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Messages - paelgin

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1
As suggested, I reached out to Behringer (The Tribe?) and received a reply:
"Dear Phil,
Thank you for your patience. We do not provide schematics.
We can offer a non-warranty repair for you, If you'd like to continue with service, we can start a claim for Non-Warranty repair. The charges are as follows:..."

So I replied and said that I had been told that but in these times I should try anyway.  I also said that I would not pay to repair it since I can do it myself but I need just the USB portion of the schematic.  Waiting for another reply.

I had sworn that I would never, ever buy a Behringer anything but I got carried away with this broken one at a good price.  My personal feeling of Behringer is that it is the Walmart of shopping, the Yugo of cars, the ... nevermind. 

Right to repair is a big issue in some cases, and Apple (and others including John Deere) are involved in lawsuits regarding some of this.  I just appreciate when a manufacturer cooperates with the end user, specifically on stuff out of warranty.  Fender and Peavey have been great to work with, while Mackie, Line 6 and now Behringer have stuck solid walls around their proprietary information (and not without cause but there should be limitations and exceptions).

Phil in gorgeous Young Harris, Georgia, USA

2
Schematics and Layouts / Re: 5th Gear Overdrive v3.0
« on: April 16, 2020, 06:17:16 PM »
Well, I just finished assembling and testing my building of this pedal.  My thought process about how to build it went through several different versions. Since I had this little box that I thought would work (boy it is really tight), I decided against my original plan for a perfboard construction.  I decided for point to point in free air.  Now all I have to do is insulate everything and fold it into the little box.  Here is a picture.

It really does have almost clean tones when the gain is dialed down.  And it gets really gritty when up!  I need to adjust the volume (output level) when I change the gain, but for testing, I just suffered...  Because I am mostly a rhythm guitarist, I probably won't use this full on, although for some boogie-woogie (Key to the Highway shuffle, for example) I might use it. Also attached is a voice memo converted to mp3 that I made while testing.

I think I will try this on my bass.  That might be pretty cool!

Thanks for posting the schematic and construction tips.  It's a fun little project.  I added an off-on switch since I got non-switching jacks although I think I could have gotten one that connects the -9 volt (ground) lead only when plugged in (but I was in too much of a hurry to research and think it through).

Phil in gorgeous Young Harris, Georgia, USA

3
Howdy Joe.  Thanks for the thought.  Originally, I had looked for any link that would get me to Behringer support and they all led to "the tribe".  This morning (April 15, 2020) I tried again but cannot connect to anything Behringer: all websites are down and clicking on any links (from Goggle for example) leave the browser just spinning with no results.

Regarding my repair, I got parts and installed the two resistors.  On the burnt one with no pads left, I scraped the traces down to copper on both sides, tinned them then soldered in the resistor on one end.  Then I added a short jumper wire (single strand from a 20 gauge stranded wire) by soldering it to the trace and then onto the top of the resistor.  I'll attach a picture. The resistors are inline with the plus/minus 15 volt rails fed to the two dual OpAmp chips (one for left, one for right) feeding the headphone jack.  Not ideal, but may be sufficient.  If I could not get that to work, I was going to run an axial 1/4 watt 47 ohm resistor between pin 8 and another chip pin 8.

When I reinstalled the power supply and turned it on, I carefully watched my Watts Up inline power meter. When the power went to 79 watts (compared to 24 watts before), I quickly turned it off, but not before a wisp of smoke came up from the solder flux left behind.  I decided to replace the two chips those resistors were "protecting". 

With the two inline 8-pin through-hole OpAmps replaced, I tested and found input power used was 24 watts again. While the headphones do work, the volume in the left channel is much lower than the right.  I found two more resistors out of spec inline with the left side output (supposed to be 47ohm, but are over 1k each.  The right side was not affected.  I wonder what happened to smoke the OpAmp (left side, but maybe both).

As before, the USB is two channels sent to the PC (Main Mix supposedly), but right now, both are incorrectly controlled by just the left channel.  I looked at the USB board but without a schematic and with no obvious trauma on the board, I did not know what else to look for.

Thanks again for the suggestion to try Behringer; I will try again.

Phil in gorgeous Young Harris, Georgia, USA

ps, I am not in love with this mixer.  The Design might be fine, but the components used (pots and switches, for example) are not impressive.  And the inputs are on the noisy side (to check for pot crackling on the channel strips, I just turned up the gain and heard the white noise while I spun the pots up and down and listened for crackling as an indication to apply DeOxit Fader Lube).

4
Howdy all (both of you who read these threads). Here is the picture showing the area of circuit board where I removed the two surface mounted resistors.  One had burnt the board before failing, and I don't know if I will need to wire a jumper or how I will attach a new resistor yet.

Once I get the parts (should be Tuesday), I will see what I can do.

