Announcement

Collapse
No announcement yet.

Lowrey Citation Theater Organ GAKH-1 - loud hum when I switch on the internal leslie

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

  • Ian Nel
    replied
    Just an update on my hum in the Leslie circuit - no luck thus far. Following the service manual, I have started identifying capacitors and replaced a few in the main power supply, with no change to the hum. The next would be the very large can capacitors in the power supply, and then the caps in the multi-channel chorus circuit, but time is the issue, and I want to play!!! In the meantime, I have stumbled across the virtual organ concept, picked up a couple of midi keyboards, and experimenting with jOrgan and the Hammond B3 - the sound is incredible - even on an 8-inch powered speaker - already better than the Lowrey, so I'm intending to give the Lowrey away and begin a project to set up my virtual organ rather. Busy looking for pedals - seems like they're the most expensive part of the setup - might be better to buy an old organ that doesn't work and modify the pedals - but this discussion belongs in the virtual organ section, so don't follow up on this thread please

    Leave a comment:


  • andyg
    replied
    Given Sony's expertise in the consumer audio field, you'd have thought that they'd turn out a decent unit for inclusion in an organ. But no, Kawai used Sony units and they were just as bad as the Bell & Howell or Bigston units. They came with a huge power supply that had to be screwed into place at the bottom of the organ. Useful thing, variable voltage and enough current capability to drive all sorts of things. I still have a couple in use around the house 40+ years later!

    Leave a comment:


  • Organfella
    replied
    These pictures belong to Comment # 10.1. The cassette decks are clearly visible on both.

    Leave a comment:


  • Organfella
    commented on 's reply
    Ian, here is a picture of my H25-3, the second picture is my GAK25
    Nico

  • Organfella
    commented on 's reply
    Aaah, Andy is the expert on these animals. Thanks Andy for mentioning the inherent failure (out of the box) of the cassette decks. I have owned more than five Lowreys fitted with those lousy cassettes and not a single one worked properly. Took one out of an ailing Lowrey and stripped it (this one was made by Bell & Howell) turned out to be a standard cassette deck recorder/player one could purchase in the days from any music store. I remember I had a similar one made by Sony. Just cannot figure why the same component would not work in a Lowrey organ.... Somehow I have come to suspect the voltages supplied to them from the organ power amp. Perhaps the voltages were too low or even erratic - just my thinking. These days it seems superfluous to want such a cassette to work in those old ones - their own sound and built-in features more than compensate for a silly little cassette player...
    Nico

  • andyg
    replied
    The cassette decks in organs back then were something of a standing joke. If you did get one where the tape transport mechanism actually worked, then the wow and flutter was usually horrendous. Of course, using a cassette adaptor (haven't seen one of those for many years!) wouldn't be affected by that anyway. There's an RCA phono plug input on it somewhere, maybe on the back? I can remember taking my synth along to one of my regular gigs - only 1/4 mile from home and I didn't drive at the time, so had to walk with it. No fun, going back uphill in the rain at midnight! So I'd have plugged it into that socket.

    The H25-3 is much revered in these parts (not sure I've heard it mentioned with the GAK prefix, though it makes perfect sense.) Yes, last and best of the 'old school' Lowreys, IMHO.

    Leave a comment:


  • Ian Nel
    replied
    Hi Nico, I bought my service manual from Kris. I believe the GAK-H25 -3 was the last of the great analogue Lowrey's?

    I'll go through the manual, make a list of all the capacitors, and go shopping

    Attached is a picture of my organ and piano (my daughter plays this mostly) and a close-up of the Lowrey.

    Leave a comment:


  • Organfella
    commented on 's reply
    Ian, fiddling with the old ones is a lot of fun and one learns a lot. I have a GAK-25 and the biggest of them all, the GAK-H25 -3. There is a trillion wires running all over the place and to fiddle in there is not for the faint-hearted. Where did you find the Service Manual? Kris Celedonia is a great guy to start looking for these books (Celedonia Organ Service)
    Good luck with your venture. Those old Lowreys provide huge combination selection options. Please post a picture of your console when you can.
    My next suspect to be the culprit would be those capacitors...

    Nico

  • Ian Nel
    replied
    Well, the old girl is all closed up, have ordered a service manual from the US, will study the manual and prepare a shopping list starting with the capacitors . Not totally unhappy with the outcome thus far, have fixed quite a few small issues while trouble-shooting the Leslie problem, and learned a lot about this organ. Thanks Nico for your assistance so far - one day I might remove a layer of boards to get to something and find a loose ground wire and kick myself

    How can I be of assistance to anyone else on this forum regarding this model?

    Ah - something you might not have been aware of - the cassette player which of course seems totally useless today, is in fact a perfect sound input via an old tape adaptor that I used to use in my car - and my electric piano sounds amazing played through the Lowrey in this way. Extending this concept further, it becomes a convenient AUX input for any device, such as a microphone.

    There you go, some value I hopefully could add

    Leave a comment:


  • Ian Nel
    replied
    I'm looking under the main switch panel where the Leslie switch is, I see there are 4 mercury switches - do these ever cause problems, hum etc?

    Leave a comment:


  • Ian Nel
    replied
    Update - I've checked every black wire that terminates on a piece of metal, made sure it has a good connection - no change. I have the Leslie box out at the moment, and disconnected - when I flip the Leslie switch, it still hums from all the speakers, Leslie is obviously dead at this stage. So I don't suspect the Leslie at the moment, a good elimination I suppose

    Leave a comment:


  • Ian Nel
    replied
    Hi Nico

    Thanks - the only metal I see is the amp, where there are a few ground wires on about three screws, I'm going to remove and re-tighten. The rest of the frame is wood, including the Leslie box, but I'm going to remove that again now and see if there is any metal there where ground wires might be screwed on. The circuit boards obviously have metal, and I'll check them all. Will give you feedback today - thanks!

    Ian

    Leave a comment:


  • Organfella
    commented on 's reply
    Hi Ian. You need to check the screw where the ground wire is terminated to the metal part of the frame. Corrosion sometimes cause a bad connection. You might also try and replace the two capacitors although I doubt if they are the cause of the hum but they could be. Cannot do any harm to replace 40-odd year old caps anyway...

    Nico

  • Ian Nel
    replied
    The two capacitors on the above-mentioned panel are 50 MFD 35VAC. I see no polarity on these capacitors. The ground (black) wire from the Leslie and a blue wire terminates on this panel, goes through these capacitors and coils, and heads off into the depths of the organ...

    Leave a comment:


  • Ian Nel
    replied
    Ok, I checked all the wires that go to the Leslie, assumed that the black wires are the ground wires, everything looks quite solid and in good condition. Lubricated the motors. No change in the hum. From the 6-connection block that connects the Leslie to the organ, there is a blue and a black wire that terminate on a panel with two coils and two capacitors, old push-on connectors but removed and replaced them, everything looks good, no frayed wiring. Hum on Leslie activation persists...

    Leave a comment:

Working...
X