[BUILD] 1176 Rev A - Back to the beginning...

[weiss]

everything checks out  ???

 

[scott2000]

I don't see another ground from the main pcb between pads 18 & 22? I think there is supposed to be another one there  tied to chassis as well? Unless I can't see it....?

 

[weiss]

I don't see another ground from the main pcb between pads 18 & 22? I think there is supposed to be another one there  tied to chassis as well? Unless I can't see it....?

this ground is connected to two cables, one shield from the cable coming from the meter board (cable 22) and the white one next to it. the ratio board ground goes with cable 15/16/17 to the opposite side. wrong?

 

[scott2000]

I'm not sure where the actual chassis is connected anywhere???? Sorry if I'm confused......I haven't studied it further.....??

 

[weiss]

it's connected to the chassis through the leg of C25 on the main pcb via input xlr ground. i checked for continuity. all grounds are connected to chassis.

 

[scott2000]

Hmmmm....Pad 28 and 29 on the meter board....those wires aren't touching there???? 

 

[weiss]

Hmmmm....Pad 28 and 29 on the meter board....those wires aren't touching there????

no they don't touch ground. but you could be right about the grounding which could be wrong. i found this schematic somewhere earlier in this thread (although it's the stereo version!)
they connect the ground between 22 and 18 directly to the output xlr  ??? ???

 

[scott2000]

So does tata's build more or less.....but I'm not sure it'll matter since you say you have continuity at these points .....

I'm wondering if it's something to do with the attack and release pot wiring....... The guide you pointed to as a reference is a bit different then the mnats rotary guide in regards to these hookups I think..... I need to check more.......not sure....

Pretty confusing which direction to follow..... But my original drawing of tata's build shows how the mnats rotary guide has them I think...... but you said you already have them like that so I'm confused even more.....

you'll get it soon I'm sure.....I really think it's these areas we are focusing on.....

 

[weiss]

just checked again. 100% like in your drawing.
there is an optional trimmer there for the threshold on the ratio board. i don't have to jumper that one, do i?

 

[scott2000]

I don't think so.....

so no bridging at pad 4 and the output pot shield on the ratio board??? just looks close in the one pic.....

 

[weiss]

nope, no bridging. checked

 

[scott2000]

Need to  figure out if there is an incorrect wiring scheme....... I even noticed that the ratio boards referred to in the mnats pdf drawings are slightly different than  these.........ugh

Maybe for now just try to check the schematic and makes sure everything is connected where it needs to be by testing continuity to eliminate any cold joints or damage somewhere..... at least on these boards......

example--- is there continuity from  release pot wiper to one leg of attack pot and one leg of R57 on ratio board at same time.... does the other side of that R57 on ratio board show continuity to wiper of Q59??? etc.....or at least to pad 18 of ratio board since you said pad 18 does show continuity to qbias wiper already.....


did you add  capacitor and resistors to the attack and release pots???? Like in the one guide you linked???? Or do the boards you have do this??? I'll check....

and also maybe put a probe on chassis and make sure there isn't any continuity/ ie grounding  where it shouldn't be?????

 

[weiss]

Need to  figure out if there is an incorrect wiring scheme....... I even noticed that the ratio boards referred to in the mnats pdf drawings are slightly different than  these.........ugh

Maybe for now just try to check the schematic and makes sure everything is connected where it needs to be by testing continuity to eliminate any cold joints or damage somewhere..... at least on these boards......

example--- is there continuity from  release pot wiper to one leg of attack pot and one leg of R57 on ratio board at same time.... does the other side of that R57 on ratio board show continuity to wiper of Q59??? etc.....or at least to pad 18 of ratio board since you said pad 18 does show continuity to qbias wiper already.....

did you add  capacitor and resistors to the attack and release pots???? Like in the one guide you linked???? Or do the boards you have do this??? I'll check....

hey, thanks for your ideas! I didn't notice that. I'm gonna check what you said. no i didn't add any capacitors or resistors because i wasn't sure which guide to follow 

and also maybe put a probe on chassis and make sure there isn't any continuity/ ie grounding  where it shouldn't be?????

how would i do that ?

 

[scott2000]

I think your ratio board already has those caps and resistors included. so that's good.....if they are installed on the boards that is...lol

...I still need to look at what exactly is what............. I'll take some notes...... Just using schematic mainly now because I'm too lost apart from it.....

As far as the grounding....I just meant put one probe on the chassis and poke around and make sure there isn't continuity on areas there shouldn't be, which would indicate a bridge somewhere.......or shield touching inside shrink or something...... just throwing stuff out there...... Something is up and, the more things we know it isn't the closer you'll be......

 

[weiss]

thanks, now i get it!
Yes i put in all the necessary resistors and caps on the ratio and meter boards

 

[scott2000]

so try this to see what's up with the attack and release pots first....... should have continuity at the colored marks and only the marks.......

like just probe the attack  ccw leg (red) and all the other (red) points while staying on the leg...etc

make sure the attack and release pot show continuity where they are connected....(blue color)

also curious if the cw (blue color) attack leg goes to c6 at all.....your voltages schematic has it but, the v1.0 schematic doesn't??? just curious.....


then check release pot same way....

I'm not sure this is 100% correct...but I think it's right....

 

[weiss]

so try this to see what's up with the attack and release pots first....... should have continuity at the colored marks and only the marks.......

like just probe the attack  ccw leg (red) and all the other (red) points while staying on the leg...etc

make sure the attack and release pot show continuity where they are connected....(blue color)

also curious if the cw (blue color) attack leg goes to c6 at all.....your voltages schematic has it but, the v1.0 schematic doesn't??? just curious.....

Okay so everything checks out. Following your scheme i checked attack and release potentiometers and couldn't find any mistakes.
There is also no continuity where it shouldn't be

But the attack signal doesn't reach C6! Is that the reason?

 

[scott2000]

But the attack signal doesn't reach C6! Is that the reason?

no ...I don't think so.... I think the voltages schematic reference  is a different board than what you have??? The v 1.0 in the pdf schematic doesn't show it connected......

Here's a couple more points from the meter board to check for continuity.....


ADDED output pot.....

Just try not to pay attention to wires....colored dots should all be common...... just looking for bad joints......


we'll need to look at the ratio board resistors after probably???? ???

 

[weiss]

X +Y show continuity to +/- from the meter. I guess that's okay?
i measured some differences (pic attached). are we getting closer?

EDIT:

1. i get no ground connection from the output pot to the ratio pcb and also not from ratio to main pcb!
2. grey and purple show continuity to each other in each of their points. is that correct?

 

[scott2000]

X +Y show continuity to +/- from the meter. I guess that's okay?

Depending on how it's switched, yes..... not both at the same time though...I need to look at what you are saying.....

1. i get no ground connection from the output pot to the ratio pcb and also not from ratio to main pcb!

all those light yellow points should have ground continuity....... Pad 16 of the main pcb is ground...... And pad 16 on main board  should have continuity to the ccw leg (yellow color) of the output pot......and the pad 16 of ratio board.....


wiper of output pot should have continuity to pad 17 on ratio board and main pcb.....

Not sure if I'm following you correctly

2. grey and purple show continuity to each other in each of their points. is that correct?

not sure what you mean here.... all colors should have continuity only to themselves.....nothing else??


sorry if it's confusing....  I've never done this before and figured checking for bad connections first would be best.....