finished my neve-pultec !problem solved, thank you pucho !

[Axelerator]

I already posted my question in the project specific link, but i am afraid nobody is looking there anymore 
so i felt free to ask here. I will transport the answers to the thread after if i get some !

I finished my nevetec clone (EA input trannys,Sowter output) and while there was no smoke, only the right (or stereo channel in M/s stereo mode) channel is working as expected and this channel is sounding really frickin awesome !

the left(or mono channel in m/s mode is not working , no signal at the outs.
The strange thing is, in M/s stereo mode i can hear all the stereo content of a signal on both channels, as it should be, obviously mono content is missing. when i switch to l/R mode the left channel is quit.
I have no clue how the passive m/s board is working, ( i think of a passive comparator here, but the way it is realized and how the trannys are involved is much to high for my little electronics knowlegde )
i have hardwired all connections here so debugging will get another challenge...

I would be very happy if somebody with more knowlegde has a tip for me where to start with debugging

many thanks in advance and greets ,
axel

 

[dirtyhanfri]

Looks like a bad wiring on the Left/Mid part of the M/S passive board, have you tried to skip the ms board and test that channel only?

 

[Axelerator]

i should have bite the bullet and do everything with molex connectors, so i could swap channels. i have hardwired everything with cables just perfect fitting  :-[  so i just started to gather informations in the hope i will not to have desolder everything.
but sure i have to do it now. i am not sure how to bypass the m/s board , as zobel and everything is also on the board. just connect the sec. to the input of the ba283 ? 

and , just now after all the years having an old oszilloskope and did not need it, i fired the oscilloskope yesterday and it seems that it is no more working......

thanks so far ,i start deconstruction right now  ;D

 

[Axelerator]

So i checked the m/s board but can see no faulty connections. I tried disconnecting the primaries of the input transformer of the not working(mono) channel in m/s mode. if i do this ,the working channel (stereo) gets louder and i get the full  content as expected.when i connect the prim. again, i can hear both channels, only stereo content.
could it one of the relays ?
i tried to figure out the m/s schemo but still scratching my head...
i attached the schematics ....
again, thank everybody who takes the time here to help us hobbiest out..

i got learning quite a lot about electronics over here and while building , and i enjoy that and my time here !
greets
axel

 

[Axelerator]

..ups this went big! sry

 

[pucho812]

when ever I test any build.
I always start with the power supply. make  sure the power supply when connected is  putting out the proper necessary voltages to run the circuits.  IF it's not that could explain why one channel is not working properly.  ONce you get the PSU sorted feed tone into the channel that works vs the one that not works and compare the two to see what is going on. It will help isolate the problem.

 

[Axelerator]

..i checked psu voltages before soldering the rest.
yes i just try to follow the signal through both channels.
my oscilloskope is not working anymore, i tried yesterday to make myself an audio probe , but also this one is not working...... but i think i made an error, i took a shielded cable , tip via 0.68 u cap to signal plus, shield to earth.
i have an old receiver with cd input and old headphones for checking.
i can hear just garbage when moving my probe araound, even when i try on the working channel or on the in.

I think my error with the probe is, that i should connect the shield to both groundings(test-object and my receiver ?) now i just have the shield connected to receiver ground via the chinch in. and i only hear some crackle when moving the probe ?
thanks again !

 

[Axelerator]

Problem solved..i screwed up the eq in/out cable and did not see this because the colours were orange and red and i did not looked with enough light..but i also had another issue with the same channel :
thanks to pucho , because of your advice i checked my power cables again and i had a faulty connection that was broken while binding them to strong with cable binder..checked voltages before so i thought that could not be a problem...
So i learned a lot. also i made myself a audio probe which led me to the problem with the in/out connection.
i even finished my 33609 this week , which was my first project and took me 5 years i think ?  8) :
Both units  are sounding wonderfull, had an issue with the treshold on the comp but cleared that by myself in almost no time just thinking a bit..