[FT] xDevs.com KX LTZ1000A fairy-tale, or the story of little jumper.

[mimmus78]

Hi everybody,

pcb were fabricated and are now travelling to my home.
I should receive it tomorrow or Wednesday.
I will post PCB photo here when they arrive.

Ciao,

Domenico

-------------------------------------------------------------------------------------------------------------

Mimmus78: 3pcs
Nuno_pt: 3pcs
msliva: 3pcs
pelule: 3pcs
klaus11: 2pc
VK5RC ;3pcs
t2kv: 2pc
HighVoltage: 2pcs
fanOfeeDIY: 2pcs

[Echo88]

Damnit, havent seen that you sell these LTZ-PCBs here. Is there still one left for me to buy?

[mimmus78]

Echo88, I don't think soo ... I already have some overbooking.

PCBs will arrive today.

[mimmus78]

PCB arrived. They screw up couple of ring guard.

What we do? Do I have to ask for a refabrication or we keep as is?

One point they forget to remove soldermask. Other two points they leaved ring guard open by cutting the track.

Here attached sono photo.






Inviato dal mio Nexus 6P utilizzando Tapatalk

[mimmus78]

Hi guys here are problems with those PCB I received today.
If for you is OK I will ask to fab to redo the lot.
Let me know what you think.

[Nuno_pt]

Let's see what more experience people say about that, if we reach a conclusion that it's ok, then no problem for me.

But in all case I think you should tell the factory about this problem, just in case.

[ManateeMafia]

Especially if they send a second batch of good boards out. Then you can pick and choose...

How do the boards look with a gerber viewing tool?

[VK5RC]

I would be happy to pay for 3 of those boards,  others may want a re-spin.
My level of volt-nuttery (if you know what I mean) isn't too high. 

[HighVoltage]

I do not have enough experience with LTZ1000 PCB's to judge if this is a real problem or not.

[mimmus78]

They have integrated GERBER PRE-VIEW, and was all OK.
You can carefully remove the solder mask by scraping and than eventually add some solder on one point, but these "broken" ring guard around LTZ1000 I don't know.
I think we are going to populate this board with 200/300 USD worth of components, and make a huge investment in time and money to characterise it.
I don't like the idea of having some unknown because someone decided to change PCB design.
I just wrote to the fab (I spotted also other solder mask not removed), let see what they say.

[plesa]

I  suppose that open guard is not big difference if any. The majority of trace is still guarded.
Similar to solder mask covering guard trace. If someone is curios about difference you can measure it by electrometer.
Of course you can ask for some discount on PCB.

[klaus11]

Because of my absolute lack of knowledge, development and manufacture of PCBs, I have no idea what he is talking about.
What the majority decides will also be good for me.

[mimmus78]

So I submitted the original project from xdevs.com and those pcb where fabricated at Easyeda

I checked the gerber files with their online tool before submitting project and it was shown like the attached image.
At fist sight seemed OK to me including ring guard, but it's clearly not now, I should have checked better!
The problem is that on this part of the pcb the "solder mask" mask layer is not aligned with the trace.
They removed the solder mask, but there is no trace down. Il will check with TiN this point as the problem is likely in the files I downloaded from xdevs.com.

Anyway, as told you can still scrub this piece to get exposed guard.
As for the other problem I'm convinced too what plesa said: "I suppose that open guard is not big difference if any. The majority of trace is still guarded.".

So at this point, who still wants the PCB please send me by PM the address and if they prefer "registered mail" or "standard mail".
I will get quote for shipping and back to you with costs.

[mimmus78]

Updates on prices:

I spent 176 EUR total instead of preventivated 160. DHL charged me other 12 EUR for the customs declaration paperwork.
Anyway because I got 22 boards instead of 20, price will remain the same 8 EUR.

[klaus11]

Mimmus, I'll stay with my two boards, if you have a post on how to correct the problem, why I still do not understand where the problem is due to my ignorance of English language comprehension

[mimmus78]

Packaging:

 - VK5RC              3pcs       -       Paid - Registered
 - HighVoltage       2pcs       -      Paid - Registered - overbooking list
 - Mimmus78         3pcs       -       that's me

Confirmed waiting for payment:

 - klaus11              2pcs       -       Spain zone 1 - priority mail 3.50 EUR - registered 7.90 EUR
 - t2kv                    2pcs       -       Australia zone 3 - priority mail 5.50 EUR  - registered 9.95 EUR
 - Nuno_pt             3pcs       -       Portugal zone 1 - priority mail 3.50 EUR - registered 7.90 EUR
 - msliva               3pcs       -       Czech Republic  - zone 1 - priority mail 3.50 EUR  - registered 7.90 EUR

