Repairing a Lexicon LXP-15 effects processor. Common fault on this unit. I went through the design and provided an overview of it's internals while it was open. Classic 90's design.
Amazing. I have three of these and today I switched on the MKII and there it was, the scratchy pots. Hopefully I can get away with cleaning them/ Also I can now convert the MK1 from the US voltage to 240v. I have a service manual so should be able to figure it out. Thank you very much for taking the time to make this video!
LOVE your videos ... I would do the same (open and study) if I would have access to the schematics ... I often wonder about the choice of components, etc. ... it is nice to see the evolution of their architectures for synth and effects units.
the schematics are out there free for you and anyone. No point in choice of components, this is old technology and being digital there were not many choices, just make it work the way most all digital stuff is made, it's not like analog where component choice matters more for sound. For digital it's basically it works or not. 0's and 1's
Thanks for your direct and well explained process of repairs. I have a problem that my limited electronic knowledge has me stumped. I'm working on a lxp15 now , had bad power caps and some damaged traces. I replaced the caps and fixed the traces .It now powers up but the lcd is just a blank screen. I measured the voltage on the +5 and its only 3.4 . I replaced the bridge rectifier , and the 7805 p still no luck. any suggestions would be appreciated .
Hi Brad great video I learned a lot ! Do you do repairs on vintage gear? Old lexicon pcm 41 in particular. Again great video very informative and excellent teaching device Rob
My LXP-15 shows a blank screen with a bar of little squares running across the top. I cannot get a signal in and none comes out. It's a quiet unit (no humming or buzzing ) and does not get very hot. Is this a software issue, age or something else ?
Hello how are you? I need your help: I have a Lexicon like that (LXP 15 version 2) and it has a hum on the output. What could be the problem? It can be fixed? I am from Argentina. Thank you
I recentmy picked one of these up, with the same issue on the Pots. It also has a hum from the transformer. Is there anything that can be done to improve/fix this, as its a great sounding unit.
What revision of mainboard? (type between MIDI outputs and Pedal Input on mainboard) - REV 1? REV 2? REV 3?... I Have mainboard REV2 (1990) with OS v2 (1994) - 120V ... and I need make for 220V ... In Your version located Diode Bridge ... In my version - no! I read In manual about RETRO FIT. Why do I need this RETRO FIT? If I want make for 220V, then I absolutely have to solder the Diode Bridge, as specified in section RETRO FIT Notes? Or I can do without the diode bridge as in the diagram on the page before?
great video. just wanted to get some thoughts. Mine powers on "normal" occasionally (shows OS version etc). but most of the time the LCD is just a top row of bars. Anyone have any good pointers where to look? Battery is good. voltages are good.
Hi Brad. Thank You! I have the same exact problem with my LXP15. It was smelling like burnt dead fish. I just opened it up and found the same leaking caps. Also leaking are the little black components next to those caps, are they diodes or resistors... labeled CR#? I have to order parts but I can't read the info on the little black parts : CR38, CR39, CR40, CR41 on the board. Thank You
Thanks for posting this. I was given a broken unit to try and fix. Can you share the schematic? The heart of the problem seems to be the transformer (buzz and some crackling/burning after a short bit). Replacing it may be out of the question but I could build an external supply of I knew the power rails and connections expected. Fun project and great video resource!
Hello! This is what I measured on my LXP 15-2 - DGND +5V = 4.98V, DGND +15V - 14.96, AGND - 15V - 15.20V. The transformer hums. After tightening the four screws the hum didn't go away, but after loosening it decreased...If I put rubber pads, transformer bushings, will this hum go away? Thank you for the video! Greetings!
@bradthx : Great video! I was wondering what component and source you would recommend for the bridge rectifier CR44, a 1N5404 which apparently is a 3A 400V diode. I am not getting 5v supply .... Thanks*
Nice video Brad! I have an LXP15 that is destroyed beyond repair but (hopefully) still has all of my years worth of custom presets. Did you ever find out which chip (powered by the battery) was reserved for the custom saved presets? I thought I might replace the chip in a newer working unit with the custom presets chip.in the destroyed unit.
