Z4 G4 912 Error work around

[tallguyNJ]

A few months ago, there was discussion on fixing a 912 Error on the Z4 G4 after an upgrade.  One suggestion was using a Z440 CPU cooler with a 6 pin to 5 pin adapter, but there was never a clear final answer other than buying a HP high powered CPU cooler that cost about $150..  I can find Z440 Cooler and a website selling a 6 pin o 5 pin adapter for about $30 for both,  but I wanted to find out if anyone was successfully able to get this to work and get rid of the 912 error.

Thank you

[SDH]

Take a look again at the post you mention,  HERE .

There might be added info to help you on it now.  I'd try to contact Sean who was posting in that thread via PM on this forum... that does work.  If you are lucky he'll read it and reply.  Then, for others in the future, please let us know what you find out.

You can take a look at what the standard lower heat capacity  Z4 G4 heatsink looks like via eBay search for 900187-001.  Note it has only 3 heat tubes.  The Z440 one (749554-001) has 4 heat tubes which is more expensive to make.  That might be the only difference that boosts the cooling capacity up high enough to handle the hottest Z4 G4 processors, but HP might also have put on a higher RPM fan for the official High Performance Z4 G4 one that has been hard to figure out.

The heatsink cooling fan's header on the Z4 G4 motherboard is back to 5 pins... it went from 5 pins on the ZX20 to 6 pins on the ZX40 and back down to 5 pins on the Z4 G4..  The fan plug end on the Z440's big heatsink/fan is 6 pins, and on recent earlier Z workstations it also has been 5 pins.  The HP CPU cooling fan plugs have been the standard ground/12VDC/rotor signals to motherboard/and finally PWM braking signals from motherboard to rotor control. Then they add on the 5th (and 6th in the case of the Z440/Z640) is just a ground jumper from the first pin swung over to pin 5.  Pin 5 then just swings over to pin 6 via a short added jumper wire in the ZX40 heatsinks so it is quite simple.  For use of the Z440 6-pin fan plug on my souped up Z420/Z620 single processor builds I just hang that 6th fan plug socket out in space the 1/8" needed and it clears all adjacent motherboard parts just fine.

I have no idea if you could just do the same with a Z440 heatsink/fan from eBay without need for a 6-pin (fan plug end) to 5-pin (Z4 G4 motherboard header end) adapter.  That is what I'd try first.  There might be some HP magic built inside that adapter, however.  EDIT:  it turns out that there is some magic in the adapter... a jumper wire method that allows the fan's rotor signal to feed back to pin-5 of the motherboard's CPU fan header in addition to pin-3 (rather ground being seen on pin-5 as is the norm for Performance level heatsink fans from the past).  See details below.  The Z440 heatsink/fan we are discussing as the HP solution are so reasonably priced off eBay it is worth a try.  The key is the adapter discussed below in this thread.

If Sean has mastered this issue he'll share if he sees your message....

[SDH]

...finally found an official image of the HP elusive adapter we've been looking for, attached below.  This image is the HP adapter, but is from ModDIY's site, and they make their own matching adapter which implies the wiring is relatively simple without some hidden resistor/diode in-line.

I'd get one of theirs, and try it with the Z440 heatsink/fan in a Z4 G4... about $10.00 USD for the adapter and about $20.00 for the Z440 heatsink/fan from eBay.  Here is the official HP adapter:

[SDH]

And, finally figured out the wiring of the adapter:

You can see from the picture above of the official HP adapter that there are two black wires feeding into the pin-3 position on the header end.  On all prior Z workstations this has never been the case.  That is the pin that provides rotor signal feedback from the fan's rotor control circuit back to the motherboard.  The ModDIY site images show their matching wiring from their non-HP adapter (before they cover it)... the unique wiring shown documents clearly presence of a jumper wire that allows rotor signals to be fed back to the motherboard via pin-5 (in addition to via pin-3).  Usually there has been a ground jumper wire from pin-1 to pin-5.  So, the Z4 G4 motherboard can recognize that a high-cooling-capacity "Performance" heatsink/fan is attached by detecting rotor feedback signals coming in from pin-5 (via the pin-3 jumper wire you can see at the black motherboard header plug end of the ModDIY adapter).  The motherboard will still be seeing rotor feedback via the pin-3 pathway, also.  If the regular "Mainstream" heatsink was attached the motherboard would be seeing ground via the pin-5 pathway instead.  That's how it knows.....

The regular "Mainstream" Z4 G4 CPU heatsink/fan has a ground jumper from 1 to 5 instead of a rotor signal jumper from 3 to 5.

Someone will buy the official HP kit for this conversion, which includes the special jumper/fan/heatsink.  Please post a picture of the fan's front label and I can check out its performance parameters to determine if HP upped the base RPMs or simply is using the same fan as on the Z440 large 4 heat tube kit.  Below is added wiring info, credit to ModDIY, and they do a good job.  I would not hesitate to buy this adapter from them.  You can see what the adapter looks like with the wire sleeving in place on their web site.  It is missing in the promo picture below, which allowed me to understand the pinout:

[SDH]

Here are two pictures showing details of the HP Z4 G4 lower heat capacity heatsink/fan that comes on the builds using less than a 155W CPU.  HP never supported upgrading from the processor that came with its workstations, but it does work...

[tallguyNJ]

Hi SDH,

Thanks for all the good information.  That cable is the one I found.  I just would like to get confirmation that the Z440 fan and that cable works before I order and replace the existing fan.  I would hate to go through all the hassle to have it not.

[SDH]

I have a spare Z440 big heatsink/fan here, and a Z4 G4.  I'll spring for the adapter.  Just send me one of those hot processors to test with...

...kidding.

[SDH · Accepted solution]

OK, I tried it here and it works fine in a Z4 G4 with the Z440 4 heat tube heatsink/fan... and the ModDIY.com adapter (which is a copy of the wiring of the official HP adapter shown above).  This kit is needed, it appears, for all Xeon or Core processors at and above 155W max TDP in a Z4 G4, and that implies that the Z440 4-tube heatsink/fan provides at least 168W max TDP cooling capacity no matter where it is used because the hottest Xeon for the Z4 G4 is listed in the QuickSpecs as the W-2295.

Using that same Z440 heatsink/fan in a single processor Z420 or Z620 build will give us some good breathing room for overclocking.  I'm sure liquid cooling as used by Bambi and Brian is better, but this info is reassuring for the rest of us wanting to use air cooling while overclocking the ZX20 workstations.

[tallguyNJ]

Wow, thank you so much for going through the trouble.  I'll order them right now.

[tallguyNJ]

FYI for anyone wanting to do this.  I just finished installing the Z440 fan and the cable mentioned above and everything worked fine.  No more errors.  Make sure you order the right cable as there are two different Z4 cables available.  Shipping time is about 4 weeks from China.

Thanks to SDH for your help.