Lexicon 200 reverb schematic?

Anyone have a Lexicon 200 schematic laying around that they could share? My box is acting up but it's impossible to navigate this unit without a road map.
thanks

Never seen one. -A schematic that is.

Fixed a few though...

First, look around the backup battery. Check for corrosion.

Is it not booting/misbehaving on startup by some chance?

Keith

As of right now it's not booting up. A couple of the led's light up and the display shows a couple of lines. Hitting the reset button will make the lights go off.... but nothing more.
thanks for the quick reply

Dumb question.

Exactly where is the battery located?
Had a quick look on mine a couple of weeks ago but couldn´t see it on the mainboard,is it behind the frontpanel?

I contacted Lexicon for some Alex circuits some weeks ago and was suprised to be given an ftp address and password to download the full set !
I think that now they are considered legacy items, they just give the information out.
Go to the Lexiconpro website, or email:
[email protected]

Martyn

open it up. (this is all from VERY dusty memory)

I think there's an upper board which you have to lift out of the way. It may hinge or something, have a look. The first time that I went in, I didn't have a map and I found the problem just my looking. The battery may be down on the bottom board, towards the rear.

IIRC, there's some CMOS nearby and the PCB may not be coated or laquered. The traces corrode...

Keith

Yes, the battery is located on the lower board near the middle of the board. Big black rectangle that I had to look at about 30 times before I realized it was a battery.
The traces to my battery look good. It's supposed to measure 3.6V but I'm only getting 1.7V out of it. Not a supprise for such an old unit.
I thought it was interesting that my display goes blank when I hit the rest button, so I decided to check some voltages in the display section. Some of the chips that drive the LEDs read at 1.5 volts when I power it on, and then jump up to 6V (and stay at 6V) when I hit the reset switch. All other voltages on the rest of the board stay the same when I reset. Does that trigger any thoughts?

I'd remove the battery if i'ts low. It can conceivably hang the boot, and it can -and will- corrode the PCB. Since it's under voltage, it can't be doing you any good, and it can be doing harm.

Other than that, I remember there being some CMOS associated with the bootup, but more than that is too much for me to remember.

Jim Fabiano might be able to fix it, but he most likely doesn't do remote hand-holding, since he makes his living by repairing the stuff himself...

Keith

Yes, Jim Fabiano fixed my Lex 200 several years ago and it was great. I've been trying to remember his name....

Wait... i think I know someone with the 200 service manual... I'll check on the way home.

Oh, I do remember that the battery is a series chain of 3x NiCad AA batteries... you could make your own replacement if you want...

Keith

[quote author="SSLtech"]
Oh, I do remember that the battery is a series chain of 3x NiCad AA batteries... you could make your own replacement if you want...
[/quote]
Thanks for the replies. I'll try that out.

Ever have any luck repairing this? I've got a balky 200 that I'm having trouble with on startup too. Sometimes it's just blank (guess battery here) when it starts up, I hit reset and it works properly. Sometimes (seems usually when it's been off for a while) I start up and the front panel flashes on and off like crazy. Seems like after I leave it on for a little while I can turn it off, turn it right back on and hit reset and it works properly.

There's a CMOS (4093??????) circuit that is RIGHT BY THE BATTERY inside. If the battery leaks or out-gasses and corrodes the traces, this is the first symptom: having to hit reset for a reliable boot...

I've said it plenty of times before but it's worth repeating: open it up and remove any dead batteries... -you CAN'T afford the corrosion..next step with further corrosion is that it won't work at all!

Do it.

NOW!.

Keith

:grin: Thanks Keith! The guy I bought this from has another, so I'm just going to send this thing back. Who knows what damage has already been done.

is there any help for a lexicon 20/200AD?
it powers up for a second, then it goes to sleep...

Never fixed mine... gonna have to someone who actually knows what's going in inside this thing.