NeXTStation Color Turbo that won’t switch on

Started by TypeLex, February 11, 2024, 09:09:20 AM

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TypeLex

Hello Everyone,

Starting this topic as I have recently purchased a NeXTStation Color Turbo but after receiving it, it won't turn on (it was advertised as untested so no worries there)

For testing I've used the following setups:
- Color Turbo with non-ADB sound box and Blackhole Inc. Y cable // Slab won't switch on
- Color Turbo with Universal IO and Blackhole Inc. Y cable, both ADB and non-ADB keyboards // Slab won't switch on
- Changed power supply to a working Color (non-turbo) power supply // Slab won't switch on
- In all cases, I used a known working battery

The other way around everything works, I used the Color Turbo power supply in my Color slab and it started correctly with both ADB Soundbox and Universal IO


Now I'm assuming that the Color Turbo slab capacitors aren't good anymore and plan to ReCap this slab

Before I go ahead with the recap job, anyone has any other idea as to what could be the issue?

nuss

Hallo @TypeLex ,

things you can test:

1. make sure that the contacts of the battery holder are in good condition. You can use paper to rub / clean the metal that connects to the battery and / or isopropanol.

2. please try to power on the turbo-slab with the big fan disconnected from board. But please let only run it very short time without working fan, if it happens to starts up. I (think to) remember (from long time ago), that a damaged fan can stop the slab from being powered on.

3. check the board for short-circuits, like tiny metal particles. Blow away all dust from the board.

Good luck :)
DON'T PANIC

Rob Blessin Black Hole

Rob Blessin President computerpowwow ebay  [email protected] http://www.blackholeinc.com
303-741-9998 Serving the NeXT Community  since 2/9/93

TypeLex

Quote from: nuss on February 11, 2024, 11:55:42 AMHallo @TypeLex ,

things you can test:

1. make sure that the contacts of the battery holder are in good condition. You can use paper to rub / clean the metal that connects to the battery and / or isopropanol.

2. please try to power on the turbo-slab with the big fan disconnected from board. But please let only run it very short time without working fan, if it happens to starts up. I (think to) remember (from long time ago), that a damaged fan can stop the slab from being powered on.

3. check the board for short-circuits, like tiny metal particles. Blow away all dust from the board.

Good luck :)

Thank you for the hints @nuss tried everything you mentioned but unfortunately it still doesn't switch on

I have all the necessary Nichocon capacitor on site so will go ahead and see if recap does the job

nuss

DON'T PANIC

TypeLex

Alright, recap done but unfortunately the Color turbo slab still won't switch on  :'(

What I find strange is that I have two color (non-turbo) slabs who switch on correctly with this setup but my two Color Turbo Slabs (one recapped, one not recapped, purchased from different sources in Japan and US) won't switch on
Tried with both ADB and non-ADB soundboxes/keyboards as well as with Universal IO and Blackhole Y Cable, same result on all slabs

Any other suggestion welcome!

barcher174

There's 3 primary board level failures I see on the turbos.

1) Trace rot
2) Bad RTC chip. You can find the datasheet and try jumpstarting it by shorting some pins
3 Bad Asic

If you post some high res pics of the board maybe we can point out potential issues.


barcher174

Yeah the boards looks pretty clean. I have the RTC datasheet here:

http://www.asterontech.com/Asterontech/Datasheets/MCCS1850.pdf

You'll basically want to start there and follow the power switch to the 13w3 connector and verify connectivity/switching. There are luckily schematics for the turbo color here in the file archive. Unfortunately if the RTC itself is bad, I don't know of any source for them except another dead board.

TypeLex

Thank you for the reply and data sheet @barcher174

Will test it out and will also see if I can find some stock in Taiwan/Japan/South Korea ecosystem (I live and work in those countries)

Further to testing out the RTC, would it make sense to try out manually switching on the slab?
I see that this can be done with pin 11 on the PSU connector, do you have a safe procedure to manually switch on the PSU?
I've read two versions so want to cross check before going ahead:
- apply 1-1.5V to pin 11 for 1sec (advise from Google Gemini 1.0)
- apply 3V to pin 11 (in another thread here)

Do I go ahead and apply the voltage between pin 10 and pin 11 on the PSU?
Here's the reference I'm using for the pin out http://heller.no-ip.org/~heller/NeXT/power_supply/pinout.tiff

barcher174

Yeah you can just connect the battery to the P_ON signal of the power supply.

If you find a source for the RTC please buy me a couple dozen too!