MXR - M-118 ( Analog Delay )

stomper romper · Post by **stomper romper** » 15 Apr 2008, 07:41

Hello there.
I am Steve from just outside London England and am having one hell of a time getting any repair info on an old MXR 118 analog delay,the unit is as dead as a dodo,well not quite but no sign of any clock pulses etc,does anybody have any advice re this old classic,are there common faults, and i understand there is more than one version of the PWB assy used in these old
green box units,i will be extremely grateful for any help,and will happily help anyone out with vintage and current valve amp issues,i have an amp repair business in Hertfordshire England and work on just about all types,and carry out many mod,s.
Thanks
Steve.

Professor SourTone · Post by **Professor SourTone** » 15 Apr 2008, 08:35

My MXR Analog Delay is currently at the tech for fixing, and he's having some trouble with it. It was modded for an LED and possibly messed with in other ways.

Its the earlier SAD1024 version with just two outputs and obviously worth fixing. Apparently "getting the main clock functioning" is the first issue. Possibly he could consult here? Thanks - PT.

ik6gpy · Post by **ik6gpy** » 15 Apr 2008, 09:14

Hi!
Here's the schematic for the sad1024 version

https://i206.photobucket.com/albums/bb1 ... gdelay.png

I would ceck first the power supply section: first ceck if the transformer is working properly, then ceck the diodes and the voltage regulator (probably is dead) .Due to the fact that this is an old pedal i would even replace all the electrolytic capacitors. If this section of the circuit gives you a 12VDC regulated power supply then i would ceck the Clock section: the dual flip flop (CD4013), Q1 and Q2. In the meantime check all the wires, bad solder joints and traces.
If the clock works properly and you've got only dry signal out of the box, use a probe to see where the wet signal gets lost.

Cheers!
Matteo

analogguru · Post by **analogguru** » 15 Apr 2008, 09:29

Below you can find all I´ve got which I found last year in an ebay-auction and edited for better/acceptable readability. Sorry that it is not better, original resolution was only 396x306 pixel.

analogguru

Professor SourTone · Post by **Professor SourTone** » 15 Apr 2008, 12:48

This was supplied in the thread I started earlier

https://i206.photobucket.com/albums/bb1 ... gdelay.png

I think analogguru sheet may be for the later version, as it appears to have three jacks.

Steve and I would appreciate any and all help.

Professor SourTone · Post by **Professor SourTone** » 15 Apr 2008, 12:49

Thanks very much for that Matteo, I passed that on to Steve, plus your suggestions, and he's now started a new thread so this one should probably now divert to that one.

analogguru · Post by **analogguru** » 15 Apr 2008, 13:01

Merged the two MXR threads since both units are green.
The mono version uses the SAD1024 whether the stereo version uses the R5101 delay line - both from Reticon.

Below some guts,
analogguru

stomper romper · Post by **stomper romper** » 16 Apr 2008, 08:20

Hello Fella,s.
Thank you very much helping with this MXR analog delay not much decent info on the earlier 118
so anything you have good people is very welcome.
All the very best 2 u.
Steve.

KHELSTROM · Post by **KHELSTROM** » 26 Mar 2009, 18:11

If anyone's interested I have PDF documents of the same sheets analogguru posted earlier. They're much larger and legible. PM me your email address if you'd like them.

Fuzzer · Post by **Fuzzer** » 27 Mar 2009, 23:04

All of these courtesy of Mr. KHELSTROM.

Fuzzer · Post by **Fuzzer** » 27 Mar 2009, 23:20

The part 7 had to be zipped, it was too big.

