8 Channel, 3U NEVE 1073 completed

[sr1200]

Try putting a regular switch without the LED/lamp/whatever or wire it without a switch to test and see if your 24v is ok.  Ive never used the power station, just the one suggested in the BOM. 

Also see, if you fried anything on the 1290 board.  I had one of mine short on the case once and wound up cooking a few components (my own fault for putting too many of em in a 2U case and not paying attention to where the lip from the case cover was touching.

 

[indiehouse Recording]

I contacted Joe at JLM about the LED issue, and he said it's normal for the LED to slowly fade like that when there is no load on the power supply, i.e., when the power isn't connected to the pres.

That being said, I don't think it's the switch, right? I mean, 24V reads fine, it's only when I try to power a board off of it, then it drops down significantly.

I looked for fried components, and components that may be shorting on each other, and I found nothing. I didn't have the lid of the case on, so nothing was shorting there.

I'm stumped and disappointed. I was so careful with every piece I installed, and read this giant thread about a dozen times. I was hoping to be one of the guys that fired this up the first time without issues.

Again, I appreciate any help I could get here!

 

[sr1200]

if youre getting +24v when nothing is plugged into the unit an then NOT when the board is pluggd in, then one can assume the problem is off the PS board.  You say the cable is good and doesnt have shorts in it (check again. dont just check continuity from end to end (ala pin 1 to pin 1) check pin 1 on one end to all other pins on the other end to make sure theres no short, move to pin 2 do the same and so on and so forth) then remove that from the list of problems.  Next start tracing where the power comes into the board, and follow the schematic and see where it goes wrong. 
You double checked that all solders on the bottom of the board are clean and there are no bridges?  All caps and transistors are in the correct orientation (you used the correct transistors...).  All things that need to be checked over one thing at a time.  Worst comes to worst, post a decent res image of the top and bottom of the board, perhaps someone here can spot something that you didnt.

 

[indiehouse Recording]

if youre getting +24v when nothing is plugged into the unit an then NOT when the board is pluggd in, then one can assume the problem is off the PS board.  You say the cable is good and doesnt have shorts in it (check again. dont just check continuity from end to end (ala pin 1 to pin 1) check pin 1 on one end to all other pins on the other end to make sure theres no short, move to pin 2 do the same and so on and so forth) then remove that from the list of problems.  Next start tracing where the power comes into the board, and follow the schematic and see where it goes wrong. 
You double checked that all solders on the bottom of the board are clean and there are no bridges?  All caps and transistors are in the correct orientation (you used the correct transistors...).  All things that need to be checked over one thing at a time.  Worst comes to worst, post a decent res image of the top and bottom of the board, perhaps someone here can spot something that you didnt.

Thanks! You're referring to the Power Supply board, right? I should start there?

 

[sr1200]

::facepalm:: no... read it again.

 

[indiehouse Recording]

::facepalm:: no... read it again.

I am so sorry. I misunderstood what you meant. I thought you were talking about the problem being "off the PS board" as in 'the problem may be a rail "off the PS board"' or a capacitor "off the PS board". What you meant was the problem was NOT the PS board.

Again, my apologies. I truly appreciate your guidance here!

By the way, I went through both the PS board and the EZ1290 board, and didn't see anything that jumped out at me. Since I tested each board individually and got the same results, I'm assuming it's more likely that there is some mistake that was made four times, rather than a random short circuit duplicated four times.

I followed the BOM very carefully, and even measured each resistor before installing, just to be sure I was sent the right component.

Here are some pictures that I took. Again, I am very grateful for your guidance. I've got so much work in these, and feel that I'm so close to getting them up and running!

 

[desol]

Keep at it indiehouse. You'll get it...

~ make sure there's a properly rated fuse on everything, while you're going through it.

 

[useme2305]

indiehouse,

one thing that caught my attention when looking at your stuffed board is that your transistors are all turned 180 degress in the wrong direction?

 

[useme2305]

also, avoid stuff like this.

clean your boards thoroughly.

