All things G1176 - the new "repost" thread.

[heybluez]

[quote author="heybluez"]
E B C
Q2--.56--1.09--1.84
Q3--1.20--1.86--12.95
Q4--11.3--11.8-- 29.53
Q5--4.4--4.8--28
Q6--28.5--27.9--14.45
Q7--29.64--28.99--14.73
Q8--13.81--14.48--29.87
Q9--13.77--13.14--0.0
Q12--22.9--8.23--26.60
Q13--25.87--26.33 --30.03
Q14--29.98--4.88--5.45
Q15--4.86--5.45--30.01
[/quote]

Ok I went ahead and replaced Q12,13,14,15 and got the below results:

E B C
Q12--22.46--14.81--26.11
Q13--25.58--26.10 --29.25
Q14--4.12--4.78--5.12
Q15--4.52--5.12--29.34

Not much improvement. I checked all the obvious components orientation, etc. The caps look fine. I am checking the poly caps and the resistors now. I cannot seem to find any shorts...I was trying to be meticulous when I stuffed the board to prevent anything like that...but hey...I am still looking.

My voltages are like 29.8V / -9.5V I am more converned with the -9.5...I believe that should be closer to ten.

Anyway, I am still looking...any thoughts?

Thanks,
Michael

 

[heybluez]

[quote author="heybluez"]
E B C
Q12--22.46--14.81--26.11
Q13--25.58--26.10 --29.25
Q14--4.12--4.78--5.12
Q15--4.52--5.12--29.34
[/quote]

I found the issue! Here are my new voltages:

E B C
Q12--3.94--4.47--14.84
Q13--14.33--14.89 --29.74
Q14--2.91--3.47--16.63
Q15--16.08--16.57--29.70

I checked the orientation of the caps and they looked fine. I checked the values of the caps and they were ok as well. SO I figured that since I had changed all the transistors anyway it must a wrong value for a resistor. I did what Gyraf suggested and looked around Q12-15. Well, I struck gold when I found that the 270R resistor (next to Q12,13 on the PCB) was not 270R but 270k! Wow.....oops. Anyway, I changed that out and my voltages seemed to fall right in place.

I redid the calibration and it seems to work now. I can see the compression acting with the meter, etc. I will be probably work on completing it tomorrow or and seeing how it sounds then.

Gyraf...thanks so much for your help! Amazing what a little thing like a resistor can do!! haha...

Mark..thanks to you as well for my previous signal amp problem.

I do have another question. Where would i find an attack pot like the original. I am going to wire mine with the push button switches and try to wire in the +8 setting. I want to put the bypass on the attack switch like the original. Do you know a) what this switch is called and b) where I could source it?

Thanks!
Michael

 

[holger honda]

Hello.
Now I did it!I built two nice board filled with all the goodies.BUT! AHHH!
It turned out that my 24vct was more like 50vct.......that smell....
I ended up with almoust 70v after the bridge.
I quickly realized the mistake and turned the thing off.On one of the boards the r89 resistor got fried.On the other no visble damage.
Now after finding the right transformer I wonder what parts to change.
I guess quite a few.
Any idea of were to start?

 

[gyraf]

Hi Holger,

Look at PRR's answer in the other thread you started - http://www.groupdiy.com/index.php?topic=5077

He surely knows his stuff..

Jakob E.

 

[idylldon]

C15 is supposed to be 470/40, but I was wondering why the voltage rating is that high since I can't see where it gets near 40?

Seems like 470/35 will work in this position.

Cheers,
--
Don

 

[gyraf]

It probably will work fine at 35V.

But 40V is what I had at the time, and what I made room for at the pcb.. :razz:

Jakob E.

 

[xsmsx]

Hi there!
just the right time to post my little problem. My unit works fine but, compared to the original, I don't get enough output gain. I just read about 1:1, 1:2 transformer configuration. What is it about? I alrady exchanged a 11k resistor to 5k, what someone suggested in another thread, but there's not much difference. So what can I do?
Thanx a lot!

Christoph :shock:

 

[Rob Flinn]

The 1:2 mod gives you more like the gain of the original

 

[heybluez]

Oh man....I think that someone is trying to drive me crazy.

