Shigaclone MKII Black - The builders Thread

[danzup]

Now after a day work at case , I am at stage where follows retouch and to make holes for LCD on front and on back holes for SPDIF , Power and power button.
I have attached pictures during the working and till the actual stage of case.

[Turbon]

Originally Posted by tvicol

If you are missing 100R resistor than means all other kits are missing this part too.
I mentioned several times that a LCR meter is mandatory to finish SHIGA MKII.
On first SHIGA GB I did my best to mark all parts. People started to solder these without measuring and switched 3,3nF with 33nF, 10nF with 100nF and other parts too. This lead to non functioning kits or malfunctioning ones.
So, I decided do not mark these parts and force you to measure them.
Please measure resistors as well, because 3300 is not the same with 332.

About LCR, I personally use an Amprobe 37XR-A. This is same with Meterman 37XR-A.

Regards,
Tibi

Never mind the LCR - I have been thinking of buying one for ages so thank you ... Found the 100R resistors - they were not 1206 size but round parts as the 0R ones... But there are R50 and R51 missing. I got one extra 10R though.

Nice box danzup!

Edit: I found the new BOM - R50/51's absence explained

Regards

[tvicol]

Building ULN LDO minireg.

You got in your KIT two minireg pcb boars. These are optional and have been added as bonus. Even there is space to mount 4 such miniregs, only two can be mounted for V3 and V4.
V3 will power oscillator section, while V4 will power the rest of LC78601R sections.
These will enhance Shiga MKII performance to next level. I highly recommend to use them.
(For V1 and V2 you may use other super-regulators able to deliver at least 100mA continuously. Due laser current needs, V1 and V2 regulators must be powered from a separate power supply, or before main 8V regulator.)

There are two types of miniregs you can build. One using fixed 5V output regulator marked LT17635 and adjustable output marked LT1763.
Will address construction for both.

Parts needed for LT1763adj:
- minireg pcb
- LT1763adj
- two resistors 33K and 10K
- two capacitors 10nF and 100nF
- 33uF/6,3V tantalum capacitor
- pins

Parts needed for LT17635:
- minireg pcb
- LT17635
- resistor 0ohm
- two capacitors 10nF and 100nF
- 33uF/6,3V tantalum capacitor
- pins

Regards,
Tibi

[tvicol]

1. first step is to prepare board for smd parts soldering.
Add solder only one one side of each component.

2. next solder 10nF capacitor. This is bypass capacitor. Theoretically this will lower output noise to value specified in datasheet 20uV.

3. solder 33K and 10K resistors as per third picture.

4. reverse pcb and solder 100nF. Add some more solder, as over this 33uF tantalum will be added.

5. solder LT1763 chip

6. last step is to solder 33uF tantalum cap. See below why.

Regards,
Tibi

[tvicol]

At this stage, if you measure output regulator with a voltmeter, you get a nice and steady 5.2V
However, in datasheet is mentioned that LT1763 is stable only with an minimum 3.3uF capacitor.
Well this is not the case (see pictures), even with a 3.3uF tantalum cap, you still get oscillations at high frequencies.
With 10uF I get a straight clean line. So any cap above 10uF will do the job. I had a bunch of tantalum 33uF so this is the value I used.

Regards,
Tibi

PS. In below pictures vertical scale is 5mV/div. output regulator noise with 3.3uF cap.

[tvicol]

Last step is to solder 33uF tantalum cap on top of 100nF and pins.
The minireg is ready. A 5 min job.

Regards,
Tibi

[tvicol]

Here are both regulator types.

Left is the one with LT17635 (fixed 5V output).
Right is the one with LT1763 (adjustable output)

The difference is that on fixed 5V output you do not mount 10K resistor and 33K must be replaced with 0ohm.

Regards,
Tibi

[tvicol]

A very important observation is do not mix fixed with adjustable regulators.
For proper operation, LC78601R need to have same voltage, or very close, on all power pins.
With 33K and 10K, adjustable version will output 5.2V and in operation this will drop to ~5.13V, while on fixed you get 5V and ~4.9V in operation.

So, take care, do not mix them.

Regards,
Tibi

[Turbon]

OK, smd capacitors soldered. U1/U3 in place...

Regards

[Turbon]

Hi Tibi.

Regarding the tantalums, electrolythics and others.
Reading the bom, occational words and looking at different pictures of where they should go is quite impossible. In most pics there are two green electrolyts. I have one as C28 is missing 220uF if i remember right. In the pics there are no 10uF elecs, I got 5 or 6 in the kit. Which tantalums can be replaced with these as I am missing tantals to fill the board.

Please elaborate on these please.

Regards