Lexicon 224 error code - FIXED -

[V9977]

I'm getting error code E91 on start-up. Otherwise opperation seems
to be OK. Have changed the battery. Anyone know what this could be?
Your help would be much appreciated!

 

[a_)_i]

Hi,

Just happened to see this post when I was posting about my G1176....

I have just got a Lexicon 224 v4.4 and have had a few problems.  I have a copy of the Lexicon 224 user manual but this does not have any details about error codes.  I have had an intermittent E09 error which hasn't happened that much. 

My problem is a H11 error when I run diagnostics.  I believe this is an NVS board error.  I think 'E' errors are ROM based errors.

I suggest that you also email Lexicon professional form their website and see if they send you the service manual.

I'll let you know if I get hold of it.

 

[wtmnmf]

224 Schematics: http://www.twin-x.com/groupdiy/thumbnails.php?album=344

No 224 Service Manual yet. 

For the 224x Service manual go here: http://www.twin-x.com/groupdiy/thumbnails.php?album=358

 

[a_)_i]

224X service manual (they don't have a 224 service manual) section 5.12:

'E91: data memory test........Error message E91 indicates a low-order byte error and E92 indicates a high order byte error.  If both bytes are incorrect, E91 is displayed, which may mean that the entire memory is faulty, or it may mean that the multiplier or T&C module is faulty...'

it goes on to explain how you might rectify the fault by swapping with the lowest order memory chip - you should have a look yourself.

As for my H11 error it would seem I have an NVS RAM problem.  I'll clean all the legs and sockets and see where that gets me.

 

[V9977]

OK thanks for that.
Unfortunately the 224 (not X or XL) uses 2117-4 RAM chips which are
obsolete and I can't seem to find them anywhere. Does someone have
a couple they can provide me with, or know of where to get them?
Any equivalents?

Thankyou!

 

[a_)_i]

Can anyone tell me what IC chips they have on their v4.4 224 NVS board?  The only one I have is in the ROM 1 space the 7 other ROM spaces are unfilled.  The smaller sockets U6 and U13 are also unfilled.  I just want to make sure all of the ICs are there before I start investigating the H11 and H12 errors further.

 

[wtmnmf]

OK thanks for that.
Unfortunately the 224 (not X or XL) uses 2117-4 RAM chips which are
obsolete and I can't seem to find them anywhere. Does someone have
a couple they can provide me with, or know of where to get them?
Any equivalents?

Thankyou!

A 4116 should work.

 

[V9977]

  > A 4116 should work.

Great! Thankyou wtmnmf. Could you point me to the right ICs to replace
with error code E91? From the schematic there seems to be two banks of
8 ICs; U1-U8 and U15-U22.

 

[wtmnmf]

  > A 4116 should work.

Great! Thankyou wtmnmf. Could you point me to the right ICs to replace
with error code E91? From the schematic there seems to be two banks of
8 ICs; U1-U8 and U15-U22.

See here: http://www.groupdiy.com/index.php?topic=34753.msg425883#msg425883

 

[V9977]

Yes I had already seen this post! However that was on a XL model
which is different to the plain 224. I have two sets of 8 ICs, any idea
which is low-order byte and bank 1?  ???

Thankyou!

 

[wtmnmf]

Just do the bank swapping procedure and you will have found the bad chip when the error code changes. It will be one of the two in the swapped pair. Next swap one of those two with it's neighbor in the same bank.  If the error code changes, then it's the one you just moved. If not, then it's the one in the other bank.  You will have learned which bank is which in the process.

Does that help?

 

[wtmnmf]

Also, you can use 4164 instead of a 4116 if you modify it.  I did this in my EMT 250 recently when I couldn't find the right thing in my parts bin.  You clip pin 1, then lift pin 8 and bend it back over the top of the chip and then extend it so you can tack it to pin 9. Pin 9 is the high order bit and will go high in board designed for the 4116 which will make the chip have 7 address lines like the 4116. Pin 8 needs to see +5 on the 4164.

Here is an animation of the hack:

http://www.robotron-2084.co.uk/gifs/4164hack.gif

Oh yeah, there is an advantage in that these use only the 5v supply and make things run cooler

 

[V9977]

OK, I think I have found some 4116 on ebay and will proceed
with replacing and keep you posted. Many thanks for your help!

 

[V9977]

a_(_i : you still around?

I can confirm all other ROMs apart from ROM1 vacant and the two smaller
sockets also vacant. Maybe you have an issue with the actual SRAM chips.
Have you tried removing, lubing the sockets and re-fitting? Also is the backup
battery replaced with a new one?

 

[a_)_i]

I managed to find out that there are 2 x RAM chips missing from the board - I think from slots U6 and U13.  I have some more on the way from the US.  The last thing I expected when I was trying to sort out the problem was missing chips!

 

[V9977]

Are you sure they are actually missing because on my board
the two smaller sockets to the left are also vacant.  ???
I do not have the board in-front of me to confirm U numbers.

 

[a_)_i]

Oh %$&^!

I really had my hopes up about as well!  I won't completely dismiss it until I've tried them but if yours doens't have them then I'm not holding out much hope. 

 

[V9977]

Don't give up just yet...

You might find that replacing the actual SRAM (Static RAM) chips or
the associated gate chips around them, will help with the problem.
I know the SRAM chips are very prone to damage.
I can find out which sockets hold these if you want, but it will take
a few days 'till I get to the boards again.
Is your unit not storing any presets at all? Have you replaced the
backup battery?

 

[V9977]

OK, I've managed to clear the fault by replacing one of the DRAM chips, with 4116.
The error code was E91 and the leds on the function buttons indicated that the bit in error
was the first one (Pgm 1). I replaced U1 which is the low-order byte, lowest significant bit and
all is fine now. Unit powers-up with no error codes!
If a E92 error is shown, the faulty chip is in the high-order byte, and depending on which led is
different, it is U15 - U22; with U15 being the lowest bit (Pgm 1 led) and U22 being the highest
bit (Pgm 8 led). This applies to the plain 224 (not X, XL).
A big thank you to wtmnmf for all the help! 

PS: a_)_i , have you had any luck with yours yet?

 

[wtmnmf]

Glad to help.  Enjoy  ;D