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2270 Power Issue

V

vmedia

Active Member
Hello.
I've just received a Marantz 2270 from a friend with a known bad power switch band-aid solution.
I have removed that disaster and before I wire in a new switch (jumped brown/yellow switch wires) am assessing what else may be wrong.
On DBT - I am not seeing any dial lamps and relay is not clicking - I see what I feel are lower than expected voltages with a 100W bulb in DBT.
Here are the numbers - any help would be most appreciated!

VOLTS
AC in – 42vAC (Measuring Red Power wire and blue wire post fuse - fuse is good)
Orange wires from trans to DC Rectifier – 23vAC
Red and White out of Rectifier +/– 10.4 vDC
Green wires from transformer to lamp circuit – 2.2 vAC
Yellow wires from Transformer to Power Supply board - 23vAC

Transformer Ohms
Green/Lamp wires - 0.1 ohms
Orange/Rectifier Wires – 0.7 ohms
Yellow/Power Supply Wires – 10.9 ohms
 
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What voltages are you getting on your main filter caps C7/C8? Expected +/-46 dc to the P750 amp boards.

Power Supply P400
J801 13.5
J802 35
J813 L amp out before relay?
J814 R amp out before relay?

If getting high DC on amp out, pull and test Output Transistors. Power amp up with no output transistors installed and see if comes out of protection. If it does, one or more output trannys are blown. If not, additional trouble shooting to follow.




I would start by disconnecting DC power to your amplifiers
 
How bright is the DBT?
Yeah check for shorts. I’ve seen actual fuses in place of fuse lamps before….
Lot of dumb people out there.
 
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