GSSL HELP THREAD!!!

[Greg]

Your wiring, as typed, is correct.
[quote author="Aaron Wiles"]The transformer gets extremely hot once connected to the board.[/quote]
This often indicates a short somewhere. Something is pulling a lot of "juice" and heating that toroid up.

 

[Aaron Wiles]

Thanks Greg.

Any suggestions as to why I'm not getting the -15v on this rail? And getting a positive 1v?

Thanks again.

Aaron

:guinness:

 

[Greg]

Measure what's on the input pin of the 7915 regulator... reference the datasheet for pin information.

 

[Aaron Wiles]

I am reading about -24.80 VAC w/ the regulator removed on the center pin (input) and also on what should be the output pin (which means voltage is coming in somewhere else through the back door. That's with the jumpers lifted too, to remove anything down the line.

Could it be a bad 22u cap?

Also, I was reading about 3vdc on the audio input connector on the board. That doesn't seem right.

 

[tommypiper]

I feel your pain. I went through the same thing. You don't need to pull those PS parts off the board to get measurements.

You need to replace that -15v regulator. Then test again. Start from the beginning of the PS.

Follow the flow of current from source to destination.

First test your toroid current before, or where, it enters the board. Are you getting equal AC there? (I actually tested my toroid before ever connecting it to the board - put positive probe on hot, negative probe on center tap. Best to use alligator clips to keep things solid, make sure they can't touch and short out. Then test other side of the toroid output in same way. Both outputs should be equal. If your toroid is getting hot during this brief test you should try a different transformer.)

When connecting to the board make sure you aren't shorting to ground, as Greg mentioned. (Try continuity tests between ground and your inputs from the toroid - WITH POWER OFF.)

Then test the current after passing through the rectifier. Are you getting proper DC there? Then where it enters and exits the regulators. Then after the caps. Etc. Then follow the traces to the chips. Etc. This is actually very easy because it is DC and it's very clear what you are supposed to be seeing at each stage. (It's harder following a faint audio signal all over the board.)

I went through several regulators which went bad on me. My last -15v regulator actually was putting out +1v too. :? I never found out why the regulators were screwing up, but I did find a detached solder pad under one regulator, so it's possible I had a weird short or partial connection or who knows.

The board is tricky. Solder pads are very close together. Parts are not numbered, like C1, C2, so it takes a while to get your bearings. I found it helpful to print out the trace artwork and schematic and begin to mark my own test points and coordinate locations. It can be a real headache. As Jacob has said repeatedly, most problems however are solder bridges and the like (human error), not faulty components.

Good luck. Use great care and caution around the power supply and toroid and always protect yourself from shock. Always assume there could be lethal voltage before you touch anything.

I'm currently stuck with a board passing audio but no compression. Driving me insane. Any suggestions welcome. See my previous posts.

 

[fucanay]

[quote author="tommypiper"]
I'm currently stuck with a board passing audio but no compression. Driving me insane. Any suggestions welcome. See my previous posts.[/quote]

Have you installed the bypass switch yet? Replaced the bad NE5532? Installed the meter to see if it's reading compression even though you don't hear it? Checked for bad connections between the main board and the control board? It's really hard to give advice when your compressor is not in the same state as mine. If you can get through all of that, then we can start comparing other things.

Matt

 

[Aaron Wiles]

First test your toroid current before, or where, it enters the board. Are you getting equal AC there? (I actually tested my toroid before ever connecting it to the board - put positive probe on hot, negative probe on center tap. Best to use alligator clips to keep things solid, make sure they can't touch and short out. Then test other side of the toroid output in same way. Both outputs should be equal. If your toroid is getting hot during this brief test you should try a different transformer.)

In my series of tests last night, I checked the voltages of the transformer. They are NOT equal. If I remember correctly (I didn't write it down). it was 38vac and 52vac on the outputs. Measured where it comes into the bridge rectifier. The output of the rectifier was equal however and I think off the top of my head it was around 34vac.

When I remove the 7915 regulator from the path (it's mounted to the bottom of the case w/ thermal glue and a screw and connected w/ a 3 pin molex on the board) the transformer does not get hot. But when it is plugged in, it immediately starts cooking to untouchable within a matter of seconds.

