NextStation only powers on if hotwired

Started by primis, August 07, 2019, 03:34:23 pm

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primis

August 07, 2019, 03:34:23 pm Last Edit: August 09, 2019, 08:39:22 am by Nitro
I've owned a NextStation since about 2013, and it's been sitting in storage ever since. Before I put it away I bought a new power supply for it, and a battery. I pulled it out yesterday to try to get it booting. I've misplaced my VGA Y cable and felt downtrodden. Determined to get it to boot I tried the headless boot trick (touch pins 6 and GND on the DB-19 NeXT monitor out with a 470 Ohm resistor) but that didn't work.
So I pulled out my multimeter and checked the voltage on the battery, it is at 2.8V right now. Confused, I tried applying 3V directly to the PSU's power sense line via 2AA's in a holder, and the machine sprung to life.
Disk spins and clicks, little red light on the motherboard goes, etc. I've ordered 2 DB-19 plugs on ebay and I'm gonna wire up myself a new VGA Y cable. But I specifically remember before putting this thing in storage the keyboard not powering up the machine.

Any ideas why this could be failing a power on command? 

(I'll followup when I get the cable together)

primis

Followup: I have a working Y-Cable made up for the machine to VGA and the soundbox. When I attempt to use the power button on the ADB keyboard (yes, I have rom version 74) nothing happens, Shorting the 3V from the battery to the power sense line works still, and i get a netboot screen. (yay!) But the keyboard can't enter rom monitor to boot from disk, and weirdly enough, the power button can shut off the system (weird...)

I've taken a multimeter to the ADB lines, data is being sent through it, as well as 5V on the power rail for the keyboard. I also checked different ADB cables I have lying around, since they're just SVideo -- None worked. I'm afraid my keyboard might be dead (or worse --  The motherboard).

Is there any easy way to check if the keyboard is bad?

KittyFae

I am having the same issue with my mono nextstation turbo. Not been able to figure it out. Jumping 3v to the psu pin turn on the machine. However, my keyboard works to get into the rom monitor and type but the arrow keys, monitor controls, and power button do nothing. I've traced the keyboard out and it looks like the power button has it's own pin that is properly being grounded when pressed. Mine is non-adb though.

barcher174

What kind of nextstation? A mono turbo? Did you wire pin 7 in your adapter?

primis

Mono turbo on mine btw.
Small update: turns out I can get to the rom monitor, but only after a few tricks -- The netboot has to fail, and get to the "Bad network screen", and then I can do command + ` and then I have to hit the power button. This manages to get into the rom monitor (very weird behavior) but the keyboard does work to type which means adb is going through to the computer. Still can't get power on to work... but again, I made a bodge fix for the power on by routing two wires through the back of the case. One for the positive end of the battery, the other to the PSU power sense, and wired up a momentary switch. It's not ideal, but it's working I guess?

barcher174

If you are having to wire the power supply directly you may have a problem with the RTC chip. The non turbo is easy to find, but the turbo rtc may take some searching. This is a very common failure at this point.

My recommendation to both of you is to check the inside of the soundbox for leaking capacitors.

KittyFae

August 18, 2019, 11:58:52 pm #6 Last Edit: August 19, 2019, 04:29:40 am by KittyFae
Quote from: barcher174 on August 17, 2019, 07:59:09 pmIf you are having to wire the power supply directly you may have a problem with the RTC chip. The non turbo is easy to find, but the turbo rtc may take some searching. This is a very common failure at this point.

Is there a way to test the RTC via something like a diagnostic floppy before replacing the IC? I neither have a hard drive in the machine, nor do I have an external CD-ROM.


UPDATE:
I went and checked a ton of stuff. Ended up tracing out the power switch circuit and found that a long trace that was corroded through on the bottom of the motherboard and was not getting any continuity. After cleaning and checking for other damage I ended up soldering up a fix and now my machine boots from the keyboard soft-power button. Hopefully this can help somehow!

primis

Quote from: KittyFae on August 18, 2019, 11:58:52 pmI went and checked a ton of stuff. Ended up tracing out the power switch circuit and found that a long trace that was corroded through on the bottom of the motherboard and was not getting any continuity. After cleaning and checking for other damage I ended up soldering up a fix and now my machine boots from the keyboard soft-power button. Hopefully this can help somehow!

I'm gonna try this fix over the weekend, hopefully it's not the RTC chip (worst case I have a kludged power switch :P)