Zenith MasterSport 386SX (ZWL-360-06) PSU pinout request

[Getafix]

Hi,
I have a Zenith MasterSport 386SX but no PSU. The machine works (HD's dead) when I put 7.2V on the battery terminals so that's great, but I'd obviously like a PSU for it. It has an 8 pin din power connector that says 11V. I can't find a user guide, service manual or any technical information about this laptop. Does anyone here have any info for it, and most importantly, have a pinout for the PSU port?
As a bonus question, any idea how to get into the BIOS on this machine? Perhaps it's more dead than I think and not getting to an ability to enter BIOS, but I don't think so.



Thank you,
Stefan

 

[Getafix]

I still haven't found the BIOS keys but I did discover that if I leave the machine on it will spin up the HD several times and eventually time out. At that point it does give me the option to press F2 to enter the bios. The machine boots from floppy now and works well . Even if I set the BIOS to have no entries for an HD it still does try to spin it up all the time and will give error beeps once in a while. But, now I can try to replace the HD, but I am still not sure about that PSU plug...
Thanks - Stefan

 

[modem7]

Even if I set the BIOS to have no entries for an HD it still does try to spin it up all the time

SCSI drives and controllers can be optionally set so that the drive only spins up when commanded to do so by the SCSI BIOS. Done in some multi-drive scenarios in order to stop an overload of the power supply. The greatest power draw of a drive is during spin-up. The SCSI BIOS starts one drive, waits a bit, starts the next drive, waits a bit ...

In a Zenith MasterSport 386SX, the drive is probably starting to spin up as soon as it receives power.

... but I am still not sure about that PSU plug

In lieu of the pinout:

The web page at [here] includes a photo that shows that the AC adapter is an Astec model ZA-360-3.
pchub.com is advertising the ZA-360-3 at [here].

 

[Getafix]

Thank you! I was hoping to make a modern one though but without a pin-out I'll have to buy one, and at least I still can.
On the HD - I found someone else looking at the exact same drive with the same symptoms. He opened it up and ended up replacing the magnets in the drive, although there's no final post to say of that fixed it. He did get to boot off of the drive by messing with it while open. The drive is a Conner CP-2064 IDE drive. I had a fun afternoon playing with an HD I opened. Never done that before. Didn't boot for me though Still, it was quite an educational event

 

[GearTechWolf]

That's a weird socket, looks like it's a mini-DIN-8!

 

[Smanux]

I've retrieved an old Zenith MasterSport 386SX from the attic, with a working PSU. I can try measuring the voltages on the pins if that helps.

I also have the same issue with the hard drive. It starts spinning and stops several times during the boot. Since the disk geometry can be configured from the BIOS I wonder if the settings were erased when the CMOS battery ran out of juice.

 

[Getafix]

Hi Smanux,
If you could measure the pins on the PSU that would be awesome! I've shelved mine for a bit - got busy with something else. I am quite keen to get back to it and to see if I can find a way to replace the HD. I ordered some connectors from Aliexpress and those have arrived - I can now try and make a custom HD cable. Probably won't get to it for a couple of weeks, though.

I suspect the CMOS is probably wrong for your machine. I can't remember what it was supposed to be set at and since I couldn't get the drive working, for me, it's now moot. I did figure it out though - I found the drive geometry online somewhere. For some reason type 44 sticks in my mind, but that may be totally bogus. I am travelling right now so I can't look where I found the drive info but if you can't figure it out, let me know and I'll look into it when I get home.

 

[Jakub]

Hi Guys,
I have a similar problem. Recently I purchased Daewoo 486SLC computer but without a charger (battery dead). It looks it is a clone of the Zenith MasterSport because it looks almost the same and has the same charger connector. I was very naive when I thought it won't be that problem to replace it by some generic charger. So as I couldn't find any functional charger on internet to buy I have bought a same spec charger on AliExpress and the connector and will try to re-solder. Unfortunately I didn't find any proper pinout schema so I'm not sure which pin I should connect to power source. Do you have any information/advise how to sort this out? Thanks a lot!

 

[Smanux]

Here is the result of the measure on the Astec ZA-360-3 PSU connector, there are 4 ground pins, 3 11V pins and one 9V pin.

 

[Getafix]

Hi - Thank you very much! Just to be sure - all voltages positive?
Really appreciate you taking the time - much appreciated!
Stefan

 

[modem7]

Here is the result of the measure on the Astec ZA-360-3 PSU connector, there are 4 ground pins, 3 11V pins and one 9V pin.

Hi - Thank you very much! Just to be sure - all voltages positive?

You will need to hear from Smanux regarding the 9V, but as for the 11V, the label on the ZA-360-3 adapter indicates that the 11V is positive.
I wonder why the 9V is not listed.

 

[Smanux]

Yes all voltages are positives. And the outer ring isn't grounded.

 

[Jakub]

In another words there's no chance to build this PSU by my own, is it?

 

[Getafix]

Jakub - I think you can. You should be able to use a cheap 12V and separate 9V charger (so 2 chargers) right now to do this. I am going to try and build a single charger using some cheap parts I just ordered from AliExpress. I'll report back once I have done so, success or fail. I still have to look to see if I have a plug that will fit, or I'll need to source that too. I am not giving up - not yet!

 

[Smanux]

Maybe the 11V line is only used for charging the battery, and the 9V line is enough to start the computer.

 

[modem7]

Maybe the 11V line is only used for charging the battery, and the 9V line is enough to start the computer.

There is even the possibility that the pin that measured about 9V is an input.

Something I can quickly think of:
- OUTPUT: 11V is only used to charge the laptop's battery.
- INPUT: Laptop signals the adapter to cease output when the laptop senses that its battery is full.

 

[Getafix]

As a test, I hooked up the 11V and ground and nothing happened. I then tried 9V and ground and nothing happened. But, now powering through the battery terminals also no longer works. Can't say if it was the test with 9/11V that broke it, or something else. It was working when I put it away so all I can say is, be cautions.

 

[Jakub]

Hi, guys. I reached a great success in this matter today. In case someone else is dealing with the same problem, here is how I did it and it worked.

1. I purchased adjustable charger with 3A on Aliexpress here. With this one you can set the voltage to 9 or 11 volts with 3 Amps.
2. I purchased several 8-pin mini din connectors. In case you are not very proficient in soldering just like me, the more the better. (Believe me, you`ll destroy some)
3. If the original (and most probably dead) battery is still inside the laptop, remove it. With the battery inside this is not gonna work!
4. I cut the connector on the power supply and separated the wires (the red one and the black one)
5. I disassembled the mini din connector and plugged it into the laptop.
6. With a use of the pinout provided by Smanux (thank you) I connected the right pin of the middler row to red wire (11 V) and the left pin of the middle row (GND) and tried to push the button and... it worked!
7. Finally I soldered the wires firmly to the connector and assembled the coating si it looks like regular plug.

Be warned that I have a different laptop then the Zenith MasterSport mentioned above (mine is Daewoo 486SLC), but I think it`s worth the try. Also this solution is not going to charge the battery. You would probably have to use different voltage for it, but I was glad that the laptop is running anyway as was waiting for this moment for year and half. Good luck.