Then test the current after passing through the rectifier. Are you getting proper DC there? Then where it enters and exits the regulators. Then after the caps. Etc. Then follow the traces to the chips. Etc. This is actually very easy because it is DC and it's very clear what you are supposed to be seeing at each stage. (It's harder following a faint audio signal all over the board.)

The current problem w/ this, is I can't leave the power applied very long as I mentioned above. But will replace/change out the regulator. Currently, the output of the regulator is not the proper voltage, but will check again w/ it disconnected from the board.

Good luck. Use great care and caution around the power supply and toroid and always protect yourself from shock. Always assume there could be lethal voltage before you touch anything.

Thanks. Yeah, I about lit myself up the other day. When I unsoldered the leads to the transformer from the 115vac switch and IEC connector, I forgot to "UNPLUG" it before desoldering. :shock: Didn't realize what I did until after I had unsoldered the connections. Doah! Last time I do that.


I'll double check a few more things this evening and see if I can get to the problem. I may just finish out this second board and try it out.

 

[tommypiper]

Aaron, that's worrisome that you are getting asymmetrical power from your toroid. I would look into that right away. Test it while disconnected from the board, just by itself. I've heard elsewhere that those toroids are occaisionally defective.

You definitely need a new regulator.

Just a tip, I'm learning it helps to power up and test a board before mounting it in an enclosure, when possible. You get free access to everything, bottom solder joints, etc. Good luck.

 

[tommypiper]

Hi Matt,
Thanks for the suggestions!

[quote author="fucanay"]
Have you installed the bypass switch yet? Matt[/quote]
No, but I've jumpered it both ways and no compression in either "off" or "on. " (This help thread has confusing information about which actually engages compression, but it appears from the schem that it is the "on" connection.)

[quote author="fucanay"]Replaced the bad NE5532? Matt[/quote]
I swapped the good NE 5532 into both channels and both pass audio just fine. I don't think one output channel missing that chip it would effect compression since the sidechain is fed by both channels and it's downstream of the sidechain.

[quote author="fucanay"]Installed the meter to see if it's reading compression even though you don't hear it? [/quote]
Yes! No movement. Tried it with the bypass switch jumpered both ways.

[quote author="fucanay"]Checked for bad connections between the main board and the control board? [/quote]
Yes.

I've tried to trace the signal through the board into the sidechain to see where it stops. It appears to disappear before the VCA 5534s. I can't find the signal in the sidechain at all.

 

[fucanay]

Could you post some pictures of your board? Just to be sure there isn't anything that is totally obvious?

Is it possible that you fried some of the 5534s when you had the PSU problems? Maybe you should order a few extras of both 5534 and 5532.

Matt

 

[JRE Productions]

Hello all. I just finished wiring up my SSL clone. Good news is NO SMOKE! and also I get what seems like good clean signal through both the left and right sides. But so far I get nothing from the control board. Nothing I do with the knobs seem to matter. Tomorrow I will start going through all 111 pages of this to see what I did wrong.

I used 2180 THAT VCA's and left out quite a few resistors that was suggested on a Table-graph found here. Not sure if this is where I should start looking, or if I need to look at my control board. I am getting no real voltage at the LED, so I am guessing I have a power issue comming out of the main board to the control board. So far I have double checked for solder blobs. I take a closer look tomorrow.

Thanks for such cool projects. I will post pictures as soon as I get this up and running.

Joe

 

[gyraf]

Joe,

Check your +/-12V supply-lines. And possibly bypass wireing, if the 12v's are alright.

Jakob E.

 

[Aaron Wiles]

Aaron, that's worrisome that you are getting asymmetrical power from your toroid. I would look into that right away. Test it while disconnected from the board, just by itself. I've heard elsewhere that those toroids are occaisionally defective.

I finished filling the second board last night. Installed new regulators. When I measured the old regulators output (not connected to the board) it was reading a +9.xx vdc. The new regulator measured less than +0.1 output. The second board...exactly the same problem.

The other strange thing, I'll need to confirm, but I think the input to the regulator on the 7915 is +28.xx VAC. Shouldn't this be a negative input? (don't hold that to me, I'll have to check it).