@@RocknJazzer ah.. that’s amazing news! So not the VLSI? I need to take a look at the board again. Thanks!!! I bought a new one and was hoping I could swap the chip over in order to keep 10 years worth of amazing painstaking presets.
@@scottwhittier5861 I should have called it by it;s proper name...Eprom as you can write to it, I would think that would be where the user presets are also stored, besides the factory presets and operating system which I do know is on them, and available loaded w latest OS and factory presets. Hope your unit was not zapped so bad to wipe your presets. VLSI I think in this is just the processing not the memory, You need both ie data in rom or eprom to run and save to, and vlsi that actually does the real time work on the data to create the effect
@@scottwhittier5861 Yeah let me know. My 2 units are the older all black USA ones with different board than this newer grey blue version, and I am planning on updating to the vers 2.0 chip soon as it gives not only faster operating but configs for thicker more complex reverbs and all new presets loaded on the new 2.0 eprom, so perhaps it also holds the user ones, but I just went thru the whole service manual and there are many RAM chips in it doing different things and they are not clear about which are for the user presets. Also if your old units memory battery died or got too low that may have wiped your user mem too, again depending on type of RAM and what RAM and if it's also on the Eprom or other ram chips.
Not a real "teardown" or "repair", you just popped the top and sprayed cleaner, lol. Hope you also changed the memory batt too when you later did the caps
Hi, thank you for this video! I'm also trying to repair one that had some problems to the power section, but I managed to solve them. The issue now is that when I power it up it gets stuck on the startup screen (Lexicon LXP-15 version 1.31 bla bla bla). Do you know what the problem could be?
its just a basic ac cord, what do you mean power supply. The power supply is inside on the board, not separate replacement, you would have to have it repaired not replaced.
Hahah YES I have one of these and when I brought it although it worked fine but when I opened it up wow those PSU caps popped all their juice and really badly corded the board, was a total bitch to fix. The original Mk1 looked very different and has slightly different hardware, this was later changed to the unit you have, when they later upgraded to what they called the mk2 the only difference was the firmware. I am running the mk2 V2.0 FW on mine , to be fair other than quicker operation of the unit I couldn't really tell much difference between the quality of the reverbs between the two versions.
I have both version now too, am planning on doing a comparison teardown between the two at some point. The capacitors they used were absolute rubbish, and the potentiometers they used were also rubbish. After another year, they were back to being noisy so I just ended up replacing them. Thanks for watching!
@@bradthx Yea totally, my friends LXP-1 had the same issue with that noise of death caused by the crappy pots. Strangely mine is ok in that regard but the data pot is absolutely knackered. Do you know of a suitable replacement? Also great videos!
![ทางเดินชีวิต - ธีเดช ทองอภิชาติ x อ.ไข่ มาลีฮวนน่า [Official MV]](http://i.ytimg.com/vi/1f3wcG16dd4/mqdefault.jpg)
Amazing. I have three of these and today I switched on the MKII and there it was, the scratchy pots. Hopefully I can get away with cleaning them/ Also I can now convert the MK1 from the US voltage to 240v. I have a service manual so should be able to figure it out. Thank you very much for taking the time to make this video!
LOVE your videos ... I would do the same (open and study) if I would have access to the schematics ... I often wonder about the choice of components, etc. ... it is nice to see the evolution of their architectures for synth and effects units.
the schematics are out there free for you and anyone. No point in choice of components, this is old technology and being digital there were not many choices, just make it work the way most all digital stuff is made, it's not like analog where component choice matters more for sound. For digital it's basically it works or not. 0's and 1's
Nice video. Thanks for that. I have the same noise going on with my LXP 15 and was searching for a video to fix this issue. Glad that I found yours.
Thorough video,! Thank you man.
Thanks for your direct and well explained process of repairs.
I have a problem that my limited electronic knowledge has me stumped.
