GSSL HELP THREAD!!!

[Majestic12]

And there still 2 issues my 10ma meter doesn't work at all, is dead,

maybe. Is it connected with correct orientation to its current sensing (not illumination) terminals ? 0V is more positive than a negative control voltage.

and sometimes when I switch it on led doesn't light, I have to switch it off and on again to make it work

78L12 is latching on startup. Maybe read pg.300..303 from this thread for a latch up fix.

Thanks Harpo I fanilly had some time to work in this,
1.-Ok the problem on starting it up was because the 7815 I changed it to Lm317 now powering up solved it.
2.-Meter is moving but very shy, only a bit i dont think is reading full scale Im using 10 ma meter on the main board the resistor for the meter is 200 ohms
3- The main issue right now is the turbo board the voltage readings are not the way it should and I dont know where to look  :-\ I´ve already check conections and orientation of components, here i post some pics...

1. The LM317 is not a direct replacement part for the 7815, you'll need at least one extra resistor to set the LM317 output voltage. Have you done so ?

 

[Harpo]

1.-Ok the problem on starting it up was because the 7815 I changed it to Lm317 now powering up solved it.

Maybe a language thing, you had the LM317 with center pin lifted from pcb and current and voltage setting resistors for 15VDC out hanging in the air? or only mistakenly fitted a LM317 and now replaced with a 7815 ?

2.-Meter is moving but very shy, only a bit i dont think is reading full scale Im using 10 ma meter on the main board the resistor for the meter is 200 ohms

The TL072 is hard challanged to drive this load and being a dual opamp will also cause misbehaviour of its other amp in the same housing. Disconnect the wrong 10mA meter for further testing until you have replaced it with a max. 1mA meter.

3- The main issue right now is the turbo board the voltage readings are not the way it should and I dont know where to look  :-\

Get all your supply rails working, FI Turbo board is missing the -12V rail...

 

[jicama]

1.-Ok the problem on starting it up was because the 7815 I changed it to Lm317 now powering up solved it.

Maybe a language thing, you had the LM317 with center pin lifted from pcb and current and voltage setting resistors for 15VDC out hanging in the air? or only mistakenly fitted a LM317 and now replaced with a 7815 ?

2.-Meter is moving but very shy, only a bit i dont think is reading full scale Im using 10 ma meter on the main board the resistor for the meter is 200 ohms

The TL072 is hard challanged to drive this load and being a dual opamp will also cause misbehaviour of its other amp in the same housing. Disconnect the wrong 10mA meter for further testing until you have replaced it with a max. 1mA meter.

3- The main issue right now is the turbo board the voltage readings are not the way it should and I dont know where to look  :-\

Get all your supply rails working, FI Turbo board is missing the -12V rail...

Hey..
1. Yeah I used to have 7815 but changed it to LM317 following the instructions here http://diyaudioprojects.com/Technical/Voltage-Regulator/
R1 I used 270 Ohms and R2 3k here is a photo...
2. I got a 1mA meter when I´m at home will try it, I hope there is a chance to use the 10mA meter as I like it more
3. My main supply rails reads 15.2V and -14.7V from the main board, where should I look for the missing -12V?  :-\
cheers

 

[Harpo]

2. I got a 1mA meter when I´m at home will try it, I hope there is a chance to use the 10mA meter as I like it more

Might require a current booster stage, maybe powered from the +/-15V rails (the +/-12V rails from the 78L12/79L12 will not supply this additional load).

3. My main supply rails reads 15.2V and -14.7V from the main board, where should I look for the missing -12V?  :-\

I already told you, this supply rail is missing on Turbo board (negative supply for the TL074 and VCA). Coming from the main pcb, this -12V rail might be missing there as well.

 

[Harpo]

Yeah is missing there you right, so the 200 Ohm resitor I was using for the 10mA meter was causing problems for the distribution of the -12V? Bad luck I don't have now a 2k resistor for my 1mA meter to test ???

