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  • Galanti Praeludium II Voicing and Other Problems

    Originally poster in the Electronic Organ Section. Reposting here seems a better fit. A newbie findingg his way.

    I have just purchased an older model Galanti Praeludium II and have some problems with voicing and a couple of non working stops. The voicing problems are with the diapason stops. In the Great division the Principle 8', Octave 4', and Mixture III do not sound like diapason stops. When a note is played there seems to be good attack that immediately fades to a high pitched whine. The effect seems to be related to the chiff switch. Rather than sounding like chiff it sounds more like a whoop. Switching the chiff switch from A to B doesn't make a difference in the sound. But, in A position the Great Mixture III does not play. In the B position the Swell Prestant 4' does not play. In either position the Great Mixture III does not sound like a mixture but like a flute stop.

    Allso, there is a problem at the highest octave on both Swell and Great. Starting with the Highest c# on both manuals the volume increases drastically when playing highest c# and above. This happens with the Great Principle stops and the Swell stops Gambe 8', Prestant 4', and Scharff III. The flute stops are not affected.

    The pedal division is fine. Every thing works and everything sounds right.

    I have read the current posts on the PII and have found them to be very helpful. I"ve checked out the battery problem on the CPU and it has not caused damage in this case. I removed and cleaned the CPU board and checked underneath the motherboard. All looks OK.

    I will appreciate any advice from members of the forum if you have experience with the same problems or if you can suggest where to look for problems. Thanks in advance for your assistance

    Also looking for source for schematic.
    Sam

    Allen ADC5400, 1910 Chickering QuarterGrand
    Past---Allen ADC4000, Galanti Praeludium II, Yamaha Clavinova, Hammond A102, W.W. Putnam Reed Organ

  • #2
    Hi,

    Sounds like there is a data line problem. First though, I would suggest that you check all the voltages at the motherboard. Make sure there is a +12vdc ,-12vdc, 5vdc. Actually there is an additional +12vdc supply for the lamps. I assume that the lamps are o.k, as you don't mention them. The amp supply also sounds like it is working.

    Since you have a variety of problems on several baords, you may want to start by carefully removing each board, starting with the CPU board. All ICs that are not soldered in, I suggest you pry them up a bit and re-seat them. Also, check all solder connections on the wire jumpers. A lot of cold solder joints have shown up over the years on these organs.

    Before re-installing the board check the voltage on the battery - should be 3.6V.

    If that does not get you anywhere, take out the slave boards one by one and do as the above (except there won't be a battery on them). Make sure the boards are properly re-seated.

    Make sure to observe proper handling of circuit boards, as these boards have static sensitive CMOS ICs on them.

    Once you get beyond that, check the connector of the Midi & Function Selector (which has the Chiff select switch on it), at both ends. If nothing else, pull the connector off and plug it back in. Cruddy connections can cause all kinds of problems.

    If you need schematics, get in touch with GeneralMusic USA. They may be able to provide you with a hard copy or a Pdf of them.

    I know it is hard to fix stuff without schematics. Sometimes even with schematics.

    These Galanti PII organs are now getting old, and the circuit boards were not of the highest quality.

    Anyways, wish you luck.

    AV

    Comment


    • #3
      Galanti Praeludium II Voicing and Other Problems

      Hello and thanks for your reply.

      Have already removed the CPU and cleaned contacts but did not pull the ICs. Was afraid that they might be fragile. Will try your suggestion. Do you know which of the boards controls the principal stops? I'm guessing that board may be the main problem as most of the problems seem to be related to the principal voices. The flute and reed stops are all OK. The chime is a buzz but it will be my last priority. You are correct, the lights are OK.

      Have requested schematics from Artie at General Music USA and hope that he will get back to me soon.

      Have disconnected and reconnected the midi and chiff switch. The chiff switch does not make a difference in the sound of the stops but each position causes malfunction of one stop on each manual. I think this switch is somehow causing trouble.

      Will work on the things that you have mentioned and get back when i have some results.

      Thanks much.

      Sam S.
      Sam

      Allen ADC5400, 1910 Chickering QuarterGrand
      Past---Allen ADC4000, Galanti Praeludium II, Yamaha Clavinova, Hammond A102, W.W. Putnam Reed Organ

      Comment


      • #4
        Hi,

        For your reference,

        The Great Princ. 8 and Octave 4 come from tone board #1 - they share resources IC4 is the voice eprom, IC9 is the music processor chip.

        The Mixture III, comes from tone board #2 - sharing with the Chimes stop IC 3 and IC8.

        The Chimes stop is divided in 2 parts. The other half of the Chimes is shared with the Gt. Flute 4 also located on board #2, on ICs 2 and 6.

        There is also a CPU IC on each tone card that could be the issue.

        But since there are problems on more than one board, my guess is a data line problem, or a data corruption issue, likely to do with the main CPU board.

        AV

        AV

        Comment


        • #5
          Galanti Praeludium II Voicing and Other Problems

          I have removed board #1 and found that IC9 had a bent prong that was not in the socket. I straightened and reinstalled. Also removed and reinstalled the other ICs. Not a good result. Now none of the principal stops work (I get white noise) and none of the pistons work. Does this mean that IC9 is the problem and needs to be replaced?

