I believe this to be a pretty early one. At least, it's fitted with the earlier K35 filters. All the jumper wire is cloth covered solid core, which makes noodling around with the board a bit more stressful. I've attached a photo of the main board I took before I did any work to it.
Ebolatone, definitely not interrupting! Probably wise to share a little more backstory on this synth anyway. Before I started on the unit the all the switches were pretty finicky and intermittent, several pots were noisy/staticky, the input to the ESP didn't work and the whole thing sounded quite noisy overall. I cleaned the offending pots and switches and reflowed many joints. I removed every 1/4 jack from the PCB and disassembled, cleaned and retensioned the contacts. Every electrolytic and tant have been replaced with new. Ive cleaned the boards with IPA (goodness I hate that part) to remove any solder flux or potential bits from the rework. After doing this, everything on the synth now seems to function as it should and noise free (relatively, the k35's and single transistor via output ain't all that quiet), with the only flaw being this vco stability issue.
Here's another thought ive had.. maybe the pcb has absorbed moisture or contact cleaner lubricant? Maybe that's extreme, but I have heard of this happening to boards before. One of the other things I feel like I might have in common with the other users in this thread that faced tuning instability is the use of DeOxit D5. I'm going to pick up a scope soon from a buddy of mine and I really hope that can help me find the source of this.
Ebolatone, definitely not interrupting! Probably wise to share a little more backstory on this synth anyway. Before I started on the unit the all the switches were pretty finicky and intermittent, several pots were noisy/staticky, the input to the ESP didn't work and the whole thing sounded quite noisy overall. I cleaned the offending pots and switches and reflowed many joints. I removed every 1/4 jack from the PCB and disassembled, cleaned and retensioned the contacts. Every electrolytic and tant have been replaced with new. Ive cleaned the boards with IPA (goodness I hate that part) to remove any solder flux or potential bits from the rework. After doing this, everything on the synth now seems to function as it should and noise free (relatively, the k35's and single transistor via output ain't all that quiet), with the only flaw being this vco stability issue.
Here's another thought ive had.. maybe the pcb has absorbed moisture or contact cleaner lubricant? Maybe that's extreme, but I have heard of this happening to boards before. One of the other things I feel like I might have in common with the other users in this thread that faced tuning instability is the use of DeOxit D5. I'm going to pick up a scope soon from a buddy of mine and I really hope that can help me find the source of this.
Statistics: Posted by humdanger — Fri Apr 19, 2024 8:15 pm