Watched the whole video since I'm planning on doing a battery swap on a 386 board to a CR2032 battery and check for trace damage and repair when necessary. I'll order a diode or two in case I screw up 1 of them. Loved the schematic diagram for the battery circuitry.
@@necro_ware Need assistance with my 386 machine. I already cut the trace from the battery's positive lead from the top of the board and soldered a wire to the diode for the external battery header onto the positive lead and it works somewhat, except it won't keep the time correctly and after about 2 hours, the settings erase. Am I doing something wrong here? I checked the voltage to the RTC from the battery's negative terminal and it gets 2.42V-2.5V, which is 0.2V-0.28V too low (between 2.7V and 4.5V for the Hitachi HD146818P RTC required). Edit: yesterday, I made a 4.5V battery compartment out of a broken DMG-01 battery chassis, soldered 2 wires to the terminals that are in the chassis, then to the board, to the external battery holder, and it works. With the diode in place, it goes to 3.8V, which is plenty and it keeps the settings.
@@RetroPCUser if your board has an external battery connector, which does not charge the battery, why did you modify the board? Just plug the battery and avoid the risk of damaging the board... :)
make sure to use shotcky diodes for lower voltage drop, silicon diodes would drop the voltage around 0.6volts which may reduce the usable time span of the battery. many calculators with a solar cell use cat-whisker diodes that have an even lower voltage drop...
That's true, the two middle pins of the header are jumpered on some mainboards and sometimes it's just sufficient to remove that jumper to prevent the battery from being charged. However, often it's a bit more complicated. By removing the jumper not only is the charging trace disconnected from the battery, but unfortunately the whole battery. But you are right, before messing around with diodes everybody should check for the jumper and understand the circuit. Thank you for your contribution!
Super great channel and superb video content. Thank to you old things getting prolonged life. Thank you, I always like to watch your videos. I do have question regarding battery replacement. Based on this video I was trying to replace barrel battery on old GM-386SAT board but ran into issues with board keeping date but not the time or better to say kepping time from few hours before when I set it and then it stoped counting. Have you ever ran into someting similar?
Perfect description of what to do. On some machines I love to use a Card bracket and a few centimeters of cable to put the battery outside of the chassis. Did you ever experience issues with the voltage drop by the diode?
No, please don't. That's a Li-Ion rechargeable battery, which needs additional charging circuit. If you install it instead of a Ni-Cd or Ni-MH battery, it can explode and burn down your house in a most unexpected moment.
@@necro_ware it should be possible to use a rechargeable coin cell, vl2032 or ml2032 if the charging circuit on the motherboard is altered to take into account charge requirements, you'd need to check the manufacturers data sheet for the cells, it'd need a shunt zener across the cell to stop charging overvoltage, and likely increase charge resistor to reduce charge current
Nice video. I have a motherboard named EXP 8049 that used to have a barrel battery on it. The problem is i can't seem to locate the charging circuit. The damage from the acid fortunately was little to none. Can you help in locating this circuit. Some told me to use the external battery but I don't want to use it.
True! But actually you never need to, since all mainboards up to 486 had a header for an external battery, so it's up to everyone's decision if it's better to use the header, or to modify the board. I just wanted to show the options, it wasn't special to this board, I just had it at hand.
Hi, I really like your videos, I am seeing all of them. Have a question, did you ever upgrade the Bios on the boards? or is difficult to find them? or just not interest on that?. Thanks
You obviously didn't see all of them, otherwise you would see, that I update the BIOS regularly, whenever it is needed. I don't remember all of the videos, where I did that, but here is my latest video, where I updated the BIOS: th-cam.com/video/J0NLGfocviU/w-d-xo.html
My 486 motherboard only comes with a external batt circuit to power the cmos. I measured the current when powered on and it was getting .5uA so very little. Should i still put in a diode? Have you ever heard of external batteries being charged? Thanks
Hi, you could also use ML2032 (depending on the charging voltage). ML2032 is a chargeable version of CR2032. I do not know if ML2032 is prone to leaking or not. BR
No, you can't. That's a Li-Ion rechargeable battery and it needs additional electronics to control the charging process. If you simply put an ML2032 into the circuit, which was designed to charge Ni-Cd or Ni-MH batteries it could explode.
