[BUILD] 1176LN Rev D DIY

[college101]

Thanks Ed.. I appreciate your help! I am starting to think the problem is with the actual Board, and not what I have done to the board...

I used all new parts(which I tested before installing) and I went threw mnats site for every step...As well as I followed along with the schematic...

I am not talking about the wire from the 5002 output transformer....I have that wire grounded as well to the chassis....

The last picture refes to the green wire connecting the cap to ground, I have that as well, and have had that since day one of building this...

I read in a previous post, at some point in this 100 page 1176 informative collection, that the main pcb board had to have an additional ground off the out put transformer wiring...  I ran a chassis ground to the board ground on the output transformer wiring connections on the pcb board...off of the violet connection to ground

I think I need to completely CUT out the traces(both top and bottom pads for R44) I have gone back threw my soldering, it is not bridged, and I dug it out to make sure...I thought maybe I had bridged it on the top printed pcb side, but it is not...

Inless this is a fault at the pcb reproduction stage...I think R44 is shorting out to ground, and its not something I've done wrong

 

[edanderson]

it is unlikely but possible that there is a manufacturing defect with the PCB.

the violet output transformer wire is connected to the ground plane on the PCB, and it is a very short distance from there to the power supply cap where you ran the big green wire to chassis.  you don't need another wire from the violet output transformer wire to chassis, but it wouldn't cause the sort of problem you've been seeing.  that wire may have helped ground loop issues with one of the older gyraf PCB layouts, but the mnats layout is different.

r44 does connect to ground via r68/r68/r70/r71/r73 etc, but it should be > 5kohm  on either end [edit:from either end to ground].  are you saying that with the trimmer out, and the unit off, you measure 0ohms from either end of r44 to ground?

ed

 

[college101]

Ed.. I will have to measure this again tonight after class to verify what your asking...

I'll clarify since reading a post and verbal communication are two different things!
**OK..when I am in GR mode, after calibrating Part A of step 3(which is setting the front controls),PartB= you switch metering mode in GR mode, needle should be dropping to zero- Once I turn GR "On" via the attack switch knob, and the needle falls to the left...it drops to -7...This is without R44 in circuit

**IF** I repeat steps and install R44, when I get to Part B of the calibration, the needle drops to -20 and no amount of adjusting does anything to the circuit... This is with R44 facing twoards Q12E or with it facing Q13E...

Once I place it in circuit, the needle drops to -20 and I can not perform the adjustment

I will check with the unit "off" and with the unit "on" just to see if there is a difference as well- in regards to the R44 grounding issue...

Ed- are you saying that R44 should have Greater than 5k reading on either end of R44?

I have a reading at R74 once I turn on compression at R74...I cant remember off the the top of my head..15 something!

 

[Hyder]

Thanks Ed.. I appreciate your help! I am starting to think the problem is with the actual Board, and not what I have done to the board...

I used all new parts(which I tested before installing) and I went threw mnats site for every step...As well as I followed along with the schematic...

I am not talking about the wire from the 5002 output transformer....I have that wire grounded as well to the chassis....

The last picture refes to the green wire connecting the cap to ground, I have that as well, and have had that since day one of building this...

I read in a previous post, at some point in this 100 page 1176 informative collection, that the main pcb board had to have an additional ground off the out put transformer wiring...  I ran a chassis ground to the board ground on the output transformer wiring connections on the pcb board...off of the violet connection to ground

I think I need to completely CUT out the traces(both top and bottom pads for R44) I have gone back threw my soldering, it is not bridged, and I dug it out to make sure...I thought maybe I had bridged it on the top printed pcb side, but it is not...

Inless this is a fault at the pcb reproduction stage...I think R44 is shorting out to ground, and its not something I've done wrong

I have come to the same conclusion, I am in the exact same situation, verbatim.

Just out of curiosity, when did you receive your board?

 

[college101]

I'll go look it up when I received  mine...one sec

 

[college101]

Early August was when I received my board..

