Allen 505-B stops not working

[Guest]

Hello, I have owned an Allen 505-B for almost a year now. When we first purchased it from a local ministry for a fantastic price, I had noticed that multiple stops did not work on both manuals and the pedalboard. This was my first organ that had a full pedalboard, so it did not matter to me that these stops did not work. However, it is now beginning to bother me. I do understand that this organ is 35 years old and will deteriorate with age, but I believe there is a way to fix this. Here is a list of the stops that do not work and the manuals they correspond to:


Swell - Flute Conique 16', Celeste Tuning

Great - Erzahler 16', Cor Anglais 8'

Pedal - Diapason 16', Bourdon 16', Gedeckt Flote 8', Choral Bass 4'

General - Chorus Tuning, Random Motion Off, Speech Artic. Off

Rocker Switches - Reverb, Antiphonal Organ, Main Organ Off


I have opened the back of the organ to see if there is any obvious evidence of any cut wires or anything out of place. I did not see any loose or cut wires, but with me not being a technician nor very familiar with organ circuitry, I could be overlooking something. I came here to the forum because where I live, there are not too many organ repairs or organ technicians around here. If someone has any idea on how to help or tips for me, it would be greatly appreciated.

Thank you!

[Admin]

When you say "don't work" are you saying they don't sound or are you saying they don't work with combination action?

Not all stop tabs are connected to the combination system. I would suspect that these may not be:
General - Chorus Tuning, Random Motion Off, Speech Artic. Off

Rocker Switches - Reverb, Antiphonal Organ, Main Organ Off

As for the other stops, again if we're talking about combination action, do they not turn on, not turn off, or both?

[jbird604]

Sounds like at least one of your four audio channels is not working. If your 505 is the standard setup, you will have four S-100 amplifiers connected to four HC-12 speaker cabinets. Perhaps one of the speakers is not connected to the amp. Or one of the amps is not plugged into the switched AC outlet in the console. It's always possible that one of the amps is defective or that the circuit breaker (red stick sticking out the back of the amp chassis) is tripped. If your speakers are connected through antiphonal relays instead of directly to the amps, it's possible that one of the relays is bad, or that the speaker wires are not on the correct terminals.

It is also possible that one of the two MOS systems is not functioning at all, and you might fail to notice that if you aren't fully aware of the way this model works and how it's supposed to sound. There is a little chrome on/off toggle switch next to each DAC board that is used to temporarily silence each MOS output for testing purposes, and you may find that one of them has been inadvertently left in the off position. Both should be "on" for proper operation.

This is a wonderful organ, and it's a shame you're not getting the full benefit of what it can do. Since you have very little invested in it, you might do well to have a qualified Allen tech come and check it out. While it's possible for you to troubleshoot it with extensive and detailed instructions over the internet, that is painfully slow and frustrating. You owe it to yourself to spend a few hundred dollars having it professionally checked out. The 505 is equivalent in many ways to a new model in the current line up costing $75K or more and will give you decades of reliable service once you have it working properly.

Good luck! Welcome to the Organ Forum. Please keep us posted on how it works out for you.

[myorgan]

Here is a list of the stops that do not work and the manuals they correspond to:
Swell - Flute Conique 16', Celeste Tuning
Great - Erzahler 16', Cor Anglais 8'
Pedal - Diapason 16', Bourdon 16', Gedeckt Flote 8', Choral Bass 4'
General - Chorus Tuning, Random Motion Off, Speech Artic. Off
Rocker Switches - Reverb, Antiphonal Organ, Main Organ Off

From the list you've provided, it looks like Channel 3 (at least it's that on my 505B) is not working. Follow John's advice and trace the signal from the speaker>cable>relays (if you have them)>amplifier>amplifier input>DAC4, etc. You get the idea. I've attached the channel chart from my organ for your reference. BTW, the sound is generated from the B computer.

I hope this information is helpful.

Michael

[Admin]

The reason I asked whether this was a problem with the combination action or the audio is that OP mentions Chorus Tuning, Random Motion, Speech Artic., Reverb, Antiphonal and Main Organ Off switches not working.

None of those items would be isolated to an individual channel. Perhaps there are multiple issues, but the nature of the problem requires clarification before a diagnosis can be made.

[jbird604]

You are correct, Admin. We do need clarification on those. My guess is that these tabs don't seem to do anything when drawn. The celeste and chorus tuning tabs only serve to sharpen the tuning of the "B" computer, so if the "B" system is dead, there would be no audible change. And if there are no relays installed, the Main Off and Antiphonal On tabs would do nothing, and if there is no reverb installed, that tab would also do nothing. Many people can't hear much of anything when the Speech Articulation or Random Motion is turned on or off, but that's because they don't know what to listen for.

More telling is the list of seven speaking stops that are said to be dead. I'd have to dig out the wiring charts for the 505 to say for sure, but I'm guessing that those particular stops happen to come from the same channel, or maybe they happen to be the only stops that are in one computer but not in the other system. So I'm guessing that either there is a dead audio channel or else one computer is not functioning.

