From Kenny Balys Sent Sat, Apr 21st 2018, 01:43
I have worked on 2 Polysix's with battery acid damage. My own was a total nightmare. Several times, I thought I had it, and then it would start going off again after a few weeks. Its good now but it took so many hours of bench time. Next came my friend's Polysix. About the same as mine and I instantly realized that I didn't have it in me to trace every single trace and pad all over again. He decided to put the Kiwitechnics replacement board and power supply into his. It was a miracle in both time saving and in feature enhancement. So much time was saved too! I will never ever repair an acid Polysix CPU board again. I will only replace it with the Kiwi board. The Polysix acid repair has got to be one of the very worst jobs. I really feel for anyone doing it. On 21.04.18 01:13 , Murray wrote: > What happens with these boards is they are made out of fibreglass and > the acid gets into the weave. This will then slowly track all over > the board and corrode the copper out of every throughhole via that it > finds and will come back to the surface anywhere there is a hole in > the board and there are lots. It is also impossible to remove as > washing in IPA will not get into the weave and remove it completely. > The only sure way to repair a board in this state is to replace the > board. > > Don't use stripped wire. A better method is to get some fine choke > winding enamelled copper wire for bridging the broken tracks. This > can be found at any hobby store and is easy to work with, does a neat > job and will not short to the board or other wires. You heat the cut > end with a soldering iron and this will burn off the enamel just at > the end for easy soldering. > > MH > > > On 21/04/2018 11:31 AM, RJ Krohn wrote: >> >> the 367 board is one of the most frustrating problems i've ever >> encountered. i solved all of the issues of a battery leak on that >> board once. it was fine for a year. then, i started having problem >> manifest. turns out, the battery acid basically sat around, and >> slowly ate thru traces over time. >> >> >> my 2 cents would be this: look at the area, and "bridge" every >> single trace manually, with stripped wire. even the traces that >> dont show problems. or, replace the board with the newly ran >> batch. >> >> >> >> ------------------------------------------------------------------------ >> >> *From:* Sam Mims <xxx@xxxxxxx.xxx> >> *Sent:* Friday, April 20, 2018 10:50 PM *To:* Christian Bickley - >> Wintersun Project; Analogue Heaven *Subject:* Re: [AH] Korg Polysix >> MG Rate Knob Issue >> >> Are you absolutely sure that every trace in that area of the board >> is working? Battery damage usually destroys traces and/or >> components, and it is easy to overlook one trace among the many >> that cross through the 'land of corrosion'. And one damaged trace >> can lead to strange operation. I have thought I had a Polysix >> board all repaired on several occasions, only to have the Polysix >> act in a very strange way. Then I would go back and find that I >> missed one little bit of trace repair. >> >> I found it most effective to make a paper copy of that area of the >> board layout (from the service manual), and then use a highlighter >> to color every trace that has tested ok. Otherwise, it's too easy >> to miss a bit. >> >> Good luck - that type of repair is not for the faint of heart! >> >> Sam Mims >> >> Syntaur >> >> >> >> >> On 4/20/2018 5:38 PM, Christian Bickley - Wintersun Project wrote: >>> Hi all, ive been painstakingly replacing the dreaded battery >>> board on my Polysix but ive run into a frustrating problem. When >>> i turn the MG rate knob it works but in a rather odd way, if you >>> have the knob set at 0 and turn the knob clockwise, it will not >>> activate the rate of the MG until it gets to about 4 on the pot, >>> from there the MG kicks in but has an extremely narrow sweet >>> spot, within two marks on the dial it has gone from zero to full >>> speed, so its literally uncontrollable, making the full sweep of >>> the pot pretty much redundant. Can somebody let me know what i >>> need to look at to sort this out, im going around in circles and >>> cannot work out where this problem is coming from on the circuit >>> or more importantly how to fix it. Ive fixed a lot of problems on >>> this board and other problems on the synth but this part is >>> really confusing me. >> >