Is the D3806 Boost/Buck DC-DC power supply any good as a bench power supply? (+D3806 user guide\manual)

Due to problems I had with LTC3780 boost\buck converter boards and the fact that they are really not designed to be used with adjustable Voltage\Current potentiometers due to the high resistance pots required (the high impedance wires easily pick up stray noise which causes instability), I decided to try the D3806 Boost\Buck converter which has user push-button + LED display. These should be easy to extend to the front panel of a bench PSU as they should be all low-impedance connections.

D3806 - DC-DC boost\buck converter with potential 38V 6A output.
P/N 321510269

The LED+button board is on a separate riser PCB and contains a micro-controller. It is supposed to have reasonable ripple\noise output too (TBD).

But is it any good...?

E2B v1.B8b Beta available + grub4dos coding tips

Changes from v1.B7 are are:

1. Improve E2B scripts to allow the user to use a greater number of grub4dos environment variables in the MyE2B.cfg file (grub4dos max is 60).
2. Add .vhdx file extension (was removed in last few versions).

About grub4dos environment variables

Why everyone is building their bench power supplies incorrectly (fix = cut the thin black wire)!

I ordered some  cheap Volt\Amp meters from Banggood and also a DC-DC buck-boost LTC3780 converter board. Many people have made YouTube videos and written Instructables about how to make a variable PSU from this combination (plus a DC source such as 12V from an ATX power supply) but nearly all of them are WRONG - but the solution is simple!

Usually described as "LTC3780 Automatic lifting pressure constant voltage step up step down 10A 130W"

Digital VA meter (note they seem to only have one decimal place for voltage, not two as shown in this stock picture!)

Note: This type of VA meter has thick Black+Red wire and thin Black+Red+Yellow wires. Do not confuse it with the other types which may have a thick blue wire or a thick yellow wire!

Many people who have built a power supply using these two modules have complained that the over-current pot on the Buck\Boost board did not seem to work. Other people have complained that the Ammeter reading was incorrect. A few have blown up their boards.

The diagram below shows the typical wiring arrangement that is used by most of these designs, but I have added in some extra purple lines to indicate the 0V traces which are already inside the DC-DC Buck\Boost board and already inside the VA meter.

My build of a 30V digitally controlled, current limited bench power supply for £45

Bench power supply for <£50

Note: Some links in this article are affiliate links. This article is not sponsored in any way and all materials used were purchased privately.

I wanted to get an adjustable current-limited bench power supply however good quality retail versions are very expensive and buying a cheap power supply is always risky.

UTP1306S - see blog post

This minileaf is on a flash sale for 2 days at Banggood, only £36 for a 30V 10A <10mV ripple, 5-star rated by 97% of customers) but always comes with the risk that it will stop working and be unrepairable after a while or will arrive in bits.

See also my blog post on the UTP1306S

Due to the problems of returning faulty products when buying from overseas suppliers, if I was going to buy a bench PSU I would buy one from Amazon for £59 as it is easier to return faulty items.

By making my own PSU from modules, it will be easy to repair just by changing the faulty module.

My fantastic KSGER soldering iron arrived today - but it had some faults...

This article contains affiliate links which I may earn a small commission from. All items discussed were purchased privately.

I have been looking for a new soldering iron for a while because my old Antex 40W iron is just not powerful enough. It can't cope with soldering to large terminals or other large connectors. This can cause heat damage to the components.

T12 soldering bit

Apparently the soldering irons that use the T12 type of soldering iron bits are highly recommended. These bits are fitted internally with a heating element and a temperature sensor. This means the heat can be controlled - only the tip gets hot which is where you need it. What's more, it can get to (say) 300 degrees C in less than 10 seconds because we are not heating a load of iron and copper in the shaft and collar of the bit - it can be left in 'standby' mode at say 150 degrees C whilst you are not using it and it will shake-and-heat to 300 degrees C in 3-4 seconds.

KSGER T12 soldering station

The KSGER station has a digital display and the 'shake-to-wake-from-standby' feature - if you shake the iron as you pick it up, it wakes from standby and heats up quickly. This helps the bits to last longer.

