Newer organ at our church

[PianOrgan]

Just a quick note to pass along some good news. We here in Wilkes-Barre Pa are the proud new owners of an Allen 301-B digital computer organ! We finally replaced our T-15B and the sounds are unbelievable. My thanks to jwl5151 for making this instrument available to us. All I need to do with it is get the capture system working and I'll really be in Heaven (or close to it!) For those techies online (including jbird, who I always count on for advice), it is Allen System 301-B, S/N 44077.

[searchinferu]

I have found that if the batteries are old or the organ hasn't been plugged in for some time, the capture system won't operate until the batteries build a charge. Apparently, the battery charger output is so low that it can't power the system on it's own, even though it can 'eventually' charge the batteries that do. They bear looking at anyway, to make sure you don't have the original batteries mounted directly over the capture system, just waiting to leak on it.

Have FUUUUNNNNNN!

[jbird604]

Yes indeed. Get those batteries off the DM board if they are still there. Of course, the older MOS organs have batteries off the board anyway.

Please post more details about the organ, such as the type of capture system. The DM (double memory) system has a keylock that toggles between the A and B memories. The sequential system has a key as well, but it is only an on/off switch for the combination system. Other difference are also notable, but the keylock style is a dead giveaway.

[PianOrgan]

As far as I saw, the combination action is the sequential type. The Key "selector" was not listed as A or B, so I'm assuming that it does not have the double memory. I did press some of the combination pistons and I heard a light "twittering" as if it was trying to set something. A question for John, where are the batteries for the capture system located? I have access to the church anytime, so getting there is no problem. Does the serial number give you any clue as to anything else on the organ (44077)? Some additional information I got from the previous owner is that the organ was made around 1973 or so.

[jbird604]

If you heard "twittering" it is sequential. You need to "wake up" the processor with an old trick -- turn the Combon keylock to the "on" position, then hold in the Set and Cancel pistons at the same time for a few seconds (maybe 4 or 5 seconds). You'll hear the scanning or twittering sound while you hold these pistons. Now, set up a registration, hold in the Set piston and tap General piston #1. Then cancel your registration, press #1 and see if it comes back. I'll bet it does. The processor in the sequential system can lock up or go to sleep and this little trick normally brings it back to life.

The batteries for a sequential have to be huge because the memory chips operate on 27 volts and draw a good bit of current. When the organ was sold new, it would have had a little 27 volt battery the size of a pack of cigarettes, but that was just a token and would only hold the memory for a short time if the power went out. Allen started offering a big old battery pack that contained 13 D-cell lead-acid batteries wired in series, and these were often placed up in the top of the organ behind the keys or else bracketed somewhere inside the console. There was a recharging circuit built into these packs. This pack was quite expensive and eventually quit working as the lead acid cells eventually stopped holding a charge.

Thankfully, we now have batteries that are being sold for desktop computer battery backup units that make perfect replacements. A "12 volt" lead acid battery actually puts out about 13.5 volts, so two of them wired in series make a perfect battery backup for this organ. Allen even published instructions for techs to build a suitable self-recharging backup system for these old sequential actions. If you are handy with a soldering iron and can get your hands on a few items from Radio Shack, I'll send you the instructions and let you make one. However, someone may have already done it for this organ, as it was very commonly done to replace that silly cigarette-pack battery.

A quick and easy way to provide battery back up for any MOS organ is to go to Office Depot and pay about $75 for a heavy-duty UPS unit and plug the organ into it ahead of the wall socket. This may be your best bet if there is not already a recharging setup in the console. This takes the place of a surge protector and provides a good bit of protection for the capture memories if the power goes off. One caveat -- if you are playing the organ and the power goes off, shut it down right away because playing it while running on battery power will drain the battery very quickly.

[PianOrgan]

I tried John's Set/Cancel trick on the organ, but it did not work. I also noticed that the twittering (sequential setting) is heard on all pistons and toe studs except for the Great divisional pistons (go figure). I did get inside of the console and took some cell phone pictures of the innards. I also have a spare capture board as well as what I think is the main computer board. Any additional help is greatly appreciated.

[PianOrgan]

Last two pics of the 301-B

[jbird604]

Pic #1 is the sequential capture memory board, the one with the large capacitor and the heat-sink. If you have a spare capture board, you could try subbing it in and see if that makes it work. The 5th pic show the 27 volt rechargeable battery pack in the floor of the organ to the left of the amplifiers. It could be old and no longer holding a charge, but I don't think that will keep a sequential from working completely. Try the set-cancel trick again and hold it for 6 or 7 seconds this time.

Before you go any further, you should verify and possibly adjust all the voltages in the system. You will see on the main power supply some pots for adjusting the -27 volts, the +5, and the -5. Use a good digital meter to measure these and set them accurately. Sweep each pot through part of its operating range just to clean the wiper a bit before settling right on the desired voltage. As you sweep the -27 volt pot to the extremes, you will probably hear the MOS board going crazy, maybe sending some weird noises through the speakers, so be sure the expression pedal is closed when you do this. There is no adjustment on the +12 volt supply (smaller supply to the left of the main supply), but it will probably read between 12 and 16 volts. The AC output (I don't recall the voltage) is the power supply for the capture action magnets, so if it is missing that could explain your capture action's failure.