The board is not mounted at the moment. I've been checking other voltages around the board. I only have the problem when I connect the 7915 into the board, and it's an instant oven.

Is it possible I have a bad batch of regulators? Even the new one, read an output of +0.01 VDC. Or is the issue upstream you think? Where does the negative voltage come from, the toroid or is it converted through the rectifier and caps?

I double checked the output of the toroid, and it's not nearly as bad of a swing as I thought. They're only about 4vac difference on the outputs.

I did go through the entire board, poked around and beeped all connections to check for shorts. Nothing appears to be funky at this moment.

I have 2 transformers, and tried both of them. Tried both boards, same thing. So this is more than a fluke, it's a problem w/ both units. Exact same thing.

I'm stumped. :?

 

[tommypiper]

Wow. Two boards with identical issues.

Well, it still doesn't sound right that you are getting asymmetrical voltage off the transformer. Both transformers are giving you the same asymmetric voltages?! Test and double test. Call Digikey or wherever you bought them and ask to talk to a tech and tell him you are getting the asymmetrical voltages, describe how you wired them and test them. Maybe you can return them for new ones.

I suspect something is wrong in the chain between transformer and regulator. Are you installing the rectifier correctly?

No, the transformer delivers two seperate positive voltages, if wired correctly.

Yes, it's possible you have a bad batch of regulators, but unlikely.

First make sure your toroids are working correct, they are wired correct, the rectifier is giving correct plus and minus and the regulators are recieving the plus and minus and ground correctly (you might want to check that without regs in place). If all that is fine, then you can try more regulators.

If your 7915 is getting AC, then you have a problem. It should be getting DC! Maybe this is your issue. That would mean your rectifier is not working. Double check your rectifiers. Check their output voltage! It should be symmetrical, pos and neg DC!

How is your transformer wired to the board? The upper left of the board near the rectifier? Or where the onboard transformer would go? You may have an error there, bypassing the rectifier by mistake. That would explain it!

Make sure your test meter is accurate. Test it on some known sources. (I had one go bad on me recently and it cost me several days of weird readings and screw ups.)

Sounds like something is wired wrong somewhere. My guess is your components are OK, or started life OK, but something may be wired or soldered incorrectly.

 

[Aaron Wiles]

Well, it still doesn't sound right that you are getting asymmetrical voltage off the transformer. Both transformers are giving you the same asymmetric voltages?! Test and double test. Call Digikey or wherever you bought them and ask to talk to a tech and tell him you are getting the asymmetrical voltages, describe how you wired them and test them. Maybe you can return them for new ones.

Will do.

I suspect something is wrong in the chain between transformer and regulator. Are you installing the rectifier correctly?

Yes. The rectifier is installed correctly w/ + on +. Installed on the upper left corner for 115vac.

No, the transformer delivers two seperate positive voltages, if wired correctly. The rectifier converts it to pos and neg.

I'll triple check again. I checked it all, but didn't write it down.

Yes, it's possible you have a bad batch of regulators, but unlikely.

I just went and picked up some different reg's here locally. I'll give them a try.

First make sure your toroids are working correct, they are wired correct, the rectifier is giving correct plus and minus and the regulators are recieving the plus and minus and ground correctly (you might want to check that without regs in place). If all that is fine, then you can try more regulators.

From what I could tell, all was good up to the point of the regulator. Voltage was stable at 28.xx Vac. The + (7815) works just fine. I can have it plugged in. All else is good until I plug in that 7915, and it cooks.

If your 7915 is getting AC, then you have a problem. It should be getting DC! Maybe this is your issue. That would mean your rectifier is not working. Double check your rectifiers. Check their output voltage! It should be symmetrical, pos and neg DC!

The input of both the 7815 and 7915 (center pin) is receiving AC voltage, but the 7815 works fine, and sends +14.80 VDC output. It was my understanding that the rectifier was suppose to do the voltage conversion, not the regulators??? Could it be I have bad rectifiers?

How is your transformer wired to the board? The upper left of the board near the rectifier? Or where the onboard transformer would go? You may have an error there, bypassing the rectifier by mistake. That would explain it!

