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I need some rehab tips

marc.hull

Experienced Member
Joined
May 26, 2007
Messages
107
I was gifted and old Laser XT machine recently and have semi started to mess with it. It is very inconsistent when reading the hard/floppy drives. Sometimes it will boot other times I get errors. I cracked it open last night and found several issues...

1) the battery had leaked. I removed it and cleaned up the flowers it left. Doesn't seem to have eaten much of anything so I think I'm OK there. It's a 3.6v with solder leads I'll have to order. In the mean time I suspect that the only thing that will happen by NOT having the battery is that the time won't hold. Is this correct ?(there is no CMOS RAM in this box.)

2) Looking inside the back-plane I appear to have a nice layer of green moss on some pins. What is the best way to remove this crap and prevent it's re-occurrence ?

3) The keyboard is very unresponsive. I suspect it is a membrane one , although I did not crack it. Is there a way to rehab these type keyboards or is it trash ? If it does turn out to be a slider(although I am fairly certain it is not) What is the cleaning method there?

4) The TTL RGB monitor that came with it is also not working. It just shows a solid horizontal blue line dead center of the screen. Any hints on where to start with that one would be appreciated.

Thank you...

Marcus
 

modem7

Veteran Member
Joined
May 29, 2006
Messages
8,474
Location
Melbourne, Australia
In the mean time I suspect that the only thing that will happen by NOT having the battery is that the time won't hold. Is this correct ?(there is no CMOS RAM in this box.)
That sounds correct/logical.

3) The keyboard is very unresponsive. I suspect it is a membrane one , although I did not crack it. Is there a way to rehab these type keyboards or is it trash ? If it does turn out to be a slider(although I am fairly certain it is not) What is the cleaning method there?
Be aware that it may not be the keyboard. If you go through the threads in these forums, you'll find cases where people will say that the battery leakage has not damaged the motherboard, and they have a keyboard problem. Often, it turns out that the battery leakage did damage the motherboard, specifically the copper tracks associated with the keyboard. Those have been cases of AT class machines, where it is typical to place the battery very close to the keyboard connector. Is it the same in your XT class machine - battery near keyboard connector?

You don't have another PC class keyboard to use?

Also, does your XT have a keylock? They often disable the keyboard.

4) The TTL RGB monitor that came with it is also not working. It just shows a solid horizontal blue line dead center of the screen. Any hints on where to start with that one would be appreciated.
That symptom is known as vertical collapse.
See picture/description at http://www.overclockers.com.au/wiki/TV_/_Monitor_/_Fault_Diagnosis#6_-_Vertical_collapse

Before you go exploring inside of your monitor, educate yourself of the risks. That web site I pointed you to earlier has a "Dangers" section.

From the web site: "Many causes, Dry joints, elecrolytic capacitors, Vertical output I.C., vertical Oscillator etc." If the problem comes and goes when you 'tap' the monitor, that suggests a dry solder joint.
 

marc.hull

Experienced Member
Joined
May 26, 2007
Messages
107
I have an XT slider keyboard that does work so it's not the MOBO. I cracked the other one open and it's got some rubber plungers with graphite buttons on the end. The problem with the keyboard is that you have to mash the keys to get a response. Sorry should have included that earlier.

The leaking battery was actually on the "multi I/O" card. There seemed to be no damage to anything but......

I am aware of the dangers of opening a monitor case but thanks for the reminder.

Still looking for a tip on removing corrosion from the backplane. Anyone ??
 
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