Strange problem on my Johannus - help!

[julianjsoh]

Hi everyone,

My Johannus Sweelinck 20 started acting real weird yesterday. Here are 2 videos of what's happening: https://drive.google.com/drive/folders/1Zwyc7Z_RSkiDoKi9xu-lcaCa4-8tByCC?usp=sharing

Essentially, some notes on both the manuals and pedals are sounding 2 notes together. These are the same notes/keys on the Gt, Sw and Pedal that act up or have the compound tone. If you notice, the problem keys are sounding the correct note together with another note a tritone apart (higher). And it is always the same interval that sounds in relation to the keys that have a problem. Strangely, this happens across both manuals and pedals. The problem notes on both manuals are exactly the same, while in the pedal, the problem notes sound their correct pitch together with a tritone below them.

Anyone has a clue what is going on? It seems like Messiaen has taken over my organ...

[jbird604]

I hope there is an experienced Johannus tech who will come in and help you here. I'd be out of my field on that one, but I'd suggest starting with following the wires from each keyboard to see where they go. At some point, the keying cables from all the keyboards intersect, perhaps at a ribbon cable junction board, and a cross-connection may have developed. It could something as simple as a metal flake or a paper clip that has fallen down into the board.

One of the most common problems I've encountered with Johannus models of that era involves the power supply. It is a standard third-party switching supply about the size of a paper-back novel enclosed in an aluminum cage and sits on the component shelf inside the console. it should have quite a few wires attached to the terminal strips using spade lugs. There is a small white adjustment knob (use a mini screwdriver to turn it), and it adjusts the +12 volts or the +5 volts, I can't recall which. But that voltage is pretty critical, and if it's off there could be various malfunctions. Use a meter to set that voltage just slightly higher than the spec, about 5.1 volts for the 5 and 12.2 for the 12.

Another issue with many Johannus organs of that era involves the plugs used to take power to all the boards. These are yellow in color and have four or five pins each. The ultimate solution to plug trouble is to hardwire all the power supply voltages to each board, but it might help to gently press down and make sure all these yellow plugs are firmly connected.

Alternatively, the problem could be related to the transposer function. Try playing in different transposer positions and see if that makes any difference.

As with all weird organ problems, general routine maintenance may actually solve the issue. A thorough vacuuming of the interior, tightening up all the connections, re-seating every cable, every socketed chip, and anything else that may have worked loose over time could work.

Worst case, you could have a failure in one of the system boards. But I have no knowledge of the functions of the individual boards in the Johannus organs, so that's why I hope there is someone here who does!

[SchnarrHorn]

It seems like Messiaen has taken over my organ...

I'm sorry - don't have any suggestions to help with your problem, but the above made my day. :->

George

[julianjsoh]

Thank you everyone for your advice, especially John, who is ever helpful. I am not particularly handy or technically inclined, so I would rather not poke around the insides. I will get a technician to look at this odd problem.

In the worst case scenario of some kind of board failure, would this typically be an expensive repair?

[jbird604]

Could easily run into a few hundred dollars, but this organ is certainly worth fixing.

[julianjsoh]

So the technician came yesterday. Lo and behold, the strange problem with the wrong-sounding keys resolved by itself within 5 minutes of his arrival. Very strange, indeed. Especially because I was tinkering around with it the whole weekend and not once did it revert to normal.

He told me that he cleaned up the contacts and reconnected all connectors, as he believed it to be a connection issue. Will have to monitor if the problem returns.

Now, I've realised a couple of new problems have come up. First, the row of accessories tabs which include the midi switches, chorus and 2nd intonation (baroque voicing) don't work at all now. Nothing happens when those tabs are pressed (they worked fine before). Second, the stops don't seem to sound a C-C# layout now (I am quite certain some stops did this previously, especially obvious on the trumpet, where the sound would pan from left to right on different notes). All stops now seem to sound from only one speaker, instead of the alternating arrangement that was in place before.