Yes, the upper left corner. The transformer is wired as such:

Primaries: Black/Violet is hot w/ 115vac. The Red/Yellow is connected to the Neutral of the IEC connector. I've double checked the voltages going into the transformer, and we have a solid connection.

Secondaries: Red/Brown tied together and going to the center pin of the connector on the board. The Blue and Green are on the 2 outside pins.

Make sure your test meter is accurate. Test it on some known sources. (I had one go bad on me recently and it cost me several days of weird readings and screw ups.)

That was the first thing I did last week.

I'd post pix, but it doesn't appear that option is available on this thread??

 

[JRE Productions]

[quote author="gyraf"]Joe,

Check your +/-12V supply-lines. And possibly bypass wireing, if the 12v's are alright.

Jakob E.[/quote]Oh thank you Jakob. I will do that tonight. I did two things different then your schematics. I used a single poll double throw switch on the bypass. I wired the comon to the center lug, and the in and out to the top and bottom lugs. It seems like that should be right. I also just strapped the makeup gain position. I assume this meant the gain is always on. I actually was thinking of adding a seperate switch for this function. SPST. Not sure if this is where the trouble is. I will have to check the +/- 12v lines. I will pull up the schematics and look for them tonight as well. I did see the +/-15 looks just fine.

Thanks again. DIY is so empowering!

Joe

 

[JRE Productions]

yep problems with the +/- 12 supply. Can't figure it out yet. On the PCB there is a -12 point which I get about -20 on. And I get nothing at the +12 point on the pcb. I checked all the orientation of parts and resolder and checked solder blobs on the main board for the 12 volt areas.

Do you think the issue could be on the control board? I did not use connectors between the boards, but if need be, I will unsolder the control board. I have not really re-checked the control board yet. I double check before installing it, but not since I found the 12v issue..

Ok I am off to read through this thread again.

Joe

 

[fucanay]

[quote author="JRE Productions"]yep problems with the +/- 12 supply. Can't figure it out yet. On the PCB there is a -12 point which I get about -20 on. And I get nothing at the +12 point on the pcb. I checked all the orientation of parts and resolder and checked solder blobs on the main board for the 12 volt areas.

Do you think the issue could be on the control board? I did not use connectors between the boards, but if need be, I will unsolder the control board. I have not really re-checked the control board yet. I double check before installing it, but not since I found the 12v issue..

Ok I am off to read through this thread again.

Joe[/quote]

The first place to start is at the 12V regs. If those are ok, then you can trace it down the path. Go back a few pages and you might see some numbers from Tommypiper and I going through voltages.

Here is what mine were: http://www.groupdiy.com/index.php?topic=187448#187448

Matt

 

[Greg]

tommypiper and Aaron Wiles:

I've been very busy with some Engineering jobs lately, so I haven't been checking lately. But I'd like to clear up a few things just for clarity since I read a little bit of bad info in your posts.
1. Measure AC across center tap and green, then center tap and blue... they should be close. AC across green anc blue will be twice that.
2. The rectifier does not convert positive to negative, it converts the AC from toroid to raw unfiltered DC.
3. Aaron, you said you were getting about -24VDC at the input of the 7915... this is perfect. This -24VDC is regulated and filtered down to -15VDC. I'd suspect something "downstream" is shorted, which might be causing the regs to get nice and toasty, and perhaps even the toroid.

Ohm out the negative rail (with regulator installed)... what are you measuring?

4. tommypiper... Based on what you described, it sounds like you have a problem in the sidechain since both channels pass audio fine. The is one super crammed part near the TL074. Measure for shorts there.

 

[JRE Productions]

Good news....I found my 12v issue. My TL072 socket was different than the others and did not have a notch in it. I checked twice, but still had the opamp in backwards. Gave it a twist, and not she fires up fine.

Ok, so I don't get a ton compression. I used a 10K pot for threshold and make up gain. Would this threshold pot cause there not to be as much compression. I also thought I was getting distortion, but it seems that depending on how I have the threshold, attack and release, and can clean the distortion up. So should I look at the threshold pot or in the side chain?

THanks again Jacob and all! :thumb:

Joe