Any comments or suggestions are welcome.

Phil in gorgeous Young Harris, Georgia, USA

5
Howdy all.  I need a schematic for the USB version of the Xenyx X1832 mixer.

I bought a broken Behringer Xenyx X1832USB mixer on Ebay and am cleaning and repairing it.  I have the schematic for the non-USB version, which I was hoping would be close enough.  That schematic is attached.

Alas, it is not sufficient and I need a schematic for the USB model.  In addition to gummed up pots and blown resistors (on the power for the Op Amps for the headphone for some reason), I discovered that the USB is sending left and right, but sadly both from the left channel.

The non-USB schematic that I have looks close enough (so far) to be usable in my repair of the headphone circuit. 

In my testing, I found that the headphone circuit was bad, but everything else worked, at least after spraying some of the pots and switches with Deoxit Fader lube.  [side note: I had heard about the loss of intentional weighted "drag" in the slide pots and that is true].

Once I get it off my phone, I will post a picture of the circuit board after removing two surface mount resistors (47 ohm). They were in line with the plus/minus rails going to the two preamps outputing to the headphone jack.  Something pulled a lot of current through them and I suspect that the two Op Amps (4580) are also toast (three on order now, along with several resistors and parts to make a "5th Gear Overdrive" pedal).

Phil in gorgeous Young Harris, Georgia

ps, the schematic of a different model of Behringer USB mixer might also work for my purposes.  I just need to see how the USB is driven.

6
Schematics and Layouts / Peavey Mixer: PV6-USB: Schematic and repair
« on: April 09, 2020, 12:11:02 PM »
Howdy all.  Attached is the PDF schematic of the Peavey PV6-USB mixer.  I am posting this as well as my journey, struggles and questions as I work to repair a broken mixer.

I have seen online comments regarding power supply for these older mixers: it is critical to note that the non-USB models require a 16 volt AC adapter, while the USB models require a 15 volt DC supply.  I will also post a picture showing the input requirements shown on the back of the mixers.

The mixer I am trying to fix had a serious power problem which blew the NCP3063 boost/buck/inverting converter surface mounted chip apart.  It was so bad that it burned the top layer of the board down to the fiberglass matting below (I think I have a picture; if so I will include it too).

My questions will start in my next post as I work with my meter to see why the mixer works but the USB does not.

Phil in gorgeous Young Harris, Georgia, USA


7
Schematics and Layouts / Re: Peavey Mixer: PV8USB Schematic and Repair
« on: April 09, 2020, 11:54:49 AM »
Got the parts, installed them in the PV8-USB and then tested the mixer.  Everything works as expected.

I did find that the USB operation had fooled me, since when I started testing, I did not see any signal going into my DAW from the mixer, but HP on the mixer allowed me to hear music playing from my DAW.  It turns out that the traffic is one-way at a time. Although it seems obvious now, if I set the switch to feed the Tape/USB into the mix or set the switch to feed the Tape/USB into the Ctrl/HP, I got the USB signal from the PC into the mixer, but no return signal. Once I unset those two switches, I got signal into my PC from the mixer.  In the schematic, I have not found any switching but it works.  I also tested one of my previously repaired PV6-USB, and the USB does work on the one that I thought was only one way.     

I went back into the board on the PV6-USB that has no USB function to see if I can repair that too.  I had to replace the +16vdc transistor (Q21) with a different model (spec'd model is obsolete) and I am not getting the +16 VDC rail to where I think it should be.  I think I will start a new thread and post the Schematic for the PV6-USB and ask questions there.

Thanks for letting me share, and for sharing so much on here. 

Phil in gorgeous Young Harris, Georgia, USA

8
Howdy.  I voted for Battery amp, since "Other" was not available (Looper Pedal?). 

Thanks for the diversion.

Phil in gorgeous Young Harris, Georgia

9
Schematics and Layouts / Re: Peavey Mixer: PV8USB Schematic and Repair
« on: April 02, 2020, 11:18:47 PM »
I have replaced the one open zero ohm SMD chip (jumper), three bad SMD resistors and seven of the SMD ICs (parts removed and locations circled in attached picture). 

I found two more ICs bad (circled in black, in the headphone and control room outputs).  I also found three more out-of-spec SMD resistors (4.7ohm, reading over 8 ohms each).  Two of the three 4.7 ohm resistors are spec'd for 1% tolerance, so I will get them all like that.

I expect parts to be delivered tomorrow and will try to get it done and working.

Phil in gorgeous Young Harris, Georgia, USA

10
Schematics and Layouts / Re: 5th Gear Overdrive v3.0
« on: April 02, 2020, 10:55:50 PM »
Thanks for the clarification. 

