Ebay Classic organs

Collapse

Announcement

Collapse
No announcement yet.

Allen 301-B Problems, behaviors, and troubleshooting attempts..

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • OrganistAnthony
    commented on 's reply
    Yes, sorry about that. I'll edit for the clarity of those that may see this in the future!

  • John Vanderlee
    replied
    I think you reversed AC and DC in your last posting. But you got the right idea. Don’t worry about that jumping around on AC that is normal. It’s random internal noise on the millivolts range.

    Leave a comment:


  • OrganistAnthony
    replied
    Larry, I was able to break in the new multimeter this morning which read voltages of 5.14 on the capture supply and -27.74 on the power supply. I'm not sure if that's far enough off to cause any problems or not, however, I did bring them right around 5 and -27 with some tedious adjusting. I'm not sure if it's the placebo effect or not, but after that adjustment the stops seemed a bit snappier and lot less likely to flutter and miss the combination. Does that sound like an accurate effect of adjusting the voltage? That damn dulciana still goes down on every combination, but it could be a different issue as jbird604 alluded to above, although I didn't have success when pulling out the prongs as he suggested.

    After I adjusted the DC voltage, I also metered the AC voltage setting as John suggested and got readings between 0.000 and 0.001, although it was a bit more jumpy to get the reading. Sounds like the voltages should be accurate now? Do they have a tendency to just drift after a while and need periodic adjusting?

    Also, to make sure that my battery pack replacement was successful, would I just unplug the organ for a little while and then plug it back in? If all of the combinations are the same does that mean the battery pack is working?
    Last edited by OrganistAnthony; 07-06-2020, 01:36 PM.

    Leave a comment:


  • John Vanderlee
    replied
    When you read the DC voltages, you should also check them on the AC range of your meter. That is to assure that the DC supply is being filtered sufficiently. The reading should be miniscule like in the millivolt range. Millivolts are one thousands of a volt.Often the DC volts reading will be way off to start with if you have a problem there.

    Leave a comment:


  • myorgan
    commented on 's reply
    Larry,

    I actually had that problem when I initially obtained my MOS-2 505B. The organ was in the guy's garage in NC, and he had cats. After removing the cat hair and prying the pins apart, the organ worked much better!

    Michael

  • Larrytow
    replied
    You have the right idea about testing / adjusting the voltages. BUT, the meter needs to be set to DC, and in the appropriate range of voltages you are working with ( if it has various ranges available - some are auto ranging ). The internal circuits are all DC ones, after the various Power Supplies which convert the AC line voltage to DC current of various values.

    Leave a comment:


  • OrganistAnthony
    replied
    Greetings again everyone and thank you for the continued conversation, support, and patience with my limited electronics understanding! Larry, Thanks for passing along the photos. Although I'm looking at an identical layout in my instrument, it helps to be able to analyze everything when I'm not behind the console. I have purchased a multimeter and read up on the basics. I'm not overly confident with my understanding yet, but it seems straightforward if the leads are on the correct terminals. From what I can tell, it also seems that a mistake is more likely to end up with a crazy reading than blowing anything up.

    Here is my understanding so far from what has been posted above... There are 3 main voltage settings on the organ that can affect how the organ performs and behaves, and if they are off, I should expect strange things to happen. There is a capture power supply at +5V, card reader voltage setting, and the -27V power supply adjustment. Is my goal to get a reading on those voltages and adjust the knobs until the multimeter reads and corresponds with the 5V and -27V listed? I'll need some guidance on where to place the leads. I think I read in another post that the black lead will go on the ground. Then does the red lead go on the screw terminal with the corresponding voltage listed? Is this the right idea? The multimeter should be on the AC voltage setting, is that correct? I don't think I'll need to adjust the card reader voltage as that was adjusted when I had a tech take a look at the instrument right after I moved it to my home. Card reader works great and is one issue I'm not having!

    Two of the J80 pins looked ever so slightly bent, but nowhere near the vicinity of touching another pin. I did straighten them out but no change in behavior.

    jbird604, thanks for your clarification on the swell to great coupler wire.

    When plugged in, I was able to hear the effects of the random motion card and I could hear the effect getting stronger when I turn the thumb wheels. However, no matter what setting it was on, any stops that were selected on the great would automatically be coupled to the pedal (no couplers on at all) in the intermittent gurgling fashion that I mentioned above. The higher the setting on the Great thumbwheel, the stronger the gurgle. It almost sounds like I'm getting the jittering effects of random motion without the fundamental straight tone present. (the great keyboard plays normally) Turning on the trem, tuning sharp, or swell to great couples the full sound of the great into the pedals as it does normally. I'm wondering if there might be a connection between my normal coupling problems that tie in to the effects of the random motion card. I would be happy to demonstrate this on video if it would be helpful.

    I did manage to bend out the left and right tongue blades that correspond to the dulciana 8' tab in the great. When I did this, I must have gone a little bit too far, because the stop wouldn't sound when depressed, even then the dulciana still committed itself to every combination even when I reset them. I pushed the blades back in a bit and the stop now sounds normally, but no improvement from that stop on combination settings.

    Leave a comment:


  • Larrytow
    replied
    I'm glad you guys who know more about these MOS Allens are giving Anthony advice as well. Although I have fixed a good number of organs now, I'm still just a retired truck mechanic who Plays With organs. One thing I am pretty good at though is taking lots of photos. In my towing career we had a saying : No Pictures - Didn't Happen !!

