Ebay Classic organs

Collapse

Announcement

Collapse
No announcement yet.

Calling all 760 buffs....

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

  • #16
    It looks like the 220 ohm resistor could be a replacement for a previous one that fried.
    Tom in Tulsa

    Fooling with: 1969 E100, 1955 M3, 1963 M100, Leslie 720

    Comment


    • #17
      Originally posted by tpappano View Post
      It looks like the 220 ohm resistor could be a replacement for a previous one that fried.
      Which might mean Rel-1 and 2 could be OK?

      I have yet to attempt a start. It was claimed to be working by the original source, but my dealer had not fired it up.

      David, not sure if this could help:

      760 PCB by unoh7, on Flickr


      760 schema by unoh7, on Flickr
      1960 Blonde RT-3
      Leslies: 2-speed 22H, 760, 105 Round Sound Machine.
      Young Chang U121
      Fatar SL 880
      Nektar Panorama T4

      Comment


      • #18
        The relays might be OK, the proof will be if the motors start and stop properly. Just a couple observations, it does look like your board has been configured to use triacs instead of scrs. The triac associated with the 'replaced' resistor has also apparently been changed, being a different style from the other one. One scenario, if the original triac failed to function by defect, bad connection, etc., the full motor current would have passed through the 220 ohm resistor instead of going through the triac like it should. This would burn the resistor up in short order. Possibly both the resistor and triac were replaced at the same time. During the failure 'event', the resistor-frying current had to travel through the reed relay contacts and could have damaged them, or they may be just fine. Looking at your picture of the underside of the board, it is hard to tell if the solder connections to the triac are good and solid. They look a little sketchy in the picture as if some oxidation or something on the leads interfered with getting a nice pretty solder joint. Assuming that it is working now, a bad triac connection could cause the same thing to happen again 8)
        Tom in Tulsa

        Fooling with: 1969 E100, 1955 M3, 1963 M100, Leslie 720

        Comment


        • #19
          I agree with tpappano's assessment that the 220Ω resistor burned up and was replaced due to a problem with the triac.

          Also, the layout you (uhoh7) posted is not the right one. I have all the schematics and documents.

          It also sounds like we are discussing something as "broken" which may very well have already been repaired.
          I'm David. 'Dave' is someone else's name.

          Comment


          • #20
            Originally posted by uhoh7 View Post
            What do you think is source of oily film on amp?


            760 inside by unoh7, on Flickr
            May be it come from a chemical capacitor ?
            Look if the case and the rubber stopper are in good condition.
            Measure for value into 20% range.

            JP

            Comment


            • #21
              You can see some green corrosion on the leads of the glass diodes which suggests some sort of chemical activity. Could very well be capacitor leakage, look underneath the aluminum electrolytic behind the power resistor. Is that an accumulation of electrolyte residue? Replacing the cap and cleaning the board might be something to consider.
              Tom in Tulsa

              Fooling with: 1969 E100, 1955 M3, 1963 M100, Leslie 720

              Comment


              • #22
                It's time to replace that capacitor anyway after 40 years in service, not to mention likely out-of-value resistors on the board. As for the board itself, just wash it down with some kind of cleaner like isopropyl alcohol. Rinse it off with CRC QD non-residue contact cleaner. No need for a major investigation.
                I'm David. 'Dave' is someone else's name.

                Comment


                • #23
                  @tpappano
                  Extremely helpful, I can't thank you enough for your excellent posts.

                  @Jyvoipabo: I apreciate your input

                  Originally posted by David Anderson View Post
                  I agree with tpappano's assessment that the 220Ω resistor burned up and was replaced due to a problem with the triac.

                  Also, the layout you (uhoh7) posted is not the right one. I have all the schematics and documents.

                  It also sounds like we are discussing something as "broken" which may very well have already been repaired.
                  The schema I posted was just from the service manual. I understand there are a number of versions. This may help:


                  760 Logo by unoh7, on Flickr

                  It would be so helpful if I had a correct schema....I'm using this to help me learn to read them.

