English Amiga Board


Go Back   English Amiga Board > Support > support.Hardware

 
 
Thread Tools
Old 05 January 2019, 13:50   #1
Englyst
Registered User

Englyst's Avatar
 
Join Date: Apr 2012
Location: Copenhagen, Denmark
Age: 47
Posts: 97
A4000 power issue (Mediator)

Hi folks.

I'm a bit baffled by the reaction of my A4000 with a Mediator Pro (the tower from Elbox). I had it shelved when I encountered some issues with it and now decided to see if I could get it running again.

First off my config:

A4000cr Rev. D motherboard with 16 MB Fast RAM
A3640 CPU card
Kickstart 3.1 mounted
Mediator 4000 ver. 1.0 with bridgeboard
Gotek floppy drive
IDE DVD-Drive
Matrox IDE 160 GB HDD
Voodoo 5500 graphicscard (working last time the machine turned on).
Realtek Ethernet card (also working)
Original PSU missing - I believe it died and that's shy I removed it.

So I went and bought a Corsair VS350 ATX PSU to mount in the tower. Now here's where my confusion steps in. Whenever I power the Amiga on, the Gotek has power, the IDE HDD does not, the DVD-drive powers on and so does the Voodoo card.

I also removed the PSU in my PC (Corsair VS550) and tried that too - same result.

Only thing I see on the monitor is a light grey screen. I believe it's Power On status. That's all that happens.

Anyone have suggestions as to what I'm missing here? I've tried it without the Mediator in it, and it's the same result. And I've also tried with 2 other A4000 motherboards (4000 Rev. B's). Exactly the same result.

Can it be that the PSU doesn't supply what's needed or the Elbox ATX power converter is broken?

I hope someone can help me out with suggestions.

Thanks!

Last edited by Englyst; 05 January 2019 at 14:24.
Englyst is offline  
Old 05 January 2019, 20:46   #2
Englyst
Registered User

Englyst's Avatar
 
Join Date: Apr 2012
Location: Copenhagen, Denmark
Age: 47
Posts: 97
Put in one of my Rev. B motherboards to see if I was getting the same result as on the Rev. D.

Here's some photos attached.

There's a screen output without CPU card in (same result with the 68040 mounted) and some pictures of the motherboard and CPU card.

Don't know if you can tell anything from these. Signal on-screen is weird..

This is with an older 350 watt PSU, not the Corsair VS350. On the VS350 all I get is a grey screen with some vague inteference lines mixed into the grey image.
Attached Thumbnails
Click image for larger version

Name:	Scart-RGB-Output.jpg
Views:	55
Size:	863.0 KB
ID:	61460   Click image for larger version

Name:	Motherboard-Rev.B.jpg
Views:	49
Size:	970.1 KB
ID:	61461   Click image for larger version

Name:	Motherboard-Rev.B-2.jpg
Views:	48
Size:	1,002.8 KB
ID:	61462   Click image for larger version

Name:	CPU-Board-1.jpg
Views:	45
Size:	1,018.5 KB
ID:	61463   Click image for larger version

Name:	CPU-Board-2.jpg
Views:	43
Size:	1,007.7 KB
ID:	61464  


Last edited by Englyst; 05 January 2019 at 20:56.
Englyst is offline  
Old 06 January 2019, 01:01   #3
elenachen
Registered User

 
Join Date: Feb 2018
Location: N├╝rnberg
Posts: 91
Has the Barrel Battery leaked?
elenachen is offline  
Old 06 January 2019, 02:46   #4
-Acid-
Registered User
 
Join Date: Oct 2012
Location: South Shields
Posts: 669
How many amps can the psu on +5v supply? it might just not be high enough for all of those add ons. Try powering it up with only essential things drawing power and see if it boots.... if it does then add one thing at a time and retest etc

Last edited by -Acid-; 06 January 2019 at 02:53.
-Acid- is offline  
Old 06 January 2019, 08:53   #5
Englyst
Registered User

Englyst's Avatar
 
Join Date: Apr 2012
Location: Copenhagen, Denmark
Age: 47
Posts: 97
No leakage on the barrel battery. And the cr Rev. D has a CR2032 battery.

I powered it up without the Mediator and only the Gotek and HDD drive. No go. I've stripped it down and it still doesn't boot. I'll be trying more today.

