EQN build thread

[peter purpose]

Any ideas?

Not a one..... but swap out the amps for known good ones at the very start.

 

[dandeurloo]

i don't have any ideas as well but it would probably help to know if it makes the same noise when the eq's are not engaged or if it's only in one band!

That should help narrow it down for ya.

 

[Marcocet]

Well, it makes the same noise with the eqs in any setting as well as the unit in bypass and it does it with the opamps removed as well.

Probably something in the power section? I suppose I'll reflow that part of the board first, but I have to imagine it's probably a bad component somewhere? What would even cause oscillation like this?

Thanks for your help! I'll get back at it on friday.

 

[mnats]

I can't remember ever being so excited to build something as this project. Thanks to Peter and all who contributed to the thread.

Mine worked perfectly from the get-go using a 51X jig, but I'm still waiting for the DC/DC converter to put it into my 500 rack. I've posted some notes on a page here:

http://mnats.net/pp-eqn_notes.html

Careless me - I lost one of the 1mm sockets for the DC converter...if anyone is building a 51X version you should have two to spare. I've got some extra bits and bobs I can trade for another socket if anyone is willing. *edit* - Sorted. Thanks to 12Volts.

 

[12volts]

I've built my EQN boards and have 16 surplus 1mm sockets. I'll post few on to you.
Could you send a PM with delivery detail?

Frank

 

[peter purpose]

Nice EQN page Mako.
The small sockets are just pulled from a turned pin strip... hardly rocking horse poo and cheap as chips anywhere on the planet.

peter

 

[mnats]

Nice EQN page Mako.

Thanks - hopefully the page is helpful to someone else building this nice project.

The small sockets are just pulled from a turned pin strip... hardly rocking horse poo and cheap as chips anywhere on the planet.

Yeah, the 0.8mm ones I got. It's the 1mm one that I lost. I have a bunch of Mil-Max sockets used for DOAs but they sit too high off the board.

I've PMed 12volts so hopefully this is sorted. Hey, anyone got a spare TDK LAMBDA CC6-2412DF-E they want to sell? *edit* - Sorted. In stock at Digikey again.

 

[12volts]

PM received and replied to. Over and out.

Frank

 

[Marcocet]

Okay, I've fixed most of the ones that had problems but one or two still have issues. They're all in the highpass filter. Either the frequencies are all wrong, or some of the settings are dead etc etc etc. I've checked for shorts everywhere and followed the signal all over the board and I cant seem to find anything wrong. Any suggestions of where I should look in particular? What could cause all of the HP settings to screw up frequency-wise? If it was just one or two I'd think faulty caps but I can't get my brain around this one.

Thanks for any help you can give!!

-marc alan

 

[peter purpose]

World's worst troubleshooter says... no idea.
If the inductors are sound, then it could be the switch.
Failing that, burn them.

 

[dmp]

Either the frequencies are all wrong, or some of the settings are dead etc etc etc.

I'd suggest check the rotary switches with a multimeter. I just finished my pair, and had a similar problem in a couple bands and it was a mistake in putting the stop pins in. Once I figured that out, put the switch back in, they both work great. Awesome project Peter.

 

[Marcocet]

Okay,

Most of them are working great! Of the few i've had problems with two are most likely in the switches, or beneath them where the resistors were soldered. However all my attempts to remove either have the switches have done is pull up a bunch of the solder mask around the pins! Anybody have any advice on how one would go about desoldering and removing one of the grayhills?

Thanks

-marc alan

 

[zayance]

Okay,

Most of them are working great! Of the few i've had problems with two are most likely in the switches, or beneath them where the resistors were soldered. However all my attempts to remove either have the switches have done is pull up a bunch of the solder mask around the pins! Anybody have any advice on how one would go about desoldering and removing one of the grayhills?

Thanks

-marc alan

Ouch, Desoldering Grayhill hmmm, possible but you have to be very gentle, i use solder pump most of the time, but for sure if you heat too much or pull to hard you will harm the board, got to pump it as clean as possible each time before atempting any pulling out, i heat up the solder pad, and right away insert the pipe of the pump right on it while pumping out, i stay close to the solder gun when doing, but are you sure it's the switch??? i mean they seem to be tough as a rock  :-\

 

[barney]

I had a similar thing with wrong freq and no signal but that was because I put the pins in the wrong spot on the hpf.  Might be worth triple checking before trying to unsolder a switch.  Please ignore if you've already tried this.

 

[peter purpose]

Anybody have any advice on how one would go about desoldering and removing one of the grayhills?

Can't think why you would want to, but I would use a pencil blowtorch and waggle it quickly over the solder.
Works a treat.

 

[Marcocet]

The reason that I'd want to is that I only just realized that I never cleaned the flux off the board under the switches and I think that's probably what's causing them to short. At least i hope that's the problem, it's all I can figure at this point.

Thanks for the tip! Now to borrow somebody's torch...

 

[haima]

if you really do need to desolder that grayhill, i'd pick up a hakko 808 kit from ebay - these things are amazing, and really quite cheap. one of my favorite tool purchases ever - you might have a chance at salvaging the part if you use a proper de-soldering gun...

 

[briomusic]

flux isn't conductive AFAI am aware, and without specialist equipment you are at risk of destroying either the pcb or the switch (or both) by attempting to unsolder the grayhill. I never had to do any cleaning under the switches and built 6 working EQN pcbs. I would double check (with magnifying glass) that there are no shorts where the switches are soldered, as those pins are very close to each other. I recommend a solder tip (and solder wire) smaller than 1mm to do this job. Also, wrongly placed stop pins are a major source of weird behaviour as mentioned above.

 

[Marcocet]

Well, I got a blowtorch before reading any other responses and got the switches off that way. All looks kosher underneath but I can't figure out what else could be wrong with them at this point, so I cleaned it up a bit. I'm planning to put them back together and test em out on friday. Thanks everybody.

 

[JBVries]

I got in a 100v 180Pf 5% Multi-layered Ceramic Cap and I was wondering if it will work for C57. It's not C0G but the right value so I thought I would ask. Thanks!