The technician doesn't really have an idea, and needs to check with Johannus on this.

[ahlborn]

The "triton" problem could be related to the keyboard matrix circuit. The problem of tabs not activating could also be a matrix circuit problem. If it is a random problem, it could be a cold weld, and a problem related to the thermal instability of some component.

Did you call an authorized Johannus technician? It would be better to call an authorized Johannus technician who knows where to put his hands.
Don't believe anyone who negatively criticizes your organ: it is actually a modern instrument that already sounds very good according to current standards (long loop sample), and also has a nice cabinet.

[mrdc2000]

Have the technician come back and do all of the reseating of terminal connections over again and to make sure to put them back precisely where they should locate. I am saying this because I once owned a Sweelinck 20 that had minor problems like yours and I cleaned the connectors and then reseated some of them just one pin over too far either left or right which gave me new problems such as you are now having. Realigning all the plug-ins solved the problems for several years. If you keep this organ you might have to clean and reseat those troublesome connectors every 2-3 years or so. Use DeOxit spray to clean the pins and seats, do the ribbon cables too but be very careful with those. Good luck !!

[ahlborn]

@ praestant: curiously, all these flaws that you see in Johannus, I see them in Allen. Do you want me to list them for you?

[julianjsoh]

Thanks, ahlborn and mrdc2000. I called the local Johannus rep who sent his technician. Thank you for all your advice.

I agree with ahlborn that the organ sounds very good - I am actually very pleased with how it sounds considering it is 20 years old. In fact, I played on the current generation Opus recently, and didn't like the sound at all. There was a very synthetic edge to the stops. I am surprised that my Sweelinck sounds better than the current Opus! I hope the problem can be resolved.

[julianjsoh]

An update on my problems so far. The Johannus technician hasn't been able to locate the source of the Tritone issue with the keys- and it is very frustrating, because it comes and goes. I can be in the middle of a piece, and it suddenly starts acting up.

Yesterday, I decided to open the organ and take a look at the connectors. I figured to reseat all the connectors I could find, and the good thing is that the row of accessories tabs now works (I think the guy put the connector in the wrong way). Anyway, the issue with the keys persisted and I gave up. Moved the organ back in place, and it was GONE! Not sure how long the good behaviour will last though. With its erratic behaviour and the Johannus tech not being able to come up with any solution, I'm tempted to call it a day with this organ.

One question - while I was exercising the amplifier pots, I noticed there were 5 pots - Volume, Bass, Mid, something market Swe and Treble. Anyone knows what Swe does? I put everything at mid point since somebody had turned most of it 3/4 way.

[ahlborn]

It is almost certainly a bad solder, or a bad connector. It is probably an easy problem, but you have to understand WHERE it is.
If you are familiar with electronics, you should check the board (or boards) where cables connect the keyboards/tabs. You must check that the welds are in place, there are no welding residues or small metal objects that create a short circuit between two tracks, the connectors connect well and transmit the signal.

The problem is locating the fault. The tabs that didn't work could be a clue: you need to understand where the cables that connect these tabs go and check. It could be a badly reconnected cable by the technician, but it could also be the original problem that shows up in other forms.

The potentiometers probably adjust the gain of the various spectrum portions. I do not recommend touching them. They are factory adjusted and should be left in their original position.
They don't have a voicing function, your organ can be voiced with software, so those pots MUST NOT BE MOVED.

[julianjsoh]

Hi all. Thank you for your advice with the strange stray notes issue. It seems to have settled - for now.

I have a new problem. When I turn on the organ, one speaker pops very loudly. This particular speaker/channel also intermittently cuts out, leaving some stops without sound. Is there anything simple I can look for myself?

[myorgan]

Julianjsoh,

A pop from a speaker when the organ is turned on sounds like a mute relay not working-at least that's what to blame in Allen organs when you hear that. That may be a direction for you to head.

Michael