EII noisy, upper third of keyboard

[sys700]

Just installed a Lotharek floppy emulator in my EII today. After getting it all back together, I notice the upper third of the keyboard sounds noisy, like glitchy almost, for every sample I load. Any suggestions? Reseat the memory chips and cables?

Thanks!

[sys700]

Couple more things to narrow it down:

1) I removed all the memory chips and reseated them.
2) I have another memory expansion board. I swapped that board.
3) I pulled all the SSM chips and other chips under the power supply and reseated them.

After all these things, the issue still remains, but I've been able to narrow it down a bit further.

For each soundbank I load, the 2nd voice assigned to the keyboard has this issue. It basically plays the sample fine until it gets to a certain point, then there is static. The static appears to be in the sample itself, in that it occurs at the very same spot within the sample, and slows down as you play down the keyboard. The 1st voice is fine, no issues, and plays the sample completely through to the end without the nasty static noise.

Any idea what this could be? The SSM VCF chips are assigned to the various keypresses, correct? So it can't be those since Voice 1 gets assigned properly to all 8 notes played.

The issue occurs with about 40 different soundbanks that I've loaded in via 5-1/2 floppy, the same issue every time. The only other thing I can figure is when I load the sounds in via floppy, the sounds are getting corrupted. When I copy them to the HXC, the issue occurs if I load them from HXC. I have a spare 5-1/2 floppy I could swap out to try it.

I have not yet tried sampling to see if the issue is with the files only. That's my next plan of attack.

[sys700]

Having a conversation with myself here, but maybe someone in the future will find this useful.

I loaded the memory test disk in HXC and apparently I have some memory chip issues. Does anyone have a guide on how to read the results? It appears to lock the screen at the first error it encounters.

I deleted the 2nd voice of one of the patches, and moved the 1st voice to the top of the keyboard. No issues. I tried loading the 3rd, 4th, voices, they sound glitchy. I tried deleting the 1st voice, and just keeping the 2nd voice, still glitchy.

At this point I'm thinking it's likely a memory chip issue. The patches are loading in, and when they get loaded into that one chip beginning with the 2nd voice allocation it starts glitching.

Anyone have a source for spare memory chips, or at the very least instructions on how to read the test disk results?

[sys700]

Quick update. I ran the memory test disk (virtual, from Lotharek EII files page) and was getting error messages. Found the EII service manual but nothing in there that said anything about how to understand the test results. Went to the Yahoo forum and they have a file in there that helps you interpret the test results. I was able to find the first faulty chip, still getting errors, but working sequentially through them. The test stops when it finds a faulty chip. It's pretty easy to determine the row the faulty chip is on:

If the error message starts with a 0, it's the bottom board, first row of chips closest to keyboard. Next row up from that is error 1, 2, 3. Piggyback board (like I have) is 4 (closest to keyboard), 5, 6. 7. A typical error message would look something like this: 50140. That means the issue is on the piggyback board, 2nd row up from keyboard.

I also found one of the chips on my board had a folded over pin. I was able to remove that chip, straighten the pin, and reseat it. The guy who sold me this several years ago was probably swapping chips and wasn't paying close attention.

By the way, it's very painful to go through this memory test procedure. Each time takes 5 minutes or longer, depending on if the issue is in a later chip. I'm sure I could just buy all new chips and swap them out...but that would be expensive.

[sys700]

Discovered 7 bad memory chips as I systematically went through the memory test procedure. I'm thankful for the Lotharek virtual floppy drive as without it I probably wouldn't have been able to source the memory test disk.

But just loaded a sample in and it's still having the distortion issue. Going to try loading in fresh from floppy and see if it's still an issue.

[sys700]

Apparently when I initially loaded all my samples in from floppy disk to save to the Lotharek HD card, it brought the samples into the memory (which was corrupted due to faulty chips). Then I saved the corrupted sample to the Lotharek HD card. Just loaded in the sample from floppy and the sound is perfect, no issues. Just have to load them all in now from floppy again and save back to the HD card. But my issues are now resolved.

[sys700]

A couple days after I got everything working, I started having issues with random notes dropping out. I tried reseating the chips on the output board, this made it worse, now two voices not working. Then after leaving the EII on for a length of time, some garbled characters appear on the screen. They don't affect operation, and go away after awhile, but still annoying.

I traced down the voice issues to the S3528 Programmable Low Pass Filter chips on the output board. When I swapped them around, different voices would cut out. Swapping the SSM chips around had no affect. So I ordered 9 S3528 chips on eBay a couple weeks ago. http://www.ebay.com/itm/221327504397

The chips arrived yesterday and I installed them. All voices are working now, but after a few hours I still have garbled characters on the display. Anyone else ever experience this? Might be a chip that needs reseating?

[Stephencl]

I wish I had answers for you, but I don't.  I did however want to complement you on an excellent thread where you diagnosed an issue, the systematically went about the resolve whilst documenting it here for everyone's benefit. 

Well done, and thank you!

[sys700]

Hey, thanks for reading!

The issue with garbled characters in the display only seems to occur in some patches, so those might actually be corrupted samples. I've had the sampler on for a few days straight now with no issues. Really enjoying the sound, and the benefits of the Lotharek floppy emulator. Very nice to have 1000's of samples easily accessible.

BTW, came across this excellent ZIP file of EII samples online (link isn't working at the moment, but try again later):

www.dblondin.com/samples/EII_HXC.zip