XT build question

Hi All -

I built the XT controller board and then built out the power supply on the filter board but nothing else (yet). I thought I would be able to plug the filter board into the controller and and power them both up. When I turn on power nothing happens on the controller. Running through the checkpoint voltages on the disconnected filter board everything’s good. When I connect it to the control board the 5v pin on the connection header goes wonky fluctuating between 200 and 250 mv.

Am I right in assuming that I can power the MoBo with just the power supply circuit built on the filter board?



Yes, you can. So you have a problem on the Digital Board…. Post Pics, please!

Thanks, and will do. I’m at work, so I’ll get these posted later.

Maybe a chip inserted backwards or the wrong chip in the wrong socket. Someone had a similar problem.

Thanks, Olivier. Not the first time this would be an issue for me :slight_smile: I’ll double check and post pics when I get home.

There is a short somewhere on the MoBo, I just can’t find it yet. Here are some pics, maybe another set of eyes can help!

And here is the way I’m connecting the boards. Also the short is there without the chips installed; I can tell because the indicator light on my power supply dims when I turn power on and have the boards connected. I can’t find the short though…

Take that foam out, it’s conductive foam??

The black foam your chips are delivered in conducts electricity, it’s job is to stop static building up.

If the metallic part of the regulators touch something…… INSTANT DEATH!
And you do a very bad job at cutting leads as close to the board as possible.

Ouch! I’m so sorry… This thing you did with the foam was a terrible idea.

You might have damaged pretty much anything by doing this. Could even be the display controller :frowning:

Is the filter board - without any connection to the control board still okay regarding the +/- 5V voltage test?

Conducting foam? Wow. Filter board is ok, still pumping out +/- 5v where it should…used a piece of the case extra plastic instead and no change. There are no chips in the MoBo now but it’s still hosed. I guess I may have to replace the oled :frowning:

Progress, I desoldered the oled and now the MoBo gets the correct power. So good news and bad, the new oled I ordered was friggin’ expensive!

Do the build instructions say to leave the display off until the power on test? it does with the old kits. It might have saved you the cost of a display.

Edit: Had a look and it doesn’t this is probably because there’s nothing under the display like the original kits.

BTW, the board runs perfectly with a Standard LCD - without any noise problems…

Hi Guys, please clean your PCB’s . Than you see better if there are cold solder points or shorts on your PCB. Than use a lens to control all Solder points. BTW , i measure here a resistance between +5V and ground (MOBO without voicecard ) from round about 340 Ohm. Is it less,(100 ohm /200ohm or 1 Ohm) than you have a short.
340 Ohm because all Pots are parallel on 5 V and ground.


PS: yes without the IC’s and OLED.

The XT Boards are matte black, so they don’t get really clean i guess, you would just smear the flux all over. Better use proper Solder.

fcd72 I haven’t tried it on any matte boards yet, buttubeohm’s method worked perfectly for me while alcohol only did result in a residue on the pcb in the past.

I use Kester water clean solder for parts that are not water sensitive (no pots, crystal, etc.) then I use Kester no-clean organic solder for the rest. It’s worked for a long time, but on matte boards the no-clean does leave a residue. I’ve cleaned it best I can with alcohol but I don’t want to put water on it.

The oled is off and all the chips are out and I still have a short somewhere…

And thanks, Andre’, I measured 5.9 to 6 Ohms on the +5 and Gnd pins so it confirms a short somewhere!

If anybody has an idea where that might be, I’m all ears. Looking closely at the board with a loop so far has revealed nothing :frowning:

any idea which components i should look at? Or any strategy for finding the short? Just to recap, I have continuity between the +5 and Gnd pins on the MoBo.