The sequential capture gets power from the main organ supply and the +12 supply. If these supplies are OK, the trouble is probably the capture board itself or some other part of the capture system. As I recall, there is a relay in the capture sytem somewhere, possibly marked "piston rail disable" or something like that. You might look for that and see if it clicks when the organ is first turned on.

The sequential system is slow and some people hate the clickety-clack sound, but for the most part it is stable and reliable. Maybe it will work with the spare board.

The organ looks pretty good, but if I were you I'd clean up the mass of tangled wires around the amplifiers. Just neaten them up, make sure they are tightly connected wherever they go, use some bread ties or something to coil them up so they don't look so unruly.

That's a good organ, even without a capture action, so I think your church will love it just for the nice sounds. I hope you're able to get the action working, but you may wind up needing an Allen tech.

[PianOrgan]

I had some time to get to the church today to try to get the capture system working. I swapped out the old capture board with a spare board that came with the organ. Upon plugging the organ in, I got the sequential twittering WITHOUT TURNING IT ON! I immediately un-swapped the board, so that the original board is now in the instrument. The twittering was gone, but now I cannot set any combinations. I tried holding down Set/Cancel with the key in the ON position for about 7-8 seconds, then setting a combination from the Swell manual to General 1. I heard a twitter upon releasing the pistons, but the Cancel does not work, nor did my combination return. In addition, the Great Divisional pistons do NOT twitter, but all of the other pistons and/or toe studs do. I did take a picture of the new board. For those who cannot make out the numbers in Black, the capture system is 1945, and the assembly number is 10169D15 with 7124 on the next line.

Any advice is greatly appreciated.

[Pipeorganbuilder]

Be very careful of adjusting the 27 volt supply. The three white and gold IC Chips on the center of this board are MOS chips that are very easy to wipe out with over voltage. Allen can no longer supply replacement chips for this board and require their reps to change system over to a new board. These chips were a Rockwell chip and have been out of production for years. You can disconnect the battery and the board will continue to work--just will not hold the memory. Check the power supplies with you meter set to AC to see if you have a leaky electrolytic capacitor in the power supplies. There should be no AC on any of the supply lines. Also may need to check the pistons to see if there is one stuck holding that scan line active. A common failure with this board is it will start scanning as soon as the organ is turned on. This is caused by the middle white/gold MOS Rockwell chip. Good luck.

[PianOrgan]

Many thanks to all who have helped with advice thus far. I checked all of the voltages on the main power supply as well as the small AC power supply, and they look all right. I also disconnected the main battery pack (pic #1 on the previous posts), and I'm still not able to set any combinations. My conclusion (along with JBird's) is that the capture board is kaput. My question to everyone is where (other than Allen of course) can I get a new or at least refurbished capture board for as cheaply as possible? Granted, the organ sounds fantastic (people in the front few rows are getting a free massage from the bass vibration) but I would like to get the capture action working if possible.

[jbird604]

I always thought somebody should make a retrofit for these actions because they are wired so simply. Every stop has a sense wire that terminates on one of the connectors, and every magnet has an up and a down wire too. And every piston terminates on the board as well. Should be a simple matter to wire in some other standard capture system, but I know of no one who has done this.

[Horseshoe_or]

Harrison Labs in Colorado provides retro stuff for MOS-1 and Mos-2 instruments. You might see if they can help you.

[Pipeorganbuilder]

Good point John. I have been using Syndine combination actions for years on Allen organs because they very quickly hook up to the Allen terminal boards using the same setup. They cost around $1000 to install and have many more features. Allen boards are two to three times this much. All you need is the stop tab input then the on coil and off coil to be wired in. The pistons connect to another set of contacts on the board. Klann makes a very nice combination board along with Petterson Elec. All pipe organ suppliers sell a contact replacement kit that consists of a very small hollow tube that fits over the broken stub. It takes only a few minutes to do and gives a permanent repair. I have used this on pipe organ consoles for years. Organ Supply Industry sells the kits. Watch Ebay under pipe organ parts and you will find several of the Petterson combination actions for sale from time to time. The last three I bought were less than $100 and came from a working console that was been rebuilt. Hope this helps.

[jbird604]

Thanks for the info! I thought it should be do-able, but haven't seen such a retrofit myself. The Allen sequential action is OK when it works, but some people hate the time it takes to go through the sequence, as well as the clattering sound. I need to find me an old MOS console with a dead sequential and try putting in a Peterson. Sounds like fun and sure would bring some new life to one of these old organs!

As to the contact repair you mention -- are you talking about an easy replacement for the silver wire vertical contacts on an analog Allen? That would be a nice item to know about as well.