This was great, I finally got answers to some of my questions regarding the barrel battery replacement. Have you experienced or heard of someone experiencing exploding CR2032 installed without the diode to prevent charging current? Thanks
I heard rumors and I saw a normal AA battery exploding as s.o. tried to put it into a charger. I myself never tried to install a CR2032 without solving the recharging problem.
Hi, I'm an idiot and I added the CR2032 without any other modification. I've used it for... I dunno, probably a month and had no problems. I will probably modify the circuit later now that I know this is an issue. :u
Hi! The barrel batteries are usually 3,6V and the CR2032 are 3V. It usually works, even when the battery delivers only 2.1-2.2V, but it is better to have this voltage as high as possible. That's why I suggest to use a Schottky diode (f.e. 1N5817), which has only a voltage drop of 0.2V. You also can use a semiconductor, like a z-diode, but it will eat 0.7V and can be too much on some systems.
Hello and thank you for the excellent video. The song in the background also intrigued me. I tried looking it up on Bandcamp with the link you provided. Could you please direct me to the correct album for this specific song as i can't find it. Keep up the good work
Hi Chris! Thank you very much and I'm also very glad, that you like the music. Unfortunately, I probably have to disappoint you. This is some experimental music by my brother, which is not available in the public, but I have an allowance to use it here if I want to. I liked it, just as you did, so it landed in this video. The main project of my brother is, what you can find on bandcamp. I know, this is quite a different type of music, but unfortunately, this is all I can provide to you. Still, thank you very much and I'll forward your Email to my brother, if you don't mind. Best wishes for the new year!
@@necro_ware Hi, Thank you for the response. The music from your brother just sounds amazing. It will be very dissapointing not to hear the full track. You can forward my email to your brother. If the music is for sale, i would very much like to buy it.
In this case it would be also possible, yes. But it's not possible everywhere. Every board is slightly different. May be I'll make another video on this topic to explain, which kind of problems can happen.
In the most cases, it's not a problem. The RT clock usually works down to about 2.1V, however, some boards reduce the voltage intentionally to about 3V by installing additional resistor or, more often, a diode. Unfortunately, I didn't mention it in this video, but sometimes you have to remove that parts as well, because the battery is already 3V.
@@peterarmstrong9116 That is a good idea a quick modification. However aren’t LIR2032 usually many times more than a 2032, and a diode costs cents. If you don’t want to modify the motherboard (something rare) or go to the trouble of an external circuit, using a LIR2032 makes sense to me too.
Would you need to do modifications like this if you removed the barrel battery and added a socket for the CR2032 battery but then use a rechargeable CR2032 battery? I just noticed they do make CR2032 batteries that show the following "Li-Ion Rechargeable 2032 Button Cells, LR2032, 3.6V 50mAh". Seems like this might work ok?
The rechargeable pendant for CR2032 is LIR2032 or ML2032. I have no experience with them yet, but I guess, that you don't need to make any changes, when using them, except the battery socket. However, the rechargeable versions cost about 10 times as much as the non rechargeable.
@@necro_ware Thanks for the reply! Very helpful. The reason I asked is because I had already added a 2032 socket to a couple of my motherboards but this was done before I knew about the charging circuit issues. Lucky for me they hadn't had issues yet as I didn't run them much at all. So I thought it might be an alternative for those already done incorrectly like mine. Really appreciate your video and the great explanation as I will do much better on my next boards.
@@matthenrich995 You are very welcome. If you decide to use the rechargeable variants, I would be also glad to know, how that works. Even if it is more expensive, I guess, it is still a valid solution as well with as little modification on the mainboard as possible. And in regards of non-rechargeable batteries, just be careful, when you try to recharge them, they can overheat and explode.... I wish you all the Best!
