leading edge boot problems-battery?

[collector]

I picked up a couple of leading edge computers the other day. One is a model 2 - 286 and the other is a 386. The 286 powers on, the floppy does not respond, and it tries to seek the hd but to no avail. No lights go on on either the hd nor the floppy at any time during the boot process. The 386 tries to boot but the screen stops at the model number info. No lights on hd nor floppy drive. I looked at the batteries in both units and they appear to be bad. Could that be the problem? If so, does it take much to replace these or do I need to be a super technician.

 

[DOS lives on!!]

The BIOS settings are stored in the clock battery. If it's dead, you'll loose everything and the PC won't boot. What battery do the computers have? Upload some pictures so we can see if they are replaceable, or like the Dallas batteries, hackable.

 

[collector]

battery pics

battery pics

solid blue battery is from the 286 and the battery with writing on it is from the 386

 

[Cevyn]

Oh how I hate those soldered on batteries!!

I used to very carefully snap the tabs off the end of the battery and then solder new wires onto those so as to avoid having to solder to the board itself.

Many of them were 7.2v rechargeables. Can you see any indication of voltage? If this is the case, a rechargeable 9v is generally 7.2v and I've used these to replace mine.

EDIT: Yours look like 3 cell batteries though and may be 3.6v....

 

[DOS lives on!!]

I agree with what Cevyn says. You could snap the metal tabs off the end and solder wires to the tabs. You can buy these batteries easily off the internet. Then solder the other ends of the wires to the tabs on the new battery.

 

[collector]

I found this type of battery on ebay as the one in my 386 is a varta v-3 v60r which is a 3.6v. Can I assume the battery in the 286 is the same type of battery?


Computer Backup Battery Varta V-3 V60R 19C9527 60R3PIN
Features
• Computer Battery Replaces Varta V-3 / V60R
• 3.6V 60mAh
• Nickel Cadmium Battery
• 3-Pin Connector

Also Known As: 60R3PIN, 60R3PIN/PW, 19C9527, GB50H, V70H, V80H


Compatibility
60DK-PC3, 60R3PIN, PW, V60R, V60R-PC3, V60R-SLF, V70H, V70H-PC3, V70H-SLF, V80H-PC3, V80H-SLF
Dantona: COMP-16-3NMH
Energy+: 3
Newark: 19C9527
Ultralast: UL60R3PIN
Varta: 3, 3-51FT, 55608303059, GB50H, V-3/V60R

I am not an electronics/soldering expert so I am not sure what you mean by "wires". Is this special wires to enable the connection to be made between the battery and the mb?

 

[DOS lives on!!]

I am not an electronics/soldering expert so I am not sure what you mean by "wires". Is this special wires to enable the connection to be made between the battery and the mb?

Sine you're not good at soldering, I'd suggest practicing first before doing this. (duh) Usually the back of the package of a soldering iron will tell you how to solder. The wires are just regular wires. Go to Radioshack to get your supplies, they will suggest the right kind of materials.

What you are doing is similar to the DS1287 rework. You can see what wires I used by looking at this thread,

http://www.vintage-computer.com/vcf...1287-Rework.-How-Am-I-Doing-So-Far&highlight=

 

[Cevyn]

I found this type of battery on ebay as the one in my 386 is a varta v-3 v60r which is a 3.6v. Can I assume the battery in the 286 is the same type of battery?

I'd go with that. They both look like 3 cell batteries. At least, trying to low of a voltage won't hurt

 

[MikeS]

Looks like it may be too late - corrosion from the leaking batteries has already damaged both boards; even with a dead battery the computer should still try to at least boot from the floppy, and no lights at all doesn't sound good.

In any case, remove the batteries ASAP; you can replace them with a 3-cell NiCd cordless phone battery that you can pick up for a buck at the local dollar store.

You should really remove the motherboards, neutralize and clean the corrosion, and inspect and repair any damage.

Good luck!

 

[Druid6900]

Or you can just cut out the old battery with a pair of diagonal cutters, clean up the mess and get a 4 x AA computer battery holder (probably prevalent on Fee-Bay or any good on-line battery store), slap some double faced tape or foam on it and stick it to the inside case back. Use alkaline batteries and take them out if you're not going to use the machine for a while.

 

[MikeS]

Well, the phone battery is cheaper, probably easier to find, the right voltage, and rechargeable just like the one you're replacing; sticking it on the back with double-sided tape is a good idea though, and if you use short pieces of wire or pins that fit into the battery connector instead of soldering directly to the old tabs you can also remove it if you want.

I personally don't like to replace rechargeable 3.6V NiCd batteries with a 6-volt non-rechargeable Alkaline pack without at least disabling the charging connection, but why bother; why not just stick with a 3.6V NiCd like the original?

But whatever you do, cut out or unsolder those leaking batteries and neutralize the corrosion as soon as possible before they cause even more damage.

 

[Druid6900]

Well, you have a point there. I just use the AA battery pack because I have a lot of them laying around.

I'm pretty sure that the charging circuit doesn't connect to the external battery pack connector or the batteries would explode, even on trickle charge.

Removing the old NiCd battery would certainly disable the charging circuit pretty effectively.

If I was doing a restoration, I'd just order a replacement NiCd, unsolder the old one and solder the new one in.

 

[Chuck(G)]

If there's a 4-pin battery header on the motherboard, I clip the soldered-in battery out and use a pack of AA cells in a holder in a nice thick plastic bag connected to the header. At least that way, if they leak, all you have is a bag of goo to toss out.

If I replace a NiCd, I still use AAs, but insert a diode (accounts for 0.7V drop) in series. The charging business never accomplished much anyway--a MC146818 just doesn't draw enough at 32KHz to matter. The other day, I picked up a battery that I'd put away about 8 years ago--a brand-new unused NiCd. It was leaking already without having been used at all.

An engineering manager I knew more than 30 years ago was absolutely unyielding on the gospel that batteries and printed circuits don't mix. If you use batteries, put them somewhere they can't do any harm.

 

[MikeS]

...I'm pretty sure that the charging circuit doesn't connect to the external battery pack connector or the batteries would explode, even on trickle charge.

Removing the old NiCd battery would certainly disable the charging circuit pretty effectively.

Well, the discussion was about soldering to the cut-off stubs of the old NiCd; if you're going to do that I'd recommend replacing with a compatible NiCd, and the 3.6V cordless phone batteries are cheap and ubiquitous.

But yeah, if there's a connector for an external battery then a 4-cell AA holder with a matching connector would work as well.

I usually remove the old battery and install a couple of pins to match the new battery's connectors where the old battery was: