XT build question

Discontinued DIY products Shruthi
#1

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?

Thanks,

Mike

#2

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

#3

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

#4

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

#5

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.

#6

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!

#7

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…

#8

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.

#9

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.

#10

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?

#11

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:

#12

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!

#13

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.

#14

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

#15

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.
Greets

Andre’

PS: yes without the IC’s and OLED.

#16

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.

#17

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.

#18

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…

#19

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:

#20

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.