EII won't boot

[dfiorucci]

So I've been working on this one for several months and no success yet.
I'm the original owner EII 6028 bought it in summer of 1984.
The problem is I get Emulator 2 Boot in Progress and 3 clicks from the floppy drive then nothing.
Here is what I've done so far.
Replaced original power supply with a Condor GPM80C.
All voltages look great
Ran Debug eprom and fixed 1 bad dram at IC13 on main digital board.
Really thought this was going to fix it since the boot loader is loaded into the first set of ram but no success.
Check the disks with the debug eprom and everything passed there was the usual error on CR1 because of the disk overrun on the first attempt.
I'll have to run it again to provide the value of the CR1 but all of the other values where 0000.
Ran the burst test and both drives where within range.
Ran exercise disk and that was a success.

So at this point I'm stumped as where to go next.
I've checked all the connections the only thing I can think of is the CR1 error which I'll have to post the value when I run it again.

Any suggestions,
TIA,
Dana

[dfiorucci]

FYI I ran the disk diagnostic again here is the results

T D 0 1
CRC: CR1: WT:  WT1: XFR:
0000 807F 0000 0000 0000

I have no clue as what the hex code for the CR1 means can't find the info anywhere
Also measured the voltage at the disk it is 12.09 volts dc

[dfiorucci]

FYI same for disk 2

T D 1 1
CRC: CR1: WT:  WT1: XFR:
0000 807F 0000 0000 0000

My gut feeling is the 807F error code is my problem but have no clue what to do about it.
Thanks,
Dana

[dfiorucci]

Forgot to mention I've replaced the Main 2.1 eprom and the Scanner 3.1 eprom.
That's where I also received the debug eprom.

[dfiorucci]

So I've replaced the both Z80A microprocessors still no luck.
Anyone no of a good tech in the Seattle area?

[dfiorucci]

I've spent some quality time today and all night going through this trying to figure out what the hell is going on with this EII and why it refuses to boot.
Just out of chance one of the times I was setting the cover back into the service condition I accidentally moved the four sliders up from the lowest position where I usually keep them.
I had given up on the Condor GPM80C power supply and reinstalled the original because I was thinking the +15 volt rail might be causing problems.
Well with the older power supply back in and re-calibrated I started it up and low and behold the disk actually loaded.
The sound was a bit garbled and some of the long samples on it seemed to change their pitch.
This particular disk had a sequence on it so I hit play and everything sounded fine being played back from the sequencer but if I tried to play it from the keyboard forget it it was garbled.
So I put all four sliders back down to the lowest position and the lcd garbled up and the front panel became unresponsive.
So I turned it off and turned it back on again The drive ran for three clicks and then nothing.
But wait it had just loaded and while playback wasn't correct it had loaded just fine.
So I turned it off again.
Then I thought okay I'll move all four sliders up about half way and turn it on again.
Booted right up and played sounds yet still a bit garbled but the sequence was fine except I did notice some fluctuation in the tempo.
So I shut it off again moved the sliders back down and now it would not boot again.Move the sliders back up and it boots fine.
I did notice that if I disconnected the modulation wheels the keyboard would playback the sounds less garbled.
So I took out the volt meter and checked the calibration on the pitch and mod wheels.
The mod wheel was fine however the pitch wheel was way out of calibration.
Also when I tried to adjust it it wasn't smooth when I approach the 150ohm to 50ohm range it jumped wildedly.
I was finaalable to get it to settle down and locked it in at 75ohms though I was trying to get it exactly at 100ohms.

I'm just wondering though if my sliders have gotten so bad over the years that they are spitting out constant fluctuating values and overloading the scanner.
Are the sliders on this 10k linear and what is the value of the capacitor that is soldered across it?
Hard to believe that the culprit all this time was not the power supply not the memory but the pitch wheel and bad data sliders.
Again if I have it up and running if I move any of the sliders to their upper or lower range it locks up the EII.
I'm unable to select anything with the sliders in the sub functions either.

[who]

It sounds like you're much more technical than I, so I'm afraid anything I have to offer is something you've already tried, but here it goes:

Have you replaced the sliders?

[dfiorucci]

They are on order now but I like the humor LOL
Thanks Mr obvious

[dfiorucci]

I would just seem weird that all of the sliders would go bad at the same time.
I'm hoping that might be the issue and it wouldn't hurt to replace them all but I'm thinking it is a red herring and actually the problem is somewhere else.
Dr.C have you ever ran across this weird issue before?
Thanks,
Dana

[dfiorucci]

Well just as I thought the sliders are not the issue though it's nice to have brand new silky smooth sliders.

So here is my theory what is going on.
Still I have to have the A data slider up at least a quarter of the way to get the emulator  to boot.
Playback from the keyboard is sporadic.
Playback from the sequencer is fine except the tempo starts to self adjust as if I'm moving slider A.
Also if I try to adjust anything with slider A it is sporadic then it just locks up if I go to the top of the travel.
Since the pitch wheel adjustment had drifted out of range from a bad pot I'm thinking that IC27 the ADC0809N has been damaged and needs to be replaced.
I'm just wondering if this could have also caused damge to IC29 the static RAM, IC45 the counter timer circuit and IC46 parallel input/output.
Anyone know if the damage would just be limited to IC27?
Thanks,
Dana

[dfiorucci]

Does anyone which of these TI replacement parts is the closest match to the IC27 ADC0809N

ADC0809CCN/NOPB-ND

ADC0809CCN

ADC0809CCN-ND

[dfiorucci]

So all of the sliders and capacitors soldered to the sliders and now the potentiometers for both wheels have been changed out and calibrated but still the problem exist.
Have a new ADC0809N IC27 coming I'm betting now it is the issue that it was damaged when the pitch wheel drifted out of range.
So I'm hoping that fixes it then I can start doing some mods.
Planned mods:
New OLED display going to use the Midas
Convert to an EII+ have the new memory ready to go just need to order new Main and Scanner eproms.
Convert floppy to HXC
Thinking about putting an Mac LCIII inside my EII and adding ports for mouse keyboard and a VGA out.
Also mounting my Emuser internally since I was able to snag the circuit board version.
Best 15 euro I've ever spent
Would love to do a custom Drem like Francois but I don't have the HD board.

[dfiorucci]

Up and running again after replacing the ADC0809N IC27 chip.
So the replacing IC27 was the solution to the problem more than likely caused by the pitch pot going bad.
So if you experience issues check the value of the pitch and mod wheels if either of them are above the recommended range  more than likely IC 27 has been damaged.

[ACEOFBASS]

Wow.  First of all thank you for writing out all that adventure you had.  I'm super stoked that you got your Eii working again!   

I'm down here in Oregon, and I'm working on an Eii that sat a long time in a damp basement. I've put a new PSU in this Eii, and made brand new ribbon cables, lots of other work.  It was working awesome for months, the only thing that remains is the Left wheel (pitch) is wonky.  I still need to find a replacement pot for that.  But sure enough, it had a no boot symptom, similar to yours.  Hanging at the boot screen.  I read through all your posts, then I look at my machine and see the faders are all down at the bottom.  I moved them to the middle, and it boots up fine.  I run the memory and scanner test disks, all pass.  Such a weird little issue.  Do you happen to have a spare ADC0809N IC?

Up and running again after replacing the ADC0809N IC27 chip.
So the replacing IC27 was the solution to the problem more than likely caused by the pitch pot going bad.
So if you experience issues check the value of the pitch and mod wheels if either of them are above the recommended range  more than likely IC 27 has been damaged.