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Search: Posts Made By: Per Hansson
Forum: General Computer & Tech Discussion Yesterday, 01:40 PM
Replies: 22
Views: 3,292
Posted By Per Hansson
Re: The PacMan ATX Computer Case - cleaning and painting

When you cleaned the floppy did you also clean the read head with IPA?
If not then do, and also grease the bearings.
This might allow the unit to work fine.
As I understand it 5.25" floppies are...
Forum: Troubleshooting Power Supplies and Power Supply Design Yesterday, 01:34 PM
Replies: 4
Views: 39
Posted By Per Hansson
Re: Lenovo 135W charger

Check the primary side 450v capacitor, it could be bad:

https://www.badcaps.net/forum/showthread.php?t=63573
Forum: Troubleshooting Audio Equipment 08-07-2020, 10:10 AM
Replies: 45
Views: 398
Posted By Per Hansson
Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

To test a diode you need a multimeter that has a diode test function.
To test a zener diode you need the same type of meter in the forward direction.
But in the reverse direction you need a...
Forum: Troubleshooting Power Supplies and Power Supply Design 07-31-2020, 01:02 PM
Replies: 11
Views: 211
Posted By Per Hansson
Re: Shock when touching power supply case (ACBel API1PC36 from PowerMac G4 MDD)

By this: "It would be impossible to be shocked by the chassis as long as you have a working PE (protective earth) conductor with low impedance to the breaker panel."
What I meant is that in such a...
Forum: Troubleshooting Power Supplies and Power Supply Design 07-31-2020, 08:46 AM
Replies: 11
Views: 211
Posted By Per Hansson
Re: Shock when touching power supply case (ACBel API1PC36 from PowerMac G4 MDD)

Primary side heatsinks are often live, are you sure you simply did not touch one of the heatsinks?

It would be impossible to be shocked by the chassis as long as you have a working PE (protective...
Forum: Troubleshooting Power Supplies and Power Supply Design 07-31-2020, 04:16 AM
Replies: 15
Views: 681
Posted By Per Hansson
Re: iMac power supply short-circuit diode to ground

Most likely it is just a dual layer PCB, the problem is the black solder mask.
Try to get sunlight through the PCB, or a really strong artificial light.
That may reveal the tracks...
Example:...
Forum: Troubleshooting Computer Displays 07-31-2020, 03:54 AM
Replies: 2
Views: 264
Posted By Per Hansson
Re: ThinkVision T2454p backlight but no display - blown SOT23-8

How are the caps doing?
When ESR rises regulators must do a much harder job.
And eventually they can become overloaded...
-Or, it could be a marginal part or a design mistake of course as you say....
Forum: BIOS & Schematic Requests! 07-27-2020, 01:29 PM
Replies: 5
Views: 171
Posted By Per Hansson
Re: DELL Optiplex 740 - Need bios please no original

You are welcome, was it the 4Mbit or 8Mbit file you used? (To know which one is tested good now)
Also when you have the ability can you check if it is SLIC 2.1 or SLIC 2.0 using SLIC Toolkit from...
Forum: BIOS & Schematic Requests! 07-27-2020, 06:08 AM
Replies: 5
Views: 171
Posted By Per Hansson
Re: DELL Optiplex 740 - Need bios please no original

Try this file, there are two BIOS inside 4Mbit and 8Mbit
Depends on what BIOS chip / version you have.
This is extracted from O740-222.exe using HEX editor.
This is untested...
Source:...
Forum: Troubleshooting Audio Equipment 07-25-2020, 12:56 PM
Replies: 65
Views: 1,227
Posted By Per Hansson
Re: Numark NS6 Usb problem

That is what they call the "XMOS firmware" in the above screenshot.
-Whatever that is, don't ask me, I didn't design it :D
That said it is of a size (24KB) which would be in the ballpark depending...
Forum: Troubleshooting Power Supplies and Power Supply Design 07-25-2020, 12:49 PM
Replies: 35
Views: 2,345
Posted By Per Hansson
Re: The Cheapest ATX Power Supply on Amazon Prime, How bad can it be?

I updated your post with the new numbers. :)
Also just to reiterate what I said, the "ghost" image or phosphor lag is not really "invalid data".
You can think of it like the option "persistence" in...
Forum: Troubleshooting Audio Equipment 07-25-2020, 12:36 PM
Replies: 65
Views: 1,227
Posted By Per Hansson
Re: Numark NS6 Usb problem

The firmware goes inside the Atmel.
The service schematic shows the USB port, but also J13 programming header is connected for this purpose.
The thing is via USB is not possible without there...
Forum: Troubleshooting Power Supplies and Power Supply Design 07-25-2020, 01:52 AM
Replies: 35
Views: 2,345
Posted By Per Hansson
Re: The Cheapest ATX Power Supply on Amazon Prime, How bad can it be?