@@necro_ware the additional cost is negligible when you consider that you're only having to change it once every 5 years or so. It would be a very different scenario if you were having to change it every few months, agreed!
hi i went to the shop and he didnt have 1n5817 but give me 1n5819 that is 40 volt instead of 20 volt schotty diode. i did the mod on 2 motherboard, but when i attach psu i have 0.2 volt on battery pins, and when i power on i have 3.5 volt on battery pins ( all that witout battery cr2032). is that ok ? i think something is frong... maybe 1n5819 arent compatible with 1n5817 ?
They are the same 1n5819 is just slightly thicker. Schottky diodes have reverse current leakage, that's why you can see the voltage. Measure the current instead, if it's very low, like some uA it's ok. The battery will survive that. Otherwise you can take a real diode and not a Schottky, but then you should place it in the way so the voltagee drop between the battery and the RTC IC is possibly low.
@@necro_ware tnx for reply. because i thought it was a diode version problem i ordered some 1n5817, but if u say it's ok that way i can leave it that way. if i measure voltage on diode to the 5v rail i have ofcourse 5 volt, but on the other side i have 3,5 volt.... maybe not much ampere, but that 3,5 volts are present. if i put a 2032 that is 3 volt, i measure 3,3 volt on + of battery and 3,3 on diode and ofcourse 5 volt on other side of diode. i did that mod to not damage cr2032 battery. if it's ok ill leave it that way, otherwise a good component guide would be good.
Hi, I don't quite remember anymore, what exactly it was. I generally suggest some low power, low voltage drop diode. In this video I used some z-diode, which I had at hand, I think. Not the usual use case for such a diode, but it does the trick as well.
If the new battery is rechargeable and is similar to the old one, you can do that. However, barrel batteries always tend to leak and to damage the mainboard eventually. That's why I always replace them, by another solution. If you put non-rechargeable battery there without cutting the trace, then your new battery can explode with all the consequences.
a cr2025 should work as well as a 2032...just not last as long....one could even use a cr2016 if you wanted...you just need the appropriate battery holder. Unoffically, some holders will let you get away with using different cr20xx batteries. I would bet that the holder used in the mod in this video would be tolerant enough to allow a cr2025 or 2016 and still work though I believe it was intended for the cr2032.
@@necro_ware Thank for yor answer! , I just discovered your channel a few days ago, so I haven't seen all your videos. As a puritan I don't like the idea of cutting a tarace.
I don't understand why people don't use a different type of rechargable battery, and instead they do all these hacks. Why isn't there a simple ad-hoc replacement for these barrel batteries?
You can replace those batteries only with the same type NiCd or NiMH and they will leak again after a while. Unfortunately you can't insert Li-Ion rechargeable batteries, because they need additional charge control circuit, otherwise they could explode.
![เจ้าผู้เดียว - ดิด คิตตี้ [OFFICIAL MV]](http://i.ytimg.com/vi/q0NLCYKBOTo/mqdefault.jpg)
The last phrase before the closing, was the most unexpected and exact in my point of view. :-D Prophetical!!! :-D
Yes, indeed, Mr. Gagarin ;)
Watched the whole video since I'm planning on doing a battery swap on a 386 board to a CR2032 battery and check for trace damage and repair when necessary. I'll order a diode or two in case I screw up 1 of them. Loved the schematic diagram for the battery circuitry.
Thank you very much! The "professional" diagram was handcrafted in weeks of hard work ;D
@@necro_ware Need assistance with my 386 machine. I already cut the trace from the battery's positive lead from the top of the board and soldered a wire to the diode for the external battery header onto the positive lead and it works somewhat, except it won't keep the time correctly and after about 2 hours, the settings erase. Am I doing something wrong here? I checked the voltage to the RTC from the battery's negative terminal and it gets 2.42V-2.5V, which is 0.2V-0.28V too low (between 2.7V and 4.5V for the Hitachi HD146818P RTC required).
