Rodgers 830 intermittent buzzing noise

[Kansas]

Hello Forum,
I have a problem with a Rodgers 830 that has a intermittent buzzing in the audio. This buzzing has been going on intermittently for at least a year but when it happens it doesn't last long enough to troubleshoot. Very frustrating!
If anyone out there has experienced this problem and has found the cause, please let me know.
To explain the problem: When turning on the organ and playing it is just fine but sometime while playing, the audio will get distorted just enough to be annoying but will go away as fast as it appears. The voices sound buzzy not clear. Not sure how to explain this problem but it is annoying. It has happened to me a few times in the last year while at the church. I have been at the church when other people are in the office and wonder if it could be interference from some type of motor like a shredder or copier as it doesn't last very long but has been noticed by the organist who has been playing a wedding on a Saturday. It seems to happen in the summer months as that is the only time I have been notified of the problem. The first time I was aware of it was last summer and now it is happening again this summer. Weird!
Hopefully, I can get to the bottom of this.
Thank you!

[jbird604]

The fact that it's intermittent and short-lived, and that it may only happen in the summer -- these point to something within the church that is interfering with the organ. Perhaps some part of the air conditioning system?

If the organ is not on its own fully-dedicated power circuit, with a direct line to the breaker panel, the power could be getting pulled down by the start-up cycle of a heavy-duty air handler or compressor unit. Or, if the amplifiers are in a closet or in one of the speaker chambers, they might be on a circuit is shared with part of the air conditioning system. (Actually, in most 830 installations the amps are in the console, but there's always a chance yours are remote.)

Other than that, I can only suggest "routine maintenance" of the entire organ system. Though there aren't a great many inter-connects in an older analog like this, as there are in most modern digitals, there are some pull-away connectors. There are in fact some on the power amp assembly in the console. And if the amps happen to be remote, there are push-on connectors at the console end and on the amps themselves. All these connectors, and all other connectors in the organ, need to be pulled loose, rubbed with a very thin coat of Vaseline, and wiped clean and dry before re-connecting.

On Rodgers organs of that era there are some three-legged or four-legged transistors and/or regulators and such that are mounted on a heat-sink in the power supply and power amplifier assemblies, often mounted on the back of the kneeboard. These devices are not soldered to the circuit boards, but their legs are pushed into sockets on the boards. This is a spot notorious for losing firm contact over time, and the result is sometimes intermittent or constant noise, hum, distortion. The prescribed cure is to remove the sockets and solder these things directly to the board. But I have had good luck just cleaning the legs of the components with Vaseline and then making sure they are firmly seated in the sockets.

Don't overlook the fact that analog organs are VERY susceptible to cell phone signal pick-up. Whenever we service an analog of almost any brand, we have to lay our phones down some distance from the console to keep the organ from picking up the strange noises and fuzzy beeps and such from a cell phone's internal transmitter.

Analog organs are also very good at picking up radio stations, TV stations, and various communications devices such as ham radios, CB radios, walkie-talkies, and such. There isn't much you can do about that, and phenomena such as this can be very unpredictable and intermittent.

I have heard of analog organs out in the country picking up pulses from an electric fence on a cattle ranch near a church.

Bottom line... it may be very hard to ever find the source of this noise unless it happens to last for at least several minutes so you can actively try to analyze it and then run around to see what machinery is running at the time. I would recommend extensive routine maintenance, at the very least. That should rule out faulty connections within the organ itself.

[Kansas]

Thank you John,
Very helpful advise. I will do what I can.

[Kansas]

After hard thinking about this problem, I realized that I had experienced a similar problem a few years back with a Rodgers rep on a model 600. He explained to me after fixing the problem that the copper wires had become pinched on the back panel and all he had to do was straighten them out and the problem was fixed. There are hundreds of these wires on the back panel and even though they are coated with lacquer they can short. Even though I didn't see him fix this, I am curious to know if anyone else has experienced this?
Please let me know.
Thank you!

[jbird604]

Yes, there are a great many bundles of this enamel copper wire inside such an organ. I can recall a problem on a Rodgers analog that seemed to go away as soon as we took of the back and started to swing out the racks. With some patience and trial and error, we found that flexing one bundle in particular would start or stop the problem, whatever it was. We probably fixed it by spreading the wires apart enough to prevent the short circuiting.

Rodgers used to advise techs to "dress" the cable bundles as a step in troubleshooting, but which I assume they meant to straighten them, to make sure they weren't getting pinched or twisted when closing the racks or putting on the back. You don't want to do any unnecessary moving about of the bundles though, as that might invite new troubles.

It certainly won't hurt anything to carefully poke around and check for such a thing. If you should discover that the buzz comes and goes when you touch or move a certain bundle, that would be an important clue.

More frequently I seem to find that it's not the wires in the bundle so much as the ends of those wires. In a recent example, I was struggling to find why a certain pitch was intermittent in a Rodgers analog. Swinging the rack in and out seemed to provoke the problem, making me wonder if it could be a short in a bundle. But I finally realized that one of the tiny enamel wires was not soldered to a pad on the oscillator board, just pressing against it by the torsion of the bundle. Any movement of the rack or even vibration of the console could disrupt that connection and the note would be dead for a while. Soldering it in place solved the problem.

Your challenge is to get the buzz to last long enough for you to locate the source. That is always the trouble with intermittent malfunctions!