Steve, It might be worth looking at the 8201 charging circuit since it's a similar platform. For the battery pack, all that is added is a resistor. I think it's something weird like 71.5k.
Kurt On Mon, Nov 23, 2020, at 1:18 PM, Stephen Adolph wrote: > thanks Bert, > I found another document (M100SIG) that suggested the components to add were > a 10 ohm resistor and a silicon diode. > Interesting. > All hacks place a circuit between the orange and red leads. > > Option 1: 47 ohm > - works, but does not prevent reverse conduction from batteries to an > unplugged wallwart > > option 2: 10 ohms + silicon diode: > - protects from reverse current, but drops the voltage for charging > > option 3: 10 ohms + schottky diode > - also protects , maybe a little less voltage drop? > > > > On Mon, Nov 23, 2020 at 4:04 PM Bert Put <b...@bellsouth.net> wrote: >> Hi Steve, >> >> Email from 2010... :-) >> >> Hope this helps. >> >> Cheers, Bert >> >> >> >> From: Frederick Whitaker <rrtfw6...@charter.net> >> To: m...@list.30below.com >> Date: Sun, 03 Jan 2010 08:15:53 -0500 >> Subject: Re: Recharging Circuit! >> >> Thank you for finding that error, I didn't see it when I did the proof >> reading. Anyone who wants to keep that information can make that change, >> or they can use the change I am adding to this email. >> >> Fred Whitaker >> >> IZ2eib wrote: >> > --- Dom 3/1/10, Frederick Whitaker <rrtfw6...@charter.net> ha scritto: >> > >> > >> >> Da: Frederick Whitaker <rrtfw6...@charter.net> >> >> Oggetto: Re: Recharging Circuit! >> >> A: m...@list.30below.com >> >> Data: Domenica 3 gennaio 2010, 02:56 >> >> >> > >> > >> >> I have no idea why it calls for 4 >> >> watts. >> >> >> >> Fred Whitaker >> >> >> > >> > Hi Fred and all member list. >> > Resistor is 1/4W (0,25W), no 4W: 4W is a typo. >> > Please look at http://www.club100.org/library/libp100.html, >> > there are all Portable 100 Magazines, download Vol. 3 No. 7 Mar 1986 >> and read on page 44: you can read "The resistor you need for >> self-charging is a 47 ohm, 1/4 watt resistor which you can find at any >> electronics or TV repair store". >> > I believe that the error is due to conversion of the original >> document, nothing serious. >> > Since 1983, and as usual, club100 is the bible of Tandy 100's family >> laptops thanks to Rick Hanson!!! >> > >> > Regards, >> > >> > Fabio. >> > >> > >> > >> > >> > >> > >> > A Simple Self-Charger for the 100 >> > BY JOHN L. MENKE AND SUSAN M. MENKE >> > >> > The Model 100 is easy to use, powerful and lightweight. It also eats >> > batteries. >> > >> > If you're tired of hand-feeding it every few hours, you can modify its >> > dietary habits to self-charge. All you need are a resistor, a power >> > line adapter (current retail cost $5.95) and a quartet of rechargeable >> > batteries. >> > >> > After you've owned your machine for 90 days, its warranty expires and >> > this modification won't affect it. If your warranty is still in force, >> > we point out that Radio Shack does not recommend what we're about to >> > describe. However, we've had no problems with our two machines over >> > several years of use. >> > >> > RECHARGEABLE BATTERIES Rechargeable nickel-cadmium (nicad) batteries >> > have a nominal voltage of 1.2 volts (V). This remains virtually >> > constant as the cell discharges, then drops quickly to near zero. Four >> > such batteries give the Model 100 a combined voltage of 4.8 volts, >> > which is lower than the recommended 6.0V. The 100 will shut itself off >> > if voltage drops slightly below 4.8V. In spite of this relatively >> > narrow voltage band, we have never experienced problems from low power >> > shutdown. >> > >> > We have tried several brands of nicads. All give about 8-10 hours of >> > use when fully Charged. Makers recommend occasionally letting the >> > cells run all the way down before recharging. Our experience is that >> > repeated partial discharge (or extensive use of trickle charging) will >> > reduce charge life to 4-5 hours. One or two cycles of full >> > discharge/recharge restores the 8-10 hour useful life. >> > >> > We have used the same nicads for hundreds of cycles over two years >> > without evident degradation. Aside from the relatively limited life of >> > each recharge, the only noticeable effect is a very short warning time >> > after the lowbattery light comes on, before the 100 shuts itself off. >> > >> > Different brands of nicads have slightly different dimensions. The >> > positive tips of Radio Shack nicads are somewhat shorter than those of >> > other makers such as Lynacharge, so use of the Radio Shack cell can >> > lead to poor positive contact and intermittent operation. If you >> > experience this, the best solution is to switch to a different brand >> > of nicad. However, it's possible to use needlenose pliers and >> > partially uncoil the 100's positive spring terminals for better contact. >> > >> > HOW TO ADD THE SELF CHARGER RESISTOR >> > >> > You probably wonder, as we do, why all portable computers don't have >> > built in rechargeable power supplies. Radio Shack has been >> > consistently guilty of this fault, and even compounds it with new >> > battery-powered products that lack automatic shutoff. >> > >> > However, if you have ten minutes and twenty cents, you can wire in a >> > resistor (without soldering) that will recharge your IOU overnight >> > from a power line adapter. >> > >> > We repeat: This change may invalidate your 90-day warranty if still in >> > effect.but there is virtually no risk from adding a resistor, nor will >> > it make troubleshooting difficult if your machine should ever need >> > repair. Simply removing the resistor before sending the 100 for >> > service will avoid any issue being raised. . >> > >> > The resistor you need for self-charging is a 47 ohm, 1/4 watt resistor >> > which you can find at any electronics or TV repair store. A resistor >> > twenty percent above or below those values will still work. >> >> >> >> On 11/23/20 2:54 PM, Stephen Adolph wrote: >> > Wondering if anyone recalls or can point to the small modification >> > needed to be able to use NiMH or NiCd batts in the M100, and enable >> > charging? >> > Seems to me there was a nice little change you could make. >> > thx >> > Steve
