Home Forums Vintage EHX Memory Man Deluxe Chip (MN3005) Alternative?

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  • #113258
    DiamondCoco
    Member
    Quote:
    Quote:
    so i have a DMM that has the blue and red print with 4 knobs. it recently got a problem. the pedal turns on but i dont get delay. someone told me that i might need a new chip, what do you guys think?

    Have you tried reseating the chips that are in there already? Also, try setting all the trimpots to midpoint and then follow this: http://www.diystompboxes.com/smfforum/index.php?topic=4050.msg23285#msg23285

    I tried reseting my trim pots but i dont think i did it correctly. what is midpoint? is it setting them to where the red lines are pointing to the top of the pedal?

    #113259
    DiamondCoco
    Member
    Quote:
    Quote:
    so i have a DMM that has the blue and red print with 4 knobs. it recently got a problem. the pedal turns on but i dont get delay. someone told me that i might need a new chip, what do you guys think?

    A bad delay chip is one of several possible causes of this problem.
    I can fix it.

    Guitar pedal design engineering, repairs, and custom mods:
    http://howardmickdavis.com

    Thamks for the offer but thats alittle far and i know of a repair guy thats alittle closer.

    #113260
    Howard Davis
    Member
    Quote:

    I tried reseting my trim pots but i dont think i did it correctly. what is midpoint? is it setting them to where the red lines are pointing to the top of the pedal?[/quote]

    Lab equipment and the correct alignment procedure are necessary to properly set the trimpots. It cannot be done without these. As you’ve tampered with them, you’ll now have to have it done by someone with the right equipment and knowhow. I can do it.

    Howard Davis, EE – designer of the Memory Man
    Guitar pedal design engineering, repairs, and custom mods:
    http://howardmickdavis.com

    howard.davis2@att.net

    #120182
    waxsimulacra
    Member

    Looks like this thread is about 4 years old I hope I can still get a reply. I been having similar problems with my MMD, power comes on when switch is flipped but no effect. I was thinking back to when I was using the pedal when I was younger I may have just plugged it into my power block with my other pedals (I didn’t know any better at the time). I recently read that doing that can mess up the MMD. So I been taking it apart and trying to diagnose the issue nothing looks burnt and everything looks like a solid connection, can anyone tell me where I should check first?

    After reading a few threads I figure it could just be the delay chips. I found some but unsure if they are what I need. my unit uses 4 mn3008’s and underneath the [strong]MN3008[/strong] is [strong]0.0[/strong] I see a good amount on eBay but under the Mn3008 are other random numbers what do those number mean and would they still work? I hope to hear from someone soon thought it would be best to post in here before starting a new thread. Thanks!

    #120183
    Scruffie
    Member
    Quote:
    Looks like this thread is about 4 years old I hope I can still get a reply. I been having similar problems with my MMD, power comes on when switch is flipped but no effect. I was thinking back to when I was using the pedal when I was younger I may have just plugged it into my power block with my other pedals (I didn’t know any better at the time). I recently read that doing that can mess up the MMD. So I been taking it apart and trying to diagnose the issue nothing looks burnt and everything looks like a solid connection, can anyone tell me where I should check first?

    After reading a few threads I figure it could just be the delay chips. I found some but unsure if they are what I need. my unit uses 4 mn3008’s and underneath the [strong]MN3008[/strong] is [strong]0.0[/strong] I see a good amount on eBay but under the Mn3008 are other random numbers what do those number mean and would they still work? I hope to hear from someone soon thought it would be best to post in here before starting a new thread. Thanks!

    First off, many of the BBD chips you’ll find on ebay are fakes, if you want a reliable supplier try smallbearelec.com
    The numbers under the chip are the batch code, you can ignore them.

    There is no reason for the delay chip(s) to be dead, in fact they rarely die at all it usually one of the other parts that has gone, people wrongly assume it’s the BBD as it’s the most expensive/rarest part.

    A Memory Man is a large pedal to debug if you have no prior experience, it could be many problems, you can send it to a tech or get a multimeter and the schematic if you’re determined to fix it your self, certainly can be done but you’ll have to put the work in.

    #120184
    waxsimulacra
    Member
    Quote:
    First off, many of the BBD chips you’ll find on ebay are fakes, if you want a reliable supplier try smallbearelec.com
    The numbers under the chip are the batch code, you can ignore them.

    There is no reason for the delay chip(s) to be dead, in fact they rarely die at all it usually one of the other parts that has gone, people wrongly assume it’s the BBD as it’s the most expensive/rarest part.

