by John A. Tuttle (120108 MMDigest)
[ Nevin Engle wrote in 120106 MMDigest:
> The 12 ampere fuse in the bottom was blown, but none of the others. ... As soon as the 'on' switch is depressed the fuse blows again. What is the likely culprit?
Hi All, Blowing out a 12 ampere fuse indicates a significant short circuit. I'm surprised you can't see (or locate) a part in the system that looks overheated or charred.
One of the first things you learn as an electronics technician is "don't replace a blown fuse and try it again until you've located the problem." The correct step to take after a large fuse has blown is to examine the schematic and determine which components in the system could possibly short and cause the large fuse to blow. Then you test those components with an ohmmeter.
If you don't have the schematic drawing, or don't know how to read it, or don't have an ohmmeter, you're not qualified to work on the device.
Be that as it may, I have sent the wiring diagram for the Wurlitzer 1203 to Robbie so he can put it in the technical section of the MMD web site.
Frankly, as electrical systems go, the Wurlitzer isn't that complicated, and, looking at the schematic, the first thing I'd check are the diodes in the DC power supply.
Musically,
John A Tuttle
Player-Care.com
Brick, New Jersey, USA
Date: Sun, 08 Jan 2012 09:42:35 -0500
Wur1203_wiring.jpg (1,314 kb)
Wur1203_schematic.jpg (1,102
kb)
[ See also http://www.player-care.com/wurlnote.html