[SBE] Harris HT40 TV transmitter question

[jer hill]

Hi Curt,
That's probably correct. I was speaking generally about some of the
alarm/monitoring designs I have seen over the years and relating how I would
approach this problem at first blush and pointing to a solution without any
particular knowledge of this transmitter. Putting a jumper on the module
connector on the back plane board is similar to jumpering the signal on the
monitor/alarm/control board.

-jer

-----Original Message-----
From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org] On Behalf Of Curt
Yengst
Sent: Wednesday, June 23, 2010 5:32 AM
To: sbe member discussion mail list
Subject: Re: [SBE] Harris HT40 TV transmitter question

Jer:
By "alarm board" do you mean the Monitor Board in the control cabinet?  If
so, then yes, I have a schematic for that.




-----Original Message-----
From: sbe-bounces at sbe.org on behalf of jer hill
Sent: Tue 6/22/2010 10:20 PM
To: 'sbe member discussion mail list'
Subject: Re: [SBE] Harris HT40 TV transmitter question
 
Carl,

 

If you have the schematics for the alarm board, you will see an input for
modules such as the aural and the exciter. It most likely is a logic level
signal. You might be able to defeat the alarms by permanently wiring those
unneeded alarms in the off position. It may take the interruption of the
signal or it may take a voltage to hold the alarm off. Whichever, you should
be able to remove a resistor or add voltage (through a resister) to the
logic of the alarm board that lights up the alarms that you don't need.
Don't forget to mark the schematic as modified in case you plan to sell the
transmitter.

 

-jer

 

From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org] On Behalf Of Curt
Yengst
Sent: Tuesday, June 22, 2010 1:21 PM
To: sbe at sbe.org
Subject: [SBE] Harris HT40 TV transmitter question

 

I'm not a TV engineer, nor do I play one on TV; but I'm currently assisting
at a local TV station.  We've installed a Harris HT40 which was purchased
second-hand.  Everything works great except for one thing.....

We're not using the stock exciters, nor are we using the aural modules in
the PA cabinets.  Since the station is digital, we're using an after-market
digital exciter and using the visual PA's to amplify that signal.  We've
disconnected the aural modules from the power supplies, and the stock
exciters are completely removed.

We now get, as can be expected, module fault alarms and exciter alarms on
the display in the control cabinet.  The exciter alarms are not the big
issue here, but the module alarms are.  We know the alarms are caused by the
fact that the aural modules are disconnected.  The problem comes if and when
we have a legitimate visual module fault.  There's no way to tell.  This
prevents us from connecting the module fault alarm to our Burk remote
system.

Has anyone else been through this configuration already, and could you
suggest a way to "fool" the transmitter into seeing good aural modules, or
even getting it to just ignore the disconnected modules?

Curt