Confirmed but in overbooking list (do not pay - wait):

 - SvanGool          2pcs        -       Netherlands  zone 1 - priority mail 3.50 EUR  - registered 7.90 EUR - overbooking list
 - fanOfeeDIY      2pcs       -       Japan - priority mail 5.50 EUR  - registered 9.95 EUR - overbooking list

=======================
TOTAL                  22 pcs
REMAINING         0 pcs


Waiting or confirmation

 - pelule               3pcs       -        please confirm and send me address for shipment quotation
=======================
TOTAL                3pcs


TOTAL CONFIRMED + UNCONFIRMED = 25

[HighVoltage]

I am also stay to word and take 2 boards
PM sent

[mimmus78]

I updated previous post with shipment costs.

A PM message with my PayPal address will be sent to everybody that sent me the complete address and get the shipment quotation.

Who is in overbooking please wait a couple of days, I'm still waiting a response from 4 members.

[HighVoltage]

Paypal sent

[fanOfeeDIY]

I updated previous post with shipment costs.

A PM message with my PayPal address will be sent to everybody that sent me the complete address and get the shipment quotation.

Who is in overbooking please wait a couple of days, I'm still waiting a response from 4 members.

Thank you for making the pcbs.
I may be in the overbooking list, I just replied to your PM.

[klaus11]

I have not received PM message 

[mimmus78]

I have not received PM message 

PM sent

[mimmus78]

Packaging:

 - VK5RC              3pcs       -      PM SENT - Paid - Registered
 - HighVoltage       2pcs       -      PM SENT - Paid - Registered - overbooking list
 - Mimmus78         3pcs       -      that's me

Confirmed waiting for payment:

 - klaus11              2pcs       -       PM SENT - Spain zone 1 - priority mail 3.50 EUR - registered 7.90 EUR
 - t2kv                    2pcs       -       PM SENT - Australia zone 3 - priority mail 5.50 EUR  - registered 9.95 EUR
 - Nuno_pt             3pcs       -       PM SENT - Portugal zone 1 - priority mail 3.50 EUR - registered 7.90 EUR
 - msliva               3pcs       -       PM SENT - Czech Republic  - zone 1 - priority mail 3.50 EUR  - registered 7.90 EUR

Confirmed but in overbooking list (do not pay - wait):

 - SvanGool          2pcs        -       Netherlands  zone 1 - priority mail 3.50 EUR  - registered 7.90 EUR - overbooking list
 - fanOfeeDIY      2pcs       -       Japan - priority mail 5.50 EUR  - registered 9.95 EUR - overbooking list


=======================
TOTAL                  22 pcs
REMAINING         0 pcs


Waiting or confirmation

 - pelule               3pcs       -        please confirm and send me address for shipment quotation
=======================
TOTAL                3pcs


TOTAL CONFIRMED + UNCONFIRMED = 25

[TiN]

Sorry folks, I couldn't post before due to this cookery, but now I'm with you all 

First hats off to mimmus78, this was unexpected joy to see someone actually going to order my volt-nut design
The issues with soldermask opening is from my gerber file, I forgot to update the file B01. My own boards were corrected B02-version.
However those will not affect anything in measurable way, so it's still alright to use. If it bothers you, soldermask can be carefully scrapped off, but I'd leave it as is.

Other thing is manufacturing tolerance specs. I obviously did not expect someone to order the PCBs on usual hobby-level run fabs, so Gerbers are at 4mil/4mil spec. It does not have to be that precise, so I'll update it to be more friendly and replace GERBER on the article.

As of resistors, I would try to have best stability/tempco resistors for 1K/13K and 120 ohm ones, as these are key for LTZ1000 operation temperature and current. 70K can be less fancy and cheaper, and even vary in value 65-80K. You can see on HP 3458A A9 ref board there are just usual metal-films, and that board is totally fine to get <0.05ppm/K tempco, I tested it.

Opamps I use on my modules are controversial LTC2057 and now ADA4522-1 on this latest module covered in this thread before. No issues discovered.
Module can work with any input voltage from 10V to ~20V without problems and should not show dependence from input voltage. Regular LDO like 7815 with few decoupling caps will do job fine. Avoid switching PSUs though. There is no polarity protection on board, so double check connections and wiring before turning power on!
Normal current consumption with 1K/13K heater setting is ~28-32mADC steady state. It warms up to operation spec within 5-10 minutes.

Be careful with output too, it's not protected and directly connects to zener in LTZ1000A. If you short it or inject current into zener you are likely to cause stress/permanent damage the chip.

[klaus11]

Paypal sent