ADC-5300 Expression issue

[wo2012]

I have run into a small issue with the ADC 5300 that I recently acquired from a church. Today I moved the organ into another room in my house, and I connected it to six HC-11 speakers with an additional sub woofer. Unfortunately, the expression for one channel is not functioning. It is channel #1, a pedal channel affecting the following stops: 8' Trompette, 4' Flute Ouverte, 4' Choral Bass, Mixtur IV, 32' Contre Bombarde, 32' Contre Basse, 32' Contre Courdon, and 16' bourdon. When any of these stops are active they play at a quiet volume. Turning up the great/pedal expression does not lead to an increase in volume. The great expression pedal does increase the volume of unaffected great and pedal stops, however. This leads me to believe that the light bulb in the expression pedal is not the issue. I have plugged Channel #1 into amps and speakers that I know work and it sounds the exact same. I ran a new audio cable straight from the channel #1 cage output to a verified amplifier and the exact same thing. Can anybody please offer me any guidance? I know that this expression issue was not occurring yesterday. I have not ventured into the cage yet to try anything with pots or boards...

[myorgan]

Wo2012,

May I suggest keeping all your posts regarding this organ in one thread? I know this is a new/separate issue for you, but later on when you try to find the information you get here, it might be more difficult to find.

On topic, though, I've never heard of this issue. Your description makes me think it has something to do with one specific card in the cage not receiving/transmitting the information properly. All expression takes place in the cage before it goes to the amplifier. I can't find the ADC-5300 cage chart you posted in another thread, but if you find all the stops listed and the related card(s), that will help us help you. Once we have that information, we can help you troubleshoot.

Michael

[jbird604]

Great troubleshooting already! You have already done 90% of what a tech would do. We should all take a cue from your actions.

Since you've obviously isolated the trouble to something inside the cage, that makes it much easier. You know that your amps and speakers are ok, and you've even eliminated the USRM and other peripheral boards, since you know that the signal coming right out of the cage is defective.

Within the cage, the possible culprits are numerous, but the most common offenders are the TG boards. Looking at the cage chart, I see that the stops you mention do not all come from the same card though. They are from 15a, 16a, and 17a. That tends to rule out the TG boards, though it is still remotely possible that all three of them have dead spots in their Gain pots. You should at least try exercising those pots

But what all of these stops have in common is that they come out of the cage on channel 1. The card in the cage that pulls together the audio from the various cards and routes them to the proper channels is the USAP. The primary USAP is in the slot labeled "AP" and is the one that carries channel 1.

So it's possible that the primary USAP card has a problem. The first thing to try is to simply pull out the USAP card, smear a very very thin coat of Vaseline onto the gold contacts on the card edge and then wipe nearly all of it off. (The Vaseline will dissolve and lift any corrosion on the surface, even if it's invisible.) Then carefully reinsert the card into the slot, making sure it goes all the way in. That MIGHT fix it, if the trouble is actually just a connectivity issue. OTOH, the USAP could actually be defective.

I don't know if you have two identical USAP boards in the cage. If you do, you can swap them and see if the trouble goes to another set of stops. Since the second USAP board is only for the Festival Trumpet, it doesn't use all seven of its channels. So it's remotely possible that putting the defective USAP into that slot will cure the trouble, IF it comes down to having a defective USAP.

There is about to be a thread on the forum about the interchangeability of the differing USAP cards. I know that some of the different versions are different only in having mutes or no mutes, since muting in nearly all ADC models actually happens in the amps, and is not needed on the AP card. Other differences might relate to some card versions having fewer than the standard seven channels on board.

One other thing that all these stops have in common is that they all get their pitch from the USFG-2 card in slot #7. That board could be the problem, though it's unlikely, given that your problem has to do with volume, not pitch.

That's all I can see from the cage chart, but it's always possible that some board in the cage that seems unrelated is causing the trouble. That is the nature of the ADC system. An EG board anywhere in the cage can affect any group of stops. But these are longshot possibilities.

[toodles]

The expression signal goes from the swell shoes to the multiplexer, and from there to the cage, where processing takes place on the AP (audio processor) card. You can eliminate the lamp and multiplexer, since the great is expressing correctly.

Try removing and replacing the AP card in slot 11; it may be a bad connection to/from that board with the edge connector. Removing and replacing can often improve the connection.

Since it affects voices across 3 tone generator cards, it seems unlikely that it is any of the voicing pots.

Do you have antiphonal relays installed? If you disconnected speaker wiring to move it, make sure they were reconnected to the correct terminals on the antiphonal card. A quick way to check is to toggle the gt/pedal main off and antiphonal on tabs and check in each position.

[wo2012]

Thank you everybody! After removing the ap1 board and applying Vaseline to the card edge, the problem persisted. However I then swapped the two AP1 boards in my organ (one for the festival trumpet I think) and the issue went away. That pedal channel now works like it should and I haven't noticed any negative effects on the festival trumpet. Can I just leave these two boards swapped permanently?

[myorgan]

Why not? Good solution!

Michael

P.S. One thing we forgot to mention-make sure the organ is OFF when you swap any cards. You can pull them out while the organ is on, but you can't put them in while the organ is on.

[jbird604]

Yes, you can leave the two cards swapped. As I suggested up above, the second USAP board in your cage does nothing at all except process the Festival Trumpet, thus using only one of the available seven channels on the card. It's perfectly fine to leave them swapped, if everything now works correctly.

[wo2012]

Excellent, thanks for your help. I have one more question. If my organ is playing in a small room, can I remove the RCA input for the low part of the bass channel from the adc amp and plug the RCA cable directly into my own small powered subwoofer? This is what I was trying when I first noticed the other expression issue... I just don't want to cause another problem.

[AllenAnalog]

Yes, that should work but with one potential problem. The ADC amplifiers have a mute function for when the organ is turned on. You might hear a very big thump on the sub on power-up. I am preparing a thread on the AP card. If you have one with relays, it should duplicate the mute function of the amps. If you have one without relays, your organ is dependent on the ADC model amp internal mute function.

You mentioned that you had six HC-11 speakers hooked up - I presume to the six main channel amps. What speaker do you have hooked up to the Festival Trumpet channel?

[AllenAnalog]

I'm going to add a note to my own post. As discussed at length on another thread a while back, some subs have a standby mode for the built-in amplifier. They shut off when there is no audio signal for a period of time and turn back on when a signal is detected again. I have no idea whether the sub you are proposing to use has that feature and how long it takes to wake up. If it does work that way, the internal turn-on delay might be just long enough to keep from hearing the thump.

[wo2012]

Thanks for bringing the issue to my attention. I'll have to see how bad it is. I actually bought home 6 additional hc13s, so I have plenty of those. I could definitely use one for the festival trumpet! Can't wait to read the ap thread.

[myorgan]

Did you bring all the speakers home, or just the ones you needed? I'm sure you could find people interested in all the other speakers as well. They are very coveted by most looking for organ speakers they didn't pick up with the organ. I was lucky to get one set with my ADC-8000, but there are still 2 additional sets out there the dealer skimmed off.

Just food for thought.

Michael