Mark IV led read out help

[cbkidd1]

Hi, I replaced the voltage regulator board-9 volts. Along with the 500mfd 75 volt capacitor in my mark IV.My question is what should the voltage be going to the channel led 5 volts? Were do i hook up my volt meter. I can't remember how or witch voltage regulator it go's to? I believe c122 is voltage adjustment? Can anyone help me out? t/y

[FIXR]

The +5 V voltage regulator for the control board is the one farthest to the rear on the synthesizer cover. You should have +5 V on the blue wire running to the control board. C122 is the VCO voltage adjustment.

Fixr

[mark4]

I take it the display is not on.
If so the PLL is out of lock.
And the trouble most likely is there.

[cbkidd1]

Hi, mark4. What happen was the radio was working fine. Then the led started to go out and come back on.So i remembered a long time ago i had the same thing happen to another mark IV i had.So i took a look at the -9volt board. And the solder had heated up the wire to the cap and resistor. So i soldered it back on and the led worked again. But the block resistor would keep on melting the solder joint.And the board was all but black. So i got both the board and cap. I just needed to no witch pins on sk 3591 voltage reg. I had to hook my volt meter to. So i could tune c122 to get +5 volts for the channel led lights. The radio is one of the first runs. ALL org you know the one with the white power cord. Don't think the radio was used a lot because both connectors are still white on the ends.I have a new pair of the black ones.Just have not got them put on yet.

[cbkidd1]

Can anyone tell me were i can find c106? So i can set the led voltage? Thank you.