Scott Dorsey wrote:

Imagine if you will a group of design engineers sitting around trying to figure
out how to make equipment more annoying for broadcast folks. "I know, we can
put the power supply all at the bottom so you have to pull all the channel
strips out to get to it, making it impossible to test under load." "Great,
and then we can use output capacitors that fail into intermittent shorts
so that the supply has to be loaded to find them!"

I didn't know you'd ever worked at KCSC-FM.

Regulators with failure modes that involve smoking the full-wave
bridge.

Capacitors that explode.

Leaking tantalum capacitors that eat the traces off the boards.

Leaking batteries ditto.

UPS battery chargers adjusted so that the "float" voltage is about 10%
too high, so that the batteries outgas, leak, and die.

Ground-loop city.

A plate capacitor on the ttransmitter's final that turns out to be
a strip of PTFE wrapped around the final tube, above the HV lead,
and which gets punched through about once a month.

A grounding hook with a broken resistor in it. The idea is to
discharge the HV PS capacitors "gently". That's fine, as long as the
resistor maintains continuity and discharge to "safe" levels (0 VDC
for me, TYVM) doesn't take a week.

--
The official state religion of France is Bureaucracy. They've replaced
the Trinity with the Triplicate.

(David Richerby)

(Mike Andrews) wrote in message ...
Scott Dorsey wrote:

Imagine if you will a group of design engineers sitting around trying to figure
out how to make equipment more annoying for broadcast folks. "I know, we can
put the power supply all at the bottom so you have to pull all the channel
strips out to get to it, making it impossible to test under load." "Great,
and then we can use output capacitors that fail into intermittent shorts
so that the supply has to be loaded to find them!"

I didn't know you'd ever worked at KCSC-FM.

Regulators with failure modes that involve smoking the full-wave
bridge.

Capacitors that explode.

Leaking tantalum capacitors that eat the traces off the boards.

Leaking batteries ditto.

UPS battery chargers adjusted so that the "float" voltage is about 10%
too high, so that the batteries outgas, leak, and die.

Ground-loop city.

A plate capacitor on the ttransmitter's final that turns out to be
a strip of PTFE wrapped around the final tube, above the HV lead,
and which gets punched through about once a month.

A grounding hook with a broken resistor in it. The idea is to
discharge the HV PS capacitors "gently". That's fine, as long as the
resistor maintains continuity and discharge to "safe" levels (0 VDC
for me, TYVM) doesn't take a week.

You had grounding hooks with resistors in them? Ours were simply 1/4"
diameter bent aluminum hooks connected to ground with #6 stranded
wire! (At least on the Gates BC-10B and RCA Ampliphase 50-Kw models).

I agree that the newer broadacast transmitters are horrow showd to
repair, but their selling point is that they are much more compact and
inexpensive. Still, putting a resistor in series with the safety
grounding hook? That's insane!

Cheap transmitters allow broadcast operators to buy transmitters for
the cost of one of the older rigs, but repairs of a failed transmitter
can linger into hours or days, unlike minites and seconds of dead air
time with a single transmitter as it was in the past.

Just as an afterthought, I remember one failure when the transmitter
of WBUD in Trenton kicked off while I was on duty. The transmitter
kicked off on a hot summer day, and on restart attempts I saw the
antenna feed current meter pin on each attempt. I was intercepted by
the station owner while I was in the process of scrambling to find a
large screwdrive and a flat file in our repair shop, who demanded to
know why I wasn't inside the transmitter trying to located the
problem. I ignored him and ran out into the antenna field, and on the
second tower of our 4-tower array found a large, carbonized insect in
the lighting gap between the tower and ground. Once found, the problem
took no more than 5-seconds to resolve and we were within 15-seconds
of that back on the air.

Given that a problem like this COULD have shut the station down for a
day or two, the station owner remained ****ed that I had ignored him
and simply done the job that he was paying me for. Fortunately shortly
after this even I received my degree and went to work for Eastman
Kodak in far away Rochester, NY.

I suppose that the only reason that I dredge up this ancient history
is that this was the expected technical performance of an FCC license
holder back in the 1950-1970 era. What is it today?

Harry C.

Harry Conover wrote:

I suppose that the only reason that I dredge up this ancient history
is that this was the expected technical performance of an FCC license
holder back in the 1950-1970 era. What is it today?

They don't have them any more.

They do have guys with SBE certifications who basically have the same
technical performance, except they spend their time removing viruses
from automation control systems....
--scott

I got a Volumax on the bench today too. Unfortunately the T-pad
on the input seems to be bad.
--
"C'est un Nagra. C'est suisse, et tres, tres precis."