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Messages - Maharg

#16
Open Discussion / Re: Help with reissue Deluxe Memory Man
December 15, 2020, 01:59:51 AM
Back again (this is serving as a useful soundboard)  8)

Well, like LaceSensor, it appears I had to disconnect the bare wire connected from the PCB to the Delay pot casing - now, I have wet signal and the appropriate voltages.  Weird.

Now, to take a stab at calibrating this thing...
#17
Open Discussion / Re: Help with reissue Deluxe Memory Man
December 15, 2020, 12:03:03 AM
Back with more - truly stumped, here...

I've tried both the stock HEF4047 that came in the pedal as well as a HEF4047 from a Small Clone. 

I've also tried two CD4047's that I have kicking around.

Each chip prefix generates the same, but unique from the other prefix, results:

HEF4047
0V @ Pin 10
15V @ Pin 11

CD4047
15V @ Pin 10
0V @ Pin 11

So, inverse results across pins 11 and 10.  I verified, before swapping around, that pinouts are the same on these chips.  Anyone have any ideas?  Quite the curve ball I've got here...thanks in advance!
#18
Open Discussion / Re: Help with reissue Deluxe Memory Man
December 14, 2020, 04:39:31 PM
Yessir, a 'legit' EHX unit.

Also, if this is helpful to diagnose the issue, per LaceSensor's earlier post re: Trim Pots

Trim 1 = U4
Trim 2 = U5
Trim 3 = Gain
Trim 4 = U6
Trim 5 = U7
Trim 6 = Balance
Trim 7 = Gain

Voltage at the MN3005 Pin 7's is just north of 5V, and there is no change when turning the associated trims (#1 and #5).  Seems voltage isn't getting to the chips as it should, likely linked to the fact that the 4047 isn't outputting properly (??)
#19
Open Discussion / Re: Help with reissue Deluxe Memory Man
December 14, 2020, 10:55:48 AM
Hey Jimilee, thanks for the reply.

Not sure I know what you mean by the "bipolar" electro cap, but I've added a couple of photos here of the board, and the LM7915 that looks like it may have some oxidization or corrosion - would love folks views on this.  It looks a little 'cakey' to me (maybe damaged by someone using an incorrect power feed?)

https://drive.google.com/file/d/1GceSNLs-RbLtCW9nArv1ISpE2XMdC32D/view?usp=sharing

https://drive.google.com/file/d/1GjJAQGjcA42pIQT4EAAb-EVSwkQmPJCS/view?usp=sharing

https://drive.google.com/file/d/1GjuU8GR7qMKFf_xW21AZ8w_3pnQa4LID/view?usp=sharing

EDIT: I've got a line on some NOS NE570 compandor chips that I'll be picking up later this morning; will pop one of those in to see if that's the ticket and report back...

EDIT 2: Tried a NOS NE570 and the same issue persists - 0V at pin 10 of the 4047, and 15V at pin 11.
#20
Open Discussion / Re: Help with reissue Deluxe Memory Man
December 14, 2020, 02:44:47 AM
Evening everyone,

I hope the thread-revival gods will forgive me on this one, but I'm having a very similar issue as LaceSensor with a DMM I just picked up.  This is an EC2002_REV_E board, with 2xMN3005's.

Symptoms are that there is no delay signal - level and blend knobs function, but no effected signal.

Initially, the compandor was exhibiting some voltage issues (very similar to LaceSensor - Pin 7 had no voltage). After re-seating the IC, swapping some NE570's, etc., the voltages on the compandor now seem pretty good.  The 4047, though, is another story.

I have tried no fewer than FIVE CD4047 chips and all exhibit the same issue - Pin 10 shows 0V, Pin 11 shows 15V.  The odds of all of these 4047's being bad are pretty low (at least 1 was pulled from a working reissue Small Clone).

Solder joints and traces on the board look good (it's a very clean pedal).  Any ideas on what I may try next?

Thanks in advance, wonderful people.