EHX - Memory Toy [gut shots]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.

Re: Electro-Harmonix - Memory Toy [gut shots]

Postby cortezthekiller » 15 Dec 2012, 02:03

Scruffie wrote:I just got one of these in a trade, I notice the second board design has changed mine is now connected via one 4-pin and one Ribbon Cable, it's damn hard to remove.

And now to my next point, I traded for it with a broken feedback pot, it had been a while since i'd used delay and I figured i'd manage without... but I need it, does anyone know where I can find a 12mm Board Mounting Knurled/Split Shaft Pot? I've e-mailed EHX but i've heard there customer support is sometimes not the best.



This is the closest one I could find. Not sure about the dimensions though:

http://www.vintagesynthshop.com/Roland- ... adacJa.asp
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Re: Electro-Harmonix - Memory Toy [gut shots]

Postby Scruffie » 17 Dec 2012, 11:57

cortezthekiller wrote:
Scruffie wrote:I just got one of these in a trade, I notice the second board design has changed mine is now connected via one 4-pin and one Ribbon Cable, it's damn hard to remove.

And now to my next point, I traded for it with a broken feedback pot, it had been a while since i'd used delay and I figured i'd manage without... but I need it, does anyone know where I can find a 12mm Board Mounting Knurled/Split Shaft Pot? I've e-mailed EHX but i've heard there customer support is sometimes not the best.



This is the closest one I could find. Not sure about the dimensions though:

http://www.vintagesynthshop.com/Roland- ... adacJa.asp

Been a long time since I looked inside but that actually looks right but 16 euros! Then again EHX service supplier asked for something ridiculous like 40.

I don't think I can actually seperate the boards inside so think i'll just buy a new memory toy at some point rather than fixing it, but that could be handy in future. Cheers for finding it!
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Re: Electro-Harmonix - Memory Toy [gut shots]

Postby cortezthekiller » 17 Dec 2012, 20:02

I just got an email back from the synthshop regarding the pot dimensions.

It is 1.5cm wide (the round metal case)
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Re: Electro-Harmonix - Memory Toy [gut shots]

Postby JRM » 19 Sep 2013, 11:06

Hi, I've just bought one of this (2nd hand). It's quite nice out of the pack (no box anymore), with a subtle modulation and no oscillation at all. Of course I've opened it and found out it's the later Revision D.
Modulation Depth is easy to adjust to taste (I wonder how much time I can resist to install another pot to make this regulation external :twisted: ) as Trimpot #7 is clearly labeled. But what about the other 7 trimpots?
As far as I know, one should expect:
    4 bias trimpots, one for each BBD chip
    1 clock speed adjustment trim
    1 gain adjustment trim (Trimpot #8)
    1 feedback adjustment trim
We don't want to mess around with clock speed and bias trimpots, unless we either don't get delay or we have both knowledge and tools (osciloscope, signal generator). But we should be able to adjust with gain trim to fit our rig and feddback if we want.
I've searched and found several oposite statements from: trimpot 1 is the feedback trim, trimpot 5 is the feedback trim and trimpots 1 to 6 are quite interactive and must be fine tuned all together to get the desired effect (http://www.tdpri.com/forum/stomp-box/311385-npd-ehx-memory-toy-delay-8-trim-pot-challenge.html). From the adjusting of my Electric Mistress, I can understand that they might influence each other but it must have one feedback adjustment trimpot.
Anyone knows which one is which or has a good hint how to find it?
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Re: Electro-Harmonix - Memory Toy [gut shots]

Postby JRM » 19 Sep 2013, 15:27

Looking to the picture on page 1 of this topic it looks like trims 1, 2 and 3 are the bias trims for BBD chips 1, 2 and 3. When I get home I'll check mine.
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Re: Electro-Harmonix - Memory Toy [gut shots]

Postby JRM » 24 Sep 2013, 11:58

There's not much information regarding this particular circuit. By what I saw on the Memory Man schematic, on BL3208 datasheets and making some measurement with my multimeter I've found out that for Revision D of the Memory Toy PCB we have:
    4 bias trimpots, one for each BBD chip, trimpots marked with numbers 1, 2, 3 and 5
    1 modulation depth control trimpot, marked "MOD DEPTH"
    1 Balance adjustment trimpot, marked with number 6, placed at the output of the last BBD
    1 feedback loop gain adjustment trim, marked with number 4
    1 unity gain adjustment trimpot (Trimpot #7), placed on the main board