I'm working on a lxp15 now , had bad power caps and some damaged traces. I replaced the caps and fixed the traces .It now powers up but the lcd is just a blank screen.
I measured the voltage on the +5 and its only 3.4 . I replaced the bridge rectifier , and the 7805 p still no luck.
any suggestions would be appreciated .
Hey I've got an LXP-15II and an eeprom reader/burner. I'd be happy to send you the data if you are still looking for it.
Very helpful, got the same problem with the Input+output controal, wish I could find replacements.
you can you just have to look
Hi Brad great video I learned a lot ! Do you do repairs on vintage gear? Old lexicon pcm 41 in particular. Again great video very informative and excellent teaching device Rob
My LXP-15 shows a blank screen with a bar of little squares running across the top. I cannot get a signal in and none comes out. It's a quiet unit (no humming or buzzing ) and does not get very hot. Is this a software issue, age or something else ?
Hello how are you? I need your help:
I have a Lexicon like that (LXP 15 version 2) and it has a hum on the output. What could be the problem? It can be fixed? I am from Argentina. Thank you
I recentmy picked one of these up, with the same issue on the Pots. It also has a hum from the transformer. Is there anything that can be done to improve/fix this, as its a great sounding unit.
What revision of mainboard? (type between MIDI outputs and Pedal Input on mainboard) - REV 1? REV 2? REV 3?... I Have mainboard REV2 (1990) with OS v2 (1994) - 120V ... and I need make for 220V ... In Your version located Diode Bridge ... In my version - no! I read In manual about RETRO FIT. Why do I need this RETRO FIT? If I want make for 220V, then I absolutely have to solder the Diode Bridge, as specified in section RETRO FIT Notes? Or I can do without the diode bridge as in the diagram on the page before?
great video. just wanted to get some thoughts. Mine powers on "normal" occasionally (shows OS version etc). but most of the time the LCD is just a top row of bars. Anyone have any good pointers where to look? Battery is good. voltages are good.
It was U43 and U44 (RAM) I replaced them and it works great. same scratchy pots though. gonna clean them
Hi, anyone here has ever tried to replace the lcd display ?? Could anyone provide me a good reference for replacement ? Peace
Hey brad. I was gifted an LXP-15 about a year ago, and I haven’t been able to get the setup page to show to load presets. Any idea how to fix this?
Is it stuck on initializing? I have the same issue.
Hi Brad. Thank You! I have the same exact problem with my LXP15. It was smelling like burnt dead fish. I just opened it up and found the same leaking caps. Also leaking are the little black components next to those caps, are they diodes or resistors... labeled CR#? I have to order parts but I can't read the info on the little black parts : CR38, CR39, CR40, CR41 on the board. Thank You
Thanks for posting this. I was given a broken unit to try and fix. Can you share the schematic? The heart of the problem seems to be the transformer (buzz and some crackling/burning after a short bit). Replacing it may be out of the question but I could build an external supply of I knew the power rails and connections expected. Fun project and great video resource!
the schematics are out there free for anyone, you dont know how to google?
Hello!
This is what I measured on my LXP 15-2 - DGND +5V = 4.98V, DGND +15V - 14.96, AGND - 15V - 15.20V.
The transformer hums. After tightening the four screws the hum didn't go away, but after loosening it decreased...If I put rubber pads, transformer bushings, will this hum go away? Thank you for the video! Greetings!
those voltages are perfect range. the trans hum has nothing to do with that, but sometimes pads work if just right
Thank you a lot for that comment, loosening the screws did the trick surprisingly. KUDOS! Many many Kudos! Pints of beer for you... THANKS
I have version 1.2 really informative video.
Those 9 filter pots have you messed with those?
