Ambika 4P voice card dead

hey there, I’m working on my build and I can’t figure out why the 4P card I built isn’t firing up when I plug it into socket 1 of the mobo.

the mobo itself seems to be working fine (display, SD, midi and panel controls all good). but when I plug in the card, the data LED doesn’t come on and there’s no sound. I checked the headers and all connections seem in place from the mobo to the card. I also checked pin 8 of the atmel and its reading 5v, so power is getting to the card. I bought my chips preprogrammed btw.

I tried reversing the two LEDs just in case I got the polarity wrong, but nothing. Since they connect directly to the Atmega chip Im not sure what to troubleshoot. Any ideas? Thanks all~~

A / B layer jumper?

yes both are set to A, since it’s the bottom board.

ive tried to check for anything obvious like that, but i guess I’m still missing something somewhere. what are some good test points to check on the 4P board?

i want to troubleshoot the Atmega more but i’m not sure what to do besides the voltage reading i mentioned.

A good way of checking if the chip is alive is to try programming it… but you can’t do that :frowning:

i do own a USB programmer that I use for writing EPROMs. any chance this can be made to work with the 328?

http://www.mcumall.com/comersus/store/comersus_viewItem.asp?idProduct=4282

no.

heh oh well. i’ll order a cheap ISP programmer for the 328. in the meantime i’ll keep poking around the board.

i should mention that i built another 4P board and it has the same problem. i measure power at the board but no LED activity or sound.

Have you ever got any voicecard to work on this mobo?

no i haven’t. i’m quite sure i’ve gotten something wrong on these cards but i’ll have to sit down and take a very close look. i’d be surprised if the problem really was with the 328 but it was my first instinct re: the LED issue.

i’ll pull the datasheets for all the IC’s on the card and make sure they’re all getting power, etc~

i think i found the problem. i soldered each of the four filter caps in the top and bottom hole, instead of the middle and bottom. i thought the extra hole was there to accommodate different sized caps but that was before i checked the layout diagram.

the sad thing is, i only checked for that because another person on the forum mentioned they had the same problem with their ambika voice cards. :stuck_out_tongue: i probably wouldn’t have caught it until further down the line.

i’ll redo the filter caps on one card and report back~~

Won’t solve the “voicecard doesn’t boot” problem sadly.

But this needs to be fixed obviously, otherwise you won’t get any audio output.

Maybe you have made other mistakes and you could post a photo of your board?

Mmh? The extra hole is not there to accomodate different sized caps? I thought it is. And it will work, if you use the top and the bottom hole. It will not work, if you use the top and the middle hole.

ok, i redid the caps properly. the voice card still doesn’t boot, but as you say olivier, it would have needed to be fixed anyway.

cj55 maybe you are referring to electrolytic caps? i think the point of the three holes is to allow use of either polarized or non-polarized caps (right?). i am using film caps but i had them soldered as if they were electros (in regards to the board’s layout).

i will post a photo of the board shortly~~

actually, i’m not sure what the point of the three holes is anymore. can you clarify please, olivier? i’m using 220pf polypropylene film caps (not polystyrene). i’ll take a picture of the board once i know the caps are connected properly.

edit: never mind, this whole thing was a big red herring. it looks like the third hole is just for different size caps after all. the top and middle pads are bridged.

alright, here’s the troublesome card. hope these pics can be of some use.

Could you check the two ceramic caps (C31, C32) on each side of the 20 MHz crystal ?
They look different, but should really be the same … one of them might be the wrong one (C31 looks like a 100nF cap).

If you made a mistake there, the MPU might not ‘tick’ at all.

C31 and C32 are definitely both 20pf. one is a MLCC and the other is a disc cap. (i ran out of MLCC’s…)

Hi, maybe problems comes from:
Change the Atmel 328 against another one. Can be that the ATMEGA is death.
Test also the arduino headers . Sometimes it gives no contact.
Last, maybe it is the cristal . Remove the cristal and both caps 18…22 nF. Substitude all against new ones.
Be sure that you have a little space between the cristal and the PCB.
This are all mistakes i found sometimes while build the AMBIKA.

If the 20 Mhz cristal is butchered , the ATMEL had no function
Hope this helps.

Greets

Andre’

hm good point, maybe the crystal is shorted. i’ll redo it~

nope, no luck with raising the crystal off the card. for what it’s worth, i soldered the master crystal to the main board completely flat with no space underneath, and the mobo is working perfectly with no issues.

i’m also waiting on an ISP programmer so i can verify the 328. (i have no equipment to test it right now) anything else i should be looking at in the meantime?

i appreciate all the help from you guys~