morning.

Got a near-panic call from WCGO in Evanston this morning. ComEd had been playing bouncy bouncy with the three phase power which had managed to trip half the breakers and take out a couple of UPSs at the transmitter site. The transmitter tripped off and wouldn't come on via remote...the remote control UPS was one of the casualties. Upon arriving at the site their engineer also noted that the phasor controller had opened the interlock even though all the towers were properly switched. So, he reset everything, switched back and forth between D and N to get it all back in sync and turned the Nautel XR12 transmitter on.

1100 watts forward, 400 watts reflected. Ugh. Since the day ND and night DA only have the transmitter and tower in common I had him switch to night pattern. 1100 watts forward, 400 watts reflected. Huh?

Off I go from La Grange to Skokie, a 45 minute drive with no traffic. :shock:

Get to the transmitter site, everything looks good, no popped capacitors, no alarms on the transmitter. No reason for it to be running this out of whack. Switched patterns once again just to check. No change. So I try to adjust the power. No change. Then I notice that the PA supply current reading is not moving with modulation. Hmmm. Turned the transmitter off.

Display and power meter sez...1100 watts forward, 400 watts reflected. The damn controller that runs the panel is locked up. :roll: Cut power to the transmitter, waited for the power supply to completely discharge and turned the breaker back on. Transmitter comes up at 10 KW like nothing was ever wrong. 10,000 forward, 0 reflected. All parameters normal, except that something managed to change the #1 preset from 10 KW to 1.1 KW. Reset that, and everything is groovy.

I think I liked it better when we didn't have to reboot transmitters to get them work right. :lol:
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ChuckG
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Re: OK here's one for ya...

Post by ChuckG »

Deep Thought wrote: I think I liked it better when we didn't have to reboot transmitters to get them work right. :lol:
Heck no. I spend enough time telling people "unplug it, count to 10, plug it back in" as it is, lol. I was hoping I'd be retired before they started tying microcontrollers to that big lightning rod in the back. :lol:
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Re: I was hoping I'd be retired before they started tying microcontrollers to that big lightning rod in the back. :lol:

Post by RGORJANCE »

How soon you forget....the Harris SX series had not one, but two u-procs. Double trouble, especially when in the early production units, the long PC board cracked and they looked at each other, said huh?, and then DUUUHHHHH!!, and then shut the rig down. Rebooting didn't help. :twisted:

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Re: I was hoping I'd be retired before they started tying microcontrollers to that big lightning rod in the back. :lol:

Post by Dale H. Cook »

RGORJANCE wrote:How soon you forget....the Harris SX series had not one, but two u-procs.
That was one of the reasons why I was early among those who began referring to the "SX Series" as the "Sucks Series." That series tried to be smart but suffered from a lot of stupid problems.
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Re: OK here's one for ya...

Post by grich »

Ugh. I didn't get to sleep until 5am because my favorite SX-1, with which I've had a 32-year-long relationship with, decided to pop a MOSFET in a PDM amp. Do the later version PDM amps have MOSFETs socketed? Mine don't (s/n 018, if I recall correctly). Out comes the solder-sucker and braid. Hands covered with heat-sink grease.

Don't think it had anything to do with the wind, but still a PITA.
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Re: OK here's one for ya...

Post by Dale H. Cook »

grich wrote:Do the later version PDM amps have MOSFETs socketed?
I dunno. I have been lucky enough to not have worked on one in more than a quarter of a century. :-)
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Re: I was hoping I'd be retired before they started tying microcontrollers to that big lightning rod in the back. :lol:

Post by Bill DeFelice »

Dale H. Cook wrote:
RGORJANCE wrote:How soon you forget....the Harris SX series had not one, but two u-procs.
That was one of the reasons why I was early among those who began referring to the "SX Series" as the "Sucks Series." That series tried to be smart but suffered from a lot of stupid problems.
I considered myself lucky back when colleagues had SX series boxes I had an MW-1 (not the A version) and it rarely gave me any problems. Of course the RCA BTA-1R was built like a tank and took anything you could throw at the old girl.
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Re: I was hoping I'd be retired before they started tying microcontrollers to that big lightning rod in the back. :lol:

Post by Dale H. Cook »

Bill DeFelice wrote:... back when colleagues had SX series boxes I had an MW-1 (not the A version) and it rarely gave me any problems. Of course the RCA BTA-1R was built like a tank and took anything you could throw at the old girl.
At about that time I had a 315R-1 for a main, which I loved, and after I overhauled the rather neglected BTA-1L it was a very reliable aux.
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Re: OK here's one for ya...

Post by kcbooboo »

Bill said: "Of course the RCA BTA-1R was built like a tank and took anything you could throw at the old girl."

Did the BTA-1R still have mercury-vapor rectifiers in it, or had Clif or someone else replaced them with solid-state rectifiers by the time you got involved? I'm reasonably sure both the AM and FM 1kw xmtrs had mercury in 1969. The nice thing was they were SOOOOOOOOOOOO quiet. Little blowers that did the job, unlike the tornado noisemakers in today's equipment.

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Re: OK here's one for ya...

Post by Deep Thought »

kcbooboo wrote:Little blowers that did the job, unlike the tornado noisemakers in today's equipment.
Of course, those transmitters liked the sauna and 150 degrees internal temp was normal. Today's solid state rigs start sweating at 75 degrees. :lol:
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Re: OK here's one for ya...

Post by Shane »

Our BTA500R was so quiet it could have been in the studio. Since it's been mothballed for over 10 years I don't believe it will be very quiet for whoever fires it up next. :mrgreen:
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Re: OK here's one for ya...

Post by RodeoJack »

So... we should expect future transmitters to include a UPS for the internal computers?
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Re: I was hoping I'd be retired before they started tying microcontrollers to that big lightning rod in the back. :lol:

Post by ChuckG »

RGORJANCE wrote:How soon you forget....the Harris SX series had not one, but two u-procs. Double trouble, especially when in the early production units, the long PC board cracked and they looked at each other, said huh?, and then DUUUHHHHH!!, and then shut the rig down. Rebooting didn't help. :twisted:
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So I should have retired in 1984? :lol:
Last edited by ChuckG on Sun Mar 20, 2016 11:41 pm, edited 2 times in total.
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Re: OK here's one for ya...

Post by ChuckG »

grich wrote:Ugh. I didn't get to sleep until 5am because my favorite SX-1, with which I've had a 32-year-long relationship with, decided to pop a MOSFET in a PDM amp. Do the later version PDM amps have MOSFETs socketed? Mine don't (s/n 018, if I recall correctly). Out comes the solder-sucker and braid. Hands covered with heat-sink grease.

Don't think it had anything to do with the wind, but still a PITA.
They're socketed in the later Gates series. I don't know if they are a direct swap to an SX, but I'd bet they are.

The last SX I worked on, it appeared that someone replaced Mosfets by prying the bad ones out with a screwdriver instead of unsoldering them. I pulled the amp board and a handful of them hadn't been re-soldered. I wonder if they thought they were socketed and just stuck really bad? :lol:
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Re: OK here's one for ya...

Post by BroadcastDoc »

RodeoJack wrote:So... we should expect future transmitters to include a UPS for the internal computers?
Nautel already has an optional UPS interface for many of their transmitters.
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