exxos blog - random goings on

[exxos]

Routing BGA is annoying

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The problem is the small chip (SDRAM) currently has 3 vias on its left side which will tally with the vias on the BGA chip.. Because they have to overlap, this means three layers have to be used.. On a four layer board, one layer is reserved for GND. So using 3 layers already eats up the VCC layer..

Even if I rotated the BGA 45deg and routed the right side of the smaller SDRAM chip, it would then use up the top and bottom of the large BGA, where I have to route other things anyway yet...

So basically it gets onto more like 8 layer PCBs which are expensive But there's no way to get everything routed without more layers long-term if the Phoenix motherboards had the FPGA stuff "built on" then be the cost of a full-size motherboard in 8 layers..

So currently keeping the board a small as possible so it can fit on the H4/H5 boards looks like the best way to go.

[dml]

BGA is not my favourite kind of soldering.

Is this going directly on a mainboard? Or is the idea to make a small adapter board with pins, stick the BGA on the adapter and plug the adapter into the mainboard? Then you only need an 8-layer adapter instead of an 8-layer mainboard.

I probably missed a lot of context here :p

[exxos]

BGA is not my favourite kind of soldering.

It will have to be factory.. @Icky and I tried for ages to manual solder.. Didn't end well most times

Is this going directly on a mainboard? Or is the idea to make a small adapter board with pins, stick the BGA on the adapter and plug the adapter into the mainboard? Then you only need an 8-layer adapter instead of an 8-layer mainboard.

It's the FPGA board talked about for the H4/H5 boards. Its a plugin board to replace the MMU,GLUE,BLITTER.

I probably missed a lot of context here :p

Context wasn't there to begin with I really need to do a new topic on it but unless there is something more "noteworthy" theres probably no point.. the project will likely be ongoing for a long time...

Just for illustration it looks like this currently...

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The white square to the middle left will be a hole in the PCB because some idiot put ROM there on the motherboards..

The top right white square is where the 68000 is on the H5.. So that will be a hole.. BUT.. Potentially being a no-go area on the PCB because ultimately the SEC CPU may go there..

That's another long epic story because we cannot drive the entire motherboard at increasingly higher speeds because of all the trace lengths bogging down signal speeds etc.. So the FPGA board becomes basically the "high speed stuff" and everything under the FPGA board (the actual motherboard stuff) basically chugs along at original speed and is really a glorified IO port at that point

[exxos]

That's a entire day gone just routing 16 data lines

Think I did pretty well to so far only use 1 layer for that stuff. Going to get harder routing all the other signals to the SDRAM!

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.. and no, I'm not length matching them all While every tiny bit bit of length matters in higher MHz stuff, I'm chosing not to care about the 0.1ns mismatch

[exxos]

<rant>
JLC strikes again Got the next batch of RAM boards made for assembly in the UK. It started out at after years of producing the same board, JLC wanted to extend the border by 0.2mm. Fair enough.. BUT I said it wouldn't match the stencil anymore and would need updating..

Some days passed.. I asked to cancel the stencil as I just know it's going to get messed up. I later see there's a option to order a stencil after your panel has gone into production.. So I set all that up and took screenshots etc for the UK fab to confirm it was all good.

Many emails later... I asked they let me replace the Gerber data and let me extend the border so the Stencil should match. However I now see the panel border has defaulted back to 5mm. The kicker is, JLC were confused of the panel still. So I grabbed the screenshot from my order history and draw out every dimension so they know 100℅ what the panel is supposed to be.

So now the PCB has got made and they ignored what I told them totally. They ignored the drawing of what the panel is supposed to me. And my original panel data specs have been somehow lost even though the number of boards per panel is the same.

So I suspect when the replaced Gerber data was enabled, it's actually done a new order where my panel data is now lost. I asked them why the panel says is wrong and tby said it's what I selected.. This is after them questioning the panel and me giving them a total breakdown of how the panel should be. This is even using the confirm before production feature! I honestly give up with JLC.

So the whole thing has been a total waste of time. I seem to have the same problems with most China suppliers. I gave up with pcbway because I just couldn't deal with them anymore. I had to repeat myslef like 20times over when I gave them all the information or assembly when I ordered the pcbs.