Edit: yesterday, I made a 4.5V battery compartment out of a broken DMG-01 battery chassis, soldered 2 wires to the terminals that are in the chassis, then to the board, to the external battery holder, and it works. With the diode in place, it goes to 3.8V, which is plenty and it keeps the settings.
@@RetroPCUser if your board has an external battery connector, which does not charge the battery, why did you modify the board? Just plug the battery and avoid the risk of damaging the board... :)
make sure to use shotcky diodes for lower voltage drop, silicon diodes would drop the voltage around 0.6volts which may reduce the usable time span of the battery.
many calculators with a solar cell use cat-whisker diodes that have an even lower voltage drop...
This was what I wanted to say too
As always good and clear detail explanations. Keep going my friend 👏
Thank you very much :)
Excellent explanation with technical terms. Thanks.
i know this video is 9 months old, but there are vertical mounts for the cr2032 battery that can be utilized
Proffetic indeed :) not only USA
Lots of 'External Battery' headers have a jumper if you're using the onboard 'barrel' battery, then the diodes are not necessary.
That's true, the two middle pins of the header are jumpered on some mainboards and sometimes it's just sufficient to remove that jumper to prevent the battery from being charged. However, often it's a bit more complicated. By removing the jumper not only is the charging trace disconnected from the battery, but unfortunately the whole battery. But you are right, before messing around with diodes everybody should check for the jumper and understand the circuit. Thank you for your contribution!
Super great channel and superb video content. Thank to you old things getting prolonged life. Thank you, I always like to watch your videos.
I do have question regarding battery replacement. Based on this video I was trying to replace barrel battery on old GM-386SAT board but ran into issues with board keeping date but not the time or better to say kepping time from few hours before when I set it and then it stoped counting. Have you ever ran into someting similar?
Perfect description of what to do. On some machines I love to use a Card bracket and a few centimeters of cable to put the battery outside of the chassis.
Did you ever experience issues with the voltage drop by the diode?
Another option is to replace the battery with a VL2020 battery. No PCB modification required.
No, please don't. That's a Li-Ion rechargeable battery, which needs additional charging circuit. If you install it instead of a Ni-Cd or Ni-MH battery, it can explode and burn down your house in a most unexpected moment.
@@necro_ware it should be possible to use a rechargeable coin cell, vl2032 or ml2032 if the charging circuit on the motherboard is altered to take into account charge requirements, you'd need to check the manufacturers data sheet for the cells, it'd need a shunt zener across the cell to stop charging overvoltage, and likely increase charge resistor to reduce charge current
Nice video.
I have a motherboard named EXP 8049 that used to have a barrel battery on it.
The problem is i can't seem to locate the charging circuit.
The damage from the acid fortunately was little to none.
Can you help in locating this circuit.
Some told me to use the external battery but I don't want to use it.
I prefer to use ext battery connector if possible
In this particular case, it would have made more sense to use the header pins, removing the need to modify the board.
True! But actually you never need to, since all mainboards up to 486 had a header for an external battery, so it's up to everyone's decision if it's better to use the header, or to modify the board. I just wanted to show the options, it wasn't special to this board, I just had it at hand.
Hi, I really like your videos, I am seeing all of them. Have a question, did you ever upgrade the Bios on the boards? or is difficult to find them? or just not interest on that?. Thanks
You obviously didn't see all of them, otherwise you would see, that I update the BIOS regularly, whenever it is needed. I don't remember all of the videos, where I did that, but here is my latest video, where I updated the BIOS: th-cam.com/video/J0NLGfocviU/w-d-xo.html
@@necro_ware That is great I will see it soon. Thanks for reply!!!!
My 486 motherboard only comes with a external batt circuit to power the cmos. I measured the current when powered on and it was getting .5uA so very little. Should i still put in a diode? Have you ever heard of external batteries being charged? Thanks
Hi, you could also use ML2032 (depending on the charging voltage). ML2032 is a chargeable version of CR2032. I do not know if ML2032 is prone to leaking or not. BR
No, you can't. That's a Li-Ion rechargeable battery and it needs additional electronics to control the charging process. If you simply put an ML2032 into the circuit, which was designed to charge Ni-Cd or Ni-MH batteries it could explode.