Some bad connection somewhere? It's been years since I fiddled with the A4000, so there are stuff that has gone dormant in my brain ??
Englyst is offline  
Old 06 January 2019, 10:04   #6
Englyst
Registered User

Englyst's Avatar
 
Join Date: Apr 2012
Location: Copenhagen, Denmark
Age: 47
Posts: 97
Weird. It seems with the new PSU it sometimes works. The power button and the power converter are a little iffy, meaning it's not always it turns on the PSU when I push the power button, and it looks like it needs a power on and a reset until it boots properly. So it's a bit of hit and miss here. But at least it works! Maybe persistence made it work?
Englyst is offline  
Old 06 January 2019, 14:34   #7
Englyst
Registered User

Englyst's Avatar
 
Join Date: Apr 2012
Location: Copenhagen, Denmark
Age: 47
Posts: 97
And it's back to being a right prick again - gurus when starting (8000 0004) when it decides it want to start. Sometimes I can boot from the Gotek, other times it just sits there doing nothing. When I finally got it booted off the Gotek, I installed WB 3.1.4 on the HDD but whenever it finally boots from the HDD and does a LoadModule and resets, it's back to grey screen and Guru land.

This is with no Mediator installed, just plain A4K with an IDE HDD, Gotek floppy and the 68040 CPU card, and 16 MB fast mem.

I'm getting pretty frustrated with it. :s Sorry for venting here, but I really want to get it running stable again.

I can put a video up of the behaviour of the A4K if it would help.
Englyst is offline  
Old 06 January 2019, 14:38   #8
grelbfarlk
Registered User

 
Join Date: Dec 2015
Location: USA
Posts: 1,842
Quote:
Originally Posted by Englyst View Post
Weird. It seems with the new PSU it sometimes works. The power button and the power converter are a little iffy, meaning it's not always it turns on the PSU when I push the power button, and it looks like it needs a power on and a reset until it boots properly. So it's a bit of hit and miss here. But at least it works! Maybe persistence made it work?

I think I have the same Mediator Pro (Mirage) tower you do and the Elbox Power adapter acts similarly for me. You have to press the power button just right for it to power up correctly.



I'd suggest just getting one of the Amigakit A4000D ATX adapters and use that instead, however you'd have to replace the power button with an On/Off type switch instead of a momentary-so it would take a bit of fiddling to do it.
grelbfarlk is offline  
Old 06 January 2019, 15:21   #9
Englyst
Registered User

Englyst's Avatar
 
Join Date: Apr 2012
Location: Copenhagen, Denmark
Age: 47
Posts: 97
I saw they had the ATX power adapter with the Mediator P9 plug at AmigaStore.eu:

https://amigastore.eu/en/420-atx-to-...converter.html

I'll probably get one when I have the funds for it. 45 EUR! Yikes...
Englyst is offline  
Old 06 January 2019, 20:51   #10
Englyst
Registered User

Englyst's Avatar
 
Join Date: Apr 2012
Location: Copenhagen, Denmark
Age: 47
Posts: 97
After a loong day testing and installing, it must be the PSU and the Elbox ATX converter that gives me issues. What I've found out is that when I turn the A4000 on the first time and the screen is a dark gray I quickly turn it off and on again, and sometimes it then powers up correctly and works. So the PSU needs to be 'double-tapped' to supply power to the A4000 properly.

Has anyone seen these symptoms on their systems?

Got the Mediator running and also WB 3.1.4. Only problem is that I have a permanent 4GB limit I can't pass, and it looks like I have to get the proper Kickstart ROM's installed before that limit will be gone. LoadModule does not do it for me. Even the LIMIT_4GBYTE=OFF (or FALSE) in HDToolbox does not remove the 4 GB barrier white line indication when partitioning the drive.

Also the two Maxtor HDD's that I have doesn't report the right settings when reading drive configuration and in both cases they report as an 8 GB harddrive. So there's still some issues to fix.


Englyst is offline  
Old 06 January 2019, 21:54   #11
amigakit.com
Registered User

amigakit.com's Avatar
 
Join Date: Aug 2004
Location: www.amigakit.com
Posts: 1,819
@Englyst

No need to pay 45 EURO, we have the adapter at 16 EURO:

https://amigakit.amiga.store/product...5&currency=EUR

amigakit.com is online now  
Old 06 January 2019, 22:08   #12
Englyst
Registered User

Englyst's Avatar
 
Join Date: Apr 2012
Location: Copenhagen, Denmark
Age: 47
Posts: 97
@amigakit.com

I can't tell from the picture but does it have the P9 connector that's necessary for the Mediator busboard? And with the power switch, instead of a logic board with a jumper to connect the power on/off switch that already is on the Mirage Pro, I just have two power buttons where the 'logical' one on the cabinet then doesn't work...

I don't mind paying more if it's the right adapter and the other one looks like it could replace the existing ATX board in the Mirage Pro tower. But I will keep that in mind.

I just have to wait a little while - Santa is exhausted after a tough Christmas

Thanks.
Englyst is offline  
Old 07 January 2019, 15:38   #13
Englyst
Registered User

Englyst's Avatar
 
Join Date: Apr 2012
Location: Copenhagen, Denmark
Age: 47
Posts: 97
I've now changed the PSU to a better one (Corsair TX750W with 30A on the 12V rails) but I still have issues powering up the A4000.

Could the Elbox ATX power converter be faulty?