I always have the same experience with China. I keep saying it's like dealing with a bunch of teenagers on their first day on the job. The company I used for the H5 motherboards and DFB1X have been great so far.

Problems are multidimensional though these days. Trump's tariffs to China are ramping up getting parts to places like JLC. That supply chain is effectively broken now.

Used to send parts to China myself. But the time and costs and hassle is a lot there. Like I'd have to constantly declare £100+ on like £20 value of goods just to get it though customs. Then I'd pay tax on shipping to China then pay tax on having them shipped back again.

I said before a couple years back that China customs want documented proof now how much things cost..like nope. I'm not looking back though years of invoices and doing loads of math working out his much stuff cost just to end up with £20 value of goods where it get stuck in customs anyway.. No thanks. So that's basically another supply chain broken. It's just not worth the time and costs anymore. China already got way more tax on my items as it is. I'm not losing more time doing more work to prove value of goods.

its what lead me to JLC in getting the pcbs made for UK assembly. Only that is more trouble than its worth. I've wasted 2 weeks of time and loads of emails. Wasted money on boards I can't even use now. It's just not worth it anymore.

So I'm just going to get a UK company to make the PCB panels and stencil. Unfortunately it costs like x10 more. But I can just give them the Gerber data and the requirements and let them get on with it.

I mean by the time I've paid shipping and tax from China anyway.. Postage and taxes never go down. I think it's just overall more cost effective to use a UK company now. I've probably lost a couple sales in all the delays as it is. Nevermind my wasted time in it all.

</rant>

I've ordered a load of FPUs from China. Prices on them have gone up like $5 a pop now.. Considering like 20% will be faulty.. Half won't even run at 40mhz nevermind finding 50mhz parts...A lot end up qualified as 16mhz and I've got loads of them now already which don't sell often.

So I've ordered some from the USA which are supposedly genuine sourced chips. The price is more than double of China.. But if they all worked at 40mhz then the likely yield of 50mhz parts should double with no faulty ones.

I think overall it's more cost effective to go that route than trying to buy from China. I mean 20x 50mhz chips out of 100 isn't bad I suppose.. But when a lot dont even work to 40mhz spec and faulty ones on top.. Time will tell...

[exxos]

So my new FPUs, I just got this email..

Hello,I am sorry but we must cancel this order. The parts did not pass our QC inspection. We attempted to resource and get replacements but were unsuccessful. Please let me know if there is anything else we can help you with. Thank you and have a great day.

Nothing can ever just be simple can it..

[exxos]

Here we go again with JLC... I sent a new email to support asking about their new via in pad service.. They replied...

Dear Chris,

Thanks for your reply.

After checking the order Y260, we noticed that you did not select the via in pad service of Epoxy Filled & Capped as shown below.

As the order Y260 is now being produced, we are sorry that we are unable to add the service now.

Can we still proceed with the shipment after production?

If you need the Via-in pad service, please kindly remember to select the option of Epoxy Filled & Capped next time.

Then vias in pad will be filled with epoxy resin and then plated over with copper to create a flat.

Your understanding and early reply are greatly appreciated.

Best regards,

I didn't reply to any emai.. It was a new email... I never mentioned my current order and it has nothing to do with my order at all... Now I have to email them telling them not to screw with my current order which they probably won't understand either.

Its enough to drive a guy insane. Its like asking one question and they reply to a question I didn't even ask... They would make good politicians...

I'm starting to find its a theme in general these days not just with China. It's like nobody reads emails properly anymore. They must skim it super fast and jump to conclusions and reply to what they think the email is about.

Same with USA suppliers. I was asking for quotes for the mc68030 CPU and wrote NOT the V version, ABC is OK... So what do they quote.. The V version FFS!

Even UK suppliers seems to be getting lazy and I have to keep chasing them up all the time. Just seem to get messed about with empty promises.

I posted a RFQ on some sites for the PC PS2 back bracket cable for my Milan. I asked for images of the item to verify they have exactly what I want.. So far 3 have replied.. No images.. Just 3 metalwork places... The must have picked up on the word bracket and not actually read what I was asking for

I could go on..

