Discussion in 'Yamaha' started by Fhamre, Aug 29, 2017.
Well I measured L1 to chassis,again 600Kohm
L1 to L2 19 ohms
L2 to L3 19 ohms
L3 to L4 19 ohms
You have a bad solder connection,broken wire or circuit board trace between R501 and L1 or L4 to chassis ground. Or...The schematic is wrong.
Thats a total of 57Ω not 600kΩ
L4 to chassis ground = zero Ω.
L1 - R501 = zero Ω at one end and 120Ω at the other.
measure around 600k ohms
Resistance from L4 to the negative lead of C521 ?
Examine L4's circuit board solder connection. Examine/follow the trace back to the power supply. You have a broken connection some where along that path..
Clip your meters neg. test lead to L4. Use the pos. test lead to probe the circuit trace's resistance along the path.
May need a magnifier and a bright light. Hairline cracks in the circuit board trace are hard to see sometimes.
fyi L1 goes to the power supply not L4.
Checked traces vis continuity and all good.
fyi L4 goes to ground in the power supply circuit.
Look at the schematic. L4 is directly connected to your power supply's bridged rectifier.
Resistance between L4 and the neg. lead of C509 ? Resistance between C511 neg. lead and the metal chassis ? Both should be less than 1 Ω.
Well no trace issues that I can see.
Here is a pic.
White arrow shows L4,Red arrow L1. Yellow arrow R501
is 600K ohm
is .2 ohm
Resistance between neg of C509 and neg. of C511 ?
You have a cracked trace or bad solder connection...
Are or was there any glue corrosion on the top side of any of the circuit boards ?
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