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@...>
>> 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
>>>
>>>
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>>>
>>> Yahoo! Groups Links
>>>
>>>
>>>
>>
>>
>>
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