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My trusty early 80's MXR Micro Flanger is now passing clear signal on and off. I suspect the chip although I haven't taken voltages as yet...
Anyone selling SAD 512D's at all just in case?
Cheers.

candletears7 wrote:My trusty early 80's MXR Micro Flanger is now passing clear signal on and off. I suspect the chip although I haven't taken voltages as yet...
Anyone selling SAD 512D's at all just in case?
Cheers.

Never just assume it is the SAD. Those are Unicorn tears and it would behoove you to make every attempt to verify that it is NOT the BBD.

In any case, I happen to have the Reticon R5106 chip if you are interested. It is known to be a good drop in replacement for the SAD512D.

Good Luck

Govmnt_Lacky wrote: Never just assume it is the SAD. Those are Unicorn tears and it would behoove you to make every attempt to verify that it is NOT the BBD.

I fully second the above.

Appreciate the input guys, thankyou.
I won't be able to check the pedal till tonight but I'll probe and take voltages from the schematic.
Depending how I go I may take you up on the offer, Lacky, thankyou.

The fact that it is still passing a modulated signal occasionally tells me that you may only need to readjust the BBD bias a bit.

Did you ever get a chance to look at this?

Hey mate, no I've been absolutely thrashed with a new job, family life and bands!
I haven't even printed off the damned schematic yet!
I briefly had a look at the trim pot but it's glued or sealed in position. I may just have to break the seal and see if it works.
I do appreciate the input from you though - I put this little guy after my dirts set to minimum on both dials. Huge thick modulated signal that just sounds massive on stage.

Well, for anyone reading along with this, all voltages on all chips and caps are as per schematic...except the 4069 Hex Inverter. That and it's hot as hell. Its out, a socket is in and tomorrow I'll grab another. Here's hoping that's the issue and not the SAD.

Fingers crossed!!

Thanks Dirk, but alas, still no joy even with a new socketed 4069.
I've got a feeling it's something to do with that oscillator...next step is to check for any dodgy connections and to measure the electrolytics.

Mods may as well move this to a vintage MXR Microflanger thread if it exists as now this is debug.