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

[scott2000]

Where can I look now ?

Maybe check everything around Q2 and Q3??? You have an LCR to check the caps too???

Also, What revision board do you have?? I saw that the early ones had some errors that required changing a few resistors... not that it would solve your problem but, should be changed  regardless I'd think....

 

[TillM]

Maybe check everything around Q2 and Q3??? You have an LCR to check the caps too???

Also, What revision board do you have?? I saw that the early ones had some errors that required changing a few resistors... not that it would solve your problem but, should be changed  regardless I'd think....

hi Scott,
i've the last revision, so there should be no errors.
Q2 changed nothing, i will try Q3 and see what happens.
But i don't think that the problem is just Q3, there must be another error.
I ordered a new 250k output potentiometer and see if it fix the problem.

 

[scott2000]

I ordered a new 250k output potentiometer and see if it fix the problem.

I thought you said it already checked ok???

Have you tested the values of the components ??? Even caps??  LCR meters are good most of the time for in circuit narrowing down.....

Maybe bad switch/ connection somewhere...

Stay at it! You'll get it figured out..... Wish I had one to help troubleshoot but never built one..... There's really not too much in these but they sure do have a lot of complications from people.... It's tough because you got yours already built.....who knows ....

 

[TillM]

I thought you said it already checked ok???

Have you tested the values of the components ??? Even caps??  LCR meters are good most of the time for in circuit narrowing down.....

Maybe bad switch/ connection somewhere...

Stay at it! You'll get it figured out..... Wish I had one to help troubleshoot but never built one..... There's really not too much in these but they sure do have a lot of complications from people.... It's tough because you got yours already built.....who knows ....

Yeah I checked the output Potentiometer with my DMM and the value seams right and working.

 

[TillM]

Yeah I checked the output Potentiometer with my DMM and the value seams right and working.

My 1176 still don't work, but now it passed audio.
I changed nearly everything and double and triple check.
I don't get it.
With a 1k Sinus at the input, my oscilloscope show this at the output.
Maybe some of you can help me to find the mistake.
I really appreciate every help.

 

[dbonin]

My 1176 still don't work, but now it passed audio.
I changed nearly everything and double and triple check.
I don't get it.
With a 1k Sinus at the input, my oscilloscope show this at the output.
Maybe some of you can help me to find the mistake.
I really appreciate every help.

How many volts AC is the 1k sine input? 

 

[TillM]

When I set 0,775 VAC at the input, the signal is to low for the output.
With my oscilloscope the sinus waveform is not visible after Q3 (I already changed it).
I really had to crank up the volume on the input to get signal at the output.
I use Orange Drop capacitor at C7.
I no that I can't calibrate the unit with to much VAC at the input, but I cranked it up to see, where I find the mistake.
I get clean signal on my oscilloscope until Q2 and R16. after R16 with 0,775VAC at the input the signal is gone.
I checked all resistors and caps and everything seams right.

 

[scott2000]

Are  your DC voltages still wonky as before in your one upload???

Maybe a bird's eye pic of the board and components/values/bands could help see anything obvious??

 

[TillM]

... well, the DC voltage didn't change dramatically.
I changed so many things. Input transformer, t-pad, output, q1,q2,q3 and so on.
I don't still find the mistake.
On Q3 i get on all legs 13v, this is way too much.
I've been clueless.
thanks for every help

 

[scott2000]

Just quickly looking Can't really make out the bands of R5.....Have you tested actual values of any resistors to make sure they're ok??

like R13 looks weird to me.....??? maybe...could be the pic or I am looking wrong...

I'm guessing those sockets are making good contact with your transistors??

 

[TillM]

like R13 looks weird to me.....??? maybe...could be the pic or I am looking wrong...

You are not looking wrong !!!
It was me who was looking wrong and don't find the simple mistake since April, cause I was so sure I made everything right.
The resistor in R13 I build in was a 4.7k instead of 47k.
Changed it and now everything works perfect !
Thank you so much Scott !
It's really embarrassing for myself.
Finally I could calibrate the unit and it works great.
THANK YOU SO MUCH and everyone else who helped me.

 

[scott2000]

That's great! Hardly embarrassing....

I've got a million real embarrassing stories and plenty of broken things around to prove it ....

How do you like the sound???.....What's it like compared to TTxOP???

 

[TillM]

How do you like the sound???.....What's it like compared to TTxOP???

I will made some test with different FETs in the 1176.
Then I can tell more. But I really like the TTxOP.

 

[weiss]

Also, What revision board do you have?? I saw that the early ones had some errors that required changing a few resistors... not that it would solve your problem but, should be changed  regardless I'd think....