Fuzzer · Post by **Fuzzer** » 27 Mar 2009, 23:22

The final cut;

Muchas gracias KHELSTROM, again.

soulsonic · Post by **soulsonic** » 28 Mar 2009, 05:49

So far, it looks like every photo of an R5101 version is missing it's original chip and has the PT2399 digital retrofit board on it that an ebay seller was pushing a few years back (still maybe?).
Anyway, I boxed up one of those retrofitted boards for a friend of mine. It turned out very nice. I wired it up to run off an external 18v supply instead of being mains powered and I had the control of the clock oscillator set up as a separate "filter" control so you can dial in how much filtering you want instead of having it tied to the delay time. This lets you dial in nice dark slapbacks that are very tape-sounding.
Even with the digital retrofit, it has a great 'analog' character to the sound.

MrHuge · Post by **MrHuge** » 07 Apr 2009, 18:23

If anyone is interested... I have about 50 of these original MXR PCBs with the PT2399 on it...
Not sure what to sell them for each....?
-MH

Dan N · Post by **Dan N** » 08 Apr 2009, 19:11

MrHuge wrote:If anyone is interested... I have about 50 of these original MXR PCBs with the PT2399 on it...
Not sure what to sell them for each....?
-MH

They sell them for about $50 plus shipping on ebay.

I've never thought that was anything but a fair price, yet too high to get me to make the plunge.

biggator · Post by **biggator** » 18 Oct 2011, 17:08

Hey all...
I found this thread while trying to debug my 118 - which worked fine until recently.

It's the original 5101 circuit, unmodded.. so looks a bit different than the pics below (if anyone wants gut shots of an original, let me know).

What's happening is that it's suddenly humming like crazy.. I can hear (just barely) that the delay is still working - if I set regen to full and tweak the delay time up and down, I can hear it pitching (so thankfully, the 5101 doesn't seem to be the culprit). I've poked around for bad grounds and even replaced a suspect jack.. but can't seem to find anything.

Voltage at R36 (and at pin 14 of the 5101) is a little over 11v. The service manual says to check for 12v +/- .5.. so it's a little low.

Anyone have any bright ideas what to check?

dmc777 · Post by **dmc777** » 07 Mar 2012, 01:37

Hi guys, hopefully someone can help me here. I have the mono version with the sad1024s...3 of em. It Works fine but I bought it used and someone had shortened the mains power line considerably. I'm taking its 3 inches long. Hardly long enough to power up unless its sitting on top of the receptacle. The line is also 2 pronged non polarized.

What I want to do is replace it with a new 3 prong with ground. Should I just take the old one off and solder the new plug like the old one and add a ground? Theres a few screws holding the board down can I use one of the for the ground?

Also would adding true bypass be a good idea if I'm planning on selling it?

Thanks in advance guys.

Fender3D · Post by **Fender3D** » 07 Mar 2012, 14:31

The upper-right screw on the pictures above is the ground-earth connection usually.
Once the cheaper trick to avoid hum (and get electrocuted

) was to unconnect earth from gnd...

dmc777 · Post by **dmc777** » 24 Mar 2012, 06:19

Fender3D wrote:The upper-right screw on the pictures above is the ground-earth connection usually.
Once the cheaper trick to avoid hum (and get electrocuted ) was to unconnect earth from gnd...

Thanks for the reply. I have the original board with the 1024 chips so it's a little different. I bought a new pigtail or 3 prong plug. Looking at the pics above are you guys just attaching the plug ground to a ring terminal and putting it under the screw? Or should I solder it?

Also, my board looks quite different and can't really tell where the neutral and hot goes on the board. Guess I will just put the new wires where the old ones were. Will that be ok? I'd have to screw up this pedal as its the closest tape sounding Analog Delay I've ever played...and I've played a lot.

One more question. Do I need to put on a new rubber gromett where the plug enters the case for safety or should the old one work fine? Any help is highly appreciated. Thanks in advance. I'm gonna try to upload a pic.

thomasdf · Post by **thomasdf** » 03 Apr 2013, 17:41

Has anybody tried to build this beautiful unit from scratch?
I would love to give it a try... I even have a few PSU transformers in my stuff...

MXR - M-118 ( Analog Delay ) [schematic]