Gulbransen Premier model PR repairable ?

[KentuckyOrganFan]

OK we had a major find of a Gully PR for free. I have no fear of electronics but no real experience either. I am hoping someone can give me a quick heads up as to how repairable it is given the symptom list.
If i could narrow down a single component or set of them to remove and take to the technician it would be most helpful.
Biggest issue is that it has a constant whistle the house organist tells me seems to be tibia major 2' F# of 4th octave - rest of voice is not sounding.
This sounds whenever organ is powered on, regardless of stops.

pedal 8 ' voices flute & cello high G comes and goes
16' tuba no sound at all

accompaniment voices
8' viola - B next to middle C highest octave no sound
dulciana -B next to middle C highest octave no sound
french horn - B next to middle C highest octave no sound
4' tibia minor 2 2/3 foot - B above middle C - seems to be same as constant sound - key has no effect

Solo - 8' tibia major - no sounds
8' violin diapason - comes and goes
8' viole de orcheste - no sounds
8' soft string -B next to middle C dead - highest octave is low volume
8' electro mute -B next to middle C dead - highest octave is low volume
8' oboe -B next to middle C dead - highest octave is low volume
8' clarinet - very low volume - sequential chords seem to cause short
2' tibia major comes and goes
piano organ - 1 st octave low volume missing b next to Middle C highest A&B - dead highest c is octave low

We get nothing other than a flashing light from rhythm stops.

Thanks for any information.

[indianajo]

Organs built after 1978? tend to have keying IC's. These can go bad, particularly if they are of MOS construction. (CMOS, PMOS, NMOS). ICs with part numbers like CD4016B or CD4052B are commercially available and cheap. I helped a guy with a Conn that had a custom MOS IC that both picked up the key contacts and released the data in serial format, so that was a single source part (bankrupt Conn or receivers or scrappers).
If you search organforum:gulbransen you'll see post by our gulbransen expert. He will know your production year and might have the schematics. Use a commercial search engine, the search within the forum finds every post with any word you type in it. You can also look at Jan Giradot's master list of organs produced, to look up your model.
If your organ is pre 1979, you might have a key contact stuck on somehow. That could happen to a later one too, but it is rare on either. Some organs used semiconductor diode keying and these can be defective.

[KentuckyOrganFan]

Saw a post by JW saying he was busy with life stuff rather than organ stuff. Don't want to pester him. Just looking to get a reasonable idea how large a project this will be for a technician. Haven't yet found a manufacture date of any kind. Only a SN#. Even with a constant f#, it sounds terrific. Hoping to find a reputable technician locally who can come take a look. If anyone has a recommendation in Louisville we'd be happy to hear.

[Jan Girardot]

Hi, Kentucky and all;

I just checked my Mother List and the Premiere PRs were built from 1967-1972 and are quite repairable, having no Integrated Circuits, just good old transistors. It's not really practical to take parts out to be repaired in a technician's shop. The high F# that plays constantly sounds like a keyswitch contact that is stuck against the buss bar, applying keying voltage to the Tibia tone generator. Most of the other symptoms also sound like contact problems, none of which should be difficult to fix.

If you are interested in buying a service manual, I have one left in my collection @ $10 + shipping. Contact me at jan@theorgangrinder.net

IMHO this organ is worth getting fixed: here are the techs listed on the MITA site.
Uncle Sam’s Jamms (4.9)
1209 Durrett Ln.
Louisville, KY 40213-2021
(502) 368-4300

Organ Service Corporation (32.7)
190 East Washington St
Marengo, IN 47140-0372
(812) 365-2207

Harmony Electronics (86.2)
2150 Sylved Lane
Cincinnati, OH 45238
(513) 451-0515

. . .Jan
the OrganGrinder

[jimmywilliams]

The Premiere is repairable and I suggest you get the service manual for starters.
Most of the problems you describe are related to the divider generator set. These are six plug in boards. Try removing cleaning and reseating. The cinch connectors are known problems. The divider set is used for the complex voices and piano.
The tibia generators are 12 large assemblies with inductors. A cipher in the tibia side can indicate a bad sustain capacitor on the affected pitch/ octave. Or you may have a misaligned key buss bar contact.
If I were you I would pull the divider boards and just start with troubleshooting the tibia side. You would do well to replace all the electrolytic caps and the emmiter resistors in each tibia generator assembly. Leave the tuning caps alone as they rarely if ever fail and they are unmarked factory selected values.
Leave troubleshooting the rhythm box for last.
Rebuild the power supply while you are at it. Flaky voltages will cause a lot of problems.
I'll try to keep in touch but as you know I do not have much time. Thanks for your understanding.

[jimmywilliams]

Also if you have completely dead stops on the divider side of things check your number 19 miniature lamps on the stop control board. Iirc turning on a complex stop activates a related lamp ; the stop control board uses lamps/LDRs. A dead lamp means a dead stop. Just going by memory here as I think this works the same way as models D and K. I'm on the train now so would have to check at home if I get to it.

[KentuckyOrganFan]

Thanks so much everyone. I sent Jan a note regarding manuals. I will open her uP this weekend and see how obvious things look with these instructions.