I think there is a small misunderstanding about the ripple, you say the scope is set to 100mV per division in this picture...
Forum: Troubleshooting Power Supplies and Power Supply Design 07-25-2020, 01:38 AM
Replies: 1,643
Views: 361,026
Posted By Per Hansson
Re: the gutless, bloated, and fried power supply hall of shame

There is a hole in a resistor on the primary side here (https://www.badcaps.net/forum/attachment.php?attachmentid=216507&d=1595638846), under the heatsink.
Really beautiful fuse, they cause so much...
Forum: General Capacitor Questions & Issues 07-24-2020, 01:35 PM
Replies: 75
Views: 32,692
Posted By Per Hansson
Re: Cap Datasheet Depot

It was also on the depot, but the company name omits "United" it is just "Chemi-Con"
http://www.paullinebarger.net/DS/Chemi-con/
Forum: General Capacitor Questions & Issues 07-23-2020, 12:38 PM
Replies: 21
Views: 12,795
Posted By Per Hansson
Re: Ltec Caps

Welcome to Badcaps :)
If you want to give it a try to repair it then here are two good threads to get you started:
https://www.badcaps.net/forum/showthread.php?t=65425...
Forum: Equipment Usage, Soldering, Techniques, and Reviews 07-22-2020, 03:14 PM
Replies: 16
Views: 429
Posted By Per Hansson
Re: How to correctly desolder through hole IC?

I also never got it to work until I tried it with a really large tip (=large thermal mass).
Then it works absolutely amazing, I can sometimes even clear multilayer PCB's (Though that is unusual) but...
Forum: Troubleshooting Power Supplies and Power Supply Design 07-20-2020, 09:36 AM
Replies: 10
Views: 282
Posted By Per Hansson
Re: Lexmark 544dn power supply buzzing sound model 40x5409

I would say that noise could likely be that the main capacitor has failed.
The reason for the unit not powering up however is likely to be any of the small caps drying out.
Since you have an LCR...
Forum: BIOS & Schematic Requests! 07-20-2020, 08:12 AM
Replies: 1
Views: 119
Posted By Per Hansson
Re: i need bios for GA-H61M-S1 rev.4.0

https://www.gigabyte.com/Motherboard/GA-H61M-S1-rev-40/support#support-dl-bios
Forum: Troubleshooting Desktop Motherboards, Graphics Cards, and PC Peripherals 07-20-2020, 05:56 AM
Replies: 6
Views: 236
Posted By Per Hansson
Re: Reattaching a small cap on a Voodoo5 5500 AGP

Also worth keeping in mind that although unusual sometimes these caps do go bad.
Case in point (there is even a Mouser shopping cart on page 2...)
...
Forum: Troubleshooting Computer Displays 07-20-2020, 05:02 AM
Replies: 42
Views: 18,090
Posted By Per Hansson
Re: Optiquest Q9 no power

Yes it is quite fun to look back at some old repairs.
Some of the stuff I repaired did not last more than a year when it was new.
And now it has been over 10 years since being repaired.
Amazing...
Forum: Troubleshooting Power Supplies and Power Supply Design 07-19-2020, 03:44 PM
Replies: 4
Views: 227
Posted By Per Hansson
Re: PowerMac G4 MDD ACBel Power Supply issues (API1PC36 400W)

The WT7515 on that PCB labeled "fan control" in your picture is the PSU supervisor.
The PSU will not work if this chip gets unstable voltage supply.
And my personal experience with small caps in...
Forum: Troubleshooting Desktop Motherboards, Graphics Cards, and PC Peripherals 07-19-2020, 03:37 PM
Replies: 6
Views: 236
Posted By Per Hansson
Re: Reattaching a small cap on a Voodoo5 5500 AGP

I'm sure Topcat would do the board if you want it.
This is not something I would recommend a novice try as his first thing.
Boards like these require allot of heat due to large ground planes.
If...
Forum: Troubleshooting Power Supplies and Power Supply Design 07-19-2020, 01:13 AM
Replies: 43
Views: 1,463
Posted By Per Hansson
Re: $20 "500W" PSU From MicroCenter, how bad can it be?

Wow, I wonder if they used human hair or cat whiskers when doing clearance checks?
More seriously the soldering looks really good, the problem is the PCB routing/layout!
It is also so bizarre...
Forum: Troubleshooting Power Supplies and Power Supply Design 07-18-2020, 11:35 PM
Replies: 43
Views: 1,463
Posted By Per Hansson
Re: $20 "500W" PSU From MicroCenter, how bad can it be?

That Rubycon looks original to me, manufactured week 43 2013.
I think the theory holds that it is a scavenged cap, how else would it be so dirty?
Did you check if the thermistor was in circuit or...
Showing results 1 to 25 of 500

 
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