The add didn't have any information or model number, but just from one low quality photograph I knew enough that it was just what I was looking for! The owner said that their parents had bought it in 1975 for $5000 CDN.
I found this organ about 2 hours drive from me advertised on Kijiji. At least I am in good company on this forum! Well, I'm afraid I may very well be showing signs of Organ Acquisition Syndrome (OAS).