I hope he'll get a tech to look at it since it's such a fine organ and it's a shame it isn't doing what it's supposed to do.

[myorgan]

The reason I asked whether this was a problem with the combination action or the audio is that OP mentions Chorus Tuning, Random Motion, Speech Artic., Reverb, Antiphonal and Main Organ Off switches not working.

None of those items would be isolated to an individual channel. Perhaps there are multiple issues, but the nature of the problem requires clarification before a diagnosis can be made.

Admin,

I agree. However, my organ came with a connection for Chimes and other effects, but it does nothing. If I were to hazard a guess, most of the rocker tabs mentioned are just engraved--not connected. Mine are all blank.

You are correct, Admin. We do need clarification on those. My guess is that these tabs don't seem to do anything when drawn. [snip] Many people can't hear much of anything when the Speech Articulation or Random Motion is turned on or off, but that's because they don't know what to listen for.

More telling is the list of seven speaking stops that are said to be dead. I'd have to dig out the wiring charts for the 505 to say for sure, but I'm guessing that those particular stops happen to come from the same channel, or maybe they happen to be the only stops that are in one computer but not in the other system.

John,

Check the PDF I linked above. It has the channels outlined as I have them set up in my organ. Channels 1 & 2 are on the A Computer, and 3 & 4 are on the B Computer. Channels 1 & 4 are paired for celestes, and channels 2 & 3 are paired for celestes. The stops listed in the OP almost entirely reside on Channel 3. I suspect there are other manual stops that are missing 1/2 their sound, but because the companion channel is working, the OP doesn't realize they're not working (except missing the celeste). With one channel missing, less than 1/2 of the manual stops will celeste, whereas normally almost all of them would (except 16' and a couple of Reed stops).

John, would the Speech Articulation Off affect the Sw. Gedeckt 8' or Flute 4'? I thought the chiff was built into those stops. That said, however, that organ does have a Chiff tab in the General section that affects the entire organ. Each manual has a separate Delay tab, and a Celeste Tuning tab for each manual.

Hope that helps. Clarification is certainly in order, though.

Michael

[jbird604]

Unless I'm mistaken, the "Speech Articulation" tab on a MOS organ only turns on or off the odd little "yip" thing that the computers do when multiple keys are played together. It is very subtle, and many people seem unable to detect it. When I went to Allen seminars, they often demonstrated it so we would know exactly what was going on.

To hear it, be sure Speech Articulation is "on" (tab not drawn). Turn on a 4' principal stop and hold down C5 with your right hand. While holding that note down, play a staccato run in the lowest octave with your left hand. As you strike and lift each of the staccato notes you will hear the pitch of the C5 briefly dip and rise, what I call a "yip."

Supposedly, the reason for this feature is to simulate what the smaller pipes do when their wind is de-stabilized by the sounding of larger pipes, lower pitches. I just think it's kinda strange.

The other tab he mentions, Random Motion, is also subtle, and you probably already know about it. With Random Motion "on" hold a single note in the highest octave and listen for the rapid "jitter" in the pitch. Turn Random Motion off and listen as the effect goes away. I do like this effect, as it is quite similar to the "spitting" noise that you hear if you listen close up to a speaking pipe, and I think it made the MOS organs sound a little more realistic.

[Guest]

When you say "don't work" are you saying they don't sound or are you saying they don't work with combination action?

Not all stop tabs are connected to the combination system. I would suspect that these may not be:
General - Chorus Tuning, Random Motion Off, Speech Artic. Off

Rocker Switches - Reverb, Antiphonal Organ, Main Organ Off

As for the other stops, again if we're talking about combination action, do they not turn on, not turn off, or both?

Reverb, Antiphonal Organ Off, Main Organ Off, Random Motion Off, and Speech articulation off do not work with combination action. All others from the Swell, Great, and Pedal work with combination action, but do not sound. Generally, none of them will sound.

[jbird604]

See the notes above by me and by myorgan (Michael). I am pretty sure your problem is either that one of the audio channels is down (the "B" flute channel) or that the "B" computer is not working at all. Could be as simple as the toggle switch next to the DAC board on the B computer. Or it could be a speaker wire not connected, an amplifier with a tripped circuit breaker, or a bad board somewhere in the B system. I could even be that the EPROM in the "suboctave" socket of the B computer has a bent pin or is not fully seated in the socket, as most of the stops you mention are EPROM stops.

If you can't spot it you should call an Allen tech. Your organ is too nice and worth too much money not to get it properly fixed.

[samibe]

The stops you have listed (that don't change with the combination action) are probably not run by the combination action. Those stops are functioning correctly. Unless they aren't doing what they are supposed to.

Couplers (swell to great, etc.) do not produce sounds by themselves. They add selected stops from one division to notes played on another division.

The other stops (reverb, antiphonal/main, etc.) don't produce sounds but they do modify the audio signal generated from playing other stops by adding effects or routing the audio to different sets of speakers.

As for the other stops, take the advice from John and Michael and check the B computer and audio path.