    So to illustrate some of the adjustment points I dug these up. On the Capture Power Supply you can see the adjusting pot real well. And on the Main Power Supply, you can see both the Card Reader lamp adjustment and the -27 volt one.

    As jbird said ( and has said many times over the years, but I forgot about that ) that -27 volt adjustment is a critical one. That is why having a multi meter is really important to doing more investigation of your problems.

    One other thought occurred to me looking though my photos just now. You can see when looking at the photo of the large Capture System memory board how the pins protrude through the connectors. Particularly take a look at the top one ( J 80 ) to see if that extra battery pack that was in there perhaps bent some of those pins so that they are contacting adjacent ones ? Unless it was tied on real well, i might have moved around when transporting the organ ?

    Leave a comment:


  • samibe
    commented on 's reply
    Also, check the sense and control wires are not bent and touching at the DM-2 board for the dulciana stop.

  • John Vanderlee
    replied
    *arbor *reight sells a serviceable multi meter for about 7 bucks I think, Sometimes with a coupon it's free!

    Leave a comment:


  • jbird604
    replied
    The extra white wire on the coupler tab is supposed to be there, as in MOS organs the swell to great coupler also activates a relay in the audio chain. That has nothing to do with the other issues. BUT..... in MOS organs, when you couple the great to the pedal, the system uses a process called "natural coupling" to accomplish that. Natural coupling means that the pedal keys in effect will then play the great keys, literally. So, yes, the random motion gets coupled down, as does tremulant, sharp tuning, even the swell to great coupler gets coupled on through to the pedals. Not what you'd necessarily expect, but that's the way it works.

    The gurgling sound when great couples to the pedals probably indicates that the Random Motion effect is turned up way too high. There is a thumb wheel on the Tremulant Gate board to adjust this effect. I really don't care for the effect myself and generally turn it all the way off, or nearly so.

    I don't see anything wrong with the Dulciana tab, but it's possible that the "sense" leaf is in fact touching the tongue blade. It won't hurt anything to pull it back out of the way a little just to be safe. Note that when a tab goes DOWN, the tongue forces its way between the two leaf switches and grounds them to the frame. If the sense leaf is already touching the tongue, the capture action will think the tab is on when it is not on, and will "set" it into every memory slot. That is the best explanation I have for the odd behavior you describe.

    If there is any adjustment on the capture power supply, it is only for the +5 volts used to operate the memory chips. So use a multimeter to check that voltage and adjust if needed.

    BTW, all kinds of weird malfunctions WILL happen on a MOS organ if the -27 volt supply isn't just about dead on. So put your meter on that terminal and check it first. Then touch up the other voltages as needed. (Note that the +12 volt comes from an unregulated supply, so it may be high, as high as 15 volts or so, but that doesn't hurt anything.)

    Leave a comment:


  • myorgan
    commented on 's reply
    Multi meter. That way you can use it to check for other issues (i.e. Ωimpedance, volts, wattage, etc.). Local big-box has them available.

    Michael

  • OrganistAnthony
    replied
    jbird604, I have posted a photo of the great tabs, dulciana is 3rd from the right. I personally do not see anything out of place that stands out from the others. However, I did take a look at all of the tabs and noticed one which has a bonus white wire which looks different from the others, the great to pedal (Edit: Swell to Great) tab which I've also taken a photo of, 4th from the right. Do you think this could be a cause to all of my coupling issues mentioned in the original post? (tremulant and sharp tuning tab in the great both couple to the pedal, random motion card couples from great to pedal with gurgling sound)

    All, It seems that there are enough elements in keeping this organ running that require proper voltage adjustment necessitating my need to have a voltmeter. I'm willing to pick one up and learn and I did a little bit of reading about it last night. Would I need a multimeter or just a voltmeter for work with the organ? Jbird just chimed in this morning and seemed to thing that my capture system doesn't have any power supply adjustments. Does this mean that the large capture board could have problems?

    EDIT: I mixed up my tabs. The tab with the extra wire is Swell to Great, which I think defeats my reasoning for coupling issues, but I'll leave the photo up if anyone has any insight about the extra wire.

    Dulciana is 3rd from right
    Click image for larger version  Name:	IMG_0537.jpeg Views:	6 Size:	372.4 KB ID:	734813
    Swell to great tab is 4th from Right, with extra white wire
    Click image for larger version  Name:	IMG_0538.jpeg Views:	6 Size:	368.8 KB ID:	734814
    Last edited by OrganistAnthony; 07-04-2020, 01:18 PM.

    Leave a comment:


  • jbird604
    commented on 's reply
    He has DM-2 capture, which doesn't have any adjustments, best I recall. The old sequential capture had a scanning speed adjustment, which could be slowed down if it was not properly setting the stops.

  • Larrytow
    replied
    I'm sorry to hear that it was not just the batteries. Looks like you did fine with making up the jumper wire. How far do you want to get into looking for other issues ? Do you have and know how to use a voltmeter ? If not, would you want to obtain one and learn about using it ?

    As myorgan alluded to, there is a voltage adjustment for that memory system, but you have to have a voltmeter to check / adjust it.

    Leave a comment:

Working...
X