My Source is crazy, but in a catatonic sort of way

[thealien666]

That's great news, spiders !

You're welcome, and thanks for the update!

[spiders]

Well, I'm back. This Source clearly intends to test me heavily. New issue, not entirely crippling, but highly vexing. After a month of lightly gigging the synth, I sat down last night to do a bass line on a recording project. Much to my dismay, the synth is now greatly varying in pitch from patch to patch. I retuned the synth per service manual instructions, so now I can at least use my startup patch and treat the source like a synth with no presets. I bought the thing so I could save patches, though........ We are talking intervals of difference between patches, not slight differences.

So- I've retuned the synth.
I checked my power rails again (+-15, 10, 5.1, 4.95)....all good
I recalibrated the DA converter---it was actually a little off


I fear that the computer is once again poking me with a stick. A pointy stick. The synth board is doing what it is supposed to do, it is just receiving bad instruction from the computer. I think.

Once again, I approach the wise masters for their insight and suggestions. I've come so far with this synth I can't quit now.

[spiders]

Hey All, the problem is definitely related to the memory, I think perhaps one of my RAM chips has kicked the bucket. Swapping the RAM yields a new set of tunings across the patches every time. But, they do correctly store all the patch info, and the level 2 functions all work, so maybe not. So many maybes. MC feel free to tell me I'm not going to get anywhere by swapping chips, just break me off a piece of your knowledge while you are at it

[thealien666]

Don't neglect to check that memory back-up battery...

[spiders]

Hey Alain. It is at 3.3v. Sigh......
I'm going to figure this one out, probably replace every chip in there, and never take this thing to a gig again. This realization makes me sad and sort of deflated. I guess the source is a great studio piece, but this one really seemed to enjoy being played live, if that makes any sense. Synth wise I'm much more of an atmospheric/terrify the squares guy than a lead dude, but the source loves leads. It makes me play like no other keyboard has before. I love the interface and the lack of knobs. Having to really craft your sound and then commit to it liberates the player. A ton of knobs are great, interactive, etc, but I think they can get in the way of really doing something sometimes. One keeps wanting to fiddle with stuff instead of actually making music. With the source you can still edit quite quickly, but you have to be more deliberate in your thinking as to what you want. The process of creating sounds with the source allows you to more clearly express your voice, if you take it seriously. So, I'm bummed.
I will fix this, as I've fixed all the other problems (it actually has had a few more hiccups that I didn't post about, quite the "handyman special" as MC put it). But yeah, once it is solid on pitch again, I feel unlikely to gig with it. This particular unit has just proven wildly unreliable. I can't sell it to anybody in good conscience either, as I have an understanding about what is wrong with it........everything. As Homer Simpson once cried as his novelty hand bell fell apart, "DAMN YOU EBAY!!!!" Oh well. Live and learn.
I'm buying a sub 37 from some dude off craigslist tomorrow, selling some other gear to make the money back. I should be excited to get such a cool new synth, but it feels off. Maybe I will totally fall in love with it, but right now I feel like I'm abandoning the best synth I've ever had. Like you dated this girl who was cool and hot and awesome in bed, but she had a real bad drinking problem and kept passing out at fancy dinners. It didn't work out, for obvious reasons. Still, you can't get her off your mind................

[thealien666]

Sorry about the battery question... I didn't re-read the whole thread before writing my previous reply...

As for the RAM chips, it's possible they may fail, since the Z80 failed previously too...

Congrats on getting a Sub37. It might not be as "beefy" as a Source, but at least you'll be able to gig with it without worrying about it.

[spiders]

Man, I'm thankful for any suggestions at all, even if they are for things I've already covered. FWIW, I figure the problem has to be in the RAM area or the MUX/DEMUX circuit. So it's probably just one of those chips. I can't help but wonder what will go wrong next, though. It seems every time I flip it on something else goes wrong; except when everything goes right, and things are amazing.

[spiders]

And it was........................... the RAM. The RAM. It failed. just for fun, I'm going to list the things that have failed on my source in the three months I've had it.

processor
line reader
10's digit display driver
one of the oscillator regulator chips on the synth board--can't remember which one now
3080 op amp that runs the AMP envelope
Membrane Connectors
RAM

If I had taken it to another tech, the piecemeal cost of all individual repairs would have been crazy. I'm not sure what I would have charged, as I never charge anybody for the R/D that it takes to figure out a problem on an unfamiliar unit, but it still would have been pretty high. Not even including parts, the bench fees alone would have been close to 300. As usual, I have learned a great deal from this process, but am ambivalent as to whether it was worth it. It usually is worth it, it's just hard to see it at the time. I had to do a lot of work repairing awful korean digital grand pianos for a while. I know so much about fixing those things, not much to do with that knowledge.


Rather than wait for the next thing to die on my The Source Computer I just replaced every single IC with the exception of the edit latches and the MOD interface. I know this is not the worlds most sound strategy, but I'm sick of taking this synth apart.

Even though I got a really good deal, I think I sort of freaked out in buying to the Sub 37. It is quite amazing in it's own right, with worlds of capability, and all the knobs right there. Quite expressive, and you can send the mod info anywhere, like absolutely anywhere. I laughed out lout when I hit the page of the manual with the list of destinations. Also, a warranty is nice. Oh well, I needed to sell some gear anyway.
The Source has a better tone, though. No two ways about it. Brighter and somehow more alive. It's those tiny intangibles that set the old stuff apart from the new.

[thealien666]

... I am ambivalent as to whether it was worth it. It usually is worth it...

You bet your ass that it is !

Congrats on getting it back up and running 100% ! Well done.

From my experience, usually when so many chips fail inside an old synth, it's mainly due to either of two things (or possibly both): overheating, or dirty power rails (bad filtering capacitors degraded with time and heat). Especially in the digital section.

I've seen a Z80 fail inside a Prophet 5 also, and soon after the ram went there too. Probably because of the address and data buses directly tied to the failing CPU.

[bevaspen]

Anyone got any ideas on where to get an eprom for the source? cheers

[electrojoe]

Hello,
I have them.
Why do you suspect the ROM is out?

GD