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ADA Preamps => Original MP-1 => Topic started by: brianiac5150 on June 07, 2015, 08:19:00 AM

Title: Flashing Display & Buttons : Malfunctioning
Post by: brianiac5150 on June 07, 2015, 08:19:00 AM
Anyone have any experience with the display flashing, then half of the green lights flashing, the other half flashing, repeats several times until only the first half of the green lights flash repeatedly?

No sounds, no buttons work, nothing...

I did a quick search here of my symptoms, however, didn't find anything.  If this has been discussed elsewhere within and someone would redirect, I'd appreciate it.

Big bummer my MP-1 is malfunctioning.

Any assistance will be greatly appreciated.

EDIT - After having it off for a few minutes, I checked the fuse and it's good, placed it back in, powered up, recall factory presets and now it displays version on power-up (v2.01) and promptly shuts off.  Hmmm...
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: rnolan on June 07, 2015, 09:06:45 AM
Hey brianiac5150, this is a new one to me, hopefully others have some ideas at least to help diagnose the problem (I'm sure there are some here who can help). You can try the usual suspects, make sure everything is mounted securely (IC/tube sockets etc) anything the may rattle loose.

@MJMP, seems like a new one ? any ideas ?
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: MarshallJMP on June 07, 2015, 03:29:19 PM
I know what this is,this is a sort of brown out,usually due to the wall voltage being to low.A failed reset circuit.Could also be the filaments of one or both tubes taking to much current at startup.A bad diode or a failing cap in the PSU and last a failing transformer (altough rare but i've had it once)But in 90% of the cases the wall voltage.Maybe in your case a bit of corrosion around the fuse altough i doubt it.Was it powered off for a long time?

What actually happends is that the MP-1 starts up and if the current is too high or the voltage too low the CPU resets and starts back up,resets starts back up ect... and that is what you see.Problem with the MP-1's is that the input voltage for the 5V regulator has to be at least 8Vdc and the MP-1 usually has between 8.5 and 9.5Vdc so it's tight sometimes.

Let us know how it goes,if you get in trouble again try to measure the wall voltage and get back to me.
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: rnolan on June 08, 2015, 03:41:31 AM
Hey MJMP, unless you've been chatting with him behind the scenes already to fix, he is in trouble. From post, currently his MP1 doesn't function.

So brianiac5150, check your wall voltage (MP1 and MP2 don't like weird power fluctuations). I use a 1 kVA (computer) UPS when I use MP2 with a generator otherwise it goes ape shit in the middle of a solos etc and I have to reboot/start it to fix. And lots here use power conditioners, UPS is the cheaper option but the UPS batteries will die eventually.
UPS = Uninterruptible Power Supply BTW, they are quite common these days for home/small business etc and not too expensive. I paid $160 AUD for mine and it's been good for a couple of years now.
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: MarshallJMP on June 08, 2015, 10:44:38 AM
Sorry read it last night,was half a sleep i guess.

Well like i said measure the wall voltage,also take the 2 tubes out and see if it will start.
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: brianiac5150 on June 08, 2015, 02:45:14 PM
Thanks for the replies, gentlemen.

I bought this unit from another person, whom I'm certain he bought used, as well.  (I - stupidly - sold mine several years ago).  Ever since I've had it, it's always been connected to a Furman power supply of one version or another, however, I'd venture to bet it'd sat for long periods of time without being powered on.  In the rack I keep it in, it comes on with several other pieces, every time I power the rack on.  It's my main DAW rack, therefore, it is cycled quite often.  The unit had been working quite well for around a year, since I purchased it.

I currently have it sitting on the floor, top off, nothing connected, both tubes out and it's displaying as it should.

Simply a tube problem???
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: rnolan on June 09, 2015, 05:21:32 AM
Hope it's just tubes, changing them wouldn't hurt anyway (not sure where MJMP was going with that thought though, it may be it indicates something else ??). While constant cycle of unit does increase wear on tubes to some extent, I cycled my old MP1 a gazillion times over the years and it's still cooking (albeit some other bits have worn out, see MikeBs post). But tubes is an easy fix (hard part is picking the ones you like LoL).
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: brianiac5150 on June 09, 2015, 05:25:55 AM
Definitely hope it's just the tubes.  Ordered a set yesterday - http://www.amazon.com/gp/product/B0002M72JS?psc=1&redirect=true&ref_=od_aui_detailpages00 - which I have zero experience with.  We'll see if it resolves the issue (fingers crossed) and hope they sound excellent, as well.  I'll post results.