When I had it started it worked fine for the most part - when testing P96 modes with the Voodoo5 it could lock up. But that's the only problem I had. And that was with the shoddier VS350 PSU, not the TX750W.
Englyst is offline  
Old 07 January 2019, 16:56   #14
-Acid-
Registered User
 
Join Date: Oct 2012
Location: South Shields
Posts: 669
Quote:
Originally Posted by Englyst View Post
I've now changed the PSU to a better one (Corsair TX750W with 30A on the 12V rails)
From what I understand it's the +5V rail which the amiga uses most, the 12V line not so much.

Last edited by -Acid-; 07 January 2019 at 17:05.
-Acid- is offline  
Old 07 January 2019, 17:10   #15
Daedalus
Registered User

Daedalus's Avatar
 
Join Date: Jun 2009
Location: Dublin, then Glasgow
Posts: 4,129
Indeed, the Amiga only uses a fraction of 1A on the 12V rail. The problem could be to do with modern supplies typically requiring a significant minimum load on their main output rail in order to correctly regulate their output. Modern PCs use the 12V rail for most heavy consumers, so that's now the main output rail on most power supplies, and not having enough load there will cause a good PSU to shut down, and a poor PSU to let the outputs (including 5V) wander out of specification, potentially damaging your Amiga and any connected expansions.
Daedalus is offline  
Old 07 January 2019, 17:10   #16
Englyst
Registered User

Englyst's Avatar
 
Join Date: Apr 2012
Location: Copenhagen, Denmark
Age: 47
Posts: 97
Sorry, I actually got it wrong. It's 30A on the +3.3V rail, 28A on the +5V rail and 60A on the 12V. So plenty to work with
Englyst is offline  
Old 07 January 2019, 17:13   #17
Englyst
Registered User

Englyst's Avatar
 
Join Date: Apr 2012
Location: Copenhagen, Denmark
Age: 47
Posts: 97
I've tried to find the minimum load specs but haven't been able to. What I did find was that it should scale really well, even on a low load. But again without the numbers it's hard to tell if it should work.

Tomorrow a friend will drop by with a voltmeter and we'll check what the output is when the PSU is turned on.
Englyst is offline  
Old 07 January 2019, 21:58   #18
Daedalus
Registered User

Daedalus's Avatar
 
Join Date: Jun 2009
Location: Dublin, then Glasgow
Posts: 4,129
Yeah, that definitely sounds like the 12V rail is the main output, with up to 720W available on that rail alone. I'm sure it scales well, but with a possible load from the Amiga of 0.1A, it might not scale all that well... Minimum load specs are pretty hard to come by because manufacturers (rightly I guess) tend to assume that the PSU will power a reasonable modern PC, and even the most energy efficient standard PC will draw a few amps. Also, being a 750W PSU, it's likely not intended for powering a small, efficient PC but a moderate gaming rig with a power-thirsty GPU.
Daedalus is offline  
Old 07 January 2019, 22:51   #19
Englyst
Registered User

Englyst's Avatar
 
Join Date: Apr 2012
Location: Copenhagen, Denmark
Age: 47
Posts: 97
So what can I do? It's not like A4000 spec'ed ATX PSU's are easy to find by the sound of this. Any suggestions as to what would work as a Mediator ATX PSU?
Englyst is offline  
Old 08 January 2019, 00:33   #20
Daedalus
Registered User

Daedalus's Avatar
 
Join Date: Jun 2009
Location: Dublin, then Glasgow
Posts: 4,129
I'd suggest maybe loading the 12V rail with some sort of dummy load, like a stack of old hard drives or big 12V fans. For a more permanent solution, a high power rated resistor attached to the chassis and connected across the 12V rail can do the job as well, but ultimately you really need to know the minimum draw requirements for the PSU. Maybe ask the manufacturer for the full datasheet. In general, the lower the maximum capacity, the lower the minimum load, though this isn't a hard and fast rule. But it might be worth trying to find a PSU that only gives maybe 150-300W of output. Just make sure that the 5V rail isn't too low as that's the important one for an Amiga. An alternative is to use an industrial PSU module instead of an ATX supply, but that requires a good deal more work for the modifications needed.

There could of course be some other issue happening, not actually related to the PSU... But the PSU seems the most likely.
Daedalus is offline  
 


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
A4000 Mediator trixster Hardware pics 60 03 September 2019 20:10
Power problems with Power Tower/Mediator/68040 Toki support.Hardware 24 02 May 2016 10:29
A4000 in Micronik tower with mediator? voyager_1701e support.Hardware 2 20 June 2014 14:47
A4000 Mediator Zorro help!!!!! titisoft support.Hardware 0 03 August 2011 23:52
FS on Ebay A4000 tower + mediator AMIGAZ MarketPlace 3 18 April 2010 20:12

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +2. The time now is 22:04.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Page generated in 0.09034 seconds with 14 queries