Hi list, Battery replaced, the diode in place blocks out just about everything (ca 4,4 volts) leaving circa 10 mV bleed through. I added another diode which took it down to 3 mV. Some of this might be leakage in a lousy multimeter etc but I think this is sufficient enough to count as not re-charging. :) The original battery in MTM 744 is now removed. Nothing had leaked outside the plastic container which is a relief. When opening the container there were plenty of leakage visible though. *yuck* Feel free to use this picture as guidance. Red wire goes to + and black to - on the new battery which is placed _beside_ the PCB, not on it. Remember to lift/remove resistor 37. Additional diode might be good but is probably not crucial. http://www.electronic-obsession.se/studio/simmons/mtm_battery_mod.jpg (just 24 hours left to SDS-2012 (Simmons Drum Season 2012). :D -- electronically yours, jesper - -- --- ---- ----- ---- --- -- - www.electronic-obsession.se WT skrev 2011-12-29 13:59: > Ah, didn´t look to much on the schematic. > > You mean if you remove the resistor that the diode will block the charging > voltage ? Possibly. I don´t know what type of diode it is. > > Remove the resistor and measure the voltage before and after the diode. > > There should be no voltage after the diode. > > WT > > ----- Original Message ----- > From: "jesper"<jesper@...> > To:<Simmons_Drums@yahoogroups.com> > Sent: Thursday, December 29, 2011 1:40 PM > Subject: Re: [Simmons Drums] MTM and change of battery > > > But, what's it for then? I thought the original charge came over the > resistor. > > /j. > > WT skrev 2011-12-29 09:55: >> That diode doesn´t block the charging voltage. If it did, how would the >> original battery get charged ? >> >> WT >> >> ----- Original Message ----- >> From: "jesper"<jesper@electronic-obsession.se> >> To:<Simmons_Drums@yahoogroups.com> >> Sent: Thursday, December 29, 2011 5:17 AM >> Subject: Re: [Simmons Drums] MTM and change of battery >> >> >>> OK, me again, with insomnia, hence the somewhat slow brain... >>> >>> I checked the schematics and noted that the two components on the + side >>> of the battery is in fact "just" the mentioned resistor (37) and the >>> diode (30) already in place. >>> >>> http://www.electronic-obsession.se/studio/simmons/mtm_battery_circuit.jpg >>> >>> So I cannot see any need for another diode. Please correct me if I'm >>> misinterpreting anything. >>> >>> /j. >>> >>> >>> jesper skrev 2011-12-29 05:00: >>>> Hi WT, >>>> >>>> so, basically just between the PCB solder point and the red wire in my >>>> photo? To block any voltage from reaching the battery? Any critical >>>> value or would any decent diode do? >>>> >>>> thanks, >>>> /j. >>>> >>>> >>>> WT skrev 2011-12-29 00:50: >>>>> I would just put a diode in series with the + side of the Lithium-cell. >>>>> >>>>> How you do it depends on where you put the Lithium-cell. >>>>> >>>>> WT >>>>> >>>>> ----- Original Message ----- >>>>> From: "jesper"<jesper@... >>>>> <mailto:jesper%40electronic-obsession.se>> >>>>> To:<Simmons_Drums@yahoogroups.com<mailto:Simmons_Drums%40yahoogroups.com>> >>>>> Sent: Wednesday, December 28, 2011 10:57 AM >>>>> Subject: [Simmons Drums] MTM and change of battery >>>>> >>>>> > Hi list, >>>>> > >>>>> > I thought I should change the battery of my latest MTM today. >>>>> But >>>>> since >>>>> > I was stupid enough not to make notes or take pictures when last >>>>> time >>>>> > doing this I dug out one of the other units to have a look. >>>>> > >>>>> > No. 114 had it's battery changed by the former owner and as far >>>>> as >>>>> I >>>>> > remember I copied the work in my other MTM. Apart from the >>>>> removal >>>>> of >>>>> > the old battery and the insertion of a AA-sized Lithium dito I >>>>> can >>>>> only >>>>> > see one change: the lifting/removal of resistor 37. I did the >>>>> same >>>>> on my >>>>> > other MTM and both works well, both functions and memory. >>>>> > >>>>> > Here's a shot of what can be seen inside no. 114. >>>>> > >>>>> http://www.electronic-obsession.se/studio/simmons/mtm_battery_mod.jpg >>>>> > >>>>> > So techs, let me know if this is wrong. Should I lift diode 30 >>>>> too? >>>>> > Anything else? The schematics aren't the best and I'm no master >>>>> at >>>>> > reading it anyway. :) >>>>> > >>>>> > Happy holidays, >>>>> > -- >>>>> > electronically yours, jesper >>>>> > >>>>> > - -- --- ---- ----- ---- --- -- - >>>>> > www.electronic-obsession.se >>>>> > >>>>> > >>>>> > ------------------------------------ >>>>> > >>>>> > Yahoo! Groups Links >>>>> > >>>>> > >>>>> > >>>>> >>>>> >>>> >>>> >>> >>> >>> -- >>> electronically yours, jesper >>> >>> - -- --- ---- ----- ---- --- -- - >>> www.electronic-obsession.se >>> >>> >>> ------------------------------------ >>> >>> Yahoo! Groups Links >>> >>> >>> >> >> >> >> ------------------------------------ >> >> Yahoo! Groups Links >> >> >> >> > >
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Re: [Simmons Drums] MTM and change of battery
2011-12-30 by jesper