Help with reissue Deluxe Memory Man

[LaceSensor]

For future reference, when trying to calibrate the EC2002-rev E EHX Deluxe Memory Man
There are typically 4 BBD positions (left to right, U4, U5, U6, U7)
These are MN3008, or rarely, MN3005 (position U4 and U7)

Trimmers relating to the BBD voltage bias are thus:

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

For the MN3005 setup, there are 3 JP (jumpers) points on the solder side of the PCB that omit U5 and U6 positions.
For the MN3008 setup, clearly you have 2 more trimmers. These are labelled SP, and noted on the board to populate those in the case of MN3008 setup. The PCB also says populate (jump) the JP markings in the case of MN3005 usage.

Its unlikely I will convert mine to MN3005s, but I might put two of them in U4 and U7 spots for shits and giggles.

For what its worth, I biased mine to 8v on each Trim, set the gains as appropriate for my taste with the Feedback knob set to self oscillate, and left the balance trim in the middle.

[LaceSensor]

hmmm

boxed it up and now it doesnt work properly again
delay only in 1st 5% of the pot rotation, then nothing.
changed ics again, still the same
so wierd

[LaceSensor]

ok so here is what I have found out.

When the potentiometer for delay is connected to the case, it casuses the delay time to mess up / stop working above 5%

the pot has a wire soldered to the body of it, connecting to the PCB ? assume to GND.

When I disconnect this wire with the PCB outside of the case, everything works fine. Connect that wire, and things go bad again.

Seems like some kind of wierd grounding issue...

[LaceSensor]

hmmm. switched the pot out again and it works now, little wire connecting to the board and everything. whew!

[Scruffie]

you the man
yours is a pint, if ever we should meet
or more than one, haha

Haha, well if you're ever down south, Becks please

ok so here is what I have found out.

When the potentiometer for delay is connected to the case, it casuses the delay time to mess up / stop working above 5%

the pot has a wire soldered to the body of it, connecting to the PCB ? assume to GND.

When I disconnect this wire with the PCB outside of the case, everything works fine. Connect that wire, and things go bad again.

Seems like some kind of wierd grounding issue...

The pot should only connect to pins 2 & 3 of the 4047...

Maybe they're using the pots body as a ground lug, in which case connect that wire to a jacks ground instead... and also make sure the wire is actually soldered to ground and has a good solid solder joint and tests for continuity.

Edit: Late again! Wonder what was going on there then... oh well if it works it works

[LaceSensor]

you the man
yours is a pint, if ever we should meet
or more than one, haha

Haha, well if you're ever down south, Becks please

ok so here is what I have found out.

When the potentiometer for delay is connected to the case, it casuses the delay time to mess up / stop working above 5%

the pot has a wire soldered to the body of it, connecting to the PCB ? assume to GND.

When I disconnect this wire with the PCB outside of the case, everything works fine. Connect that wire, and things go bad again.

Seems like some kind of wierd grounding issue...

The pot should only connect to pins 2 & 3 of the 4047...

Maybe they're using the pots body as a ground lug, in which case connect that wire to a jacks ground instead... and also make sure the wire is actually soldered to ground and has a good solid solder joint and tests for continuity.

Edit: Late again! Wonder what was going on there then... oh well if it works it works

I can only think that the original pot is in some what damaged , either previous or a combination of me desoldering and resoldering it numerous time to test it and also meaning I was (over) heating the pot body.

Anyway, seems stable now with a new B100k, and in fact there is a lot less clock noise despite the pots measuring the same value.

Definitely something wierd going on there.

So, for less than £100 inc postage, plus a 4047, sa571 and B100k, I have a big box which current market value seems to be approximately double the price paid

[Maharg]

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.

[jimilee]

Does that have me have the bipolar electro cap? That was my problem on the first one I built.


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[Maharg]

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.

[jimilee]

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.

Is this an EHX or a clone? EHX I'm guessing.


Sent from my iPhone using Tapatalk

[Maharg]

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 (??)

[Maharg]

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!

[Maharg]

Back again (this is serving as a useful soundboard) 

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...

[LaceSensor]

wierd indeed. as long as it is working though, lol

[Maharg]

Just for the archives, in case anyone searches the interwebs with a similar issue:

1. JP3 needed a fresh solder joint;
2. Both the "Delay" and "Blend" pots needed replacing - in both cases, as soon as any part of the pot shaft/casing touched the box, the whole wet signal grounded out;
3. Ground wire from the "Delay" pot casing was relocated, connecting to a jack's ground rather than the body of the pot;
4. Calibration was challenging (with a signal generator and a scope) but ended up getting it rocking again...

Pedal sounds amazing, great one to have in the big box EH collection.  Speaking of, I've spent some time over the holidays showing my EchoFlanger and PolyFlange some love:

- Replace all IC sockets and IC's (except the SAD-1024's, of course)
- Replace power regulators
- Replace filter caps
- Calibration/Alignment both with scope and by ear
- Sound great

/end EH fan boy rant

Happy Holidays everyone!