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Author Topic: ATX Power Adapter Issue (3000T)  (Read 540 times)

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Offline madgrizzleTopic starter

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ATX Power Adapter Issue (3000T)
« on: February 19, 2018, 08:33:16 PM »
I have one of Ian Stedman's ATX adapters that I'm trying to use with a 3000T.  Prior to connecting it to the motherboard, I want to triple check everything and make sure I'm getting the correct voltages at the plug going into the motherboard.  However, I can't seem to get the PSU to turn on.  I've installed a jumper on JP4 and set the switch to latch, but when I turn on the PSU via the switch on the mains, I get nothing (no voltage and no fans turning on).  I've emailed Ian but he hasn't responded (its only been a few hours).. Has anyone tried to use one of these before and know if you can use it without it plugged into the motherboard?

Edit: The first power supply outputs ~3V on pin 14 and the second output ~5V. When I jumper pin 14 to ground, both PSUs will power up.  I looked at the device in my microscope and it appears the lead to the jumper passes through an IC.  Github says this is a PIC microcontroller, so I suspect there is an an issue with it as it should operate from 2V to 5.5V (per a datasheet I found)
« Last Edit: February 19, 2018, 09:12:43 PM by madgrizzle »
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Offline HyAmi

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Re: ATX Power Adapter Issue (3000T)
« Reply #1 on: February 20, 2018, 06:52:04 AM »
Have you tried using some load on the 12V rail? Some powersupplies do not power up if there's no electrical load.

I'm also working on replacing the innards of an A3000T powersupply, but I've used the ATX poweradapter that has been created by Matze from the A1k.org forum. This adapter has some large resistors for drawing some power from the powersupply. It works flawless.
« Last Edit: February 20, 2018, 06:55:30 AM by HyAmi »
 

Offline madgrizzleTopic starter

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Re: ATX Power Adapter Issue (3000T)
« Reply #2 on: February 20, 2018, 12:20:57 PM »
Yes, I plugged in a scsi drive with no success.  If I jumper the pins on the atx PSU plug, they turn on.  I'm pretty sure there's an issue with the PIC at this point.  Just waiting for a response.  Thanks

Can you post a link to the adapter you are using?
« Last Edit: February 20, 2018, 12:24:14 PM by madgrizzle »
Only Amiga *woo-woo* Makes It Possible
Only Amiga   ... Makes.. It .. Happen!
Amiga 2000, 2MB Chip RAM, OS3.9, GVP Combo 030/22 13 MB, Supra 4MB
Amiga 3000, 16 MB RAM, OS3.9, A3640 v3.2 with 060 Processor, Picasso II, A2065, PCD-50B
Dead VA2000/CX :(
 

Offline HyAmi

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Re: ATX Power Adapter Issue (3000T)
« Reply #3 on: February 20, 2018, 07:44:26 PM »