Archive of the former Yahoo!Groups mailing list: Discussion about the Korg PolySix synthesizer

At 14-mei-2015 18:38:07, backshall1@bellsouth.net [PolySix]<'PolySix@yahoogroups.com'> wrote:

Most of the damage is usually on the eight data lines (D00-D07) and that
includes IC30 as well as IC31. The best way to test these is to use the ohm
meter to test continuity from one starting point to all the other places these
lines are connected. From a suggestion from Andy Jury a long time ago, I usually
test from connector CN10 to all the other chips. This can be a bit tedious. D00
is pin 4 on CN10, and needs to be tested to IC31, IC26, IC33, IC28, IC34, then
do the same set of tests for the other seven data lines on CN10. Alternatively,
you could start from IC31 pin 6 and test continuity to IC26, CN10, IC33, IC28,
IC34. When you get to D04-D07, it will be a different set of chips (IC30, IC34,
CN10, IC29, IC35).

Don Backshall

From: mailto:PolySix@yahoogroups.com

Sent: Thursday, May 14, 2015 12:13 PM

To: PolySix@yahoogroups.com

Subject: Re: [PolySix] some defects after battery
leak

Thanks for the reply. I repaired traces that were broken and I checked if there was continuity between traces that should not be connected to each other. I did this only for IC 31 maybe I will take a wider aerea to check on continuity. The weird thing is that most things work as they should and then when you turn one knob several parameters are changed and not only the one you turn. I put it in manual mode so all knobs function as they are set and then I can get some rather good sound but for example when I then turn the resonance of the VCF a bit then other parameters seem to have changed....any other info? I replaced the IC31 and put it on a socket. Could it be that another IC is defective when I have this strange behavior or do you think this is mostly a result of the corrosion? Thanks again for the reply Johan Sent from Yahoo Mail for iPad At 14-mei-2015 17:13:41, 'Chromatest J. Pantsmaker' chromatest@azburners.org [PolySix]PolySix@yahoogroups.com'> wrote: There are two things (well, more than that actually) that the corrosion will do that we need to pay attention to. First is the broken trace, or lack of continuity. You've checked this with your meter. Second is the shorted trace, or too much continuity. By this I mean that a trace can have continuity to a trace next to it. That would cause the signals to affect each other. When you check continuity on the traces, it's important to not only check 1-1, 2-2, 3-3 (and so on) but also to check 1-2, 1-3, 2-3 (and so on) You want all of the 1-1, 2-2, 3-3 traces to have continuity, and you ∗DON'T∗ want the 1-2, 1-3, 2-3 traces to have continuity unless they are actually connected via the schematic.