All things Green Pre

[imo]

I was wondering if any of the resistors are 1/2 watt in the green pre design? I don't see any mention of it in the schematics, bom, or layout docs. On the PCB however there is a larger layout for the 2 100r's that go to the phase switch, and i wanted to double check before getting too far into it.
Thanks for the help
Ian

 

[peterc]

Ian

The bigger diagram on the PCB is there because of the distance the resistor has to stretch, the block on the PCB is automatically drawn by the PCB programme.

All resistors are 1/4w

Peter

 

[Yoannv]

Hi all !

Just a few words to say that my Green is finally done !
After many issues in this last month (caused by a mistake), I've finally solved everything (in particular a problem with a ledmeter), and now everything works perfectly !

Also, the last Peter's suggestion for the PSU (change the two first 1000µF by two 2200µF), to "kill" the hum caused by my modification for a 48v LED works too, and now I don't have any hum !

Here e few pictures :



My Quad Green is now in my rack, and is going to record this week-end !

I've learned so much making this project, it's amazing, and now I'm starting a SSL 9k.

Thanks to all people on this forum for sharing knowledge, and thanks to Peter for sharing his work, his time and his boards :thumb:

:guinness: :sam:

Yoann

 

[bluezplaya]

Where do you get the rainbow ribbon cable and terminals for your LED's? That would come in handy for me and be a lot cleaner wiring.

Adam
:sam:

 

[Yoannv]

I get this cable from Farnell, I'm not shure if they sell in USA.
Anyway, the reference for Farnell is 150433

The manufacturer is Pro Power and his ref is "USE 150429 ( 50 MTR)"

Hope it could help.


Yoann

 

[bluezplaya]

Okay, I blew my caps on the PSU. First of all, these pre's were working for the most part but with some 48v and grounding issues. While troubleshooting, I noticed that two of the 1000uf 16v caps had paint peeling off of the side of them. I thought that might be the culprit. After searching through the threads, I found a PSU overlay pic with voltages showing 21.5v across those caps. I then replaced those caps with 35v caps. Powered it up and within 7 seconds "poof" and white smoke was billowing out of it.

Okay I need some help on this because these pre's sound great and I would like to get them working soon! I have checked my component values and they all seem to be correct. Is it something with the diodes? How about the bridge rectifier? I'm wonder if I have the legs in the wrong places. I know the positive leg is in the right place but there are 3 more legs.

Adam
:sam:

 

[matta]

Adam,

Shoot a HIGH quality picture or 2 of the PSU and post it here, if you can't host it, then e-mail it to me. I will just check it over for you. Also note that there are different revisions of the PSU board, so let me know which one it is. The only difference, though a major one is one diode faces the other way on a previous revision.

Cheers

Matt

 

[bluezplaya]

I bought the PSU and pre PCBs and parts kit from PTownkid so I guess whatever version of the PSU he had. This bridge rectifier is not square but linear so the 4 legs are in a row. Do they have to be in a certain place or not?

Adam

 

[matta]

If you give us a part number or datasheet I can check the pin out, I can't comment not knowing what you have, and yes, it does make a difference as to where you put what legs.

Matt

 

[Ptownkid]

It's simple, the + goes to the + on the pcb, and then the - goes to the hole diagonally from the + and then the other two legs can go to the other two holes, one in each, doesn't matter which.

 

[bluezplaya]

Okay, well then I had it right the whole time. Hey PTown, I want to get a couple more of these things. Are you ready for me to send you $$$?

Adam

 

[matta]

You must have had it right if the PSU was working :green:

Since you bought the kit and boards form Ptown he will be able to tell you which REV of the PSU board you have, but from our convesations it seems your PSU is fine, or was fine.

If you want you can still shoot me a pic and I'll double check your components if you like.

Matt

 

[bluezplaya]

Okay gang, I have reversed the lytic caps to their correct orientation on both my boards. I hooked up the first board alone on the PSU and it's kickin' some butt. I am getting 15.2 and -21.2 on the rails, however. My second board I hooked up along with the first on to the PSU, powered up, and two 10ohm resistors on that board started smoking and now they are burnt.

Here is a diagram of where the resistors are:

Can anyone help me understand why those resistors are burnt. Both boards are identical. I have bombarded Matta with a bunch of questions (in which I am grateful) and I don't want to bug him too much :grin: .

Thanks,
Adam
:sam:

 

[Ptownkid]

Please post a good pic of two of the non-working one

 

[peterc]

Measure between the power rails & gnd on the good PCB to get a quick idea of what readings to expect.

Then do the same to the bad PCB.

Take out the IC near those resistors & use your meter to measure for a short between the power rails & gnd. If there is not short, then put in a new chip & try again!

The burnt resistors are probably owing to a bad chip or a short between a power rail & gnd.

Peter

 

[peterc]

Double post

 

[Ptownkid]

That's what I was thinking, as you walked me through the same problem on my first pair, but i wasn't positive so I didn't want to guess.

 

[bluezplaya]

Measure between the power rails & gnd on the good PCB to get a quick idea of what readings to expect.

Yhen do the same to the bad PCB.

Take out the IC near those resistors & use your meter to measure for a short between the power rails & gnd. If there is not short, then put in a new chip & try again!

The burnt resistors are probably owing to a bad chip or a short between a power rail & gnd.

Peter

So just pull the IC's near the resistors or the resistors as well? Because they were glowing red as they were burning up in a blaze of glory. I don't want to burn up anything else. :shock:

Also, where is a ground point on the PCB?

Adam
:sam:

 

[bluezplaya]

Peter, BTW, what say you on the -21.2 on the negative rail?

 

[bluezplaya]

Okay, I pulled all the 5532's from both boards (6 IC's) and compared voltages from the rails. All seemed to be pretty damn close. I then swapped the IC's from good board to bad board and fired up, opened Pro Tools, plugged in the condenser and voila, it was working. So that tells me that the IC was bad.

HiHo Mouser, AWAY!!!!!

Thanks Peter for the input. I still am curious about those rails giving me -21.2 on the negative side. Is that bad?!

Thanks,
Adam
:sam: :sam: :sam: :sam: :sam: