grievousangel

Any idea why I am seeing ~ 4VDC at the ML2 output? This seems like an usual  failure point ... has anyone seen this before?

This happens only if ML2 is active and A3 or A4 is installed.

First thought was something related to K2 (relay that by-passes A4/T2 ouput. Looking in this area now.  Appear OK so far. I checked all diodes for proper junction voltage drop, all OK.

I am also looking at the DF.1 (A1 and A2).

Not likely a bad 2520 right? I see the DC when either A3 or A4 is plugged in.

CMR adjustments would have no bearing on this correct?

Since this is  a coupling capacitor design, I would think a electro capacitor related issue, but test OK so far.

TP V+ / TPV- read as expected, ie. ~ Input voltage.

Suggestions?

Thanks.
GrievousAngel
B. Johnson
USA


Re: [BUILD] VC528 ML2~500 Series~Missing Link 2~Official Support Thread
« Reply #61 on: August 29, 2020, 12:23:27 PM »
The overall concept is identical to the first version. Most people have been buying my Extension Jig which has the proper R's fitted to it as well as instructions. There is a pic in the ML2 Assembly Guide that shows where to measure the signal.

Is there any more detailed information on the CMRR final adjustments? I'm really struggling to understand the directions and can't find any other resources on this.

Thanks,
-G

jsteiger

4 volts of DC at the output is not likely since the final output transformer would be blocking DC. I suspect you have a problem with the relay circuit.
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grievousangel

4 volts of DC at the output is not likely since the final output transformer would be blocking DC. I suspect you have a problem with the relay circuit.

Thanks. I'm digging around in the relay circuits now.
 
GrievousAngel
B. Johnson
USA

grievousangel

Has anyone building a ML2,  found  their Elma fader with the rear PCB wafer (SMT side)  NOT facing  the front faceplate?

It was posted a little while back that his gain structure was off a few steps due to due the SMTs on his Elma were facing the ML2 faceplate and NOT the rear. He said it corrected his problem.

My Elma's wafer PCB SMTs are facing the front which seems to agree with Elma's Web site product date sheet.

I am having  some ML2 issues and ran into his post while checking the ML2 post out.

Later.
GrievousAngel
B. Johnson
USA