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Title: Fender 5f6a build Post by: steves3972 on June 04, 2012, 11:02:53 PM I’ve been trying to finish a build using the ceriatone 5f6a layout using classictone transformers.
I am getting very low voltage readings at all tube sockets. I have double checked that all the resistors on the board are the correct value and tested all of them. But I am still losing voltage somewhere. There is a 100k resistor on the standby switch and I am not sure of it’s purpose. On one side of the standby switch I was getting 400volts then on the other side after the 100k resistor I was getting around 100volts. This doesn’t seem right to me. Can anybody suggest what I need to do? Many thanks Title: Re: Fender 5f6a build Post by: wyatt on June 05, 2012, 03:35:03 AM Please be very careful while checking this, it is high voltage.
So, when you put your red probe on the Standby switch's solder lug connected to Pin 8 of the rectifier...and your black probe to Ground...you get 400VDC? And when you put your red probe on the Standby switch's solder lug that connects to point "A" on the layour...and your black probe to ground...you get 100VDC? You haven't even reached the first filter caps? If this is the case...there is only three things inbetween..the switch, its resistor and its cap....try jumping the switch lugs to bypass the Standby switch. Now does your 400VDC pass on to the filter caps and choke? Here is your schematic, it's what you need to trace everything through to troubleshoot...layouts are for construction. http://www.amparchives.com/Amp%20Archives/Fender/Schematics/bassman-5f6-a-schematic.gif |