61 replies to this topic

[syamajala]

I started building my fm a few days ago. So far, I have managed to get 2 opl3s (broke a pin on the first opl3 i got off), and 2 yac512s off of some soundblasters. I have also mounted the opl3 and 2 yac512s on the fm pcb. I will post more pictures as I progress. My dyndns account seems to have been deleted. So for now you can see the pics at http://75.68.225.205/fm/

[syamajala]

the opl3 module has been populated. I posted updated pics, check the link above. I will work on the din module tomorrow.

[napierzaza]

Why does it look like there is a broken trace between your YMFs?

Also the interconnections to the Pic board have pins, I think people usually recommend direct connections in place of the pins. But I can tell you that it will make your life easier.

[stryd_one]

Did you know that you can attach pics to your posts? ;)

[syamajala]

Do you mean the trace that goes behind pin 16 of the upper ymf to somewhere behind the lower ymf? Also, I think I might get rid of the pins, because it doesn't look like i put them in straight. I'll try taking the pictures with less light, because right now the solders look horrible.

stryd_one: i know i can, but i need to resize them. I'll also get a new dyndns account, so that i will actually be able to see the pics in the preview.

[syamajala]

I also finished the din board today. Thats about all i can do for now, as i'm waiting for pcbs from smashtv. Anyway, I need to start ordering parts for the cs.

[napierzaza]

Yes I do, I looked at mine, and it's fine (unbroken).

[syamajala]

so, is there an easy way to fix this?

[smashtv]

so, is there an easy way to fix this?

Yes....I'm working on a full report on the error and some macro photos of how to easily fix it now.

I will post the whole mess this afternoon here, and edit my OPL info page to match.

The short answer:  This trace feeds a test pin (TST1) 5v used only in the manufacturing process for the chip. I'm wondering if the module works fine with that pin left floating/unconnected for most people? (since the error has gone un-noticed for so long)

Obviously I'll be tossing these in the bin and creating a new layout with TST1 tied high as called for in the datasheet and correct the legends to match the official schematic and -possibly- changing it over to a CORE sized double sided layout with easier interconnect to the CORE.

This was not a dirty photoplot at the PCB fab etc....The .brd file I fed the CAM processor in Eagle shows a normal solid trace, but the gerber files the CAM processor kicked out have this dashed line.....Most likely the reason e-testing on these did not catch the issue, since the e-test files are derived from the gerber layout.  :(

To be continued later today......

My apologies for the error, hopefully it has not caused anyone to question their sanity  :-\

Best regards

SmashTV

[smashtv]

A quick trace rework, complete with bad photos! :


First scrape away the a bit of the green soldermask to expose the copper underneath.  A hobby knife works well for this, but almost anything with a straight edge will work, like a small flat-tip screwdriver.  The soldermask is brittle and will scrape away easily.


Grab a cut resistor lead and clip it down to stretch between the pads.


Tin one pad with a small amount of solder.


Hold the jumper wire in place with pliers heat the wire with the iron just long enough for it to reflow the solder on the pad.  Let it cool for a minute.


Heat other end and just long enough to flow some solder into the connection.

At this point you can use a small screwdriver to hold it down while you clean up the soldering/flux....as you can see I solder like a drunken monkey so you might not need as much cleanup as I do.   

I'm working on a correction rev now, to be run asap.

Best regards

SmashTV

[nILS]

smash: Sorry for kinda going off-topic a bit, but: What camera did you use for those pictures? Those are some hard-core close-ups

[stryd_one]

smash: Sorry for kinda going off-topic a bit, but: What camera did you use for those pictures? Those are some hard-core close-ups

Yeh!!

My 2C: Do you realllly need to throw these out and start over? I think that if someone's building an FM they will have enough skill to solder a bridge.

[syamajala]

yeah, save a few for me, i'll buy them. It turns out i'll need a second fm without a control surface that i'll control with sysex messages from this one. I'm still working out all the details and will email you when i'm ready.

[lief138]

Sign me up for 2 of the gimped ones,  but please, I only want them if there is something wrong with them.

[nILS]

In about 60 years we'll all be able to tell our grand-children:"yep, I got one of them super rare special boards with the broken trace!"  ;D

[nILS]

Hahaha, the n00b strikes again ;D

[smashtv]

smash: Sorry for kinda going off-topic a bit, but: What camera did you use for those pictures? Those are some hard-core close-ups

Fuji S700, stock lens, set to auto+super macro, lens ring touching the board (I cropped that shadow out of these).

My 2C: Do you realllly need to throw these out and start over? I think that if someone's building an FM they will have enough skill to solder a bridge.

Jury still out on that one, If I can make a good enough explanation of how to correct it they might not be re-tasked as business cards, but I would really like to fix this and the differences in part designation between my board and the official release.

SmashTV, kindly please send me a "cut resistor lead" as I do not have this part, thank you.

LMAO  ;D ;D

Best regards

SmashTV

[Smithy]

My 2C: Do you realllly need to throw these out and start over?

YOU BUY FO ONLY 2 DOLLA!

"CHEAP-CHEAP!"

http://ie.youtube.co...h?v=wdMDWEpbrHU

SmashTV, kindly please send me a "cut resistor lead" as I do not have this part, thank you.

One for the midibox hall of fame!


@ napierzaza
You have Eagle eyes (no pun intended  :P) man! A great asset to the community.
It took me a good while to even spot the broken trace in the pic after you alerted us to it.

It reminds of the scene in Platoon, where theres a fox hole right in front of Charlie Sheens eyes,
and he cant see it, so Alias spots it out for him.

Youve got that "500 yard stare man!"


@syamajala
Thanks for taking the time to do this thread, the Midibox FM doesnt get much attention,
with the dominance of the MB Sid, its real helpful what youre doing.

[Jaicen]

Smash, you can pop one of the dodgy boards in my order next week, I think I can handle it ;)