[KentuckyOrganFan]

Follow up. First thanks again. Once I had it open a few things were obvious. The visible mechanical nature of the stops makes those very repairable. Put a few contacts back in place. The multi position stops require a diagram of proper working function before i can figure out which contacts go on which position. I think the pedal sustain is stuck in an on position but it appears to require a closed switch in all positions at the moment. A few of the divider generator boards clearly needed to be seated fully. We have all voices now. Some are quite soft. Could not see any obvious lamps in the stop boards though. Now if I can just fix the F# annoyance. The tibia generators looked a little daunting and I could not figure out how to open the casing to get to the key rails and contacts. I did note that one of the electromagnetic actuators doesn't seem to energize regardless of stop position. I am hoping this is the cause of the volume issues in specific voices. I am going to wait for the Service manual before diving in the deep end. Would anyone have access to or be able to point me toward a simple users manual so I can figure out what stops actually interact?
Final question for the night : what is a good method for cleaning the stop contacts? I saw a post about using ink style erasers.

[jimmywilliams]

Hello KentuckyOrganFan,

I am mining the depths of my (unfortunately fading) memory for this information but here goes ...

I am very happy to hear you ordered the manual - it will be invaluable for this project. You can do the restoration of the tibia generators to start and you will have an overall very nice sounding "half" of the organ at least. Like I said however to do a complete overhaul you will need to replace the e-caps in the power supply ... as well as replacing any on your complex voicing boards (IIRC there are some there as well).

Complex Side:

If you still have dead complex voice stops (not clear if you are still having that issue) the number 19 lamps are usually under square metal "box" shields. Having never taken a PR apart and not having the manual in front of me it is hard to say...

The main/complex divider generators rarely need rebuilding. It is usually contact issues. I still can't get my Model D dividers to seat right so my Model D is for all intents and purposes a Model E for now! If for some reason something does go down even those divider "packs" can be cobbled together with discrete parts - the manual will explain better than I can. There are no "mystery chips" in this organ.



Tibia Side:

If the magnet not actuating is on your upper manual it is probably for the chime humtone pitch which is only engaged when using the Chime "omega" piston. So that is normal. It is a 6-2/5 pitch that is not available via any other stop.

You will notice that certain stops are really tibia combinations. These on the PR I think have blue stop tabs - clarinet and mixture are two that come to mind - and green tabs - all "percussion" voices like music box, glock, etc. - EXCEPT the piano (and Harpsichord if the PR has this..) which uses complex voices. The green tab tibia combinations of course also engage the percussion long "omega" effect. White tabs with GOLD lettering are tibia stops as well.

The tibia generators ... if this is anything like the organs I am very familiar with (and I think it is as it was the last of the old world tibia oscillator design) there are several steps necessary to remove the tibia generators.

You have to remove the front panel of the organ - when doing so be careful of the speaker mounted against the front panel. There you should see the multi-pin sockets on rails where the generators plug into. BEWARE take note of what rail is accompaniment and which is solo - the generator harnesses for these are NOT interchangeable! You have two harnesses per generator. One is shorter than the other. Take careful note of this. The rails should be marked as well as having stickers denoting the generator pitch. Be very careful unplugging the multi-pin harness from the socket. You may need to "rock" them a little bit but be very careful not to be too rough or else you can break pins/wires and that gets ugly to fix.

Then remove the back of the organ. You should see the tibia generators in a rack on your right. I think in the PR they are marked TG-18? Does that sound right? Anyway there should be two screws per chassis - actually the bottom screw for generators in the top rack is the same as the top screw for generators in the bottom rack. Remove these screws and carefully pull out the generators. Take not of the order they are in for when you put them back.

The standard rebuild for these generators is as follows (I am doing this all from memory so please double check that this makes sense!):

(a) replace ALL electrolytic capacitors. Note that some octaves have different values than others. This is especially true of the sustain capacitors (only there for the top manual). Take careful note of what goes where. By the time you do your 4th of 5th generator it will be old hat. The low value caps (5uf, 10uf, and I think 15uF?) - you can replace 5uF with 4.7uF) are for various filtering, keyclick suppression, etc. The higher value caps (IIRC 75, 100, 125, 150, 175, 200uF) are for the sustain circuitry in the top manual. You will notice the lowest octave does not have sustain caps. That is normal. I replace them with 82, 100, 120, 150, 182, 220. I can almost guarantee that you have a shorted sustain capacitor in the F# divider which is causing the cipher even when no stops are turned on.

Just so I know, does anything change when the omega "off" piston is engaged (which turns all sustain off).? That should be the left-most piston.

(b) replace ALL the 230-ohm emitter resistors with easily available 220-ohm metal film 1 percent tolerance 1/2 watt resistors. This will usually eliminate any soft/weak notes in the tibia section. The old carbon comp resistors there tended to drift with age and I have measured some that were over 1k! Even if they measure out good now, save yourself the trouble later on and replace them all.

Now you may need to "cheat" and put certain components on the foil side of the boards, since that is a very tight space! If you do so make sure you use insulation where appropriate.

I have to run now but I hope this helps. Again forgive me if some of this is not spot-on ... I have not worked on a Gulbransen for several years now...

- jimmy

[KentuckyOrganFan]

You make this sound doable. In any new venture I tend to have more issues with confidence in my abilities than competence. I have to start at square one if the electronics learning curve and distinguish all the various pieces. As long as I can pull a board and complete it in a few days, the house organist shouldn't be to difficult to live with. When I open it up again I will be sure to have the manual, cable tags, camera, and paper handy.
I appreciate all the expertise in such a share the knowledge format. It is rare these days.