@@necro_ware Sorry, your are right. The old one was NiMH or NiCd, I suppose.
This was great, I finally got answers to some of my questions regarding the barrel battery replacement. Have you experienced or heard of someone experiencing exploding CR2032 installed without the diode to prevent charging current? Thanks
I heard rumors and I saw a normal AA battery exploding as s.o. tried to put it into a charger. I myself never tried to install a CR2032 without solving the recharging problem.
Hi, I'm an idiot and I added the CR2032 without any other modification. I've used it for... I dunno, probably a month and had no problems. I will probably modify the circuit later now that I know this is an issue. :u
What value diode do you need for the place of the barrel battery?
Hi! The barrel batteries are usually 3,6V and the CR2032 are 3V. It usually works, even when the battery delivers only 2.1-2.2V, but it is better to have this voltage as high as possible. That's why I suggest to use a Schottky diode (f.e. 1N5817), which has only a voltage drop of 0.2V. You also can use a semiconductor, like a z-diode, but it will eat 0.7V and can be too much on some systems.
Hello and thank you for the excellent video. The song in the background also intrigued me. I tried looking it up on Bandcamp with the link you provided. Could you please direct me to the correct album for this specific song as i can't find it. Keep up the good work
Hi Chris! Thank you very much and I'm also very glad, that you like the music. Unfortunately, I probably have to disappoint you. This is some experimental music by my brother, which is not available in the public, but I have an allowance to use it here if I want to. I liked it, just as you did, so it landed in this video. The main project of my brother is, what you can find on bandcamp. I know, this is quite a different type of music, but unfortunately, this is all I can provide to you. Still, thank you very much and I'll forward your Email to my brother, if you don't mind.
Best wishes for the new year!
@@necro_ware Hi, Thank you for the response. The music from your brother just sounds amazing. It will be very dissapointing not to hear the full track. You can forward my email to your brother. If the music is for sale, i would very much like to buy it.
Goodnight just piggyback the battery container for the new battery with the diode on it?
In this case it would be also possible, yes. But it's not possible everywhere. Every board is slightly different. May be I'll make another video on this topic to explain, which kind of problems can happen.
the varta bat is 3.6v the coin bat is 3v wil that cause problems ?
In the most cases, it's not a problem. The RT clock usually works down to about 2.1V, however, some boards reduce the voltage intentionally to about 3V by installing additional resistor or, more often, a diode. Unfortunately, I didn't mention it in this video, but sometimes you have to remove that parts as well, because the battery is already 3V.
Or you could use a LIR2032 which is also 3.6v and do away with having to modify the board.
@@peterarmstrong9116 That is a good idea a quick modification. However aren’t LIR2032 usually many times more than a 2032, and a diode costs cents. If you don’t want to modify the motherboard (something rare) or go to the trouble of an external circuit, using a LIR2032 makes sense to me too.
@@av_oid if using a lithium rechargeable you'd need a shunt zener to prevent it going overvoltage during charging
Would you need to do modifications like this if you removed the barrel battery and added a socket for the CR2032 battery but then use a rechargeable CR2032 battery? I just noticed they do make CR2032 batteries that show the following "Li-Ion Rechargeable 2032 Button Cells, LR2032, 3.6V 50mAh". Seems like this might work ok?
The rechargeable pendant for CR2032 is LIR2032 or ML2032. I have no experience with them yet, but I guess, that you don't need to make any changes, when using them, except the battery socket. However, the rechargeable versions cost about 10 times as much as the non rechargeable.
@@necro_ware Thanks for the reply! Very helpful. The reason I asked is because I had already added a 2032 socket to a couple of my motherboards but this was done before I knew about the charging circuit issues. Lucky for me they hadn't had issues yet as I didn't run them much at all. So I thought it might be an alternative for those already done incorrectly like mine. Really appreciate your video and the great explanation as I will do much better on my next boards.
