BE FM-30 Transmitter

[zachm]

Does anyone still use an older BE FM-30 transmitter? I'm talking about the older one with the a controller with the two digit readout on it and a separate apc control box.

I'm having serious problems with both the apc and the controller. Anyone else have this problem? Right now, none of my output metering is working, and the front panel indicators are dead.

Thanks!<P ID="signature">______________
Zach Morton
Chief Engineer
Legend Communications Of Wyoming, LLC.

</P>

 

[tpt]

Zach, not familiar with this transmitter, but I would first look for the dumb and simple.

I'll assume you've had a chance to stare at the circuit and looked for burned components, or weird power supply voltages.

1. Check any connectors for corrosion, flaky connectors, etc.
2. If you can pull the circuit board bring it under a bright light and look for bad solder joints. Found this problem on Harris's MW-1 series boards.
3. A dead indicator would indicate low voltage power supply problems to me. Or simply the DC not getting from the supply to the display. This may also prove to be the key to the APC problem.

 

[RadioDoc]

> Zach, not familiar with this transmitter, but I would first
> look for the dumb and simple.
>
> I'll assume you've had a chance to stare at the circuit and
> looked for burned components, or weird power supply
> voltages.
>
> 1. Check any connectors for corrosion, flaky connectors,
> etc.
> 2. If you can pull the circuit board bring it under a bright
> light and look for bad solder joints. Found this problem on
> Harris's MW-1 series boards.
> 3. A dead indicator would indicate low voltage power supply
> problems to me. Or simply the DC not getting from the
> supply to the display. This may also prove to be the key to
> the APC problem.
>

A common problem with the old BE's, at least in the "B" series, is dirty edge connectors on the controller cards. If that's the type you have, pull out the cards, and clean the board edge and socket real well.<P ID="signature">______________
</P>

 

[tpt]

Also, if the transmitter has some years and heat on it, shotgun the low voltage electrolytics.

Remember a 2.5 kw Collins with controller circuits on plug-in circuit boards like those described above. Was very unstable, but when I looked carefully at the cards I found some very dried out caps. I replaced these electrolytics and everything settled down.

Don't use the Radio Shack sweepings unless you have to, get 105 C caps from someplace like Mouser or Digikey. They are cheap--you can usually replace most of the caps for under $25. Heat is usually the culprit for capacitor failure.

 

[saveng]

> Does anyone still use an older BE FM-30 transmitter? I'm
> talking about the older one with the a controller with the
> two digit readout on it and a separate apc control box.
>
> I'm having serious problems with both the apc and the
> controller. Anyone else have this problem? Right now, none
> of my output metering is working, and the front panel
> indicators are dead.
>
> Thanks!
>
Zach, make sure your voltages are all correct on the terminal blocks behind the controller. Also, check the OCRs in the power supply. Sometimes they start acting erratic. I would also shotgun the capacitors if it has been more than 10 years since this was done. You get a lot of heat coming off the exciter, driver and IPA modules right, and that heat drifts straight up into you controller. Your Power meter is in the same circuit as you APC. Make sure you check your voltages and caps in there.

<P ID="signature">______________
Robert Combs
Cumulus Broadcasting - Savannah
Any opinion expressed here are my own and do not reflect any opinions or association with Cumulus Broadcasting.</P>