Compaq LTE 386s/20 refuses to power on

[dmitrybrant]

Hello!
I happened to come across an old Compaq LTE 386s/20 that I thought I might try restoring. The major problem is that it looks like it's been dropped -- one of the display hinges is broken, and of course it's on the side that contains the display ribbon cable, which is severed.

It's also missing the power adapter, so I improvised my own, by basically connecting a variable power supply directly to the pins of the power port. So I tried powering it on, but needless to say it's dead as a doornail.

I took the whole thing apart and stripped it down to the motherboard, i.e. disconnected the display, the hard drive, floppy drive, keyboard, and modem. And still, nothing happens when flip the power switch. I did also replace the CMOS battery, but it made no difference.

Does anyone know how to begin diagnosing what might be the issue here? Does it require any of the peripherals to be plugged in to operate? Any particular spots I could check with a meter? All of the components on the motherboard look OK visually, and there's definitely power coming into it, but I don't know where to proceed from there.

 

[Timo W.]

If it is anything like the smaller LTE Lite, it has another battery somewhere for power-management. It will not turn one without that battery working.

 

[dmitrybrant]

D'oh, I figured it out:
While researching the power supply specs for this model, I found pictures of a power adapter that outputs 18.5V, but apparently this is for a newer LTE model. The original power supply for this model actually outputs 30V.

My variable power supply doesn't go up to 30V, so instead I realized I could just hook it up to the battery terminals instead, which is 19V, and that worked! The whole thing powers on, but now I've found that the floppy drive belt has disintegrated, so that will need to be replaced next.