Unlikely, there might be other faults/shorts. Just disconnect the wrong GR-meter and confirm that all needed supply rails are operating. I suggest to disconnect the turbo board for now in order to build a working standard GSSL. You can easily add/reconnect the turbo circuit at a later stage.

 

[jicama]

Yeah is missing there you right, so the 200 Ohm resitor I was using for the 10mA meter was causing problems for the distribution of the -12V? Bad luck I don't have now a 2k resistor for my 1mA meter to test ???

Unlikely, there might be other faults/shorts. Just disconnect the wrong GR-meter and confirm that all needed supply rails are operating. I suggest to disconnect the turbo board for now in order to build a working standard GSSL. You can easily add/reconnect the turbo circuit at a later stage.

Ho my god!! 0V and -12V Turbo board was connected in the wrong way from my main board, of course wasn't receiving the proper energy, some times we are blind to obvious things!!  ;D now my turbo TL074 is receiving as well my -12V
Hopefully later when I do my checks will work properly, tomorrow I´ll buy the 2K resistor for my 1mA meter, I´ve been reading 2k resistor is not enough to get a proper gain reduction values, some people suggest 5K trimpot and calibrate it.?
Thanks Harpo

 

[Greg S.]

@ Jicama!!!

Thank you very much.

right beside the 79L12 is a measurement point printed at the pcb, parallel to a 100nF Poly.
should be -12V but I got -20V there!
Thats why I was asking!
resoldered and replaced anything close, but it stayed -20V, so I;ll gonna order new 79L12 and 78L12

Thanks again Mate

 

[jicama]

@ Jicama!!!

Thank you very much.

right beside the 79L12 is a measurement point printed at the pcb, parallel to a 100nF Poly.
should be -12V but I got -20V there!
Thats why I was asking!
resoldered and replaced anything close, but it stayed -20V, so I;ll gonna order new 79L12 and 78L12

Thanks again Mate

Hey Greg, Im learning like you but before changing the 79L12 and 78L12, try to look for shorts and orientation of components it will be better first to read voltage at the IC´s sockets and read as well if you control board is recieving the -12V

 

[ram75]

Hi there, I have a problem with one of my gssl turbo mod

- the gain is very weak and I have more sound when I activate bypass
- Have a loss of sound for a second when I pass from the original mod to turbo one
- It doesn't compress as much as the other one.

Where should I start?

Thank you

Philippe

 

[Harpo]

Hi there, I have a problem with one of my gssl turbo mod

- the gain is very weak and I have more sound when I activate bypass
- Have a loss of sound for a second when I pass from the original mod to turbo one
- It doesn't compress as much as the other one.

Where should I start?

Maybe start with completing/correcting the wiring of the turbo switch and bypass switch (both will have 3 wires connected).
The 47K summing resistor that goes to the center pin of the turbo-switch is lifted from pcb at the virtual ground node side ?

 

[ram75]

Maybe start with completing/correcting the wiring of the turbo switch and bypass switch (both will have 3 wires connected).
The 47K summing resistor that goes to the center pin of the turbo-switch is lifted from pcb at the virtual ground node side ?
[/quote]

Thanx for responding Harpo,

better to answer with pictures, here what I have, looks completly wrong.
By pass is the black switch, turbo is the blue one.

 

[ram75]

And for the lifted part, there it is.


thank you

 

[Harpo]

Your one side lifted resistor doesn't look like a 47K, maybe only optical artifact.

If you want to make it switchable between GSSL-mode and turbo-mode, a wire from the free top throw position at your turbo switch back to the freed up hole of the lifted 47K resistor is missing. (actually you have it wired for either turbo mode with sidechain listening to both side audio or GSSL mode only listening to one side audio and ignoring the other channel). Make sure, the one side lifted 47K resistor connects to the switches center pole.

For your bypass switch, confirm the red wire soldered to the left side center pin connects to 'com' on pcb and the orange wire connects to 'on' on pcb. The missing wire at the switches top left and top right throw position connects to 'off'/0V reference voltage on pcb. The missing wire at the switches right side center pin connects to the hole next to the 750K on pcb with the makeup gain link removed. The missing wire at the switches right side bottom pin connects to the hole next to the makeup gain pot center pin/wiper connection.