But, but, but... I don't know if I can afford that because that one Darlington transistor costs 45 cents each!  (Mouser, as of 4/2/2020).  lol

Of course shipping is $7.99, so I wish I had seen this yesterday (I ordered the 2nd round of parts for the Peavey mixer I am repairing), but I forgot to turn "Notify" on.  I'll see if I need more stuff once I get the known bad parts replaced.

Phil in gorgeous Young Harris, Georgia, USA

11
Schematics and Layouts / Re: 5th Gear Overdrive v3.0
« on: March 29, 2020, 09:38:42 PM »
Thanks for posting that. Looks cool, might try it.

Which diode is the LED and which is the 4148?

Can two general purpose NPN transistors be configured as the darlington, or does the sound depend on the characteristics of that particular transistor?

Phil in gorgeous Young Harris, Georgia, USA

12
Schematics and Layouts / Re: Peavey Mixer: PV8USB Schematic and Repair
« on: March 28, 2020, 05:51:56 PM »
Here is a picture from the repair in process.  I have removed the seven known-bad preamps using ChipQuik.  Here is a picture after removing one of the chips and cleaning with solder wick to remove the excess solder.  The chip is a 4565 in SMD form (square, 5mm per side) apparently (hopefully!) and I've got 10 on order (at less than the unit cost of $0.39 each at Mouser).

I will try to keep this thread updated as I progress.  The PV6USB models that I repaired were only broken in the power supply, so this is way out there for me.

Phil in gorgeous Young Harris, Georgia, USA

13
Schematics and Layouts / Peavey Mixer: PV8USB Schematic and Repair
« on: March 28, 2020, 10:34:43 AM »
Howdy all.  Hope you are all doing well during this shelter-in-place time (Covid-19).

Several years ago (2014), I bought a broken Peavey PV8USB mixer on Ebay hoping to repair it with my amateur skills and tools.   After diagnosing that the NCP3063 boost/buck/inverting converter would not function with the corner blown clean off (reminds me of Dirty Harry), I set about attempting to repair it.  Mouser got my order for several NCP3063s, a Zehner that I thought might be bad, and a couple replacement LM317s. 

I took my soldering iron to the NCP3063 which is surface mount.  I got it off, but also accidentally took one trace up from the board.  So in frustration, the mixer went into a drawer for future consideration.

It is now the future (compared to 2014).  In February, I bought two broken PV6USB mixers off of Ebay to practice on (since I really want the PV8USB).  I spent several weeks watching YouTube videos about soldering SMD (surface mount devices) and discovered a new product that I had never heard about before: "Chipquik" SMD removal solder.  It has a lower melting temperature and stays liquid longer: add flux, then melt onto the leads on both sides of the chip, keep it hot and the chip floats off.  Works AWESOME!

So I worked on the PV6USB (similar problems: I discovered that a common fatal error made by users is to try the power supply for the PV6 non-USB, which is 16VAC, with the PV6USB which uses 15VDC 500ma and that blows the power regulator[side note: seems like a weak design when adding a diode might avoid issues]).  One PV6USB works almost as expected (the USB receives but doesn't send) and one PV6USB works with no USB. 

So here is the schematic from Peavey. I could not find it online (and still cannot), so I had emailed Peavey who then sent it to me. This PDF has been indispensable, but I wish the part numbers were searchable on the layout page as well as the schematic to make locating parts easier. Maybe the PDF has layers that my Adobe Reader cannot see.

More later (have to replace all seven 4565 dual preamp SMD chips connected to the inputs, and more).  Thanks for allowing me to share.

Phil in gorgeous Young Harris, Georgia, USA

14
Schematics and Layouts / Re: Bogen GS-150 Schematic, and Help Needed
« on: March 03, 2016, 10:12:33 PM »
In moving, I threw the dissassembled one back together, but managed to lose some tiny screws for the faceplate. Now I'm in our new home but have not gotten back to this.

Thanks for your insight. I will see about the caps C121 and C122 when I get to it, but I'm in no hurry.

Phil in gorgeous Young Harris, Georgia, USA

15
Amplifier Discussion / Re: Cant find anything on Kustom K8320 Powered Mixer
« on: February 03, 2015, 06:45:33 PM »
Thanks for the thoughts. 

I did not bid, nor did anyone else for $35 plus $30 shipping.  I wonder if he will re-list.  (Bad timing for me, since we are moving next week and shouldn't take the time to add another project. But I wanted to so bad...)

The only info I found was a small write-up saying it's from 1990.  Never did even find a third-party picture of it (just the auction photos), even on 20 pages of Google images.

Kustom website has no contact email, but I tried once to call the Customer Service number, but no answer. 

I'll see if it comes up again...

Phil, in beautiful Talking Rock, Georgia, USA, soon to be in gorgeous Young Harris, Georgia, USA.

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