Yesterday I've played a little bit with the #4 and found out that finding a sweet spot wasn't easy :( I've measured the bastard and found out that a slight turn made a huge change in the resistance value (0-20k). I'll do some more experimentation tonight.
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Re: Electro-Harmonix - Memory Toy [gut shots]

Postby JRM » 25 Sep 2013, 13:13

Revision D images:
Image
Image
Finaly tuned the feedback loop trimpot. Oscillation is now possible but not too much: I prefered to keep "almost infinite" repetitions on the longer delay times as it is nice on the end of the musical phrases.
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Re: Electro-Harmonix - Memory Toy [gut shots]

Postby Bernardduur » 27 Mar 2014, 09:21

Could someone make me HQ pics of the area around R80? I have a unit in that has a burned R80 and it left a gaping hole in the print....... all leads underneath are disconnected and I'm trying to reconnect em :).
'No more....... loud music.......'
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Re: EHX - Memory Toy [gut shots] REV. G

Postby magneto538 » 02 Jul 2015, 09:54

Hello people,
I am running into some issues with my Memory Toy Rev. G. Basically, when the pedal is turned on and the blend knob is turned all the way clockwise I cannot get any sound. I get sound if I turn the blend knob to minimum.
There must be some kind of an issue in the part of the circuit which manages the delay part. I already performed all the basic checks that you have mentioned in previous posts (checked the connection between main and secondary board, which seems solid, and tried both an external power supply and battery, as I saw here that someone had my same issue and solved it by just changing power supply) but no good news. I have noticed that there is an almost broken pot (meaning that it clicks when I turn it, even though I have measured its value and it seems to be correct and with no drops or such).
Maybe the previous owner played a bit with trimpots? Burnt IC? Something else? There are evident signs of repairing, as the wire that connects the switch to the main board doesn't seem to be original (but it seems to be connected correctly).

If you know factory levels for trimpots, or you own Memory Toy's schematics, or if you could help in any way... Please do it!
Thank you.

Image Image

Image Image

Image
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Re: EHX - Memory Toy [gut shots]

Postby Bernardduur » 13 Jun 2016, 12:10

According to this site R80 is 10R

I've tried replacing the resistor with another 10R with no succes. The voltages of the board are still below 2V

Busy with tracing this unit........ very slow more information is available.
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Re: EHX - Memory Toy [gut shots]

Postby Bernardduur » 14 Jun 2016, 20:47

On my way fixed the problem

R80 was shot because C13 short circuited. C13 is a bypass capacitor and is located near U2. When removed the problems were over (after replacing R80 with a 10R resistor)
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Re: EHX - Memory Toy [gut shots] REV. G

Postby patient81 » 23 Nov 2016, 20:04

magneto538 wrote:Hello people,
I am running into some issues with my Memory Toy Rev. G. Basically, when the pedal is turned on and the blend knob is turned all the way clockwise I cannot get any sound. I get sound if I turn the blend knob to minimum.
There must be some kind of an issue in the part of the circuit which manages the delay part. I already performed all the basic checks that you have mentioned in previous posts (checked the connection between main and secondary board, which seems solid, and tried both an external power supply and battery, as I saw here that someone had my same issue and solved it by just changing power supply) but no good news. I have noticed that there is an almost broken pot (meaning that it clicks when I turn it, even though I have measured its value and it seems to be correct and with no drops or such).
Maybe the previous owner played a bit with trimpots? Burnt IC? Something else? There are evident signs of repairing, as the wire that connects the switch to the main board doesn't seem to be original (but it seems to be connected correctly).

If you know factory levels for trimpots, or you own Memory Toy's schematics, or if you could help in any way... Please do it!
Thank you.

[ Image ] [ Image ]

[ Image ] [ Image ]

[ Image ]


Hello, your situation is exactly the same as mine. RevG board and no delay signal at all.

Did you ever manage to fix it?
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Re: EHX - Memory Toy [gut shots]

Postby zmix » 09 Oct 2018, 02:28

After reading this thread I did some experimenting with my "Rev J" Memory Toy.

I tack soldered a 330kΩ resistor across R70 ("914") which brought the LFO rate up to the old Deluxe Memory Man "Vibrato" setting, and then I adjusted Trim 8, the LFO depth control until there was no shift in delay time when switching the modulation on and off, this ended up being about 4:00 on the trimmer, which is *slightly* more than you may want but it certainly nails that spooky memory man vibe:

Screen Shot 2018-10-08 at 21.26.42.jpg
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