[Amps] 3CX1500A vs el cheapo GS-35B

[Jim Thomson]

Date: Wed, 01 Aug 2012 13:04:35 -0700
From: "Bill, W6WRT" <dezrat1242 at yahoo.com>
Subject: Re: [Amps] 3CX1500A vs el cheapo GS-35B
To: AMPS <amps at contesting.com>
Message-ID: <de2j18pjf2vn2fer0uvjioon4p8u6nvenk at 4ax.com>
Content-Type: text/plain; charset=us-ascii

ORIGINAL MESSAGE:
On Wed, 1 Aug 2012 14:10:57 -0400, Randy wrote:

>The timed replacement is to prevent downtime not to waste
money just because someone else is paying the bill. Its purpose is to save big
money. Think about it. At $2000 a study, 3 per hour (or more) and an average
12 hour working day = $72,000 per day gross lost if the MRI is down not to
mention the separate loss to the Radiologist who are not making money since
there are no MRI studies to read. Radiologists get incensed (in about 1 micro
second) if you mess with their income. I know this from personal experience.
Don't forget the patient who now has to reschedule their appointment. The
manufacturer knows where on the tubes failure rate curve that the sweet spot
between replacement cost and downtime exists. I have worked with Radiology
techs on equipment before and no one wants to hear that any modality is
non-functional if it can be prevented.
>
>
>Randy E. Randall AB9GO
>Network Engineer
>UC Health
>Randy.Randall at UCHealth.com
>Phone 513-585-7146
>Fax 513-585-7159

REPLY:
Everything you say confirms what I said. Everyone - not just the MRI makers -
could not care less about cost when either insurance or the gummint is paying.

If the MRI makers wanted to, they could make a quick-change module that anyone
could swap in about two minutes when the red light comes on. They're not
interested.

And that's only the beginning. It's just not a priority when money flows like
water.

73, Bill W6WRT

###  Bill, you just don’t  get it.  Check out the detailed YC-156 tube operating procedures
written by Eimac, for MRI use.   Eimac sez to only turn it on and off  no more than ONCE
per day.   And no LESS than  9 hours per day, of continuous fil usage.   Our local hospitals
were  clogged up  with long waiting lists for MRI + cat scans several years ago.  They wanted
to buy more machines..at 2 million per copy.   I suggested to em to instead, just  operate
the existing machines  from 8 am  to midnight, instead of the 8AM to 5 pm   schedule. 

##  The machines were never turned off anyway, since they were located in close proximity
to the energency  dept !   If  car accident victims etc, had to be stuffed into a MRI machine
at midnight, they require a  functioning MRI machine, ready to go.   It was explained to me
that they didn’t want to keep cycling the fils  on and off all night long, after each use, IF
the MRI  was required for emergency dept use.  With a 9 minute warm up, the  doctors and
techs would be just pissed..waiting for the fil to heat up. 

In the end, they took the suggestion, and just  hired more MRI techs  and put on a  2nd shift,
from 5 PM  till 11 PM.   during the week.  End of back log.   I needed a few MRI’s  myself, for
a kidney stone problem, and  going in and out  at 8PM  after dinner was better for me, vs 
skipping out from work 15 miles away.   My home was close by the hosp, and zero traffic
at night, so it was a win-win for everybody. 

Its  called.... MTBF  or  mean time before failure.  No brainer here.   They have an  hour meter
on the fil, that is logged  every  day.  After  XXX  fil  hours, the tube is swapped out on spec, its that simple.

Now if you want to push your luck, and extend the fil hrs...and the tube craps out, and folks die as a result ,
the cost of a new tube pales in comparison.   IF the MTBF is say 12  K hrs....  and you change the tube
on spec at 10 K hrs,  who cares.  They got their money’s  worth out of the tube anyway.   Do you change the oil
in your car when the check engine light comes on after  4 years with the same oil.   You change it on spec every
6 months.   You don’t want to damage the motor.    Any motor can be replaced or rebuilt.  Lives  cant  be replaced. 

Two million dollar  MRI machines  with a dud tube in it, when you need  it in an emergency is  useless  to the hosp,
tech, and the car accident victim. 

Broadcast TX  with tube finals  will either have redundant TX, or change the tubes on a similar fil hour schedule.
Some broadcast TX  will  use  2 x 25 kw tube amps..and a 50 kw combiner.  One goes bad,  you still have the 2nd
TX,,, and are only down 3db.   Or  2 x 5 kw amps  etc.    These days, its  several  SS modules, and combiners.     

The operating  costs  for a typ large hospital  running 24-7-365 are massive.   An army of techs, nurses, doctors,
and dozens and dozens of cleaning staff, cafeteria folks, back up gen sets and electricians, IT geeks, etc.
And you are worried about the cost of some rinky dink YC-156.   They were  buying em by the pallet load back then. 

Moot point these days.   They are ALL  SS now.    AM  + FM replacement  TX’s  are also microprocessor controlled  SS  types. 
Tubes are toast.  The telco’s  stopped using Eimac Klystrons   for microwave links  by 1987.   SS after 1987.  Maintenance
dropped to almost zero. 

Jim  VE7RF