I have pretty much replaced all the FET's and transistors on my board to get it to work. I think i blew them up when I shorted my regulator a while back. Anyway, I can set the QBias (using KDawgs procedure) and last night I thought I had. I did have trouble setting the GR indicator (i.e. -6vdb) and when i would switch ratios it would definitely jump everywhere. I figure I better change Q10 just in case. When I did it seemed to work. I still had some trouble getting to calibrate it but it seemed to not jump anymore.

I had some music playing through it and it seemed to work...at 4 is what not "as loud" as 20 and it looked on the meter to be compressing.

Anyway, I decided to go to bed and box it tonight. SO....in my brilliance, I figure I changed everything else I might as well just replace the last three transistors just in case..these are Q5,6,7.

Now I don't know if that did something or what! But not I cannot calibrate to save my life. The meter jumps again when I switch ratios (i.e. without signal) and I cannot drop it to -6 and keep then calibrate the meter at 0. It just won't do it. I did put signal in it and it does seem to compress.

I am so frustrated I had to leave it alone before I tossed it! Anyway, I was reading in the thread about Orson's troubles with the GR indicator so I will see what I can with that. I am curious anyone have any ideas as to what I can look at? I think everything is right? Could my FDH333's be toast?

By the way, the only time I had it the closest it seems I did not have to turn my QBias more than a little half way...not it is a little more than that.

I did turn these pots just to see if that did anything...i hope I am allowed to do that without damaging anything else!

Anyway, thanks for your help!
-Michael

 

[xsmsx]

hey Rob,

thanks, that's what I thought. But how do I do this 1:2 modification?

Christoph

 

[gyraf]

Christoph,

Search the Meta.

Michael,

GR jumping (and staying off) when switching ratios, could indicate leaky FDH333's. But it COULD also be component-value problems around point 20/21 - the "threshold offset" for the different ratios.

Jakob E.

 

[xsmsx]

Hi again,

I think I found it. It describes how to change the connections of the Input AND Output Transformer. I don't have the Input Transformer. So can I just go on changing only connections at the Output transformer? Or do I have to make some more effort?

Thanks again
Christoph

 

[idylldon]

[quote author="xsmsx"]Hi again,

I think I found it. It describes how to change the connections of the Input AND Output Transformer. I don't have the Input Transformer. So can I just go on changing only connections at the Output transformer?
Thanks again
Christoph[/quote]

Yes.

Cheers,
--
Don

 

[heybluez]

Hi Gyraf,

Just for the record I am using the NTE177 substitute. In case that matters.

Anyway, I checked the orientation of the 6.8u and 100u caps (C19,20,21) and they seemed ok. I also switched from 4:1 to 20:1 and measured a DC voltage change at point 7 (on the ratio board where the release and attack are connected) and this did change and stay steady. I believe it was in the -3.x to -1.x range when i switch back and forth.

How would I tell if the NTE177's are leaking? I also noticed that the jump is the worst when switching from 4:1. After that it aint so bad. I know this worked once...at least I thought it did but I was never able to get the GR tracking to calibrate. Nonetheless there is obviously a problem.

-Michael

 

[gyraf]

Michael,

We've had several problems with NTE subs - mostly on pin-outs.

I would'nt use any NTE's - it's almost always easier to find a different component with the needed specs - and then you'd know what you got.

Jakob E.

 

[radiance]

I want to make a 'hard bypass" on my 1176 using 4 relays.
Is it o.k. to use the "VU lamp" power for this?
I'm using a 0,6 A , 2 x 25 V torriod transformer.

Also, if I use four 5V relays (with the coil's powered in series) I will consume less power than four 24V relays (with the coil's powered parallel) right?
Al the realys need to be switched at once so...

 

[heybluez]

Gyraf,

What do you recommend to replace the NTE's? Anyone know where I can source some FD333's?

Thanks!
Michael

 

[radiance]

[quote author="radiance"]I want to make a 'hard bypass" on my 1176 using 4 relays.
Is it o.k. to use the "VU lamp" power for this?
I'm using a 0,6 A , 2 x 25 V torriod transformer.

Also, if I use four 5V relays (with the coil's powered in series) I will consume less power than four 24V relays (with the coil's powered parallel) right?
Al the realys need to be switched at once so...[/quote]

Edit: I want to take the "vu lamp" power out which than will be regulated by a 7824 regulator ....

 

[heybluez]

Gyraf,

What do you recommend to replace the NTE's? Anyone know where I can source some FD333's?

Thanks!
Michael

 

[mnats]

Mouser carries them.