Needless to say it's a huge annoyance and time sink these days.

[exxos]

My FPUs came. From China unfortunately as normal

So far I have tested 10 FPUs, and 5 fail to run at 40MHz. That's 50% failure rate right out of the box!

Annoying thing is, almost no point returning them, wherever FPUs are purchased from they won't be much good !

I've got 100 to test in total.. So I hope my luck improves.. Sign of the times trying to find working parts these days!

EDIT:

Found my previous results:

viewtopic.php?p=107981#p107981

Results are in! So the alleged MC68882FN40A are...

50mhz - 20
40mhz - 26
16mhz - 30
Faulty - 24

But basically 54 out of 100 were "bad" and just 20 were overclockable for 50mhz.

[mrbombermillzy]

That sounds like the general gist of how things are nowadays.

Although sounding completely different, the mindset is the same in this example:

So, many years ago I bought some chocolate bars that *all* had the hard caramel middle leaked out and hence unable to open the packet without completely tearing the chocolate apart and causing a right mess and a choc that looks like a dogs dinner.

It wasnt crushed or damaged, it was a production fault, so I actually wrote to the company (wow I must of had lots of time back then ) explaining that they had a production fault.

I received a chocolate in the post and a general 'sorry to hear that' response.

What was really annoying, was that the replacement had the same problem and there was no acknowledgement of the error in the reply.

I would rather they *didnt* send me another bad one and just fixed the problem instead!

Anyway, although not quite at the same level of annoyance, Im sure you would agree, the sentiment is the same: just send another dodgy item out if someone complains, but dont bother checking/testing if its saleworthy.

[exxos]

...
Anyway, although not quite at the same level of annoyance, Im sure you would agree, the sentiment is the same: just send another dodgy item out if someone complains, but dont bother checking/testing if its saleworthy.

Yes. I had Arla milk which started to have a pink tint to do. Went on for weeks. I stopped buying their stuff in the end. Emailed the address on the carton, no reply. I even emailed the food and drink administration people about the problem they basically said they had no powers to do anything anyway. The whole thing was just incredibly pointless. There was clearly contaminated milk on the market and what can you do about it ....

As to what the pink tint was, no idea. I half assumed some machine processing milkshake or something causing tint and not been cleaned properly between usage.. But with me having food intolerances, I could not simply risk consuming basically contaminated milk!

I reported similar when buying car exhausts online where sellers literally put the shipping label on the exhaust and civic through the post, I kid you not exactly like that! They of course arrive dented. I emailed the seller saying they need to release but some bubble wrap over the ends protect them from getting damaged.. To their credit they shipped another one out... But also arrive dented because there was literally nothing on it other than the shipping label..

Also similar when I purchased the motor through the post where it was in a thin cardboard box and arrived completely destroyed. This was on eBay and I mentioned it before a few years back.. EBay remove my negative feedback to the seller. So what was the point in feedback saying the seller doesn't put bubblewrap around stuff and accept any accountability for doing basically dumb sh*t..

It really is quite perplexing and frankly astonishing how police can operate incredibly badly such as eBay and get away with it purely due to the sheer amount of customers they have...

I just same to someone earlier in fact.. A big ebay seller in Ireland started doing a video guide on how to start a business on eBay.. Three days in he got banned!! I've been writing some comments on that video as well





He had his main account suspended about a week ago. I think the gist of it is, eBay's algorithm only looks for things like 10 open cases and then your banned until they all closed.. REGARDLESS of how many sales you have.. I mean 10 sales 10 cases, that's 100% fail. 1,600 sales and 10 cases.. ~ 0.625%... That's my gist of it anyway....

Its amazing how anyone could make your business on eBay even a decade ago. I got banned once for asking how much postage was to a seller!! As I was buying stock on eBay at the time, I inherently was emailing a lot of sellers for bulk buying etc.. It wasn't even a phenomenal amount of emails, maybe like 10 a day kinda thing.. got banned for messaging too many people... I could not function as a business under such stupid restrictions all the time never mind everything else I had to deal with....