Order'd my main kit from hairball...wired up as Pushbutton...orderd end of July, got it a week later

Mouser for my parts using Kato's parts list-modified the heatsink, and used electrolytics in C19 and C20)

MNATS sent me the board I used

 

[Hyder]

Early August was when I received my board..

That's when I received mine as well.

 

[Hyder]

mnats, any thoughts on this, has there been any other reports of possible defective boards from that time period?

Thanks

 

[edanderson]

while i wouldn't rule it out completely, the chances of two defective PCBs with identical errors is very low.  despite all the checking and double checking you've done, i'd guess that there is a mistake in the wiring, soldering, calibrating etc.  don't take this personally -- there's just so much to do, so many details to get just right that it can be difficult to get right the very first time through.

i based my advice about measuring from each end of r44 to ground on a look at the schematic; i haven't actually measured the real PCB at that location.  i will see if i have one that i can dig up and measure later today.  certainly if you see 0 ohms from either end of the r44 PCB pads to ground with the trimmer out, there would be a problem.

ed

 

[college101]

Thanks Ed again for taking the time to answer our questions...

I did have some problems with a few transistors at the start of my build...once I got that sorted out, my wiring matches what MNATS has up on his site...as well as my voltages are very close to schematic voltage chart that mnats has listed...

My Neg rail is a little low, but after going over everything again, and replacing a lot of parts, everything still measures the same...even with replacement parts

Its pretty frustrating, cause I have followed his videos-done exactly what they have stated( my calibration needle movement even reacts/behaves the same as the videos)  I only question this, because my needle movement mimics what happens in mnats videos... its exactly the same...

 

[synchroman]

Help....

I am having a problem with my rev 2.2 1176LN Rev D DIY build

I have check all components I have check all wiring of the front panel It passes audio and I have calibrated Qbias and Zero GR went fine.

The problem is the ration switches… I rebuilt it to make sure all resistors where correct… and check the wiring for continuity Everything checks out.

The problem is when I have no buttons pushed in the compressor compresses. When I push a button in, it does not matter which ratio,  the compressor does not compress and GR meter shows  0 on  the vu meter.

Double and tripled checked everything… Any Help would be great…

 

[college101]

synchroman...show us some pictures of your build... then we can all help

 

[synchroman]

Here is the PCB

 

[synchroman]

Here is the ratio board

 

[synchroman]

When I get home... I will upload the full build

 

[Echo North]

Help....

I am having a problem with my rev 2.2 1176LN Rev D DIY build

I have check all components I have check all wiring of the front panel It passes audio and I have calibrated Qbias and Zero GR went fine.

The problem is the ration switches… I rebuilt it to make sure all resistors where correct… and check the wiring for continuity Everything checks out.

The problem is when I have no buttons pushed in the compressor compresses. When I push a button in, it does not matter which ratio,  the compressor does not compress and GR meter shows  0 on  the vu meter.

Double and tripled checked everything… Any Help would be great…

Weird.  Make sure "GRN" on the ratio isn't connected to ground.  "GRN" does not stand for ground on the UREI schem and that can be confusing (at least I think so!).  Black goes to ground.

 

[synchroman]

Green is not connected to ground black is

 

[synchroman]

Here are more pictures my orange is brown and my blue is violet

 

[synchroman]

Here are more

 

[college101]

Ok..first...looks like all of your trimmers are backwards...This the BLACK Rev D Board...not the BLUE Rev A that is pictured on mnats site...see the BOM rev D link at the bottom of the calibration section from mnats page...

Second...why are you using those huge yellow caps? Those are way too big to use on such a tiny board...

Third...from your pics..I would start checking my continuity off the ratio board to make sure it was testing correctly

Also..The ratio has lot to do with the actual board wiring...wheres all the pictures of it all wired up?

I want to help...Believe me...once we get it figured out, I am going to continue to help people with their builds...people are helping me and I want to help out...

I just wish someone could figure out my problem