GSSL HELP THREAD!!!

[Mowenw]

You're getting 0VAC, but you are inserting a 0dBV (1V RMS) sine wave into the GSSL?

Erm....can't quite remember. Maybe I wasn't running the sine wave. I'll try again tomorrow. In the meantime I've blown a 10 ohm resistor . 

Will have to get a new one and try again tomorrow.

 

[Mowenw]

Mow,

Have you looked through this thread for similar malfunctions?

Distorted when compressing usually points to missing wire link on control board. Distorted while NOT compressing could be vca or associated (5534) circuit. Shorts. Wrong value resistors.

Jakob E.

Hi Jakob,

I've checked loads of posts under the smart search(gssl distortion). None of it has really sorted out the problem.

I've listed the voltages of unpopulated ic/vca sockets above. Are these ok ?

I've put the jumper on the control board next to the meter.

Ive checked component values for the whole build. They all appear fine.

I've gone through all solder joints looking for bridges or cold solders. There appear to be none.

The unit distorts massively when in bypass mode and when in not in bypass.

I put a jumper from pin 1/8 on 2180 sockets and the audio path was clear and levels were fine.

Your voltages appear to be ok.
Did you already receive the new THAT chip and replaced the one in the right channel? Is the left channel still working ok or is this too sounding distorted?

I know how frustrating this can be, but I also know that I've spotted wrong resistors after checking them three times. It's just very easy to overlook when you assume that it should be alright. Don't just check the colorcodes; desolder one leg and measure them. Start doing this in the VCA sections. I've had GSSL's passing clean audio with VCA PIN 1 and 8 jumpered, but still had a wring value resistor in there...

Check reply #4199 of this thread for a basic troubleshooting guide. I've got every not working GSSL working with that guide.

Thanks Tzman (and eveyone who has responded)....



I haven't got the new THAT chips yet. I am getting distortion from both channels now though. The left channel appears to be slightly cleaner but ye, both are crazy distorted.

Whilst on the subject, the THAT chips I received with the kit are 2180b. I assume these need the 5k1, 1k(x2) and 120R resistors in the VCA section ye? The new one's I've ordered are 2181's. Depending on the post, I've read different things regarding the 2181. Some people say they are an identical upgrade. Some people say they require a trimmer. Will I need to source some trimmers when the 2181 arrive or can I just stick them straight in with the current resistors ?

I will desolder and check resistors.

I'll also gladly check the troubleshooting guide. Does clean audio when jumping pin1/8 on 2180 sockets eliminate the possibilty of opamp failure or any other possible causes of distortion ?

Thanks again for your input.

The 2181 is NOT an drop-in replacement for the 2180. You would be better off ordering the exact same part when troubleshooting. Otherwise refer to this website for the change in resistors and added trimmer: http://diy.fischerworks.com/gssl_vca.shtml

Shorting pin 1 and pin 8 of the audio VCA and getting clean audio does not mean that your unit won't distort when putting in the VCA.

I understand that. What DOES it mean though?

Does mean opamps are ok ? Does it eliminate certain solder issues ??

 

[tzman]

It just means your unit passes audio from input to output. So you could assume the input opamps and output opamps are working ok. You could verify that by working through the steps of the guide.

 

[Murdock]

Yesterday I powered my unit on for the first time. I'm happy that it even powered on without exploding because I really don't know nothing about electronics...
Anyway, one meter LED illuminated very bright for like 3 seconds than it went off. I have the + soldered on to the 12V pad and the - to the 0V pad. Is that right? The meterLED has an internal 600 ohm resistor. Could it be that this is not enough?
Other than that, signal passes through the unit but the controlls don't work...
I measured some points. (http://postimg.org/image/jlqlt1zy5/) All measurements were taken without signal passing through, black probe on ground pin on the IEC and red probe on the pads. 
The controll board receives 12V.
Are these OK? Where should I start looking for the fault?

 

[Gustav]

Yesterday I powered my unit on for the first time. I'm happy that it even powered on without exploding because I really don't know nothing about electronics...
Anyway, one meter LED illuminated very bright for like 3 seconds than it went off. I have the + soldered on to the 12V pad and the - to the 0V pad. Is that right? The meterLED has an internal 600 ohm resistor. Could it be that this is not enough?
Other than that, signal passes through the unit but the controlls don't work...
I measured some points. (http://postimg.org/image/jlqlt1zy5/) All measurements were taken without signal passing through, black probe on ground pin on the IEC and red probe on the pads. 
The controll board receives 12V.
Are these OK? Where should I start looking for the fault?

Hi Murdock.

Great job measuring the voltages on the supply and regulators..

