PT has numbers "606-4-11", "L010020", and "CSA 827". Puts out 690VAC (higher than schematic), B+ is 416VDC, and 285/270 VDC after the 1K & 10K dropping resistors (lower than schematic). Odd.... Amp sounds good, breaks up at 5-6.
Is a 1974 I think, SN is 43561. OT is 022905 (std). Couldn't find anything online with the #s except the Champ Registry page. Thanks!
P.S. It's a VibroChamp...might this be why the higher AC sec voltage?
Is a 1974 I think, SN is 43561. OT is 022905 (std). Couldn't find anything online with the #s except the Champ Registry page. Thanks!
P.S. It's a VibroChamp...might this be why the higher AC sec voltage?
Attachments
well, first, it is a VibroChamp, not a Champ. I have handy both the AA764 and AB764 versions. Look inside the rear on the side wall of the cabinet. Is there a tube chart label? Does it have one of those numbers on it?
010020 is a stock power transformer for a AB764 VibroChamp. It is an alternative export transformer with a dual primary, so it can be wired for 120v or for 240v operation.
The AB764 schematic shows the transformer as producing 365-0-365, or 730vAC, and calls for B+ of 420vDC. All schematic voltages are approximate and are to be considered ballpark estimates. Most Fender schematics call out voltages as +/-20%.
Your second and third B+ node voltages do sound a bit low, so with amp off and discharged, check the value on the 1k and 10k B+ resistors in case it has climbed.
Amp sounds good? Stop fixing it then.
010020 is a stock power transformer for a AB764 VibroChamp. It is an alternative export transformer with a dual primary, so it can be wired for 120v or for 240v operation.
The AB764 schematic shows the transformer as producing 365-0-365, or 730vAC, and calls for B+ of 420vDC. All schematic voltages are approximate and are to be considered ballpark estimates. Most Fender schematics call out voltages as +/-20%.
Your second and third B+ node voltages do sound a bit low, so with amp off and discharged, check the value on the 1k and 10k B+ resistors in case it has climbed.
Amp sounds good? Stop fixing it then.
Dual PT
Late to this but I now have the same transformer on a rebuild and wondering about the wire setup.
I have
G/G no center tap - for the heaters
R/YR/R - Leads to the Rectifier w/ center tap for ground
Y/Y - to the Rectifier
Orange or Pink - hard to tell - no connection to anything or the housing
GR-BL / RB - continuity
BL/YB - Continuity
When the amp arrived - One Green, YR, Orange went to ground
Primary side
GR-BL was tied to B on the switch
RB was tied to YB on the fuse.
Are the primaries tied to get 120V?
Can I use the two G's to do a twisted pair with faux 100ohm's to ground
Hope this is clear.
A
Late to this but I now have the same transformer on a rebuild and wondering about the wire setup.
I have
G/G no center tap - for the heaters
R/YR/R - Leads to the Rectifier w/ center tap for ground
Y/Y - to the Rectifier
Orange or Pink - hard to tell - no connection to anything or the housing
GR-BL / RB - continuity
BL/YB - Continuity
When the amp arrived - One Green, YR, Orange went to ground
Primary side
GR-BL was tied to B on the switch
RB was tied to YB on the fuse.
Are the primaries tied to get 120V?
Can I use the two G's to do a twisted pair with faux 100ohm's to ground
Hope this is clear.
A
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