                  Under the relays there are signs of melting. Looks like the relays themselves.

                  So on the one hand, this may be a problem "fixed", on the other I have some old parts anyway.

                  Those relays appear deformed to me and are cheap. The two big blue capacitors...a good idea, right?

                  I'd just as soon refresh it, as I have another speaker working, so it's not time critical. It's a good learning opportunity, and I've got the gear now to solder correctly. Fluke 87V too.

                  What else should I order---that long silver cap also, not sure which it is....

                  I can get the plastic off the covered triac to get better view if it helps, also.

                  I promise not to kill myself

                  I'm pouring over the old 760 threads now, and I will go over the parts list from the manual I have. I hear some complaints about the 760 treble, though I have no clue, yet. Are there mods to the 760 I should consider, while I'm at it? Some suggest the design of the box is an issue vs the older louvers... I get the lack of tube style distortion, and I was interest to see that add on board with a small tube which I referenced early in the thread. Have not been able to reach the guy. Looks like it could be made up pretty easy. Carsten Meyer was the guy's name. Is he around anywhere?

                  What sorts of things have been done to them, commonly? or uncommonly LOL
                  Last edited by uhoh7; 12-02-2018, 06:22 PM.
                  1960 Blonde RT-3
                  Leslies: 2-speed 22H, 760, 105 Round Sound Machine.
                  Young Chang U121
                  Fatar SL 880
                  Nektar Panorama T4

                  Comment


                  • #24
                    Glad to be of help! I'm going to guess that the little relay coils might be glued to the circuit board with epoxy or some such. Their odd appearance is probably because they are simple coils of wire wrapped with plastic tape.

                    These capacitors are what I used to replace the 'big blue' filters on my 720:

                    https://www.mouser.com/ProductDetail...2fDKX2GA%3d%3d

                    I'll bet that the long silver cap is C3, this one should work as a replacement:

                    https://www.mouser.com/ProductDetail...8H8ORCpA%3d%3d

                    Like David suggests, I would use a soft brush and *generous* amounts of 70% isopropyl to flush the board, tilting it up on edge so that the 'runoff' doesn't get into the connectors, if possible.
                    Tom in Tulsa

                    Fooling with: 1969 E100, 1955 M3, 1963 M100, Leslie 720

                    Comment


                    • #25
                      Originally posted by tpappano View Post
                      Glad to be of help! I'm going to guess that the little relay coils might be glued to the circuit board with epoxy or some such. Their odd appearance is probably because they are simple coils of wire wrapped with plastic tape.

                      These capacitors are what I used to replace the 'big blue' filters on my 720:

                      https://www.mouser.com/ProductDetail...2fDKX2GA%3d%3d

                      I'll bet that the long silver cap is C3, this one should work as a replacement:

                      https://www.mouser.com/ProductDetail...8H8ORCpA%3d%3d

                      Like David suggests, I would use a soft brush and *generous* amounts of 70% isopropyl to flush the board, tilting it up on edge so that the 'runoff' doesn't get into the connectors, if possible.
                      Jeez another golden post! Glue!, that would explain it. Maybe some real noise is closer than I thought

                      Thank you also for those links

                      I've been using 99% isopropryl and q-tips, mopping up as I go. I'm beginning to think I should attempt a start before I go soldering. I've got some motor inspection to do.

                      What oil is best, I have newer TG and old hammond oil.

                      After reading an old thread Wes made, I see I'll want to watch which way they spin, what do I want? Opposed? I see my converted 22H has both spining counter-clockwise. It sounds pretty good. My16 year old cat has discovered she can walk accross the pedals and play some scales....I was surpised she was heavy enough to push them down! I fire up the pedal solo for her sometimes now That thing is hilarious.