Now, if you can, measure them for the two 12V regulators and the supply voltages on the IC pins as well, that would help take you a step forward

600ohms suits 15mA current draw/2V voltage drop across LED perfectly. I dont see why this would blow the LED, but I could be wrong, so hopefully someone else will verify. (You should also make sure the 600ohms refer to an internal resistor in series with the LED and not "just" the meter circuit rating.

Also, please share if you are using a 2 x 18V transformer.

Do you have any mods installed?

Does the bypass switch seem to do anything at all?

Could you share a picture of your work (top and bottom)?

Gustav

 

[Mowenw]

Hello,

I have what I think is a short on the 7815 that is causing a 10 ohm resistor to blow.

I just wanted to check whether or not any of the 7815 pads do actually connect to each other . Because I'm trying to wick the pads but they are still testing as connected.

Thanks.

 

[Gustav]

I just wanted to check whether or not any of the 7815 pads do actually connect to each other . Because I'm trying to wick the pads but they are still testing as connected.

They are not supposed to be connected.

You can always refer to the board layout if you have doubts about connections while scanning for shorts.

https://pcbgrinder.com/download/GssL/ssl.pdf (scroll down in the document).

Gustav

 

[Mowenw]

I just wanted to check whether or not any of the 7815 pads do actually connect to each other . Because I'm trying to wick the pads but they are still testing as connected.

They are not supposed to be connected.

You can always refer to the board layout if you have doubts about connections while scanning for shorts.

https://pcbgrinder.com/download/GssL/ssl.pdf (scroll down in the document).

Gustav

That is what I thought and remembered from before. I just can't seem to fin any bridge whatsoever. There are literally no visible bridges on the pads themselves and I'm getting strong continuity.

Weird.

 

[Gustav]

I just wanted to check whether or not any of the 7815 pads do actually connect to each other . Because I'm trying to wick the pads but they are still testing as connected.

They are not supposed to be connected.

You can always refer to the board layout if you have doubts about connections while scanning for shorts.

https://pcbgrinder.com/download/GssL/ssl.pdf (scroll down in the document).

Gustav

That is what I thought and remembered from before. I just can't seem to fin any bridge whatsoever. There are literally no visible bridges on the pads themselves and I'm getting strong continuity.

Weird.

There are traces going to and from the pads. Short can be anywhere along those lines. You may have a short from your positive 15V supply to ground somewhere in the build, or something else may be wrong - no way to tell with the info at hand.

Posting a few pictures covering the solder work would help give an idea about the quality of your work in general.

Gustav

 

[Murdock]

Yesterday I powered my unit on for the first time. I'm happy that it even powered on without exploding because I really don't know nothing about electronics...
Anyway, one meter LED illuminated very bright for like 3 seconds than it went off. I have the + soldered on to the 12V pad and the - to the 0V pad. Is that right? The meterLED has an internal 600 ohm resistor. Could it be that this is not enough?
Other than that, signal passes through the unit but the controlls don't work...
I measured some points. (http://postimg.org/image/jlqlt1zy5/) All measurements were taken without signal passing through, black probe on ground pin on the IEC and red probe on the pads. 
The controll board receives 12V.
Are these OK? Where should I start looking for the fault?

Hi Murdock.

Great job measuring the voltages on the supply and regulators..

Now, if you can, measure them for the two 12V regulators and the supply voltages on the IC pins as well, that would help take you a step forward

600ohms suits 15mA current draw/2V voltage drop across LED perfectly. I dont see why this would blow the LED, but I could be wrong, so hopefully someone else will verify. (You should also make sure the 600ohms refer to an internal resistor in series with the LED and not "just" the meter circuit rating.

Also, please share if you are using a 2 x 18V transformer.

Do you have any mods installed?

Does the bypass switch seem to do anything at all?

Could you share a picture of your work (top and bottom)?

Gustav

Hey Gustav,

thanks alot for your help!

Here are the measurements (I hope these are the ones you meant):

12V Regulators
79L12: -11,9 and -14,7
78L12: 12,2 and 14,7

ICs
TL074CN: -12 and 12,2
TL072CP: 12,2 and -11,9
NE5534P (Left VCA): 15,2 and -15
And 12,7 for both Bal/Comp Pins
The same for the Right VCA
Input NE5534P: both at -15 and 15,2
Output NE5532P: both at -15 and 15,2

VCAs
Sidechain: 12,2 and -2,9
Left VCA: 15,2 and -2,9
Right VCA: 15,2 and -2,9

I'm using a 2x15V transformer.

The Bypass does nothing.