    A Memory Man is a large pedal to debug if you have no prior experience, it could be many problems, you can send it to a tech or get a multimeter and the schematic if you’re determined to fix it your self, certainly can be done but you’ll have to put the work in.

    Ah okay thanks for the good info! I have a multimeter and am In no rush so I will see what I can find.

    #120186
    Scruffie
    Member
    Quote:
    Quote:
    First off, many of the BBD chips you’ll find on ebay are fakes, if you want a reliable supplier try smallbearelec.com
    The numbers under the chip are the batch code, you can ignore them.

    There is no reason for the delay chip(s) to be dead, in fact they rarely die at all it usually one of the other parts that has gone, people wrongly assume it’s the BBD as it’s the most expensive/rarest part.

    A Memory Man is a large pedal to debug if you have no prior experience, it could be many problems, you can send it to a tech or get a multimeter and the schematic if you’re determined to fix it your self, certainly can be done but you’ll have to put the work in.

    Ah okay thanks for the good info! I have a multimeter and am In no rush so I will see what I can find.

    Great! :) First thing to do, plug it in, power up and take voltage readings on every chip (black lead to a ground point such as the enclosure, set on the 20V range and use the red lead to probe) you measure the pins in this order with the tab, notch or dot indicating the top of the chip (if the chip has a notch and a dot, go by the notch) http://www.remotefactory.com/images/8-pin-dip.png post them up and i’ll check them.

    #120188
    waxsimulacra
    Member
    Quote:
    Quote:
    Great! :) First thing to do, plug it in, power up and take voltage readings on every chip (black lead to a ground point such as the enclosure, set on the 20V range and use the red lead to probe) you measure the pins in this order with the tab, notch or dot indicating the top of the chip (if the chip has a notch and a dot, go by the notch) http://www.remotefactory.com/images/8-pin-dip.png post them up and i’ll check them.

    Awesome! I will check them today. I really appreciate the help it’s vey kind of you. We had a faulty dryer go south on us yesterday with a gas leak otherwise I would have already got the readings.

    #120189
    Scruffie
    Member
    Quote:
    Quote:
    Quote:
    Great! :) First thing to do, plug it in, power up and take voltage readings on every chip (black lead to a ground point such as the enclosure, set on the 20V range and use the red lead to probe) you measure the pins in this order with the tab, notch or dot indicating the top of the chip (if the chip has a notch and a dot, go by the notch) http://www.remotefactory.com/images/8-pin-dip.png post them up and i’ll check them.

    Awesome! I will check them today. I really appreciate the help it’s vey kind of you. We had a faulty dryer go south on us yesterday with a gas leak otherwise I would have already got the readings.

    Sorry to hear about that, hope you get it sorted soon!

    Just remembered that the DMM is actually positive ground so put the red lead to ground and probe with the black one, sorry about that.

    #120190
    waxsimulacra
    Member
    Quote:
    Quote:
    Quote:
    Quote:
    Great! :) First thing to do, plug it in, power up and take voltage readings on every chip (black lead to a ground point such as the enclosure, set on the 20V range and use the red lead to probe) you measure the pins in this order with the tab, notch or dot indicating the top of the chip (if the chip has a notch and a dot, go by the notch) http://www.remotefactory.com/images/8-pin-dip.png post them up and i’ll check them.
    Sorry to hear about that, hope you get it sorted soon!

    Just remembered that the DMM is actually positive ground so put the red lead to ground and probe with the black one, sorry about that.

    Alright I had some free time so I was able measure everything. For the most part it all read very quickly, but a few spots just kept changing numbers randomly the entire time I held the pin down. I double checked my connection and rechecked a few times to make sure I was reading it right.
    Oh and everything at home got taken care of :) thanks! i would have not had not known to ground the lead wow, is that common?

