[Solved by MarshallJMP] MP1 doesn't start up - mysterious blinking

[MarshallJMP]

First voltage looks normal but the second isn't.The green blue differ too much from each other.Could be diode D38 or D39 is busted.Also with this type of transformer the 9V is also a bit low,should be more like 10 to 11V.

Now something to try out is bridging that big white resistor.Just solder a wire over this resistor.This could also solve your problem.But i would take a look at D38 and D39 also.These are 1N4007 diodes,really cheap and quite easy to replace.

[hal2000]

Hey MJMP,
guess what! I've bridged the white resitor and ADA is coming up! So, first of all: Thank you very much. You make me believe to get that beast repaired.
OK, is'nt that bridging of the white resistor dangerous? Could that damage any other parts? Can i leave the bridge or do i have to choose another resistor?
What obout the diodes? Must i do this job too, even when this resistor-thing does the job?

[MarshallJMP]

No,it's no problem bridging this resistor,later mp-1's didn't have this resistor anymore.

Do you have a diode tester on your multimeter?

[hal2000]

Yes, my multimeter has a diode tester. But i don't know how to use it. The manual doesn't tell anything about it.
Do i have to solder the diodes out or can i measure them leaving them on board? If yes, do i have to switch the
ADA on? (I think the multimeter makes his own voltage, right?).
So, if i have to solder them out, i can replace them without measuring. Do i have to prefer a type, or is it the standard
IN4004 ?

[MarshallJMP]

Read this on how to test them  http://www.allaboutcircuits.com/vol_3/chpt_3/2.html

No you can leave them in but you need to pull the connector comming from the transformer.Also don't start it up when testing.And to be safe unplug it.

You need to use 1N4007 diodes should you want to replace them.

[hal2000]

The diodes are all OK. So i will remove the resistor and bridge it and all is OK?
Thank you for so much assistance and patience.
@rnolan: Thank you too.
Greets from Cologne
Harald

[MarshallJMP]

yes,just find the voltages you measured strange.