humble request- MXR flanger

[jdub]

Howdy-
Would anyone be able to provide, or point me toward a source for, IC and tranny voltage measurements for an MXR M117 flanger?  Trying to debug a clone- power, vref and gnd voltages are where they should be, but I could use some of the other pin voltages.  Much appreciated. 

[Govmnt_Lacky]

+1

Would also be interested in an "alignment" procedure specific to the M-117. The only one I could find was for the Electric Mistress.

Someone out there HAS to have this info 

[oldschoolanalog]

I'm pretty sure I posted those some time ago. Have you tried the search function?
After a long nasty divorce I recently got back all my pedals, notes, workshop, and basically everything music related that my ex was holding "hostage".
If you can't find the info, I'll find my notes & re-post the V's. Or just take some new readings from one of mine (I have 4. Anybody wanna' buy one or two? ) Might take a couple of days as I have LOADS of boxes to sort out.
First, UTSF.
All the Best!
PS: The alignment procedure is real easy, IIRC. Just 3 trimpots, if memory serves me correctly.
More later...

[Thomeeque]

After a long nasty divorce I recently got back all my pedals, notes, workshop, and basically everything music related that my ex was holding "hostage".

Hi Dave! Good to hear from you again, I'm glad you and your music related stuff are back!! T.

[jdub]

Dave, I'm sorry to hear about your ordeal.    Glad you got your stuff back, though!

I've used the search function extensively to try to find voltages for the MXR (or the Ross), but all I found was clock frequencies from the 4013.  Couldn't find voltages for the (other) ICs and trannies.  If you get a chance & could post, I'd be most appreciative.  Alternatively, I can post what I have & you could point out ones that deviate from yours.  Whatever's easier for you.  Thanks much, man 

[Fender3D]

Dave's right:
just 3 trimpots
first set MANUAL and WIDTH fully CCW,

500K (trim clock in shredaholic schematic): as per Dave's measurements on other pedals, trim for ~29KHz/~32KHz @ SAD's pins 3-14 or 8-10 (you'll need a frequency meter or o-scope for this)

20K (trim dist in shredaholic schematic):  hook a signal generator (sine wave is better) at input set it 80-100mV @ 1KHz and trim for minimum distortion @ SAD's pins 5-6 AND 11-12
(you'll need a o-scope for this or better a distortion analyzer and a signal generator)

20K (trim level in shredaholic schematic): set REGEN fully CW and trim until feedback arises and trim slightly back to stop feedback (your ears will be enough   )

PS
this is THE standard BBD alignment procedure   I wonder how those choruses work...

PPS
I will skip any post requesting for tranny measurements 'cause I'm a lazy ass****  

[bean]

I'm actually putting together a DIY project for the SAD1024 version right at this moment. If I can get it working, I can get you some voltages.

I picked up the 1024 from Smallbear a few months ago with the intention of building this killer flange

[oldschoolanalog]

Thanks for the kind words & support guys.
I should be able to locate the chart w/the V's today (nite, at work now), I'll post them tomorrow if somebody doesn't first.
@Brian: There is a project for this at Shredaholic (or something like that). However, I look forward to your layout as you always seem to find a way to fit things into a smaller enclosure. 
Also, for those SAD1024less folks, a nice MN3007 retrofit was done for this flanger. It's here or maybe "over there". Have a look/see.

[Fender3D]

Voltages will add to confusion I guess.
This is not a circuit you can trim properly with just a tester...
Find the needed instruments or a good technicians

[jdub]

Thanks, guys.  My prob is that I'm not getting any sound at all out of the board, effected or otherwise. I've triple checked component placement & values and also for solder bridges.  Adjusting trims (especially the bias trim for the SAD) does nothing.  As I said above, V+, Vbias & gnd are OK; getting signal at pins 2 & 15 of SAD (which is good, BTW- tested in an Elec Mistress).  Also getting good clock from pins 1&2 of the 4013 and at the SAD.  I'm kinda stumped & I'm hoping that having the other voltages can point me in the direction of the problem- which will probably turn out to be something dumb.  Again, thanks for the help. 

[Fender3D]

SAD1024 is a dual 512 stage BBD and EM would eventually work if one of the two side is not working since they are paralleled, with MXR it's different 'cause they're cascaded...

you say you have signal @ pins 2 and 15, then you should have signal @ pins 5-6 (out for first 512 BBD);
if you have no signal @ pins 11-12 then the 2nd half is not working

check the clock at SAD's pins

BTW
what clone is it?

[jdub]

It's the MXR flanger clone from Shredaholic.

I have clock at pins 3, 8, 10 and 14.

if you have no signal @ pins 11-12 then the 2nd half is not working

Well, that would well and truly be a bummer    I assume, then, with the MXR if the 2nd half of the SAD is not working, then no signal at all goes to the output?  I'm not quite clear on how a Mistress could work if one side of a 1024 was bad.  Wouldn't this be the same as using 512-stage BBD?

Well, if worse comes to worst, I can try your MN3007 retrofit for the MXR and keep the SAD in the Mistress... 

[Fender3D]

Whether you have signal @ SAD's pins 5-6 AND no signal @ pins 11-12, then R10-R11-C6-R2 or SAD's 2nd half have issues.

Whether you have signal @ SAD's pin 2 AND no signal at all @ U4's pin 1, then IC4's 1st half has issues, itself or its surrounding parts.

