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Dorkfest. Recording junk. May include lengthy details of electronic circuitry or the innane. (Just like every other blog) Mostly the whatsit and whosit of whatever audio and recording related things I'm working on but I want you to participate. |
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wFriday, January 24, 2003 |
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thank god. i finally tracked down soren. he's alive and in the country. he's gonna nurse it back to health and i can look over his shoulder while he does.
posted by
two tickets to paradise at 9:50 AM
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Pele's Soccer was some Hot Action. I really wish I had Tempest all arcade style in my house. I just love that game.
One of the suspects. But, I don't think that's really it.
posted by
two tickets to paradise at 8:59 AM
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wThursday, January 23, 2003 |
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I don't have an MX70, I could only afford the 2600. Berzerk and Pitfall are total classics, and Activision's got a lot of good titles: Starmaster, Laser Blast, Decathalon, Seaquest. And Pele's Soccer, well shit, my sister can still beat my ass in that game.
posted by
stv slv at 4:27 PM
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i totally feel like i'm on the brink of figuring some stuff out, i just wish there were someone there to walk through the troubleshooting portion of it all. i mean, almost all of my problems center around some sort of logic problem - the signal isn't being turned on or off at the right places. maybe that's another clue towards the relays? i'm at that crappy point where i know enough to be dangerous, but still don;t really know what i'm doing with fixing this stuff. i'm gunshy at going back in there, since the last time i probed around with the oscilloscope and multimeter i took a sort of functioning card and made it a broken card. crap. well, recording these demos on 12 tracks is sucking balls. i guess it can't really hurt to probe more on the broken ones. soren measured the logic levels (which i think are +5v and +15v) at either side. damn. noone's gonna swoop in and fix this. i guess i just gotta dive in headfirst again and hope to get lucky.
posted by
two tickets to paradise at 12:00 PM
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wWednesday, January 22, 2003 |
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good idea on the blog, xon. as far as the MX70 goes, i'm afraid that i won't have much to contribute. i have recorded on xon's otari so i've seen it in action... but that is the extent of it!
i'm planning on recording some music with my new band pretty soon so i'll probably have a lot of questions in the future. as for my own recording ideas, i'd love to be an analog person. however, i've neither the space nor the funds for it so we are planning on recording digitally, using a PC. At this time we are simply an electronic duo but we do have tube amplifiers for our guitars and (future) analog synth's... so maybe i can get some advice down the road. cheers.
finally: one could consider this a shameless self-promotion... but i worked in a pic of the MX70 on my [latest webpage design]. it's just damn neat lookin'.
posted by
usb at 4:16 PM
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whoooo - the first real post! thanks for getting in here shawn... keep us informed!! i turned up this past info on "spaceghost" on RAP. Shawn - do you have an extender card? How far have you got on diagnosing?
posted by
two tickets to paradise at 2:57 PM
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here's an original message concerning the generations of cards and known problems:
Nick, There are (2) different generations of cards. The 1st generation has
only (2) internally mounted(not on edge) trim-pots(usually blue in color) in
the middle of the right side of the board if you are holding it flat with the
connector facing away from you. Both of these pots are facing up from the
surface. These are trims for "Erase-current"(vr-1) & "Erase symmetry"(vr-19)
The 2nd generation has (3) trim-pots in this area: vr-1 facing 'up' as
usual, and
vr-19 & vr-20 facing 'forward' toward front edge. This new-style card now
has a
"Bias symmetry"(vr-20) This info is not really known by many users. This new
bias symmetry
adjust allows for a finer tuning of reducing punch In/Out noise.
As far as mixing generations, this is only of course is a Record-related
issue, and the
symptoms of 'mixing' them would result in older-ones having noisier punch
I/O's
The good news is that there is a Mod available, Part# PB-7EKA Bias Symmetry
Mod.
This small daughterboard PCB will mount up in that same area and provide the
new circuitry
and trim-pot(vr-20) for that function.
The other, even more audible factors on these cards is OUTPUT DRIVERS &
REC/ERASE RELAYS
I believe that I had mentioned these upgrades to you in my previous email,
but I'll explain
with a little more detail:
The improvements from the old I-0050 or I-0125 Output Drivers (IC-6) to the
new I-0178-B version is very significant as far as sonic performance and
less heat. The old drivers tend to crackle and boost the 'noise floor' when
they heat up. As far as the Relays (RL-1&2) are concerned, they are
responsible for switching the audio path in and out of record, if you have
the old matsu.(clear-case)relays, these are old technology, and are not
"Gas-sealed" like the new Omrom replacements, so the contacts inside tend to
'oxidize', and when you switch modes, or go into record, they usually
exhibit a "wind on microphone" effect, AND THIS DOES GO TO TAPE. Needles to
say, both of these improvements make for a much better signal to noise
ratio. So, if you are running the later PCB's or the old ones with mods,
I-0178-B Drivers
and new Omron gas-sealed relays in positions RL-1 & RL-2, you have fully
upgraded Audio PCB's.
posted by
two tickets to paradise at 11:48 AM
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got this response from a former otari tech in the u.k.
Sorry Nick,
I am away on holiday myself now so can'thelp much. Only to say that 90% of the card problems are cused by: Dodgy relays and bad Otari hybrid chips. Neither of which is any help to you as you can only get them from Otari.
If you plan to keep the machine try nd get a couple of spare cards as this will keep happening until the bad relays/chips have all been replaced. Oh also an extender card!!
Pip pip and good luck
posted by
two tickets to paradise at 11:44 AM
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the posts just keep coming.... i've tried to invite some cool people here, we'll see what happens. i guess this shouldnt be so MX70 specific, i want it to be more of a studio tech kinda thing i guess. talk about what you're working on. what problems you're running into. kinda an online studio log.
anyway, to give this some more girth another thing i'm trying to figure out is racking up a pair of neotek strips i got. i'm kinda intimidated, but i think it wont be that bad. the seller on ebay is being an ass and not giving up the schematics./ choad.
posted by
two tickets to paradise at 10:21 AM
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Argh. Liam and I have been fighting with the tape machine more and more and now it's just not funny. I can't get ahold of my normal tech and have posted messages, searched R.A.P. emailed Dana Hathaway at Otari and another dude in the UK and noone can help. I'm creating this blog out of desparation. If I can get a bunch of real MX70 users together to post on this and talk about their machines, I KNOW we can all figure it out together and not have to pay a shitload for our techs to come out. Viva la Doors!
Here's the rundown of my current problems.
- 1 card senses an input and registers it on the meter, but will not commit the signal to tape, nor will it play back a recorded signal.
- 1 card seems to be stuck in both repro and sel-rep as it plays back a tape delay sound.
- 1 card when installed seems to be "stuck" in whatever mode i put it in. for example - i press play after powering up, and then the machine won't respond to any other transport controls, i have to power down. When this card is removed, everything works fine. This used to be a "tape-delay" card like the one above, but i then replaced IC29 (my hack attempt to fix) and this is the resulting behavior. I checked continuity on the connection and it all seems fine. Perhaps of note - it is now in a Radio Shack socket.
- 1 card when inserted produces an oscillating sound much like a helicopter at a low frequency - perhaps 300hz? (this seemingly came out of nowhere)
- The easy one i can live with for the time being by swapping cards... won't record, but will playback. But if you have any suggestions, i'd be awesome to fix.
Hopefully I can get some more people out here. Please let me know and I'll add you to the blog. Word.
posted by
two tickets to paradise at 8:18 AM
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Nobodies home.
posted by
two tickets to paradise at 8:13 AM
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