so... i've finally benched my e2 and am happy it's only taken 2 years since i said i'd do it.
anyway, i've replaced all the switches and the thing is so much less annoying to use. most of the switches were fine, but some on the 10-key may it very frustrating to use. all better now
everything seems to function, but maybe not as well as it should. i'd like to know if there is some test/calibration procedure to attempt prior to pulling chips. luckily i have a puller, scope and a real test bench and a part store not too far away. my thought was to sample a 1k test tone at perhaps 1.2v (is the sampler +4 ref or -10)
My brother bought this new in '85 and it's been under my care for the past 15-20 years.
specs:
output board is Rev.1 - 15 May 1984 (30 years, yikes!)
memory option board Rev.0 - 30 april 1984
scanner 2.1
os 2.3
digital board Rev.0 - 10 April 1984
2 floppy drives
current issues:
-the backlight is out and i plan to swap with an LED ala
http://www.vintagesynth.com/forum/viewtopic.php?f=3&t=48114&p=514848- it seems some of the voices are a bit brighter. i use to think there was a stuck LFO on the filter freq but after picking through this board it sounds like the voice circuits are the issue so i need to learn how they work. I always used this think on its mix out so last night played with the voice outs. for each of the voice outs, if i play a note 8 times it will trigger once. is that normal? without plugging it into my scope to look at the waveform, the note played out the individual voice outs sounded similar in tamber/level. I also noticed that there seemed to be less noise out the individual outs compared to the mix out. hmmm...
- while playing a note and adjusting filter settings with the sliders (which are shot btw) i experience some serious lag (~half second to a second) betwixt playing a note and hearing the note. i don't think that's normal.
- sliders are shot - what are the specs for them? i'd like to replace them with a newer part.
- it's a bit noisy and there's some distortion that wasn't there before, but i kinda like it. i don't want it there all the time though so i'll need to fix that.
- i've learned that emuser isn't possible for me. that makes me super sad. I thought emuser negated the need for rs422. Anyway, i don't have some piggy-back board plugged into the computer interface connector (protocol converter i'm assuming) maybe i'll make one. any specs on that thing?
Planed work:
- replace display (
http://www.powertip.com.tw/products_2.php?product_id=1171043433&area_idbk=1170985616)
- install HxC (
http://hxc2001.free.fr/floppy_drive_emulator/index.html#SDCARDFloppyemulator)
- replace LEDs - what's the LED package size? i'm assuming 5mm
- replace sliders - mouser/digikey part# or just the length should suffice.
- find spare chips
- replace PS with modern/efficient one. (maybe build my own? - just need to know proper voltages)
cheers and pics soon!
oh, i've got extra buttons
-L
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