    [strong]-U9


    Sa571n
    j81874
    jnr0209[/strong]
    1)13.51 9)12.90
    2)12.81 10)6.69
    3)12.82 11)8.38
    4)14.72 12)12.92
    5)12.91 13)0
    6)12.71 14)12.81
    7)4.80 15)12.81
    8)12.90 16)13.56

    [strong]-Mn3008


    [/strong]
    [strong]-U4-[/strong]
    1)0
    2)7.52
    3)4.42
    4)4.42
    5)14.94
    6)7.52
    7)0
    8)13.9

    [strong]-U5-[/strong]
    1)0
    2)7.52
    3)4.58
    4)4.59
    5)14.94
    6)7.52
    7)0
    8)13.89

    [strong]-U6-[/strong]
    1)0
    2)7.52
    3)6.63
    4)4.64
    5)14.94
    6)7.52
    7)14
    8)13.86

    [strong]-U7-[/strong]
    1)0
    2)7.52
    3)4.64
    4)4.54
    5)14.94
    6)7.52
    7)0
    8)13.89

    [strong]-Co4558n


    0417[/strong]

    [strong]-U1-[/strong]
    1)7.49
    2)7.47
    3)7.13
    4)14.74
    5)6.10
    6)6.69
    7)6.69
    8)0

    [strong]-U2-[/strong]
    1)6.55
    2)3.28
    3)3.18
    4)14.74
    5)3.18
    6)7.48
    7)7.49
    8)0

    [strong]-U3-[/strong]
    1).14
    2).12
    3)0
    4)14.74
    5)7.13
    6)7.47
    7)7.48
    8)0

    [strong]-U8-[/strong]
    1)7.49
    2)7.48
    3)7.25
    4)14.79
    5)7.25
    6)7.49
    7)7.46
    8)0

    [strong]-U10-[/strong]
    1)Random numbers
    2)7.16
    3)7.Random numbers
    4)14.95
    5)7.19
    6)7.10
    7)7.Random numbers
    8)0

    [strong]HEF4047bp


    aq320 02
    ungo5053[/strong]

    [strong]-U6-[/strong]
    1)6.71
    2)8.14
    3)8.01
    4)0
    5)0
    6)0
    7)14.94
    8)14.94
    9)14.94
    10)7.52
    11)7.52
    12)14.94
    13)6.8
    14)0

    [strong]poteniometers[/strong]



    [strong]-Blend-[/strong]
    1)0
    2)0
    3)0

    [strong]-Level-[/strong]
    1)7.47
    2)7.48
    3)7.48

    [strong]-Feedback-[/strong]
    1)0
    2)0
    3)0

    [strong]-Delay-[/strong]
    1)8.17
    2)6.Random
    3)8.01

    [strong]-Chorus-vibrato-[/strong]
    1)8.72
    2)6.random
    3)7.random

    #120191
    Scruffie
    Member

    The moving numbers are fine, that’s the LFO. What’s wrong is that none of the BBDs are showing any bias voltage… apart from U6 which has 14V on pin 7 and U3 pins 1,2&3, which is the opamp feeding that BBD are all basically shorted so i’d start digging around there…

    #121875
    waxsimulacra
    Member

    [em]

    Quote:
    The moving numbers are fine, that’s the LFO. What’s wrong is that none of the BBDs are showing any bias voltage… apart from U6 which has 14V on pin 7 and U3 pins 1,2&3, which is the opamp feeding that BBD are all basically shorted so i’d start digging around there…

    Hey been gone for a long time.. Had some major stuff go on and haven’t really touched any gear since until now. Haha I told ya I wasn’t in to much of a rush right…
     
    So with the BBD chips all shorted, I should just replace them and check the components around them for any other shorts?
    Or your saying the opamps are all shorted and I should check the opamps and around them?
     
    On a side note I love this stuff but know very little any suggestion on where to learn electronic design? I would eventually like to design and mess around building my own effects and amps, just as a hobby. [/em]

    #121877
    Scruffie
    Member

    No i’m not saying the BBDs are bad or shorted out, i’m saying something around them is causing a problem.

    Have you messed with the trimmers in this? I can’t work out why you’re not seeing a bias voltage on the BBDs unless you’ve set the trimmers to the ground side.

    Measure the voltage at the center pin of Trims 1,2,4 & 5 you need to adjust them for approximately half supply (that isn’t optimal but should at least let some delay signal pass) if they measure at ground.

    #121881
    waxsimulacra
    Member
    Quote:
    No i’m not saying the BBDs are bad or shorted out, i’m saying something around them is causing a problem.

    Have you messed with the trimmers in this? I can’t work out why you’re not seeing a bias voltage on the BBDs unless you’ve set the trimmers to the ground side.

    Measure the voltage at the center pin of Trims 1,2,4 & 5 you need to adjust them for approximately half supply (that isn’t optimal but should at least let some delay signal pass) if they measure at ground.

    I haven’t messed with them but that’s where I’ll check next, then start digging around the BBDs. Thanks!

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