View unanswered posts | View active topics It is currently Fri Dec 15, 2017 11:14 am



Reply to topic  [ 36 posts ]  Go to page 1, 2, 3, 4  Next
Neil's belated and painfully slow 0.4 alpha build 
Author Message
QFP80 - Contributor

Joined: Thu Jan 12, 2012 12:54 pm
Posts: 62
Location: South Africa
The target vehicle turned out to have serious problems which I am still battling with, but I belatedy started building the board anyway with the thought of using it as a test for edis on a rover v8.

The board arrived from Andy with smd's already installed. A work of art before I started my slash and burn.

I decided to get the components locally which led to some frustration but had the unexpected benefit of finding the map sensors nos at a bargain price.

First step was to drill some random holes on the traces.
Attachment:
File comment: Traces cut for Q12 mods
IMG_20130927_194011.jpg
IMG_20130927_194011.jpg [ 1.38 MiB | Viewed 2787 times ]

Then build cpu power supply. I could not get the right size tants at this stage. I might eventually replace them.
Attachment:
File comment: cpu power
IMG_20140106_215103.jpg
IMG_20140106_215103.jpg [ 1.44 MiB | Viewed 2787 times ]

Tests OK at exactly 5.00V on my fluke.

Then I built the sensor power supply. By this time I had found the rights tants. The only MOV I could find was a bit of a monster but it fitted. Tests OK. Pic later.

then it was some patches for the Q12 mods. Untested at this stage. If it looks wrong tell me now!
Attachment:
File comment: patches
IMG_20140114_215044.jpg
IMG_20140114_215044.jpg [ 1.25 MiB | Viewed 2787 times ]


Tue Jan 14, 2014 9:36 pm
Profile
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 14913
Location: Home sweet home!
Hooray for this thread! :-)

Highly recommend replacing the regulators with bent legged regulators. Sad, as your current one seems very accurate, and it's a shame to waste them. Thing is, if/when you mount this up, those leads are on borrowed time without strain relief. You can wing it and repair as necessary, but it will fail eventually, likely sooner than later, without a strain relief.

I have no idea if the clamp fix is OK or not, but you can carefully test it by attempting to raise the voltage gradually and ensure it stops at 5.15 or whatever it's supposed to be, and stop at ~5.6 or so if you don't get that result, to avoid damage. Use resistors to a higher voltage to achieve this, start with higher ohms, lower step by step.

Fred.

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Tue Jan 14, 2014 10:45 pm
Profile WWW
QFP80 - Contributor

Joined: Thu Jan 12, 2012 12:54 pm
Posts: 62
Location: South Africa
The regulators are at risk even from handling the board (I'm clumsy). I haven't found any enclosure even vaguely the right size so I don't know what I'm going to put this in.

Attachment:
analog_power.jpg
analog_power.jpg [ 1.23 MiB | Viewed 2760 times ]
Here's the analog PS. If you look carefully you can see some traces cut in preparation for the smd map sensors.

I'm now stuck because the analog regulator is getting too hot and I can't see why. I can see it will always flow a little current even when no sensors are being powered but not enough to make it hot. I am using 2940's instead of 2937's.


Thu Jan 16, 2014 10:54 am
Profile
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 14913
Location: Home sweet home!
From cold, if you power it up, is it putting out a steady 5V? How long does it take to get hot? Could there be a short on the output somewhere? If it heats up slowly then that's likely just normal loading generating heat? What is your bench supply Voltage? 15? 7? 10? This makes a HUGE difference to regulator heat.

So, either:

1) You have a short on the output
2) It's oscillating badly at high frequency
3) It just needs a heat sink
4) Something else?

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Thu Jan 16, 2014 8:48 pm
Profile WWW
LQFP144 - On Top Of The Game

Joined: Tue Dec 27, 2011 5:37 am
Posts: 268
I was having a hot regulator problem a while back. I had mixed up the leads on a tantalum capacitor. It took a surprisingly long time to release its magical hydrogen cyanide smoke. It might be worth double checking.

_________________
:-p


Thu Jan 16, 2014 9:38 pm
Profile
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 14913
Location: Home sweet home!
Solid suggestion! On the 12V side they release it with a bang, but on the 5V side, that's a gooooood point. I'd have "liked" or "+1ed" your post instead of posting, but it's not possible, so here is some worthless commentary instead.

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Thu Jan 16, 2014 9:52 pm
Profile WWW
QFP80 - Contributor

Joined: Thu Jan 12, 2012 12:54 pm
Posts: 62
Location: South Africa
Sadly it wasn't that. It was the very last thing I could possibly unsolder, the regulator itself. Seems to have internal low resistance. almost a short. Replaced it and it still gets hot, but I can still hold it after 60 secs whereas before I had 3rd degree burns after 20 secs. Nothing a heat sink won't solve.

In the process of unsoldering I broke a leg off the smd regulator over voltage thingy, the TL431. Might replace it with a through hole version since all the tracks around it are cut anyway.

Theres something I really really don't understand and that is the smd resistors R106 R107 and R109. 109 measures correctly at 600 or so but the others measure at 6.5K when they are meant to be 10K. When I measure across the 3 in series it measures 6.2K. WTF?


Sat Jan 18, 2014 8:14 pm
Profile
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 14913
Location: Home sweet home!
Other connected components interacting, I guess. Measuring parts in-circuit is never easy.

You don't need the clamp, you could just forget about it, and be careful with your wiring.

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Sun Jan 19, 2014 10:15 pm
Profile WWW
QFP80 - Contributor

Joined: Thu Jan 12, 2012 12:54 pm
Posts: 62
Location: South Africa
That's the logical explanation but I can't see what. Everything that I can see on that circuit is either unsoldered or the traces cut.
Yes I will proceed without the clamp for the meantime and maybe add it back later. The smd tl431 seems to be unobtanium here and not sure about the specs for the through hole ones that I can get.


Mon Jan 20, 2014 9:44 am
Profile
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 14913
Location: Home sweet home!
Think of it as semi-idiot-proof technology development, and then realise you don't need it, and stop caring :-)

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Mon Jan 20, 2014 11:45 am
Profile WWW
Display posts from previous:  Sort by  
Reply to topic   [ 36 posts ]  Go to page 1, 2, 3, 4  Next

Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group
Designed by ST Software for PTF. ColorizeIt.