@bradthx
: Great video! I was wondering what component and source you would recommend for the bridge rectifier CR44, a 1N5404 which apparently is a 3A 400V diode. I am not getting 5v supply .... Thanks*
why would you not replace it with the same exact thing? makes no sense why you ask. easy to find anywhere. That is probably not your problem tho
Nice video Brad! I have an LXP15 that is destroyed beyond repair but (hopefully) still has all of my years worth of custom presets. Did you ever find out which chip (powered by the battery) was reserved for the custom saved presets? I thought I might replace the chip in a newer working unit with the custom presets chip.in the destroyed unit.
the Rom with the big white sticker on it, you can get new ones
@@RocknJazzer ah.. that’s amazing news! So not the VLSI? I need to take a look at the board again. Thanks!!! I bought a new one and was hoping I could swap the chip over in order to keep 10 years worth of amazing painstaking presets.
@@scottwhittier5861 I should have called it by it;s proper name...Eprom as you can write to it, I would think that would be where the user presets are also stored, besides the factory presets and operating system which I do know is on them, and available loaded w latest OS and factory presets. Hope your unit was not zapped so bad to wipe your presets. VLSI I think in this is just the processing not the memory, You need both ie data in rom or eprom to run and save to, and vlsi that actually does the real time work on the data to create the effect
@@RocknJazzer That’s great news! I’m going to swap out the EPROM tomorrow and I’ll let you know back. Thanks for the helpful info!
@@scottwhittier5861 Yeah let me know. My 2 units are the older all black USA ones with different board than this newer grey blue version, and I am planning on updating to the vers 2.0 chip soon as it gives not only faster operating but configs for thicker more complex reverbs and all new presets loaded on the new 2.0 eprom, so perhaps it also holds the user ones, but I just went thru the whole service manual and there are many RAM chips in it doing different things and they are not clear about which are for the user presets. Also if your old units memory battery died or got too low that may have wiped your user mem too, again depending on type of RAM and what RAM and if it's also on the Eprom or other ram chips.
Not a real "teardown" or "repair", you just popped the top and sprayed cleaner, lol.
Hope you also changed the memory batt too when you later did the caps
Just subscribed to your great channel !
my adjust knobs skips sometimes.... should a contact cleaner do the job?
I have the same issue, Adjust pots skips really badly. If anyone know of aftermarket replacements please let me know. Sounds great though.
@@Jim_KYB This is a really common issue with these units. One of mine has it too.
Hi, thank you for this video! I'm also trying to repair one that had some problems to the power section, but I managed to solve them. The issue now is that when I power it up it gets stuck on the startup screen (Lexicon LXP-15 version 1.31 bla bla bla). Do you know what the problem could be?
I have the same issue. Did you manage to solve it?
@@slacknote unfortunately not, but I've also paused the project since then...
are you in southern mich by chance??
Hi, in my LXP-15II doesn't work the light of the display, what can I do? thanks
Same. did you find a way to fix the light?
not yet...
@@a.stockton4817
Someone can tell me where can I find a power supply for this lexicon lxp- 15?
its just a basic ac cord, what do you mean power supply. The power supply is inside on the board, not separate replacement, you would have to have it repaired not replaced.
the transformer hums on my unit, otherwise a beautiful unit
Hahah YES I have one of these and when I brought it although it worked fine but when I opened it up wow those PSU caps popped all their juice and really badly corded the board, was a total bitch to fix.
The original Mk1 looked very different and has slightly different hardware, this was later changed to the unit you have, when they later upgraded to what they called the mk2 the only difference was the firmware. I am running the mk2 V2.0 FW on mine , to be fair other than quicker operation of the unit I couldn't really tell much difference between the quality of the reverbs between the two versions.
I have both version now too, am planning on doing a comparison teardown between the two at some point. The capacitors they used were absolute rubbish, and the potentiometers they used were also rubbish. After another year, they were back to being noisy so I just ended up replacing them. Thanks for watching!
@@bradthx Yea totally, my friends LXP-1 had the same issue with that noise of death caused by the crappy pots. Strangely mine is ok in that regard but the data pot is absolutely knackered. Do you know of a suitable replacement? Also great videos!
Could have been a good fuzz ;)
16:47 noooooooooOOOOOOO!