From October 2012 the description here came from Pascal in France who had a st5742. (t5740 with no flash and no operating system - see HP's naming system). He had found a relatively cheap st5742 from the US to replace his t5700 which was acting as a low power home server. You'll find a description of what he did under the mods tab.
Finally [Feb 2015] I've got my hands on a t5740, albeit with no flash memory, no bottom cover and with no stand but it was working and has enabled me to fill out this entry to match the others.
Intel Atom N280
2GB (max 4GB)
2048 x 1536 32-bit colour
1920 x 1200
8 x USB2.0
Dimensions H x W x D (mm) 267 x 44 x 222 with Stand
The operating system is Windows 7.
From HP's datasheet:
Intel GL40 graphics with support for two high-resolution monitors up to 2048 x 1536, or up to 32 bit color depth. Output through VGA and DisplayPort connectors. Optional adapters available for DisplayPort to VGA or DVI-D connections.
The power supply is a laptop-style 19V one with a coax connector. The outer diameter of the plug is 4.8mm. I believe the inner diameter to be 1.7mm but it's not the easiest thing to measure the diameter of the recessed pin in the socket, it might be 1.4mm. When I searched on line for 't5740 PSU' I was surprised to find a number of offerings claiming to be replacements that were fitted with 5.5mm/2.5mm plugs. I can assure you anything with those dimensions does not fit my t5740!
The CPU is an Intel Atom N280 CPU, a single core 32-bit CPU but with Hyperthreading. For those to whom it matters here is some detail from Linux's /proc/cpuinfo
vendor_id : GenuineIntel cpu family : 6 model : 28 model name : Intel(R) Atom(TM) CPU N280 @ 1.66GHz stepping : 2 flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl est tm2 ssse3 xtpr pdcm movbe lahf_lm dtherm
From the lspci command:
00:00.0 Host bridge: Intel Corporation Mobile 4 Series Chipset Memory Controller Hub (rev 09) 00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 09) 00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 09) 00:1a.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #4 (rev 03) 00:1a.1 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #5 (rev 03) 00:1a.2 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #6 (rev 03) 00:1a.7 USB Controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #2 (rev 03) 00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 03) 00:1c.0 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 1 (rev 03) 00:1c.4 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 5 (rev 03) 00:1c.5 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 6 (rev 03) 00:1d.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #1 (rev 03) 00:1d.1 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #2 (rev 03) 00:1d.2 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #3 (rev 03) 00:1d.7 USB Controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #1 (rev 03) 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev 93) 00:1f.0 ISA bridge: Intel Corporation ICH9M LPC Interface Controller (rev 03) 00:1f.2 IDE interface: Intel Corporation ICH9M/M-E 2 port SATA IDE Controller (rev 03) 00:1f.3 SMBus: Intel Corporation 82801I (ICH9 Family) SMBus Controller (rev 03) 00:1f.5 IDE interface: Intel Corporation ICH9M/M-E 2 port SATA IDE Controller (rev 03) 04:00.0 Ethernet controller: Broadcom Corporation NetLink BCM57780 Gigabit Ethernet PCIe (rev 01)
Click on the image for a larger version.
Flash: As mine came without any flash fitted I'm not 100% certain what type of flash is included. The board offers two ways of adding the flash - a 44-pin IDE connector or a SATA socket. The SATA socket is one of the combined power and data sockets and is to the SATA II standard.
However I've had an email from Christian who tried to use a 3.5" disk with the t5740 and found it wasn't recognised and actually didn't spin up.
"...so I've checked the pins from the power connector with a multimeter and found out that there is no power provided on the three 12V pins - not on the Combo-Connector nor on the unequipped connector near the 44pin IDE connector. The 5V and 3.3V pins provide the correct power. It works with 2.5" HDDs because they usually don't use 12V, only 5V (some older ones also 3.3V)."
RAM: The motherboard has two sockets for SODIMMs, one on the top of the board and one on the bottom. The one on the bottom is accessible by removing a small metal panel - you don't have to take the motherboard out of the enclosure. The datasheet mentions '1 or 2 GB DDR3/667MHz system memory'. In my model there was a single 1GB Hynix SODIMM fitted, PC3-10600S, part # HMT112S6TFR8C-H9. I don't know from personal experience what the maximum amount of memory that can be installed but I have seen mention of 8GB. The N280 is a 32-bit processor and so can only directly address 4GB. However it does support PAE and so could physically use more memory if the operating system supports it.
USB: Like a lot of the HP thin clients of this era the t5740 includes two 'secure' USB sockets within the housing. There are also two on the front panel and four sockets on the rear panel.
PCIe x4: There is a PCIe connector on the board adjacent to the SATA socket.
PCI: There is what looks like a PCI slot. However this is a non-standard connector that is used with an expansion housing that doubles the width of the thin client. The words on the expansion Module mention gaining a x4/PCI slot and a parallel and second serial port. Obvious connections to the latter must pass over this interface. An email I received about the t610 showed that in some models at least the pin-out of the socket starts off as a genuine PCIe socket. So it is possible that pins 1-32 offer a standard PCIe x4 socket in a similar way to the x4 socket that Al found on the t610. I haven't yet checked this but will do so in due course.
Any comments? email me. Added February 2015 Last update December 2016