Here are some pictures. Sorry for the mess, I will clean it up once its running properly
http://s21.postimg.org/o2ksxc4t3/IMG_6394.jpg
http://s10.postimg.org/larh00qmh/IMG_6392r.jpg
http://s21.postimg.org/xxby3k8rb/IMG_6393.jpg
http://s21.postimg.org/uvpr7cl07/IMG_6391.jpg

Concerning solder bridges; they don't matter if the pads are connected anyway right?
Thanks again for your help!

 

[Harpo]

http://s21.postimg.org/xxby3k8rb/IMG_6393.jpg

Control pcb is either missing a 47K or a zero-R jumper in the same spot in series to the threshold pot.

 

[Murdock]

http://s21.postimg.org/xxby3k8rb/IMG_6393.jpg

Control pcb is either missing a 47K or a zero-R jumper in the same spot in series to the threshold pot.

Thanks for pointing that out!
I thought I would try the sensitivity first before reducing it. Didn't knew I had to place a jumper on it then.
I placed a 47K resistor in there but didn't change anything...

And I have no mods installed.

 

[Gustav]

http://s21.postimg.org/xxby3k8rb/IMG_6393.jpg

Control pcb is either missing a 47K or a zero-R jumper in the same spot in series to the threshold pot.

Thanks for pointing that out!
I thought I would try the sensitivity first before reducing it. Didn't knew I had to place a jumper on it then.
I placed a 47K resistor in there but didn't change anything...

And I have no mods installed.

Voltages look good, solder work looks fine, so I would not suspect a 100% non working unit based on this (solder bridge wouldn't silence the side chain ime.

I managed to check the SC jump switch based on the pictures, and it seems fine. Did I overlook the bypass? I would definitely check the bypass, since it all looks fine, and you are just not getting any interaction on the controls.

Gustav

 

[Mowenw]

I decided in the end to de-solder everything, clean the board and components up and start from scratch, measuring each component and checking for short as I go.

So far so good, just a couple of things I was wondering about.

Firstly, the ceramic caps all read a higher level than the stated amount. The 101 caps all measure 186 nf. The 33 caps all measure around 99nf, the 22 caps measure 85 nf and 10cap measures 60 nf. I assume they are ok as it is a cross-the-board "inaccuracy".

Also, I've found one or two 22uf caps that are measuring around 19uf. Going by the law of 10% I suppose that would make these ones and any falling below 19.8 unusable, correct ??

Thanks

 

[bpucekov]

Tolerance for electrolytic caps is usually 20%

 

[Harpo]

Firstly, the ceramic caps all read a higher level than the stated amount. The 101 caps all measure 186 nf. The 33 caps all measure around 99nf, the 22 caps measure 85 nf and 10cap measures 60 nf. I assume they are ok as it is a cross-the-board "inaccuracy".

Most multimeters can't measure these low  capacitances (these are pF, not nF values).
Measuring results are highly depending on charge state of battery as well.

Also, I've found one or two 22uf caps that are measuring around 19uf. Going by the law of 10% I suppose that would make these ones and any falling below 19.8 unusable, correct ??

Maybe only the result of measuring method or low battery...
Looking at the caps datasheet will tell you its parts tolerance, depending on type up to -20/+80% for ancient parts.
When measuring polarized parts, watch out parts orientation in order to not damage the part while testing. The multimeters [COM] port is not always the caps negative lead connection.

 

[Murdock]

http://s21.postimg.org/xxby3k8rb/IMG_6393.jpg

Control pcb is either missing a 47K or a zero-R jumper in the same spot in series to the threshold pot.

Thanks for pointing that out!
I thought I would try the sensitivity first before reducing it. Didn't knew I had to place a jumper on it then.
I placed a 47K resistor in there but didn't change anything...

And I have no mods installed.

Voltages look good, solder work looks fine, so I would not suspect a 100% non working unit based on this (solder bridge wouldn't silence the side chain ime.

I managed to check the SC jump switch based on the pictures, and it seems fine. Did I overlook the bypass? I would definitely check the bypass, since it all looks fine, and you are just not getting any interaction on the controls.

Gustav

Hmm here are some photos of the bybass switch. It really could be the fault. Because I had some problems soldering the wires to it and two of the contacts became loose because I took to long. But the contacts are still in there and the "glue" dried.
Is it possible to just desolder the bypass switch temporarily so I can see if thats the problem? Or would I have to place those zero R Jumpers in there too?

http://s10.postimg.org/7h2zc09ax/IMG_6466.jpg
http://s10.postimg.org/x2f7buwih/IMG_6469.jpg
http://s10.postimg.org/ujtib6as9/IMG_6467.jpg
http://s10.postimg.org/lrcjnhpnd/IMG_6468.jpg

Thanks!

