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Power Supply connectors different?

By raticus ·
I want to shift: Mobo, cpu, hd's x4, floppy, cdrw, dvdr,and so on into a larger case. The power supply that I currently have does not have enough plugs for all this. The power supply in the larger case does.
But- my Mobo has smaller connection on board than other ps needs. Can I do anything about this, ie connectors?????????????????

I have 4 hd's because they are all small and I cannot afford parts. I also want to do this so as to kinda build a puter from ground up. (just to see if I can)

I have a Compaq presario 5000 = Intel Pentium 3e, 750mhz, 20GB HD, 320mb SDram and running Win98se. Also good monitor, keyboard and mouse, 1 LG Dvd r, 1 LG cdrw, NEC floppy drive, realtek ethernet adapter x1, intel 810e chipset graphics driver(DC133,FSB133)3D accelarator-Intel i752, EssTechnology Allegro-1. Comm Audiodrive, Conexant HCF V90 56K dataFax PCI modem, USB 1.0

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by dmiles In reply to Power Supply connectors d ...

The ATX power supply connectors that requires converting can be done by using a 20 to 24 converter needs or vice versa.The converter can be purchased from a computer store.
If you ahve a P4 and their is a smaller connector you can use both on the board
Hope this helps

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by HAL 9000 Moderator In reply to Power Supply connectors d ...

With a P3 M'Board you should have a 20 pin ATX connector for the Power Supply.

The new cases tend to have a 24 Pin ATX Power Supply Connector to work with the new family of M'Board Chip Sets but there is a catch here. The 24 Pin Plugs lack one 5 VDC + lead that is on the 20 pin ones so a straight converter from 24 to 20 pins may not work properly with your M'Board as one of the 5 V DC rails will remain un-powered which can cause problems.

The best idea is to move the old PS over to the new case it should bolt straight in if it is a standard ATX PS and then all you'll need are a few splitters for the added Power Leads for the devices which you should already have in the old case. It doesn't look pretty but it works and provided you don't have a clear side or leave the cover off no one will be any the wiser.


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by HAL 9000 Moderator In reply to

Well the things that you really need to look out for are the Front Panel connectors as they can be put on incorrectly and can be hard to see the printing on the M'Board.

If you could pick up a 400 W + Antec PS with a 20 Pin ATX Plug it would be quite nice but the 250 W one will most likely work OK but may not offer the protection that a High End PS will.

The worst that should happen if you over power it is that the PS Fails but I've seen at least one case where a cheap no name PS has allowed mains into the case and as it was the Domain Controller it fried the entire Network as the LAN lines provided a very nice path for the mains voltage out of the server.

I've also seem the results of a tree falling onto overhead power lines and bringing the High Voltage into contact with the Low Voltage Mains the cheap PS allow the power through where the good PS sacrifice themselves and save the computer.

While 250W is a bit on the small side many years ago I was running a 486 with SCSI HDD's and a lot of power hungry hardware hanging off a 250 W PS and it worked A OK.

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by sgt_shultz In reply to Power Supply connectors d ...

i believe it is possible the poster is talking about floppy drive and ide drive molex connectors. Otherwise why mention 4 hard drives?

You can get 'y' power adapters to expand your available number of hd power connectors. call the people you bought your new case from and ask them this question and they will help you...otherwise you can chain together 'y''s to get what you need. available couple bucks at compusa or similar.
just add up the watts each hd and othr device you plug in consumes and see if your new power supply has plenty of watts...

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by dlaslo In reply to Power Supply connectors d ...

Looking at the new power supply, does the oversized connector have two colors? I had recently bought a new ps with the 24 connector and the extra 4 was able to be removed. I was able to just slide it off and use it as normal.

So if the connector does have two colors, you should be able to remove the extra 4.

In my situation, I was going from a 250w to a 450w. The 250w didnt have the juice for a new video card.

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by TheChas In reply to Power Supply connectors d ...

Just for grins, can you describe or detail the different connectors?

The standard 20 pin ATX power connector looks like this:


and is about 1 3/4" long.

The old 12 pin AT style looks like this:


From the power supply, the AT connector is usually 2 - 6 pin connectors.

So, does your motherboard have AT, ATX, or some other connector?

Does the power supply have AT, 20 pin ATX, 24 pin ATX, or some other connector?

