My LCD screen project, boost, WBO2, Knock, etc

The UA7805 seems to be very similar to the LM7805 just a different manufacturer so I bought two of them (one as a spare) and a cooling fin. I'm gonna see if it resolves my issues.

http://pics.unlogic.se/3000gt/projekt/IMG_0345.JPG

The original part number is LM7805 manufactured by fairchild. Datasheet can be found here: http://www.fairchildsemi.com/ds/LM/LM7805.pdf
Here is the pin out info.
http://i782.photobucket.com/albums/y...009/LM7805.png

Also other tips for flashing.
(1) You do not need to hold down the rotary encoder button down like the previous version, the default serial port is the one you connect the PC to.
(2) Make sure the COM port number from your PC is correctly selected.
(3) If you can get CoolTerm to datalog, then it will confirm (2) is correct.

I've taken the unit out of the car and rigged it on my bench inte garage.

http://pics.unlogic.se/3000gt/projekt/IMAG3016.jpg

Something must be drawing a lot of current on my board cause both variants of voltage regulators get really hot as soon as I turn the unit on.

With a heatsink and thermal paste on the Fairchild voltage regulator hits 70 degrees centigrade in less than two minutes.

http://pics.unlogic.se/3000gt/projekt/IMAG3020.jpg

I still got no luck with CoolTerm either so I'm gonna try to find an old PC with a built-in serial port and see if works better.

Got any clue what could be wrong with my board?

Unlogic: I just checked two boxed LCDBC devices and measured the current it is consuming: 60.6mA and 54.0mA (LED color choice has influence on current consumption). The 7805 voltage regulator is rated for 1000mA, so that means they're only operating at 6%. I am curious to see how much current yours is taking?

I wonder if you can find a hot spot with your Infrared meter?

Have you tested if that glue/silicone goop is conductive?

Checking for heat spots was a smart idea!

The goop on the image above was hot glue. I measured it with my multimeter and it's not conductive but I removed it anyway as a precaution.

When I checked for hot spots I noticed that the smaller of the two integrated circuits was above 60° C. I presume that's not normal so I powered down immediately.

Any idea what to check for next?

Edit: The current circuit in my multimeter is fried (the work of my father in law...) so I couldn't measure that. But I'll see if I can buy a new multimeter tomorrow.

The integrated circuit that's getting hot seems to have something to do with RS232 communication which could explain my problems. The overheating problem started yesterday when I tried to update the unit.

I also noticed now that if I set Datalog=TxtMode2 or Datalog=TxtMode3 the unit doesn't boot properly. It only shows "Connecting MUT" on upper line with nothing on the lower line of the display. After a few seconds it switches to showing squares on the upper line and just sits there.

If I hold down the rotary encoder I can boot into the configuration menu just fine though. If I set the Datalog=OFF the units boots just fine again.

http://pics.unlogic.se/3000gt/projekt/IMAG3022.jpg

http://pics.unlogic.se/3000gt/projekt/IMAG3023.jpg

Unlogic: Yes you're correct the smaller IC chip is responsible for RS232 communication (datalogging, and MUT). MAX232, or MAX3232 are both compatible. It's 25C in this room, and it runs 28C for me.

I will send you new ones in the mail.

In the mean time, remove the smaller IC and power up the LCDBC and see if the 7805 runs cooler now.

Thanks thats very kind of you but I can order a few from a local company (Elfa.se) they seem to be pretty cheap. Is there any specific version I should get? There seems to be quite a few versions available designated by different letter combinations.

https://www.elfa.se/elfa3~se_en/elfa...=max3232&cat=0

Would a MAX3232CPE+ in a DIL-16 package work?

I removed the MAX232 chip and now the voltage regulator hovers around a much healthier 29°C. Do you think a faulty MAX232 could be the reason for the disconnects and failed reconnects that me and Marty have been experiencing?

CPE+ version only works 0C and above. EPE+ version works down to -40C temperature. MAX232EIN (Texas instruments) is another good version, that works in cold temperatures also. Yes it must be in DIL-16 or DIP package.

I guess you could buy a CPE+ version to get by for now until the EPE+ version I send you arrives.

It certainly is possible for disconnects/reconnects.

I found the correct version of the uprated MAX232A chip here:

https://www.elfa.se/elfa3~se_en/elfa...=MAX232AEPE%2B

Should I order some new capacitors as well in case thats the reason why the chip fried in the first place?