ADA Depot - A Forum To Support Users of ADA Amplification Gear

ADA Preamps => Original MP-1 => Topic started by: Hamer95USA on February 08, 2016, 07:51:27 PM

Title: 3TM mod MP-1 preamp turns off by itself
Post by: Hamer95USA on February 08, 2016, 07:51:27 PM
  Hey guys,

I had to use my ADA Depot 3TM mod MP-1 preamp as a backup rig for my Marshall 6101 combo amp since I didn't properly repair the speaker cable.  :(  I turned on the preamp and while I played it onstage, it turned off and then turned itself back on again while playing onstage. Very embarassing to say the least. I was like "WTF?!!"  How would l fix this problem? Any information or suggestions would be greatly appreciated.

Guitar George
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: rnolan on February 08, 2016, 07:56:02 PM
Hey George, well that sucks  :facepalm: Does it have the MDRT, I assume that's part of the 3TM mod ?
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: MarshallJMP on February 09, 2016, 02:07:51 PM
If it has the original tranny this can happen if you get a voltage drop on the power line.
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: Hamer95USA on February 09, 2016, 02:30:36 PM
  Hey rnolan,

No, it doesn't have the MDRT transformer.

Hey MarshallJMP,

It does have the original transformer. Is there anything that I can try to do that will fix the issue? Replace the transformer? Contact ADA? They're back in business and will do repairs for their gear.

Guitar George
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: MarshallJMP on February 10, 2016, 12:51:14 AM
Can you take a pic of the inside near the transformer?
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: rnolan on February 10, 2016, 02:02:54 AM
Hey George, the MDRT is a very good idea as it's a much better transformer, and even more so as the 3TM has an additional tube so will draw more power (a feature of the MDRT is more and better power available (http://www.marshalljmpmodshop.net/miscellaneous_parts_and_replacement_tubes.htm)).
For power surges (which it's sounding like ?), you can use a power conditioner (Furman seems to get the nod around here) or use a computer uninterruptible power supply (UPS). I use a 1kva UPS with my MP2 rig as we typically run off a generator and the MP2 shits itself when the voltage drops, display goes hieroglyphics and I have to power cycle it to get going again (really great in the middle of a solo NOT  :facepalm: ). The Furmans are quite expensive here in Oz >$500 AUD, The UPS cost me $160 but down side is the battery in the UPS will go eventually.

Cheers R
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: Hamer95USA on February 10, 2016, 05:44:50 AM
  Hey rnolan,

I had the 3TM mod MP-1 preamp mounted in a rack and connected to a Furman PL-Plus power conditioner when the preamp decided to power off/power on by itself.

Hey MarshallJMP,

I'll post a few pictures later on. I remember buying this preamp off of kurtstuff about 10 years ago. Do you think that I would need to replace the lithium battery?

Guitar George
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: rnolan on February 10, 2016, 07:07:40 AM
Hey George, mm sounds like the MDRT may be the fix you need, lets see what MJMP comes back with after you get some pics.

The batteries are very old now (if it's original battery) and are definitely due for a change (CR2032) but I don't know/think it would cause a power cycle ? My understanding is they still work with dead battery but wont hold presets when turned off as the battery powers the ram when turned off. We were posting about this a while ago and quite a few MP1 members were needing to replace batteries. However, it would be good if it's that simple as that's a cheap and cheerful change but does require solder  :thumb-up:
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: MarshallJMP on February 10, 2016, 03:40:19 PM
Ok post them here or email them (or both) so i can have a look.

Battery has got nothing to do with it,if there's something wrong there you will loose your presets but it won't give a brown out.
A safe voltage is 2.7V or above.(a new one is 3.3V)

Did you got anymore troubles with it,or did it happen just one?
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: Hamer95USA on September 26, 2017, 12:54:57 PM
Hey guys,

I brought my 3TM mod MP-1 preamp to my amp tech. He told me tested it and there's an issue with the MIDI board which makes it shut off after being turned on for a period of time. Any recommendation on where to find a MIDI board?

                                                                                                                                            Guitar George
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: MarshallJMP on September 26, 2017, 02:00:39 PM
If your tech knows what the problem is why doesn't he fix it? Don't see the need to find a another midi board?
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: Hamer95USA on October 04, 2017, 04:18:29 PM
  Is there anyone in the northern California area that can fix the problem with my 3TM mod MP-1 preamp or do I need to send it to someone here who can fix it?

                                                                                                                                        Guitar George
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: Hamer95USA on October 12, 2017, 06:03:19 PM
  Hey MarshallJMP,

If I send it out to you in Belgium, can you fix the issue? I can't find a tech here in California that would know how to fix it and Todd Langner passed away a few years ago.

                                                                                                                                            Guitar George
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: MarshallJMP on October 14, 2017, 08:26:57 AM
Yes you can but maybe we should some other things first? Besides the 3TM is anything else been done to it?
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: Hamer95USA on November 01, 2017, 09:16:45 PM
Nothing else has been done to it.

                                                                                                                                                 Guitar George
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: MarshallJMP on November 02, 2017, 09:51:32 AM
Do you have some soldering experience?
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: Hamer95USA on November 02, 2017, 09:09:38 PM
Yes. What do you have in mind? Do you know what's wrong with my 3TM mod MP-1 preamp? Do you have a diagram for me?

                                                                                                                                                 Guitar George
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: MarshallJMP on November 03, 2017, 12:24:08 PM
Well I would start with changing the 3300uF/16V cap (big cap) near the transformer and the 2 diodes (1N4007) next to the 6 pin red connector.

Also check the 78ML05 for cracked solder joints (top and bottom side). Reflow if possible.
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: Hamer95USA on January 30, 2021, 10:05:23 PM


Hey guys,

I've been away from here for awhile dealing with life's issues. I brought my original 3TM Ultra mod MP-1 preamp with issues to the local amp tech 3 months ago and was notified that the motherboard wasn't working properly.
I ended up buying a stock MP-1 preamp from my friend, having my local amp tech swap out the 3TM mod tube circuit board/nose mod/battery holder & battery, v2.01 EEPROM chip, and rear input jack mod to the new stock MP-1 preamp. It now has the 3TM Ultra mods installed! :headbanger:
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: Hamer95USA on July 01, 2021, 10:57:07 PM
https://photos.app.goo.gl/4RgsCxs7zztBaJfP6 (https://photos.app.goo.gl/4RgsCxs7zztBaJfP6)

  The updated new ADA Depot 3TM "Ultra mod" MP-1 preamp installed into the revamped monster wet/dry/wet guitar rack rig! It is alive!

                                                                                                                   Guitar George
Title: Re: 3TM mod MP-1 preamp turns off by itself
Post by: MarshallJMP on July 02, 2021, 01:04:10 PM
Ok nice, too bad the other mp-1 wasen't fixed. I'm sure it wasn't a big deal to get it fixed.