 

[Gustav]

http://s21.postimg.org/xxby3k8rb/IMG_6393.jpg

Control pcb is either missing a 47K or a zero-R jumper in the same spot in series to the threshold pot.

Thanks for pointing that out!
I thought I would try the sensitivity first before reducing it. Didn't knew I had to place a jumper on it then.
I placed a 47K resistor in there but didn't change anything...

And I have no mods installed.

Voltages look good, solder work looks fine, so I would not suspect a 100% non working unit based on this (solder bridge wouldn't silence the side chain ime.

I managed to check the SC jump switch based on the pictures, and it seems fine. Did I overlook the bypass? I would definitely check the bypass, since it all looks fine, and you are just not getting any interaction on the controls.

Gustav

Hmm here are some photos of the bybass switch. It really could be the fault. Because I had some problems soldering the wires to it and two of the contacts became loose because I took to long. But the contacts are still in there and the "glue" dried.
Is it possible to just desolder the bypass switch temporarily so I can see if thats the problem? Or would I have to place those zero R Jumpers in there too?

http://s10.postimg.org/7h2zc09ax/IMG_6466.jpg
http://s10.postimg.org/x2f7buwih/IMG_6469.jpg
http://s10.postimg.org/ujtib6as9/IMG_6467.jpg
http://s10.postimg.org/lrcjnhpnd/IMG_6468.jpg

Thanks!

My brain almost exploded trying to follow the colors and cables going to the switch, so rather than trying to check it, I will recommend that you try desoldering the switch, checking if it still works with your meter (set to continuity test, measure if the connections are made while switching, or if it broke), and redo the connections according to the guide.

In any case, I would not leave a switch done like that in a finished build, so it is work you should do regardless...

Gustav

 

[Murdock]

http://s21.postimg.org/xxby3k8rb/IMG_6393.jpg

Control pcb is either missing a 47K or a zero-R jumper in the same spot in series to the threshold pot.

Thanks for pointing that out!
I thought I would try the sensitivity first before reducing it. Didn't knew I had to place a jumper on it then.
I placed a 47K resistor in there but didn't change anything...

And I have no mods installed.

Voltages look good, solder work looks fine, so I would not suspect a 100% non working unit based on this (solder bridge wouldn't silence the side chain ime.

I managed to check the SC jump switch based on the pictures, and it seems fine. Did I overlook the bypass? I would definitely check the bypass, since it all looks fine, and you are just not getting any interaction on the controls.

Gustav

Hmm here are some photos of the bybass switch. It really could be the fault. Because I had some problems soldering the wires to it and two of the contacts became loose because I took to long. But the contacts are still in there and the "glue" dried.
Is it possible to just desolder the bypass switch temporarily so I can see if thats the problem? Or would I have to place those zero R Jumpers in there too?

http://s10.postimg.org/7h2zc09ax/IMG_6466.jpg
http://s10.postimg.org/x2f7buwih/IMG_6469.jpg
http://s10.postimg.org/ujtib6as9/IMG_6467.jpg
http://s10.postimg.org/lrcjnhpnd/IMG_6468.jpg

Thanks!

My brain almost exploded trying to follow the colors and cables going to the switch, so rather than trying to check it, I will recommend that you try desoldering the switch, checking if it still works with your meter (set to continuity test, measure if the connections are made while switching, or if it broke), and redo the connections according to the guide.

In any case, I would not leave a switch done like that in a finished build, so it is work you should do regardless...

Gustav

Hey Gustav, thanks for your fast answer.
Is this the correct wiring?
http://www.hausverwaltung-heger.de/al_leck_trick/GSSL_bypass.gif
It does not look like in your guide.

EDIT: ok it is definitely the bypass switch. I rewired it and the gain poti worked shortly but because of a loose contact I could not test the rotary switches. So I will order a new bypass switch. I need 2 position dpdt switch right?
Another weird thing is that the meter didn't work either.

 

[Mowenw]

Update. I stuck in some new THAT chips in the VCA's and the compressor is now passing audio clearly.

I am however unaware whether or not it is compressing properly as the issue now is with the control panel. There appears to be some degree of function from the lorlin  switches but the pots don't appear to be affecting the audio and the meter is not moving at all.

The bypass switch also appears to be having little effect ( I would say no effect) on anything.

I have actually installed the push-button bypass/onoff now as well.

I can't imagine that there are any issues with soldering or component orientation and was wondering if there are any chips that might affect how the pots/meter/bypass work.

Do the TL072/074 have anything to do with front panel control ?

Thanks.