I ask this, because I would not be the least surprised if Compaq used a unique connector.

I also am making the assumption that the larger case is used, not new.

Now, as one peer posted, you can use "Y" cables to add more hard drive power connectors.
However, you need to be careful, as with 4 hard drives, you may end up needing more power than either power supply can deliver.

An old tower case just might have a 250 Watt AT style power supply in it.

Once you determine what style power connections you have on both the motherboard and power supplies, the next thing to do, is check the power rating of both power supplies.
You want to use the power supply with the highest power out rating.

Personally, I would want at least 350 watts for this system.

One side point to be mindful of, if the larger case does have an AT style power supply, you will need a different power switch and some mechanical modifications to use an ATX style power supply with it.
The power switch for an AT power supply switches AC main power to the supply.
An ATX power switch switches a DC signal from 5 volt standby power to the power control circuit on the motherboard.


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by TheChas In reply to

The 250 watt supply in the tower case is better than the 145 watt in the Compaq case. So, that is an improvement.

As to the issue of having an undersized power supply, the power supply runs hotter, and can fail catastrophically. The best case is that the PC just stops working. Worst case is that the power supply fails in such a way that it fries other parts in the system.

With the system all set up and running for at least 1/2 hour, check and see how warm the air is blowing out the power supply cooling fan. If it is a lot warmer than room air, get a larger supply as soon as you possibly can.


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by westec77 In reply to Power Supply connectors d ...

You may find a local computer store that has adapters to fit the connectors. Also check the power supply rating.

see you @ www.sacramentocomputertechnician.com

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by raticus In reply to Power Supply connectors d ...

Chas-Yes case is used, not new.But is large tower no rust, good design. Seems to have a Seasanic 250w atx 20 pin ps. Motherboard I want to use seems to have 20pin atx connectors. Dunno why I thought they different. Musta been real tired last night. Cant find the wattage on the Compaq PS at all, output max is 145watt not sure if that helps.
250 watt PS not great but what would happen? Would it just be slow or could it freeze lots or what? Would be heaps easier not to have to switch PS as well. Still nervouse about switching the Mobo. Never done it before.

Hal-I do want to be able to mod the case somewhat eventually, fans and lights. Plus I want it to be easy to work/see inside. Thus the large case. Although I am tossing up whether I want a second Mobo slaved to the first. That could cause difficulty if I put a clear side in the case, plus still figuring out how to safely switch the mobo. I dont have a Mobo manual and compaq/hp site only has basic info/mauals.

sgt_shultz -"just add up the watts each hd and other device you plug in consumes and see if your new power supply has plenty of watts..".How can I find out what watt each HD etc consumes?

Why all the rigmarole? 1. To see if I can. 2. Old parts, no money, need more power & HD storage. 3. For fun.

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by electricdragon In reply to Power Supply connectors d ...

I'm sure you'll reject this, because you probably won't like my suggestion at the end, but I can help out a little before that.
To answer one of your questions, you calculate your HD wattage using Ohm's law, chances are the HD has on the label something like "5v-500ma 12v-500ma"
Volts times amps equals watts, in the above case you would have 5v at 2.5 watts and 12v at 6 watts, so the drive has a total power consumption of 8.5 watts.

What you want to do cannot be done, sorry, the 145w (max) supply will have an average output more on the order of 90-110 watts, that is just not enough to run all that equipment. There is no such animal as an AT to ATX PS converter cable, reason being there is no 3.3v output from an AT PS.(your ATX mobo will not start.)(There is the reverse however, ATX to AT, but don't even think it,lol)

Here comes the part you won't like, but I call it like I see it, and I really am just trying to help, I hope you view it in the way it is meant.

I think it would be a good idea for you to hit the library and check out a book, I recommend "Que-upgrading and repairing computers", any edition, as it seems you have a few things to brush up on before you attempt a project like this. No offense, but someone that makes a statement like this:
"Although I am tossing up whether I want a second Mobo slaved to the first."
But does not know how to calculate wattage, is trying to sound like they know more than they really do.
There is a bit more to building, let alone modding, a computer than just plugging cards and cables together.
We went to school for this for a reason. :-)
ps, if it help's, and you can find at least a few bucks, check eBay, you can get ATX PS's for little more than the cost of shipping, go with the earlier suggestion of 350 watts.

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