GSSL HELP THREAD!!!

[panda]

yeah, i get excitable like that. wanted to run more tests.. but there it was.. i had to put in the ICs, hook up sound and go!! i might have blown something, thats OK. i have a electrical engineer friend coming over to check it out. haha.. i couldn't sleep though.. so i had to!

so i was going to make a custom case for this thing. i was thinking of making the face out of wood. like a par-metal case, just the face replaced with wood! there is no reason that wouldn't work.. and look total cool with the right stain, knobs n' ****.. i dont' wanna just put some wood over the metal front.. cause i want it to still be flush in my rack.
though i'm thinking to far ahead. my unit may already be dead! :shock:

anyways.. now its time to once again read through this thread. i'll find my answers in your guys previous words. exciting times. [ i like trouble shooting for some reason.. maybe its that.. d'oh/ah!! at the end ]

panda

 

[panda]

so i have a friend coming over to help out with this thing. yeah me.
i finally do have audio passing. through 1 channel. and the controls seems to do nothing. anyways. i'll figure it out. one thing is weird, that i haven't read anyone mention.

i am blasting through fuse's. now i'm sure it just m touching the wrong thing to the wrong thing with my meters. but like bam, 2 fuse's in one night of tests. could there be a real problem somewhere that i'm not away of. my PS seems to be giving off all the right power. i'm thing i might have some reversed things, or blown ICs.. but the fuse's,, just pop,pop,pop..
is that normal? should i go out and buy like a bag full of fuse's? anything more specific on the fuses beyond 5 x 20 mm?

gonna hook my edgewise meter i got today up today too.. maybe that will do something fun also? like burst into flames!! :shock:

sadly this might be more fun then actually using it. i know how to use a compressor, and record things.. but this.. it's all new.. like a new GF or something. got figure out the inner workings.

panda

 

[Greg]

If you're popping fuses, check for shorts !!!

 

[Flundran]

I have no compression on signal. Passing signal thru fine and make-up pot work. Same behavior on both channels. Meter responds when I turn threshold CCW by moving up a bit, frozen in the same position. Output signal then becomes slightly weaker.

TL072 measurements:
Voltage at pin1 at TL072 varies with threshold, and voltage at pin7 varies with make-up pot. However, when I vary the input signal, these voltages is hardly affected at all. +/- 0.05 V at most.

All voltage rails is ok.

/Flundran

 

[panda]

ok, so i spent all day on this.
learned allot. but haven't moved forward. i think i found the problem, but can't figure out whats causing it.

on my left channel on pin 4 of the 5534. i get nothing. no 15v. zip. [think / thought it was a short]
so thats just to start in that channel. so of coarse nothing goes right from there.. i have that 2180LB pre trimmed. so i have the 10k and 68r gone, no trimmer. i have been tracing the rails all day. and its just not at the 5534 right. i replaced the socket, and i've tried all my 5534s. i replaced most of the componets in the left channel. other then the 100p thing.
the right channel. has all it power flowing correctly.. so i know my 5534 and VCA are in the right way.

when i do hook it all up. run audio in and out.. of coarse i only get one channel. but its really low singal. and scraggly. and no compression or anything of any sorta, knobs and switches appears to do squat.

so, if the left channel doesn't work. would that effect the right channel?
i have the XLR connected with just hook up wire.. could that be a problem? [for the low / bad signal problem?]
how do i test my ICs to see if they are blowen / damaged?

my rails are cool all the way untill they hit the 5524 on the left. and they appear to be fine everyplace else.

?? lost to the point of.. should i just get some new PCBs and try again? they [the pcbs] are taking some damage from replacing the parts on the left channel..

thanks.

panda

 

[emtee]

Panda, I'm no expert at this having just finished my 1st Gssl, but one thing that caught me out was missing one of the wire links that carries the +15 rail from one part of the board to another. I found this when I metered out the Power before installing any of the socketed components. I'm wondering if you've fried a few things when you powered the board up at first as well.

I was very careful to follow the BOM for all the other components, but these links are just shown as lines on the PCB and are easy to miss. I also missed the very small link on the control PCB which turns the compressor into a really crappy fuzz box...

Stick with it, it's definately worth it! :green:

 

[tdstotler]

Hello All,

I just finished my first SSL. Tested all voltages on the main board before
installing the ICs, voltages were good all around.
Double checked for any solder bridges, shorts etc...
Tested everything with ICs.
Unit passes audio perfectly, no hum or buzz, signal is
about the same on output levels.
The main issue I am having is the entire control board seems
non functioning. None of the switches seem to work, even the bypass
and output. The Led faintly glows, and the voltage at the LED is
-2 volts. No meter functions.
Can anyone give me some pointers on what to trace/check and
if there any spots on the control board that I can check for
some reference voltages.
If I missed something in the posts please forgive me.

thanks

Todd

www.echoesrecording.com

 

[loz]

Just a quick post to say hello to all you techy nutters.
Thought id better introduce myself.
I found this web page a few days ago and i am amazed to see everyone being so helpfull to one another.