Hey i am having similar issues like Till.. what exactly do i need to change with v1.0 revision boards? I have the first revision but nothing works at the moment. No signal, no meter movement. I just hear a tiny Click/burst when changing ratio. Resoldered all points. Also can i trust my voltage meter if the values of the resistors differ from the values needed? Because if i measure a resistor the value slowly starts to increase until it stops but most of them are way lower than they need to be. Some are spot on. I find it weird.

 

[scott2000]

I think I was referring to the board errors on earlier 1.2.5?  That's mentioned on the mnats page. 

If you are checking the resistors out of circuit, they should read right. If you're checking them in circuit, you need to pull a leg to get an accurate reading if you're unsure.... I usually just double check the markings if I get a goofy in circuit reading because chances are they are just picking up another part of the circuit. I think Mike was saying to be careful not to pull too many components too often because of stressing the board. I'd imagine resistors are pretty durable unless something crazy happened??

TillM just had a misplaced value resistor... But it was  spotted from it's markings....

Do you have some voltages to post where things are goofy? That seems to be helpful when trying to narrow down stuff in these.... and maybe upload a pic of the board if you want some more eyes on it to see if there's anything obvious that may be out of place.?......

 

[weiss]

I think I was referring to the board errors on earlier 1.2.5?  That's mentioned on the mnats page. 

If you are checking the resistors out of circuit, they should read right. If you're checking them in circuit, you need to pull a leg to get an accurate reading if you're unsure.... I usually just double check the markings if I get a goofy in circuit reading because chances are they are just picking up another part of the circuit. I think Mike was saying to be careful not to pull too many components too often because of stressing the board. I'd imagine resistors are pretty durable unless something crazy happened??

TillM just had a misplaced value resistor... But it was  spotted from it's markings....

Do you have some voltages to post where things are goofy? That seems to be helpful when trying to narrow down stuff in these.... and maybe upload a pic of the board if you want some more eyes on it to see if there's anything obvious that may be out of place.?......

thanks for the clarification!

yes, that would be great. i already posted my voltages but i'll do it again.
board picture and voltages are below. I used a 2k trimmer instead of the front panel trim pot.
thanks for your help, really appreciate it!!

overview:

detailed:
https://i.imgur.com/qggod0M.jpg
https://i.imgur.com/VWBDEPM.jpg
https://i.imgur.com/ODGMeaI.jpg
https://i.imgur.com/cTW8Nef.jpg

wiring:
https://i.imgur.com/fVay2Qg.jpg
https://i.imgur.com/oFaYvVZ.jpg
https://i.imgur.com/2pUvHwZ.jpg

 

[scott2000]

Oh right...I remember this one.... Nice pics.....  I'll definitely look at them when I get a chance...... I did notice the possibility of some solder bridging in one of the pics when I was downloading them but I haven't looked at what was what so could be nothing........

I definitely suggest you enlarge your pics and study some things too if you haven't already ....It's sometimes better than going over the boards with a magnifying glass....... and more comfortable

 

[weiss]

Oh right...I remember this one.... Nice pics.....  I'll definitely look at them when I get a chance...... I did notice the possibility of some solder bridging in one of the pics when I was downloading them but I haven't looked at what was what so could be nothing........

I definitely suggest you enlarge your pics and study some things too if you haven't already ....It's sometimes better than going over the boards with a magnifying glass....... and more comfortable

thanks for the effort, man. i'll do that.  Wouldn't know who else to ask!

 

[scott2000]

I didn't catch anything weird as far as components being out of place from what I've checked so far..... Looks good....at least from what's visible....

Seems like maybe a possible wiring issue  ....in your ratio/meter areas???

When I get more time I'll try to decipher what's what.....hopefully someone else can jump in to help.... I'm not versed in these..... actually not versed in much of anything...lol



Also, it's hard to tell what's going on with the wiring and if there are any components in those separate boards???? I know it stinks but, maybe draw out a simple diagram of what you have going where so anyone following along can check with the guide to see anything obvious.........???....

 

[weiss]

I didn't catch anything weird as far as components being out of place from what I've checked so far..... Looks good....at least from what's visible....

Seems like maybe a possible wiring issue  ....in your ratio/meter areas???

When I get more time I'll try to decipher what's what.....hopefully someone else can jump in to help.... I'm not versed in these..... actually not versed in much of anything...lol

Also, it's hard to tell what's going on with the wiring and if there are any components in those separate boards???? I know it stinks but, maybe draw out a simple diagram of what you have going where so anyone following along can check with the guide to see anything obvious.........???....

thank you for the effort! that's what i also suspect. I'll upload a schematic for you later this evening. thanks again, mate!