MJMP's post does have me a bit skittish, though.  Hope my MP-1 isn't cashing out.   :(
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: rnolan on June 09, 2015, 06:12:38 AM
As I said I'm not quite sure where he was going with that (he will have a good reason) but it certainly indicated the unit is fine without the tubes in so it rules out a bunch of possibilities, though tubes can fail, they tend to just get mushy over time.. Fingers crossed it's just tubes though. Tube selection is a big topic here, focused though on ADA preamps MP1/2 MB1.

Have a read of the tube topics (http://adadepot.com/index.php?board=38.0) and lots of other posts here to get some ideas for tubes, the EHs would be later on my list, not that they are crap and will work fine, just IMO there are better choices for MP1/2 etc, but it's very (very, very) subjective, personally, I would have gone for the Mullards (long or short plate), MJMP probably the JJs, and boogie STRs (typically re-badged JJs) work very well in MP1 (in my personal experience). And if you want it to sound MP1 stock, the closest to the original Chinese tubes are probably the TADs (from SCs experiences and posts).

While all 12AX7 tubes are to some extent electrically equivalent (the pins you plug them into and the circuit doesn't mind so they work fine), they all sound different. You've gone with the EHs, they will be fine (hope it gets it working i.e. is just tubes..) and hey you may prefer them, some do.
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: brianiac5150 on June 09, 2015, 08:02:56 AM
Situation considered and having some gift card credit on Amazon, I simply went with a cheap set to see if it gets up and running.  I do appreciate the redirect for more tube info and will consider those once I confirm the unit works.

Back in my serious live performance days I ran an MP-1 into a Carvin X100B (which was always a head turner) and I'll never forget getting a set of Sylvania Mil-spec tubes from Abell Audio into that thing.  WOW!!!  It became a demonic beast of clean gain bliss.  Serious difference from what were in there.

Anyway...we'll see what happens...
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: MarshallJMP on June 09, 2015, 01:14:56 PM
Well the filament and the 5V (including the display) share the same power supply,so sometimes the tubes draw too much current and this browns out the cpu.This can also can caused by other components like D38 and D39 or C131.
So try new tubes first and if that doesn't help change C131 and D38,D39.
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: brianiac5150 on June 11, 2015, 01:29:57 PM
Well...tubes are not the solution.  Remains the same with the new tubes.  Still can power on without tubes and it powers right up, staying that way. 

 :dunno:

I'm no electronics guys, therefore, I'm not sure how I'll move forward with this...  hmmph
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: MarshallJMP on June 12, 2015, 10:12:17 AM
Can you measure the wall voltage?
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: brianiac5150 on March 15, 2016, 08:59:44 AM
Well...after shelving this unit for quite some time, a recent acquaintance working for an area electronics guy offered to take a stab at it to (after quite some time of having it) no avail.
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: MarshallJMP on March 15, 2016, 11:43:26 AM
Hey if you like ,maybe i could help your friend (with some tech support) to get it fixed anyway?He can always email me if he wants.It's up to you.
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: brianiac5150 on October 23, 2017, 06:11:05 PM
Man...it's been ages since I've been here.

I put this issue off for quite some time, however, took it to a tech recently and had it repaired.  Thought I'd post the fix:  "an open diode in the 8VDC supply causing the voltage to sag severely under load of the tube filaments."

Got it back, was crankin' it like the glory days ('cept current days: into my interface and Two Notes WoS III) and a tube blew.  Ugh.  Replaced that and all has been well since.  Sounds fantastic and makes me smile every chance I plug into it.

Anywho...FYI.   :whoohoo!:
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: rnolan on October 24, 2017, 05:29:06 AM
Great news  :thumb-up: :whoohoo!: and thanks for posting it  :wave:
Title: Re: Flashing Display & Buttons : Malfunctioning
Post by: MarshallJMP on October 24, 2017, 07:50:33 AM
So it was either D38 or D39.