 

[ram75]

Your one side lifted resistor doesn't look like a 47K, maybe only optical artifact.

If you want to make it switchable between GSSL-mode and turbo-mode, a wire from the free top throw position at your turbo switch back to the freed up hole of the lifted 47K resistor is missing. (actually you have it wired for either turbo mode with sidechain listening to both side audio or GSSL mode only listening to one side audio and ignoring the other channel). Make sure, the one side lifted 47K resistor connects to the switches center pole.

For your bypass switch, confirm the red wire soldered to the left side center pin connects to 'com' on pcb and the orange wire connects to 'on' on pcb. The missing wire at the switches top left and top right throw position connects to 'off'/0V reference voltage on pcb. The missing wire at the switches right side center pin connects to the hole next to the 750K on pcb with the makeup gain link removed. The missing wire at the switches right side bottom pin connects to the hole next to the makeup gain pot center pin/wiper connection.

Ok, did the first part, now the second one

I'll let you know how it goes.

Thank you very much for your help!

Philippe

 

[ram75]

Well, did everything and nothing works anymore
no compression, no action on any switch.

Any ideas what's going on?

thank you

Philippe

 

[Industrial Waves]

I'm here trying to finish my GSSL. I have read the build guide. I just have to solder the 4 wires from the toroid to the PCB. In the guide says '' To wire them in series, combine the end of the
first secondary with the start of the second secondary (blue with green). The combined wire goes to 0V on the main PCB, and the two remaining single wires go to 15 V pads on the sides ''
I have: 1st sek  - red/yellow
          2nd sek - blue/green
So I have understood that I must to solder YELLOW with BLUE .

 

[ram75]

Your one side lifted resistor doesn't look like a 47K, maybe only optical artifact.

If you want to make it switchable between GSSL-mode and turbo-mode, a wire from the free top throw position at your turbo switch back to the freed up hole of the lifted 47K resistor is missing. (actually you have it wired for either turbo mode with sidechain listening to both side audio or GSSL mode only listening to one side audio and ignoring the other channel). Make sure, the one side lifted 47K resistor connects to the switches center pole.

For your bypass switch, confirm the red wire soldered to the left side center pin connects to 'com' on pcb and the orange wire connects to 'on' on pcb. The missing wire at the switches top left and top right throw position connects to 'off'/0V reference voltage on pcb. The missing wire at the switches right side center pin connects to the hole next to the 750K on pcb with the makeup gain link removed. The missing wire at the switches right side bottom pin connects to the hole next to the makeup gain pot center pin/wiper connection.

Hi Harpo here is the picture of my wiring, is there anything wrong with it?

thanx

Philippe

 

[Harpo]

The combined wire goes to 0V on the main PCB, and the two remaining single wires go to 15 V pads on the sides ''
I have: 1st sek  - red/yellow
          2nd sek - blue/green
So I have understood that I must to solder YELLOW with BLUE .

Yepp (and assuming you didn't mix up the colour sequence printed on your transformer label. Colour of wires is not standarized between different manufacturers), going to the Center (3rd. from left or right) hole of the 5 drill holes (a provision to fit a 3-pin terminal connector with either 0.1" or 0.2" pin spacing).
Remaining red wire goes to one of the left from center holes, remaining green wire to one of the right side from center holes (or the other way round, doesn't matter for AC).

 

[Harpo]

Hi Harpo here is the picture of my wiring, is there anything wrong with it?

Wiring looks OK, but your switch might be damaged from too long soldering on. Some parts are more temperature sensitive than the rest. Prove continuity per switch position by ohming it out.

 

[ram75]

Hi Harpo here is the picture of my wiring, is there anything wrong with it?

Wiring looks OK, but your switch might be damaged from too long soldering on. Some parts are more temperature sensitive than the rest. Prove continuity per switch position by ohming it out.

Ok, I'll change the switch.

Thank you.