English Amiga Board


Go Back   English Amiga Board > Support > support.Hardware

 
 
Thread Tools
Old 13 October 2021, 17:11   #1
Misko78
Registered User

Misko78's Avatar
 
Join Date: Sep 2021
Location: Belgrade, Serbia
Age: 44
Posts: 27
Voltage drop, Amiga 500

I had a significant voltage drop from 4,85V on power connector to 4.6V on floppy connector. Here is what i've done so far.

1. Packed RT-50B into an Amiga PSU case. Same thing, but more severe, new PSU was 5,01V and it still drop to 4,65V so i bump up the voltage to 5,3V to have 4,8V at floppy connector.
2. Changed all capacitors with new ones, and triple checked polarization
3. Did a continuity test all over the board, no problems at all.

Everything works fine otherwise, i use the HC508 accelerator and Gotek drive.
Misko78 is offline  
Old 04 November 2021, 20:15   #2
OldAmigan
Professional old fart!

 
Join Date: Dec 2017
Location: Dumfries, Scotland
Posts: 39
Hi Misko78,

Did you get any resolution of this problem?

Were those voltages you gave with the PSU connected and the Amiga powered on?

Did you get the same dropped voltage at the PSU at this time?

It sounds as if something in the Amiga is drawing too much current. You could try removing the accelerator and retrying.

Fred
OldAmigan is offline  
Old 05 November 2021, 00:12   #3
Misko78
Registered User

Misko78's Avatar
 
Join Date: Sep 2021
Location: Belgrade, Serbia
Age: 44
Posts: 27
Quote:
Originally Posted by OldAmigan View Post
Hi Misko78,

Did you get any resolution of this problem?
Unfortunately not.

Quote:
Originally Posted by OldAmigan View Post
Were those voltages you gave with the PSU connected and the Amiga powered on?
Yes Amiga is powered on and voltages varies a lot, i did monitored it while using it, I connected a multimeter and played a game and some demos and it goes from 4.65V low to 5.0V

Quote:
Originally Posted by OldAmigan View Post
Did you get the same dropped voltage at the PSU at this time?
No, this PSU is fine on other Amiga.


Quote:
Originally Posted by OldAmigan View Post
It sounds as if something in the Amiga is drawing too much current. You could try removing the accelerator and retrying. Fred
It's the same with accelerator and without it. Yes i guess something is drawing too much current, chips are warm to the touch, everything works fine. Maybe one of the new capacitors is dodgy.
Misko78 is offline  
Old 05 November 2021, 10:02   #4
Daedalus
Registered User

Daedalus's Avatar
 
Join Date: Jun 2009
Location: Dublin, then Glasgow
Posts: 5,593
What about the power connector itself - perhaps it's making poor contact and the excessive resistance there is causing the drop? I would measure the potential between the PSU's 5V output and the 5V as close as possible to the connector on the motherboard, and see if the drop is there. I would then do the same for the ground connection. It's not uncommon for those connectors to get tarnished and worn...
Daedalus is offline  
Old 05 November 2021, 20:57   #5
Photon
Moderator

Photon's Avatar
 
Join Date: Nov 2004
Location: Eksjö / Sweden
Posts: 5,174
1. Have you measured drop with original PSU and nothing attached but PSU?
2. Does the drop cause problems, if so which?

Can't find HC508 MKII power draw quickly, original is 2.5A which leaves 1.5A for HC508.
Photon is offline  
Old 06 November 2021, 19:30   #6
Misko78
Registered User

Misko78's Avatar
 
Join Date: Sep 2021
Location: Belgrade, Serbia
Age: 44
Posts: 27
Quote:
Originally Posted by Daedalus View Post
What about the power connector itself - perhaps it's making poor contact and the excessive resistance there is causing the drop? I would measure the potential between the PSU's 5V output and the 5V as close as possible to the connector on the motherboard, and see if the drop is there. I would then do the same for the ground connection. It's not uncommon for those connectors to get tarnished and worn...
Yes, i measured voltage at the power connector and the drop was there. I sprayed contact 60 into it and used a little bit of cotton on a toothpick to clean it. Now it is rock solid at 4,85V with original supply and 5,0V with Meanwell RT-50B.

Thanks for your help fellows!!!

Last edited by Misko78; 07 November 2021 at 03:51. Reason: typos
Misko78 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
Amiga 4000 _iorst voltage mortenkjerulff support.Hardware 0 13 May 2020 16:51
Amiga 500 and voltage rating on caps turrican9 support.Hardware 6 29 February 2020 23:50
What voltage transformer to buy for Amiga 500 Power supply ? Amifan23 support.Hardware 9 16 May 2018 18:16
Need help with Amiga 500 voltage converter ! Amifan23 New to Emulation or Amiga scene 7 15 May 2018 19:52
Voltage drop down, what could be the reason? Sim085 support.Hardware 7 03 August 2013 23:38

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 09:38.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2022, vBulletin Solutions Inc.
Page generated in 0.07515 seconds with 15 queries