@@matthenrich995 You are very welcome. If you decide to use the rechargeable variants, I would be also glad to know, how that works. Even if it is more expensive, I guess, it is still a valid solution as well with as little modification on the mainboard as possible. And in regards of non-rechargeable batteries, just be careful, when you try to recharge them, they can overheat and explode.... I wish you all the Best!
@@necro_ware the additional cost is negligible when you consider that you're only having to change it once every 5 years or so. It would be a very different scenario if you were having to change it every few months, agreed!
hi i went to the shop and he didnt have 1n5817 but give me 1n5819 that is 40 volt instead of 20 volt schotty diode. i did the mod on 2 motherboard, but when i attach psu i have 0.2 volt on battery pins, and when i power on i have 3.5 volt on battery pins ( all that witout battery cr2032). is that ok ? i think something is frong... maybe 1n5819 arent compatible with 1n5817 ?
They are the same 1n5819 is just slightly thicker. Schottky diodes have reverse current leakage, that's why you can see the voltage. Measure the current instead, if it's very low, like some uA it's ok. The battery will survive that. Otherwise you can take a real diode and not a Schottky, but then you should place it in the way so the voltagee drop between the battery and the RTC IC is possibly low.
@@necro_ware tnx for reply. because i thought it was a diode version problem i ordered some 1n5817, but if u say it's ok that way i can leave it that way. if i measure voltage on diode to the 5v rail i have ofcourse 5 volt, but on the other side i have 3,5 volt.... maybe not much ampere, but that 3,5 volts are present. if i put a 2032 that is 3 volt, i measure 3,3 volt on + of battery and 3,3 on diode and ofcourse 5 volt on other side of diode. i did that mod to not damage cr2032 battery. if it's ok ill leave it that way, otherwise a good component guide would be good.
Cool :) but I just use 16650 cells for the job :D with this cell the PC will be keeping CMOS setting forever hehe :D
True, and thy are rechargeable, so you even don't need to remove the diodes.
@@necro_ware exactly :) they do not leek and the capacity is so high for that purpuse that it will last for 100 years hehe :D
What is the type of diode?
Hi, I don't quite remember anymore, what exactly it was. I generally suggest some low power, low voltage drop diode. In this video I used some z-diode, which I had at hand, I think. Not the usual use case for such a diode, but it does the trick as well.
Hi, what would happen if I didnt cut the wire that recharges the battery and instead only soldered a new battery in
If the new battery is rechargeable and is similar to the old one, you can do that. However, barrel batteries always tend to leak and to damage the mainboard eventually. That's why I always replace them, by another solution. If you put non-rechargeable battery there without cutting the trace, then your new battery can explode with all the consequences.
if use a 2025 battery instead of a 2023 would that cause a problem?
you mean instead 2032? Well, I never tried. May be
a cr2025 should work as well as a 2032...just not last as long....one could even use a cr2016 if you wanted...you just need the appropriate battery holder. Unoffically, some holders will let you get away with using different cr20xx batteries. I would bet that the holder used in the mod in this video would be tolerant enough to allow a cr2025 or 2016 and still work though I believe it was intended for the cr2032.
It's is possible to simple remove the barrel battery and use a CR2032 case in the external battery connector?
Yes, I showed it in one of my 486 builds as well.
@@necro_ware Thank for yor answer! , I just discovered your channel a few days ago, so I haven't seen all your videos. As a puritan I don't like the idea of cutting a tarace.
@@Jorge_Ramirez Yeah, there is no need to do so, if you don't want to.
i thought the barrel batteries were rechargeable, the CR2032 are not.....right?
Right, that's why you have to cut the charging circuit. The battery holds the charge for years.
I don't understand why people don't use a different type of rechargable battery, and instead they do all these hacks.
Why isn't there a simple ad-hoc replacement for these barrel batteries?
You can replace those batteries only with the same type NiCd or NiMH and they will leak again after a while. Unfortunately you can't insert Li-Ion rechargeable batteries, because they need additional charge control circuit, otherwise they could explode.