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Post by rick99 on Oct 8, 2024 20:43:00 GMT
Hi there,new member here so please forgive my ignorance. I have recently acquired a 1957 Wurlitzer 2100.I received it not working.It lights up,the selector seems to work but the selector crank does not turn.In the process of tracing some wiring I found the voltage from the amp is 56 volts.The diagram shows it should be 28 volts at that point.Am I misunderstanding the diagram or does the amp have an issue.This is an issue I found while trying to figure out the other issues.It may not be a cause of other problems but perhaps a symptom.Any suggestions would be appreciated. Thanks .
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Post by jukenorman on Oct 9, 2024 9:18:58 GMT
The transformer secondary winding is shown as 36V so since the DC is unregulated, it will read quite high with no load. This would also be greater if the original selenium bridge rectifier has been replaced by a silicon one (over 50VDC) as is often the case. What AC voltage is going to the rectifier?
Norman.
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Post by rick99 on Oct 9, 2024 16:35:29 GMT
Thank you Norman.Just to clarify,this machine is U.S. built and located in western Canada.Forgive me if I am not clear but here we go.The rectifier has four wires.The transformer lead has 50v.The lead to the fuse has 50v.A lead to the plug socket has 110v. Lead that goes up to what appears to be a diode?in the heat sink has 0v. There is a wire from the heat sink diode that goes to ground. I hope this helps.
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Post by jukenorman on Oct 9, 2024 20:49:55 GMT
The two transformer wires going to the rectifier (see attached, LHS), what AC voltage are you getting across them? You will note that it's marked as 36V.
 Norman. |
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Post by rick99 on Oct 10, 2024 1:23:29 GMT
Hi Norman, I measured 40v across the rectifier.Sorry about my confusion.
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Post by jukenorman on Oct 10, 2024 8:58:11 GMT
40VAC on a silicon rectifier and no load will give you the DC voltage you are getting. The 40VAC you are seeing does seem a bit high to me but I'm not sure what you can easily do about it? Is your line supply 120VAC, what does that measure? Is there any possibility your meter could be reading high?
Norman.
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Post by rick99 on Oct 10, 2024 13:59:24 GMT
Hi Norman, I will take some other readings with another meter and see how it looks. I am away for a few days so it will have to be when I return. Thanks very much for your help,I’m certain I will be posting more questions. I will post my finding’s when I return.
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Post by rick99 on Oct 15, 2024 16:34:03 GMT
Hi Norman, I rechecked the voltage with a digital meter.Across the rectifier I saw 38.6AC and the DC voltage measured at the transfer switch (a convenient spot) is 50.6V.A better reading I would think.Thanks again.
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