          Should I repeat the process or continue on to board #2?
          Sam

          Allen ADC5400, 1910 Chickering QuarterGrand
          Past---Allen ADC4000, Galanti Praeludium II, Yamaha Clavinova, Hammond A102, W.W. Putnam Reed Organ

          Comment


          • #6
            Correction---Have not lost the pistons. They just lost the settings. Pistons are OK.
            Sam

            Allen ADC5400, 1910 Chickering QuarterGrand
            Past---Allen ADC4000, Galanti Praeludium II, Yamaha Clavinova, Hammond A102, W.W. Putnam Reed Organ

            Comment


            • #7
              Have not made any progress with the boards. Am waiting for the schematic to arrive. In the meantime I had a couple of pedal ciphers. When I opened up I found that the contacts/gates (not sure of the correct terminology) were covered with oil that had collected dust causing them to stick. I cleaned with WD40 and all the ciphers have cleared. The contacts are metal plate and return spring that slides in a plactic housing. Should they be coated with light oil or left dry?
              Sam

              Allen ADC5400, 1910 Chickering QuarterGrand
              Past---Allen ADC4000, Galanti Praeludium II, Yamaha Clavinova, Hammond A102, W.W. Putnam Reed Organ

              Comment


              • #8
                I don't think those shutters need oil. They should be dry and clean in order to work smoothly.

                RE: your other problems. When I work on these organs I have to take pains to get each board back down into the socket correctly so that the pins in the socket actually mate with the conductive lines on the boards. They don't always line up correctly when you insert the boards into the sockets. When they fail to make good contact, you get all kinds of malfunctions. Might give that a look.
                John
                ----------
                *** Please post your questions about technical service or repair matters ON THE FORUM. Do not send your questions to me or another member by private message. Information shared is for the benefit of the entire organ community, but other folks will not be helped by information we exchange in private messages!

                https://www.facebook.com/pages/Birds...97551893588434

                Comment


                • #9
                  I am working on the boards removing and re-seating the ICs. Have found that IC 5 on board #2 is not positioned the same as the IC5s on boards 1 and 3. Each IC has a half moon indentation at one end. On boards 1 and 3 the indentation is towards the top of the board. On board #2 the IC is installed with the indentation towards the center of the board. Is this correct? Should I leave it or turn around? All of the other ICs on the slave boards are installed with the indentation towards the top of the board.

                  Checked the voltage on the battery on CPU. Battery looks good and is not leaking but reading 4.1V. Is this OK? Still don't have the schematic and am hesitant about checking other voltages without it.
                  Sam

                  Allen ADC5400, 1910 Chickering QuarterGrand
                  Past---Allen ADC4000, Galanti Praeludium II, Yamaha Clavinova, Hammond A102, W.W. Putnam Reed Organ

                  Comment


                  • #10
                    Hi,

                    Yes, that IC is to be oriented the same way on each board. Hopefully you didn't blow something up.

                    AV

                    Comment


                    • #11
                      No kabooms but no sound either. All the stop lights are on--no sound. I think that the boards are properly aligned and re-seated but difficult to see. What about the ICs on the CPU? They're positioned with the indentation oriented towards the bottom of the board.
                      Sam

                      Allen ADC5400, 1910 Chickering QuarterGrand
                      Past---Allen ADC4000, Galanti Praeludium II, Yamaha Clavinova, Hammond A102, W.W. Putnam Reed Organ

                      Comment


                      • #12
                        Hi,

                        I can't speak with any authority on the orientation of ICs on the CPU board, but can say, if the combo action works, the stop action works, the CPU is running.

                        As for the ICs on the tone boards, looking at one of those cards, I see that they are all oriented the same way, the half moon facing upwards (away from the connector). Just follow the silk screen on the board which shows how they should be plugged in.

                        AV

                        Comment


                        • #13
                          Currently nothing is working. You are probably correct that I have blown up something. All the stop lights are on but nothing operates. No combo action, no stop action, no pedal, no sound whatever. The ICs on the CPU are installed correctly as are the ICs on the other boards. Thanks for pointing out the silk screen on the boards. I had not noticed that. I assume that the ICs are proprietary and can only be replaced by the manufacturer. Is it possible to reprogram an IC? I suppose at this point I have to start looking for replacement parts.:-P
                          Sam

                          Allen ADC5400, 1910 Chickering QuarterGrand
                          Past---Allen ADC4000, Galanti Praeludium II, Yamaha Clavinova, Hammond A102, W.W. Putnam Reed Organ

                          Comment


                          • #14
                            Good news! I experimented with removing one board at the time and have isolated the problems to board #2. With that board removed everything works except the flutes. And, the principal stops are speaking correctly---a very acceptable sound. The reeds also work as do the pistons and stop tabs. The non working stops are Pedal 8' gedeckt and 2' flute; Swell 8'bourdon, 4' flute, 2' octave, and 2' flautino; and Great 4' flute,2' fifteenth, Mixture III, and chimes. Also, the problems with the highest octave on both keyboards has disappeared. Sound is normal throughout each high octave.

                            Will now attempt to identify the problem on board #2. Still no schematic. Can you tell me which IC is the CPU IC on this board? Can I test by substituting an identical IC from a different board? Or, is each CPU IC unique to its own board. Am I correct to assume that the remainder of the ICs on board #2 generate the flute, mixture, and chime sounds?

                            The reading on the battery is 4.1V. Is this OK?

                            So happy! Feel that I'm making progress and appreciate the assistance.

                            Sam
                            Sam

                            Allen ADC5400, 1910 Chickering QuarterGrand
                            Past---Allen ADC4000, Galanti Praeludium II, Yamaha Clavinova, Hammond A102, W.W. Putnam Reed Organ

                            Comment


                            • #15
                              Hi Sam,

                              The stops you listed as not working are indeed on tone card #2.

                              The masked CPU IC you asked about is the one that either says on it "8052" and or "GEM 10711" Although it is probable that this IC is identical on each tone board, be careful what you do. If board #2 has stuff on it that is blown up, and you replace an IC with one that works, you could end up blowing that chip up as well. Remember too, that there are a number of static sensitive ICs on those boards.

                              Battery reading seems slightly high, but is o.k.

                              AV

                              Comment

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