E2B v1.B7 released

v1.B7 changes:

1. Support .isomemgrub file extension (loads iso into memory before running it)
2. Fix bug with .vhdmem file extension
3. SWITCH_E2B v1.1.29 (bugfix for 'error 52' issue)
4. Display date&time function now in new grub4dos
5. grub4dos help menu entries added to the Adjust_E2B_Menu2.mnu file (also included in PimpMyDrive.cmd)
6. Latest grub4dos 0.4.6a 20191028 for small bugfix and time+date update new function
7. "\_ISO\docs\Make_E2B_USB_Drive\Make_E2B_Choose_Size_of_Ptn1 (run as admin).cmd" added if you want to make a USB drive with smaller size Ptn 1.

Early release available in Alternate Download Areas for few days before on main site - please report any issues ASAP.

https://rmprepusb.blogspot.com/p/e2b-alternate-download-areas.html

Weird USB problems with Windows 10 1903!

In the last week or so I have been experiencing very odd things with some of my USB drives under Windows 10 x64 1903.

Windows seems to think that the USB drive is corrupt. However, I can look at the drive sectors using RMPrepUSB and it will show what looks like a good MBR and PBRs. However, Windows cannot read the volumes and wants to format both of them!

Rebooting the system does not help.

If I run TestDisk, that also reports very 'wrong' results.

Windows Disk Manager shows the drive with two partitions but it refuses to let me assign a drive letter to them and asks me to 'refresh' Disk Manager (which does no good).

The strange thing is that the USB drive is OK when connected to another system.

The fix!

1. Download and run NirSoft USBDeview.exe (USB Device Viewer).
2. Highlight the USB drive
3. Right-click - Uninstall Selected Devices
4. Now unplug and reconnect the USB drive.
5. Reboot if required.

Magically, Windows now sees two good partitions and gives them both drive letters and all is sweet!

I also found that none of my Sandisk Extreme Pro 128GB USB flash drives would be recognised by Windows (no 'ding' when inserted) when I plugged either of them into the 2nd USB 3 socket on the front of my PC (but all other USB sockets worked OK and other USB flash drives worked OK in all the USB PC sockets!).  Clearly it did not like 'Sandisk Extreme Pro' + USB port 2' as a valid combination! Using USBDeview also fixed this too (after finding the 'Sandisk Extreme Pro' device and uninistalling it and then rebooting).

Add Medicat 18.10 to E2B

Because Medicat uses incompatible and mixed versions of syslinux, the ISO may not work 100% by just extracting the files from the ISO. You can use Rufus to prepare a spare flash drive first. Rufus should update and fix any incompatible versions in the ISO as it installs it onto the USB drive. The alternative if to use the E2B MPI ToolKit on the ISO file to make a .imgPTN file.

Note that the Medicat WinPE is NOT intended to be run as a DVD/ISO (even if it could be made to fit) - the files MUST be extracted from the ISO. MiniWindows will not work correctly unless the files are extracted.

Once you have prepared the spare flash drive you can test that all menu items work and then make a .imgPTN file using the spare flash drive as the 'source' by dragging-and-dropping the spare USB drive icon\letter in Explorer onto the MPI_FAT32 Desktop icon.

Note that Medicat has bugs even when you prepare it in the 'official' way using Rufus.

If you don't have a spare USB drive then just use the Medicat ISO as the source. The latest version of the MPI Tool Kit should prompt you to use syslinux '604' too.

When prompted by MakePartImage to AUTO-CORRECT - answer N, do NOT update the configuration files.

AFAIK the functionality is the same if you directly use the ISO file instead of a 'Rufus' flash drive as the source.


You can also UEFI64 boot from the .imgPTN file to MiniWindows x64.

Medicat - notes and bug fixes

XMLtoE2B version 2.0.48 with bugfix

The previous version sometimes added an extra
</RunSynchronousCommand>
line when adding an SDI_CHOCO section.

This new version should fix the problem.

Easy2Boot v1.B7b with bugfix for non-contiguous files hanging menu loading

I just came across a long-standing bug in grub4dos which has the affect of making E2B freeze when listing a non-contiguous ISO file, as shown below...

It is not supposed to hang!!!

Version 1.B7b avoids this bug by not showing the Volume and UUID details of the ISO which is normally listed under the menu and so avoids the issue.

By habit, I always make files contiguous after I copy them to the E2B drive, so I never noticed until now!  This issue must have been present since E2B v1.B0!

The grub4dos bug report is here.