As mentioned in my About section, I own a few Spinet Organs. A Hammond L100, Yamaha Electone CSY-2E, and most recently, a Wurlitzer Funmaker Custom 475 (One of the ones with the Orbit 3 installed!). I've managed so far to avoid doing any serious work to them, but unfortunately this Wurli did not even power on when I got it. Finding an organ like this has been on my want list for a while, so when it appeared for free on Facebook, I felt up to the challange!
So far, things have been relatively easy! Thanks to a kind gent on one of the Organ Facebook groups I'm in, I was able to localise the main issue to the Power Supply/Amplifier board, and view the schematics for this.
Finding the issue
When I received the organ, I was told that one day it made a large pop and never turned on again. Although I knew this would not be the issue, I decided to change the fuse in the plug. WHen I tried to turn the organ on, I also got a very loud bang and tripped the circuit breaker in the building I was in. After inspecting the inside of the organ, and paying special attention to the Power Supply, I noted that all of the fuses on this board were intact. Mr W advised me that the problem was likely in the power switch, or the mains cable, as any problem in the actual power supply would likely have shorted one of it's own fuses. This was when he provided me with a copy of the schematic for the Amplifier + PSU!
Using this diagram, I was able to test the connection between the switch-mains plug, and switch socket-mains plug. I found no issues, but decided to re-wire the plug for good measure. I then decided to power on the organ while recording a slow-motion video: this is what happened!
The speaker went bang, something arced inside the PSU casing, and send some debris flying out of the top of the casing. The organ actually stayed on for about 10 minutes, and I was able to turn it on and off again during this. After this however, the organ once again went bang and tripped the circuit breaker. While playing the organ I noticed some issues with certian voices, but that's a problem for later!
Removing the PSU
Removing the PSU was fairly easy, although I was pretty uneasy the whole time due to the fear of death. However, I managed to get the board out, and uncovered a large burn mark on the insulation beneath it. This gave me an idea of where to look on the board.(PHOTO)
Looking at this capacitor, it's pretty clear that it's the issue. This cap is connected to the mains cable, and bridges the Live and Neutral contacts. The plastic housing appears to have cracked, and the capacitor insides have welded to one of its legs due to the arcing. This would line up nicely with Mr As's diagnosis, as this capacitor is pretty much the first component in line after power enters the board, so there's nothing insulating it from the mains plug.
[Article in progress - repair unfinished]