You might as well have several issues leading to the same result (Murphy rules)
Also I didn't check the Shredaholic PCB 'cause I find faster design my own than debugging the others' work, but I don't like those long tracks from IC3 and A1 at all...

[jdub]

Thanks, Federico.  I'll check out those areas I see what I can find.

[Govmnt_Lacky]

John,

Here are the voltages after I set the trimmers according to Fender3D's instructions. (Thank you by the way for the instructions!  )

The circuit was running on 15VDC REGULATED and ALL pots (Speed, Manual, Regen, Width) were set to middle.

The circuit was pulling between 20 and 22mA during the whole evolution.

** I DIDNT GET TRANSISTOR VOLTAGES. LET ME KNOW IF YOU NEED THEM**

IC1, IC2, and IC4 (JRC4558Ds)

Pin1 - 7.5V
Pin2 - 7.5V
Pin3 - 7.5V
Pin4 - 0V
Pin5 - 7.5V
Pin6 - 7.5V
Pin7 - 7.5V
Pin8 - 15V

IC5 (TL082CP)

Pin1 - Variable from 1.5V to 14.5V
Pin2 - 7.8V
Pin3 - Variable from 1.5V to 14.5V
Pin4 - 0V
Pin5 - 7.8V
Pin6 - 7.8V
Pin7 - Variable from 1.5 to 14.5V
Pin8 - 15V

IC3 (CD4013)

Pin1 - 7.5V
Pin2 - 7.5V
Pin3 - Variable from 14.4 to 14.8V
Pin4 - 0V
Pin5 - 7.5V
Pin6 - 0V
Pin7 - 0V
Pin8 - 15V
Pin9 - 15V
Pin10 - Variable from 8.8 to 9.15V
Pin11 - 15V
Pin12 - Variable from 14.4 to 14.8V
Pin13 - 15V
Pin14 - 15V

A1 (SAD1024A)

Pin1 - 0V
Pin2 - 5.97V
Pin3 - 7.5V
Pin4 - 0V
Pin5 - 9.8V
Pin6 - 9.8V
Pin7 - 15V
Pin8 - 7.5V
Pin9 - 15V
Pin10 - 7.5V
Pin11 - 10V
Pin12 - 10V
Pin13 - 0V
Pin14 - 7.5V
Pin15 - 5.97V
Pin16 - 0V

[Govmnt_Lacky]

Here are the transistor voltages:

Q1 (2N5087)

C - 9V
B - 14.9V
E - 15V

Q2 (BC549C)

C - 2.5V
B - 2.6V
E - 9V

Q3 (BC549C)

C - 0V
B - 0.55V
E - 2.5V

Q4 (BC549C)

C - 0V
B - 0.48V
E - 0.48V

These were taken based off of a 15VDC regulated input voltage.

Looking at the datasheets for a Fairchild BC549C transistor (what is called for in the layout and BOM) it looks like there is a problem 

If you look up the BC549C datasheet from Fairchild, and bounce that off of the Shredaholic layout, ALL of the BC transistors are shown backwards!!

This does not make sense to me because I installed all of my BC transistors according to the layout and it works 

I need to research this more and post results.

[Govmnt_Lacky]

Well, I just hooked up the Flanger circuit to 15VDC regulated again and played through it.

It appears that one of two things is happening:

1) The Fairchild datasheet shows the BC549C pinout WRONG or
2) The circuit does not care that the BC549Cs have their Collectors and Emitters reversed.

The circuit sounds great. The only problems are static on the LFO and radio interference due to it not being in the enclosure,

I dont want to remove the BC549s and try them turned 180 degrees because I dont want to run the chance of screwing up the circuit (Especially the SAD chip  )

Any advice or should I let sleeping dogs lye? 

[Govmnt_Lacky]

I finally decided to reverse the BC549C transistors and try the circuit.

THE LAYOUT IS DEFINITELY WRONG ON SHREDAHOLIC! 

With the 549s installed according to the FACTORY SCHEMATIC, the pedal operated much better and quieter. The output is right at unity (it was a bit low with them reversed) and much clearer.

I will need to readjust the trimmers but I think it sounds FANTASTIC now! 

[Govmnt_Lacky]

first set MANUAL and WIDTH fully CCW,

500K (trim clock in shredaholic schematic): as per Dave's measurements on other pedals, trim for ~29KHz/~32KHz @ SAD's pins 3-14 or 8-10 (you'll need a frequency meter or o-scope for this)

Fender,

When this is performed, does the MANUAL pot need to be fully CW?

I am asking because when I was trimming the 500K and measuring frequency, I was getting 920 to 950KHz with the pot set this way. It was only when I turned it fully CW did the frequency go down to be adjusted between 29-32KHz.

So, either the Shredaholic layout for the MANUAL pot is wired backwards (definite possibility as there are other errors with the transistors and the Speed pot) -OR- the MANUAL pot needs to be fully CW for the trim.

Could you elaborate?

I started a thread trying to get pictures of the pot to circuit wiring from an original unit but I have had no luck. Any chance you have one or pictures of the wiring?

Thanks for the help

[Fender3D]

I said fully CCW, because at the min. clock frequency you have the max delaytime, then a "bassier" flange effect.
BTW This is how I wired the pot to my MN adapted clone.
This min. clock freq. should be ~29KHz/~32KHz @ SAD's pins 3-14 or 8-10.

I don't know about shredaholic layout, but I feel it more natural dealing with the manual control set this way