Prodesk 600 G4 MT i5-8500 replaced with i7-8700 No POST (or any display out) Issue

[TRTechRev]

Hello. I purchased a bulk lot of Prodesk 600 G4 from my Uni computer lab. Ive done this with Optiplex but not any HP systems yet.

So they came stock i5-8500 with 1x8G RAM, I purchased i7-8700s to replace the i5s, As well as RX 6400, RX 6500XT (2x SATA to 6pin PCIE) and GTX 1650 to experiment with the fastest budget 1080p gaming box to sell to people on a budget.

I understand this is likely not sanctioned by HP but I would simply like to know if there’s some kind of configuration lock on the BIOS of these machines (considering theyre deployed in business/schools) that will block a boot with hardware change without first booting it stock?

The new configuration I tried in two units now is i7-8700, 2x HP 8GB 2666 Ram (combining with a single stick pulled from other unit, in correct slots). The only major hardware change being the i5 to i7, and installing a DGPU (first test with RX 6400) and no im positive i didnt damage any socket pins. The only other thing I changed (while I kept stock heatsink and rear fan) was installing 2x 80mm Coolermaster Sickleflow fans on the interior of front of chassis after punching out 5” bay covers to switch config to positive pressure. I used a 3 way fan splitter on the Chassis Fan header and left stock exhaust and the two CM intake fans (only about 0.1A each) on that header. Not sure if that’s relevant.

Upon inserting boot media drive and pressing power button, all the fans (and GPU fan/leds) power on, seem to spin at a consistent RPM. There is a single, relatively short beep, and power button light stays dimly lit white. The GPU and CPU heatsinks  heats up (ive tried swapping GPU to RX 550 and same issue, not GPU issue) indicating something?

Yet absolutely zero display out from either using motherboard display outs or the DGPU display out. Nothing. No BIOS, no Boot/HP logo, no black screen with a blinking white cursor with some error/no boot media, literally nothing. The monitor is receiving no output and remains in sleep mode.

have tried clearing CMOS, different ram slots/config, different USB ports for boot media, different monitors, different graphics cards. I cant figure out what the problem is here. Anybody well versed in HPs desktops have any ideas? Thank you!

[NonSequitur777]

@TRTechRev,

Welcome to our HP Community Forum!

Well, I would consider myself to be well versed in upgrading legacy HP desktops.

So, with your indulgence, allow me to verify a couple of things first.

1.) Are we talking about the HP ProDesk 600 G4 SFF (small form factor) as referenced here: HP ProDesk 600 G4 Small Form Factor Business PC Specifications | HP® Customer Support, or the MT (Microtower) model as referenced here: HP ProDesk 600 G4 Microtower Business PC Specifications | HP® Customer Support.  This is most relevant, the SFF's power supply is a meager 180-watt PSU, which almost certainly would explain the single 'beep': it can't power the desktop plus any of the graphics cards you mentioned.

2.) Are the desktops fitted with a primary (boot) drive with Windows (or any OS) installed?

Let's start the discussion.

Kind Regards,

NonSequitur777

[TRTechRev]

Hello. I appreciate the reply. And sorry, I should have specified, they are all the MT/Mini-Tower model. Not the SFF, however I would think the SFF should be able to power an RX 6400 as well as it draws only 43 watts with a sustained load.

As far as the OS. I am not entirely sure what OS they (ie my University) had installed. Some version of windows 10 presumably, not sure if its a special Education Edition of Win 10 for mass deployments or possibly Windows 10 Pro. However the University Sanitizes/completely  wipes the SSDs before selling their PCs at auction like many other institutions do. So they were entirely wiped of the OS/data. However as they’re small 256GB SATA drives, I removed them and replaced with a 1TB blank SATA drive and inserted my Windows 10 Boot Media USB in both the front and rear USB ports.

Typically, like with the Dells or any other PC for that matter, I’ll get the Boot Logo and then the Navy blue splash screen that pops up with the prompt to install Windows on the blank drive. None of this happened in this case no matter what I did, I tried pressing the Clear CMOS button on the board itself and physically removing the battery and holding the button to discharge caps and still the same behavior.

The power button lights up white immediately along with the system and GPU fans spinning up, followed by a single beep, but then no response or output on the display whatsoever. I ruled out some kind of memory training or long first boot as I left it alone for about 30 mins to see if that would get something to show up and still nothing. Fans spinning, power button lit up, no display out. Really puzzling issue and I could not find an answer that seems to fit checking thru forum posts before asking myself.

This is why I wonder if theres some kind of configuration lock or something on the BIOS blocking the POST from even initializing? Perhaps a jumper needs to be moved or returned to stock and booted into bios to change a setting first? Not sure. Hope this helps, thanks.

[NonSequitur777]

@TRTechRev,

I never encountered a config lock, and I wouldn't even be sure how to check for that.

Anyway, what I would do in your situation:

1.) Make sure that you got a green jumper (see red circle) on your motherboard:

2.) Reinstall the i5-8500, two 8GB RAM sticks (either in the black/black, or white/white slots), no discrete graphics card, connect your monitor via the desktop's DisplayPort (DP) video port, the one closest to the center of the case.

3.) Install a single Windows installation flash drive (properly prepared using Rufus) in one of the USB 3.1 Gen 2 ports (see blue square):

Just would like to see if your HP ProDesk 600 G4 MT can boot and install Windows.

Kind Regards,

NonSequitur777

[NonSequitur777]

@TRTechRev,

Whilst I await your response, I would like to revisit the single beep you mentioned earlier.

In my experience -especially with legacy HP desktops, I insist that a single beep is most typically a power issue. Either bus being held down or you got a defective power supply.

So, in addition to the steps I posted in my previous comment, I would like you to disconnect the power supply, take it out of the case, and use compressed air (aka "canned air") to thoroughly blow out the PSU.  Then -and no, I am not kidding you, use a regular hot air hair dryer and from a distance of about 2 inches (5cm) blow hot air in from the PSU's air-intake side, for about three minutes.

Speaking of canned air, I assume you cleaned out the motherboard already, and dis- and reconnected every cable.

Kind Regards,

NonSequitur777