HP Pavillion RAM upgrade - wont turn on ! No POST!

I've been fixing computers for quite a while but this problem stumps me. HP Pavillion t430.uk with MS-6575 Ver 3.1 mobo (all standard). Only 256MB DDR333 (Hynix) in so was trying to upgrade it with a DDR400 512MB stick (Major). I've never ever had to match brands of RAM before and in past experience sticking in a DDR400 stick will step it down to DDR333 automatically (this is the most the motherboard can support anyway).
When i stick the 512MB RAM in, i press the power button, fans spin for a fraction of a second, power light comes on for a fraction of a second, then nothing.

Take the 512MB stick out, works fine. Take the 256MB stick out and put the 512MB in. Doesnt start up.

My main concern is that WITHOUT the 512MB stick in (i.e. factory standard) the power button doesnt seem to work too well. It needs to be held IN for a few seconds sometimes to stay on, otherwise the power will cut, and when holding the power button in for 10 seconds to force the power off, it will reboot unless i take my finger off at the right time!

Is my problem that I haven't matched brands and speeds of RAM or do I need to take it apart and have a look at swapping the PSU and etc?

I've made sure POST (and the internal buzzer) works by leaving both sticks of RAM out, and theres a relieving BEEP to show it works.

On the HP support forums someone (not HP staff) said that the RAM doesnt meet JEDEC standards and I should only buy from Crucial or Kingston, but i've never had this problem before!

Any help would be much much appreciated! Let me know if anymore info is needed and I'll reply ASAP.

Thanks again,

Dan Gent
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  1. Hmm....your motherboard does support 512Mb sticks right?

    I would try to verify that the 512Mb stick works in another computer.

    Check the timings of the 2 Ram sticks. The reason why it is suggested NOT to mix up RAM is because timings also play a role in addition to speed in making a stable system.

    What are the specs of the DDR400 stick of RAM compared to the DDR333 stick?

    BTW, some motherboards do not work with some types of RAM; I don't know why, but some manufacturers post compatible RAM chips with their MB's.
  2. yeah, for an HP machine, i would only suggest getting kingston ram. and also get ddr333 with same timmings, while mobos usually will step down the speed, they sometimes wont change the timmings with it.
  3. The 512MB PC3200 stick I used for the problem, I tested in two of my computers today on Memtest and Memtest+. Both reported thousands of errors. Could all this be down to this particular stick of memory being faulty? (although on these other two PCs it actually bootemup)
    Or is it possible the motherboard have damaged the RAM by giving it to high a voltage? Therefore meaning its not safe to try some more RAM, even if its same timings and speed from Kingston?

    Thanks for the help so far, much much appreciated
  4. Did you test the 512Mb stick alone and ensure that the proper voltage and timings were reported in the BIOS and by Memtest?

    If so, then the RAM is faulty; it is doubtful to have damaged the memory slots, but you can try testing that good stick of RAM in the slots you think could have been damaged.
  5. To reply to your post PCkid, on the HP website it says it supports up to 1GB of memory
    the current 256MB stick in this PC is CL2.5, so is this 512MB stick. Its not OK to mix DDR400 CL3 with DDR333 CL2.5? I think i've done it a few times before and thought the slower clock speed meant it could make the two and a half clock cycles as its five cycles for the RAM?
    I think i'm way way off with that explanation!

    I'll have a look for a list of compatible RAM chips so I can match one up.
  6. wow PCKid, i was replying to your previos post! thats an amazing reponse time.

    I'll explain a bit more throughly. This particular 512MB stick of RAM I took to someones house to put in their abovementioned PC, to upgrade their current 256MB stick. With the 512MB stick in this PC (with and without the 256MB stick) the PC didnt turn on. the fans just started and stopped.

    I took the stick of RAM back home and tested the stick in two PCs (each of those PCs ONLY having the 512MB stick in during the test), using memtest and memtest+. Both reported thousands of errors, so the stick is definitely faulty
  7. Haha, thanks, I just happened to be on at the time.

    Looks like the DDR400 RAM is faulty.

    In regards to DR400 CL3 RAM running at CL2.5, that should be doable. Most DDR RAM chips have certain ratings, like 2-3-3-6 @ DDR333 or 3-3-3-8 @ DDR400, etc, all dependent upon the RAM quality, voltages, and what not.

    Getting into technicalities, the clock cycles all deal with the rise and fall of voltages or frequencies I believe. (I think there is a guide on this forum for more specifics).

    This RAM may be compatible and a relatively cost effective upgrade:



  8. Yeh it was faulty RAM. I bought some quality Corsair stuff just in case, put it in, worked first time, and memtest reported no faults after 6 hours.

    Thanks for the help guys
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