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Fixing the switching power supply

This particular power supply is used in Broadcast Electronics AM1A, AM2.5E, AM5E, AM6A, AM10A, FM1C, FM20T, FM30T and FM35T transmitters. It is a Computer Products NFN 40-7610, 40 Watt, +5 VDC, +/- 15 VDC BE part number 540-0006.

BE AM1A ECU power supply, C-15 marked with pen for replacement

Generally, one component fails over time on this unit, C-15 which is a 680 uF 35 V electrolytic capacitor. When that capacitor dries out, the power supply will fail to start, do odd things like start and fail after a second or two, or cycle on and off. This will happen after the transmitter has been off for a few minutes. Replacing C-15 with a 1000 uF 50 V capacitor will fix the problem. There is enough room for the larger capacitor if the leads are left a little bit long.

BE AM1A repaired ECU power supply re-installed

We have several of these repaired units on various shelves at various transmitter sites.

As always, when replacing electrolytic capacitors, pay attention to the polarity otherwise this will happen:

Blown Electrolytic Capacitor installed backward

I suppose somebody was in a hurry to get home that day. After I installed this repaired unit, it ran for about 15 seconds and then there was a pop. I opened the door on the ECU and white smoke was wafting out from under the power supply cover. Since the Pope is still The Pope, I knew it was the electrolytic capacitor.

Our beloved BE AM1A is back in service. This transmitter is 22 years old and we can keep it going for as long as parts are available.

Salvaged classic equipment

During the early days of COVID, we were engaged to move a studio out of an old location in a hurry. There had been a long-simmering dispute with the landlord, who finally changed the locks (illegally), but then gave 30 days’ notice, and so on. Regardless, we were building a new studio a few blocks away and were told to take anything usable, which we did.

I noticed the old RCA on-air light for one of the studios and the owner said he’d like to have that installed at the new place. There were two other ones that were not working. In total, we ended up with three of these:

As far as I can tell, they dated from around 1960 and were filthy. Sixty years of dust, dirt, cigarette smoke, etc needed to be scrubbed off of them.

The original light bulb was a bi-pin 110-volt incandescent lamp. Over the years, the sockets became brittle and fell apart.

Rather than trying to source replacements for the lamp holder, I figured it was easier to install a 12 VDC LED module. That way this would become a low-voltage device and the LED module should last for as long as the studio is in use.

I took the two best units and installed them in the new studio. One of those units needed minor touchups to the black paint. The third unit’s paint was in bad shape. I opted to strip off all the black paint and repaint it, this time with red.

This is fine

How’s the weather? Well today, it will be orange outside.

No need to panic, however. Something or other about wildfires in eastern Canada is the cause.

Fortunately, I have some protective gear in the vehicle. I always carry a hard hat, high vis vest, steel towed boots, and this mask. It comes in handy if there is mold or in this case smoke. A P-100 respirator will filter out Organic Vapors/ Acid Gases (chlorine gas, hydrogen chloride/sulfur dioxide or chlorine dioxide or hydrogen sulfide) – Class 1 and Particulate.

The P-2.50 Particulate monitor had a peak of 248 micrograms per cubic meter, which is very unhealthy.

I had to do my normal weekly outside maintenance items. Looks silly, I know, but I feel great! This was about three o’clock after the worst of the orange had passed.

This, on the other hand, is slightly worrying…

It’s Survey Time!

What do you think about Digital Audio Broadcasting; aka HD Radio, DRM, and DAB?

I thought it might be an interesting exercise to canvass my readers from time to time on various topics. I am going to send this out via email and social media as well. I don’t know how long I will leave it open, but when it is complete, I will share the data here.

This week’s survey is ten quick questions about Digital Audio Broadcasting in the United States. If you hail from somewhere else, feel free to participate. I would be interested in those answers too.

Digital Audio Broadcasting Survey

Depending on how this goes, I may do other surveys about various broadcast topics.