                      My mechanical experience:

                      Spanish Horse by unoh7, on Flickr
                      1960 Blonde RT-3
                      Leslies: 2-speed 22H, 760, 105 Round Sound Machine.
                      Young Chang U121
                      Fatar SL 880
                      Nektar Panorama T4

                      Comment


                      • #26
                        Ha, yes! I think at this point a startup might not be a bad idea, its good to know where you stand before going in deep. I would check to make sure that someone didn't install ridiculously oversized (30 amp!) fuses like in the 720 I rebuilt- it resulted in the thing catching fire after a lightning strike 8)

                        Nice bike! I did some English Trials riding back in the '70s. I built a 'Frankenstein' cycle on a Bultaco Sherpa-T frame with the engine from a Triumph Trophy 250 8)
                        Tom in Tulsa

                        Fooling with: 1969 E100, 1955 M3, 1963 M100, Leslie 720

                        Comment


                        • #27
                          Frugality is the mother of......well my 760 switch anyway

                          IMG_6547 by unoh7, on Flickr
                          I used the screw on the metal plate above the great to fix it. It's firm, 3-way, and works great

                          IMG_6550 by unoh7, on Flickr

                          I made up my own custom wiring harness, plugging in the 760 locally to AC and sending 4 lines back the organ. I think it's safe to say this 760 has ssen some heavy use. I had to adjust the volume pots on the inside, because they had suffered brutality from scrrew drivers on the outside.

                          I have a 22H, converted to 2-speed right behind my bench. I put the 760 about 10ft in front onf me, crossed my fingers, fired up the RT3 and then powered up the 760, at first with the 22H disconnected. Vroom. slow fast and stop working.

                          I then plugged in the 22h. Holy Sh.... It is so much fun, I played several hours tonite. Having both switches going is alot of fun, and seriously impressive. I see now just how good the 22H really is. Somebody really went through it when they added the two-way switch board. The 760 is louder, but it's further away so the combo is fine. The 760 is the gruffer of the two, to my surprise. But it's nice to have that full stop, which i have between the other speeds.

                          I can't thank you guys enough for all the input. Over time I will upgrade the 760. I actually found that little add-on board with the tube, the MIG-L, and am in process of ordering it from Germany. Meanwhile I will play this incredible thing
                          1960 Blonde RT-3
                          Leslies: 2-speed 22H, 760, 105 Round Sound Machine.
                          Young Chang U121
                          Fatar SL 880
                          Nektar Panorama T4

                          Comment


                          • #28
                            When I first opened the 760 and inspected the PWS board, there was a blob of putty sitting in the middle of it. Yuck, I thought.

                            Now that I am using the speaker, I realize this was important part

                            I have upper rotor wobble, enough to shake the cabinet. So that's my next project: balance the 760 upper rotor.

                            Any particular type of putty is best?

                            I've removed the belt, and I notice: I can tip the rotor/horns either way. It settles at one spot, but is not fixed. I can also raise it up and down. Is this normal?

                            ahh....loose rubber grommets. Like idiot at first I thought, let me make these last, I will use silicon paste. Then had to clean them of course. I did a few wraps of duct tape around pin to firm them up till I get new ones. Struggled to line everything up, then...much better
                            Last edited by uhoh7; 12-08-2018, 03:55 PM.
                            1960 Blonde RT-3
                            Leslies: 2-speed 22H, 760, 105 Round Sound Machine.
                            Young Chang U121
                            Fatar SL 880
                            Nektar Panorama T4

                            Comment


                            • #29
                              Great news that it is working!
                              Tom in Tulsa

                              Fooling with: 1969 E100, 1955 M3, 1963 M100, Leslie 720

                              Comment


                              • #30
                                The proline 760 model on wheels does shudder a bit on tremolo. The horns should not need balancing and it is correct for them to lift up and down. I would at least change lower rotor rubber and bearings. That should quiet things down a bit.
                                Hammonds; BV, M101, T202, T402, R100
                                Lowreys; Heritage DSA, Berkshire Deluxe TBO-1
                                Farfisas; Compact Duo MK2, Professional 110R, Compact Deluxe
                                Analog Korg CX3
                                Leslies; 147, 145, HL822 ‚Äč

                                Comment

                                Working...
                                X