![]() That's 1 million hours then, which again is 41,7 years. After the modification, the NV circuits draw 1♚ from the battery according to my multimeter. 24 Hours per day (assuming you don't turn it on all the time) = 208,3 days and your battery is gone. If your battery has 1000mAh, you need 5000 hours to drain the battery. Use your calculator - 2,5V - 0,5V = 2,0V. This goes over the resistor, at the other end (the +5Vd) around 0,5V are left from this power. The 10KOhms resistor used as pullup for the CARRY signal is connected to +5Vd, which is the main power for all other electronics. But there is a completely different problem. And even if you would, it should make no trouble, as the CARRY signal also doesn't leak to the keaboard scanner (partially left in the photo). For Q0 this doesn't matter if you don't hit any keys on the keyboard. Pulling RST of the 4022 high sets CARRY and Q0 high. Besides this, what you can't see here, the RST pin is pulled high by the same signal turning off the RAM access when the main power goes away. As you can see, it gets power from Vnv, the non-volatile power. ![]() This near shot worked.) You see the 4022 here. So why that? Let's have a look at the schematics: If you want to know, you may want to first measure the current flowing through the battery. If you are not interested on what you did in detail, you are done now and may reassemble your MultiTrak. Have a look at the photo (sorry, it is very blurred, i seem not to be capable to do those near-shots in a better quality :) to see how it has to look. Of just use a piece of wire stiff enough to keep everything in place. Maybe you want to fix everything with some hot melt glue or another piece of isolation tape. Now connect the resistors open end to pin 16 of the 4022. Next, isolate the board and maybe the neighbour resistor, that your modification can't touch something it shouldn't. Desolder the pin of the left resistor which is nearer to you (goes to a thick trace, which connects it with its neighbour resistor), you can also cut it, but we need to connect it elsewhere, so be careful when cutting it. The left one (more away from the 4022) is the one we neeed to touch. Left of this chip, there are 2 resistors of 10KOhms. Near the keyboard connector, you see a large 40 pin chip, which is the keyboard processor, and right of the keyboard connector, you find a CD4022 (maybe it has other letters, but it must have the number 4022 on it). Remove the voice board (the upper board of the stack of 2 large boards) to reveal the CPU board. If you want to fix this, disassemble your MultiTrak (i don't describe the procedure here, you can find out yourself or somewhere else i think), remove the keyboard cable and put the electronics assembly in front of you, with the connectors away from you. In fact, my MultiTrak had a design bug, which lead to the short lifetime of the battery. And i did.įor i impatient and the ones not interested in the technical description of this problem, just the following show modification is needed to fix the problem. Until today, where i wanted to track down this problem and find a solution, if there is any. So i purchased the large cell this synth usually needs, but as i didn't feel very comfortable with this very short lifetime, i didn't put it into the synth. Even after the second one, after 3 months, end of lifetime. It took about 3 months to drain the power from this battery. After the repair, i had a temporary battery in it, a button cell 3V lithium battery. ![]() I found this fix today, when i searched the last problem of my MultiTrak after the monster repair i initially did on this synth. Anyway - if you have problems with your backup battery only keeping up power for several months, you may want to modify your synth a bit. ![]() Maybe intentionally, as you don't like the lifetime of your backup battery of your MultiTrak, or just by browsing. "SCI MultiTrak (Model 615) battery drain fix Unfortunately the additional images referred to further below are gone, however you can make out the mod (albeit blurry) to the left. ![]() The following is from the Internet Archives WayBackMachine. Update: The original site appears to be gone. ![]()
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