 

[alexidoia]

Hello,
I am having some difficulties to choose the place where to place the transformers inside the 2U rackcase  from CollectiveCase. The depth is quite limited and I have just enough space at the back of the PCB to put the output trans. Since the PCB are quite high, I was thinking placing the input transformer underneath the PCB. According to my calculation, it won't touch the board, but I wonder if that is a good idea. The other idea is to place all ouput trans next to each other, which could give me some room at the back for the input trans, but they will be stuck one against the other.
Is there among you guys anyone who bough that same case ?
I have to say that I am quite disapointed by the case. That is not the only issue. The wholes for the screws of the faceplate do not align themselves with the rest of the rackcase. I'll have to hack it which is very not ideal. In the future I won't buy a second case from Dan. I guess I also wanted to let you know this.
Alex

 

[sr1200]

Didnt get to see this till this morning but useme is right, your orientations are all messed up.  Make sure your caps are in the right way too.  (the tant's) cant tell from the pics if you put em in correctly or not.  You may have to replace those transistors, no telling what kind of damage was done from having them in the wrong way.  (not a particularly nice thing since the original transistors are getting harder and harder to come by since they were discontinued...) did you use the accepted replacement for them or the original spec'd?

 

[indiehouse Recording]

Didnt get to see this till this morning but useme is right, your orientations are all messed up.  Make sure your caps are in the right way too.  (the tant's) cant tell from the pics if you put em in correctly or not.  You may have to replace those transistors, no telling what kind of damage was done from having them in the wrong way.  (not a particularly nice thing since the original transistors are getting harder and harder to come by since they were discontinued...) did you use the accepted replacement for them or the original spec'd?

I used the MPSA18, as the BC184's were hard to find and expensive. I'm supposed to mount the MPSA18's backwards, right?

This was from Martin on page 1: Another option is to use MPSA18. One important detail about using MPSA18 in place of BC184C is that MPSA18 will need to be mounted backwards (rotated 180 degrees on its vertical axis) on the PCB.

Did I not mount them right?

Also, I will check the caps again, but I double checked every piece I put in to try to avoid this sort of situation. Whatever is happening, it's happening on each board, so I must have done the same thing wrong on each board.

Again, really appreciate the help. I don't know where to begin on troubleshooting this.

 

[sr1200]

Are you still getting 24v on the PS board with nothing plugged in?  (wondering if the LM's were compromised).  Beyond that you need to get some voltage readings on the board (only do 1 board at a time). Im assuming your 3055 isnt grounding out and is properly seated. ALso in that same area, make sure you dont have any legs touching in that area of the board... looks kinda tight up there.

 

[indiehouse Recording]

Are you still getting 24v on the PS board with nothing plugged in?  (wondering if the LM's were compromised).  Beyond that you need to get some voltage readings on the board (only do 1 board at a time). Im assuming your 3055 isnt grounding out and is properly seated. ALso in that same area, make sure you dont have any legs touching in that area of the board... looks kinda tight up there.

Yep. With nothing plugged in, the PS reads 24V. I plug in, (powering only one board at a time), then I get something like 3.5V. To measure power on the board, I use the 24V and 0V insert points on the board, right? Are there other places to measure to try and trace the problem?

Also, I had to make the 3055's as low profile as I could get, so that they would clear the top of the case. I actually had a look at those today, and the heatsinks aren't touching any of the components, though it is tight.

 

[indiehouse Recording]

I think I found something....

A serious mistake, I know. I have wired a capacitor backwards on one of my 1290's. The rest of the boards (4 total) are correct.

The very first time I powered the boards, I had everything connected, and 24V/0V going to all four boards at the same time. I connected the PS to all four pre's at the same time the very first time I powered them on. 

Now that I have discovered this mistake, what does this mean in terms of damage done? I still have the issue with voltage drop even when connecting a single board that has capacitors installed with correct polarity.

 

[alexidoia]

My kownledge is quite limited, but this caps only stabs the power input. I would bet only that caps is to be changed, check the 1W resistance but they rarely if never failed.

 

[alexidoia]

My kownledge is quite limited, but this caps only stabs the power input. I would bet only that caps is to be changed, check the 1W resistance but they rarely if never failed.

If it does not look damaged, it may be not, try to put it back the way it should and powerup again, it may well work again (or not). You are lucky I have seen some of them explode in that  context (or maybe it was with excessive power) :.

 

[indiehouse Recording]

There doesn't appear to be any visible signs of damage to any component. However, even when hooking up a 1290 board that has the capacitors installed correctly, I am still getting 3.5V from the PS. WIth no load, 24V. With a load, 3.5V.

 

[sr1200]

youhave all the transformers hooked up as well when you're testing yes?

 

[indiehouse Recording]

I did the first time, but have since disconnected the input tranny. Is it essential to have these connected?