I would like to attempt to build the gssl comp as my digi 001 rig would be most happy with some high end gear. all i got at the mo is a tla valve eq.
Not sure where to start really i wanna take it slow and learn exactly what it is im dong while i go along but i dont know where to get the Pcb boards from.

i feel a bit rude in asking for help right away :? sorry


Loz

 

[panda]

tdstotler, have you checked that all your wires going from your main board, to you controls are in the right place? i had mine flipped!
if not all i can say is try to trace your power to and through you board. this is all i am doing.. it may not answer your question. but it might atleast help you pinpoint where the problem may be [though no so much what the problem IS]. sorry thats all the help i can give. since obviously. mine is working less then yours. :shock:

panda

 

[Greg]

hey Panda:

First things first. Get all ICs out of the board until the PSU is working and power is being distributed properly !!!

When you say the left 5534, I assume your talking about the one in the VCA section, not the debalancing one. I'll try and help you this one. Do you have the jumper installed next to the two 47K's... this jumper provides power to pin 4 of the left channel 5534.

 

[panda]

[quote author="Greg"] Do you have the jumper installed next to the two 47K's... this jumper provides power to pin 4 of the left channel 5534.[/quote]

i totally did that early this morning and cleared up my problem. i just didn't want to already jump in with more problems. so that seems totally fixed. all my rails seem right on now. so popped back in my ICs. and was checking away. and the 5532 in the output.. nearest the edge of the pcb. started to get really hot. so i powered down.. and check the rails again. seemed fine, so i pulled my other 5532 into the socket, and powered up. and IT proceeded to get really hot! so i have no left channel.. at all. just noise.
but the problems appears to be at the output stage.

my gain and bypass knobs/switches now work. but no compression.
i've tried different VCAs in the side chain. no difference. all my power seems to be running into the controls OK. any idea where to look?

thanks thanks and thanks!

panda

 

[panda]

[quote author="RogerFoote"]Panda

Sounds like the output 5532 might be plugged in backwards?[/quote]

won't i fry the 5532 is i put it in backwards?
i'm pretty sure it is not though. as its the same direction as the working channel. i just must have a short someplace pulling down the signal.
bla.. talk about lessons in volatage tracing. :shock:

:guinness:

panda

 

[Greg]

Look at the PCB layout and Jakob put a little "o" that corresponds to pin 1 of the ICs. Also double check the VCA orientation. The sidechain is opposite from the channels.

 

[Flundran]

I have no compression on signal. Passing signal thru fine and make-up pot work. Same behavior on both channels. Meter responds when I turn threshold CCW by moving up a bit, frozen in the same position. Output signal then becomes slightly weaker.

TL072 measurements:
Voltage at pin1 at TL072 varies with threshold, and voltage at pin7 varies with make-up pot. However, when I vary the input signal, these voltages is hardly affected at all. +/- 0.05 V at most.

All voltage rails is ok. Have checked resistor values. Is there an easy way to check a capasitor if broken?

/Flundran

 

[Sender]

I'm not using the fused IEC so i just bought a regular fuse holder. Do I put the fuse on the 115VAC or the common?

 

[Greg]

The 115VAC !!! :thumb:

 

[Greg]

Flundran:
It seems the TL072 is behaving properly, so take a look around the TL074... perhaps a diode in the wrong way?!? And maybe also double check the 10-pin continuity from the main to daughter PCB. Make sure all pins are connected properly.

 

[tdstotler]

After doing some testing I am pretty sure my problems are lying
somewhere around the TL074.
Everything up to there seems ok, voltages on the tl 072 and before.
Here is what I am getting from the Tl074

Pin 1 -.43 constant
Pin 4 +12 Volt
Pin 11 -12 Volt
Pin 14 +12 Volt

I am going to double check all the components around that area,
resolder some connections. Also I notice when I was testing the
TL074 with my tester I would get intermentent sound. I then
lightly tapped the top of the TL074 and got the same thing, sound going
in and out, maybe a bad solder joint?

One thing I am a little unclear of, where the Bypass switch hooks
into the control board (I am using a Lorlin just like in the
schematics) and I notice a area that shows a jumper line, but I am
unclear if this is to be bridged or not?

Also does anyone know the correct voltage from Pin 1 on the TL072,
Mine is .45 - 3.09 with the threshold change, is this correct?

Thanks again for all the help.

Todd

www.echoesrecording.com

 

[Sender]

So I powered up my SSL for the first time. I was getting proper voltage off the transformer. The problem that I'm having is that I'm getting AC instead of DC all over the board, which is very problematic! Is it possible that I have that rectifier mounted incorrently? I have it mounted flat side up with the + in the upper right corner.

Any suggestions?

 

[tdstotler]

Yeah it sounds like rectification at least to my ears. I would double check
the schematic of the rectifier placement. Double check the
AC inputs and outputs of the Rectifer to make sure they are in the proper place, again refer to the schematic. Also measure
the voltages at your rectifer, you should be getting AC on 2 pins and DC
out the other pins. If your getting AC everywhere on your rectifier your
rectifier might be bad.
Try putting in a new Rectifer and see if that solves your problems.
Remember your voltages before the regulators will be alot higher
then normal, which is fine.

Todd

www.echoesrecording.com