Still looking for a short …
About “No MBNet response” message, it’s strange because when U20 removed, at each boot there’s “Cloning slave” operation ! and it seems to be ok after reboot ! that’s the proof the Can Bus for MBNet is ok, isn’t it ?
Found a shot between Pin 3 and 4 of U18 !
The “Cloning slave” operation happens when you hold down “Menu” button when you power on.
So a short might be causing this to happen.
Yes Wilba i have seen that in the manual and i have checked “menu” button and it’s ok ! But the cloning operation happens only when U20 is not fitted. When cloning operation (slave 3) is finished i have the normal menu like my sammich. But after when i put '165 into his U20 socket i have the famous message “No MBNet …” !!
But i’m sure that i have a short somewhere !!
If cloning operation succeed is it a proof that pic’s communicate between them ?
And about contact between pins 3 and 4 of U18 is it normal ?
Thanks for your answer !
U16,U17,U18,U19 are connected to the rotary encoders.
U20 is connected to the switch matrix.
So, it’s possible that pins 3,4,5,6,11,12,13,14 (which connect to the D0-D7 pads/ribbon cable/CS PCB) for U16-U19 might be connected, because of the position of the rotary encoders will be “shorting” some of those pins to ground. That’s normal. This makes it very hard to test for shorts for those pins, but it doesn’t really matter because you will discover problems later when encoders don’t work correctly. For U16-U19, shorts between those pins should have no effect on the switch matrix.
However, there should not be shorts between pins 3,4,5,6,11,12,13,14 of U20.
Putting the 74HC165 in U20 is effectively turning on the switch matrix so that any short on the CS PCB is now being read by the PIC. In this case, it’s possible that one of the SID 1,2,3,4 buttons are being triggered. So you’ll need to check the tracks from U20 for shorts… also tracks/pads near the SID 1,2,3,4 buttons on the CS PCB.
Normally shorts occur there by the LCD being mounted… but if this is not the problem, then it’s most likely a soldering issue… some blob of solder shorting between pins of the switches etc. and it’s definitely a short, not a broken track or a bad solder joint that is not connecting a pin to the track… missing connections would not create an “always pressed switch” effect.
Yes Wilba i begin to understand better ! Thanks for all this very interessant informations !
I have decided to remove every wires between CS and base board ! And i have always pb with “no MBNet response” but short on U18 is no longer present but present of course in CS board !!
Let’s go to find all these short !!
Thanks.
One question about T2 to T9, i used BC547C, in wiki that’s noted BC547 is it a problem if i used them ?
Thanks.
No, the suffix does not matter, I think it relates to different hFE/gain values, but in this context, the transistor is either fully conducting or not conducting.
Hi Wilba,
i have removed wires between CS and baseboard Pcb ! I have removed all Ic’s and after put them each them on by one to test mainboard card. Everything is correct i have normal comportment until i fit U16 in it’s socket ! Without U16 is fitted, boot is normal and i read on pcb Preset 001 but when i fit it boot is normal and instantly my lcd become mad and it’s like i move all knobs and write that can bus is out no sid 4 ??? But CS board is not attached !! I have looking for a short in U16 socket but none pin connected with another one !! and tested around it and i have found nothing ! I have tested few IC’s but same problem !!!
I dont’ understand !
Thanks for your help.
K.
Do you know how the 10K pullup resistors work on the DIN module?
http://www.ucapps.de/mbhp/mbhp_dinx4.pdf
In addition, the Core will have a 10K pullup on the input pin of the PIC, so that if no ICs are connected, there are no DIN events (button/encoder events).
So perhaps when there is no IC in U16, it “works”, but when you put an IC in U16, some “garbage” going into U16 from U17 is making lots of false button/encoder events.
Normally this should not happen if there is only one IC in U16, as either resistor R61 or the 5th resistor in resistor network R30 (the pad that is outside the white rectangle!) will pullup the input into U16… i.e. the data being shifted through U16 from U17, U18, etc.
Perhaps something is wrong here… so that pin 10 of U16 is “floating” or always 0V, causing garbage to get into PIC.
Check you are using 6-pin resistor networks, and they are correctly positioned (pin with dot marking is at the left end, in the square pad, next to the R30 etc. label). Check also if R61 is not shorting to ground, or U16 pin 10.
If you assume the IC is good, this is the only thing I can think of at the moment… because when the IC is out, you do not get the garbage… and if the IC is in, then the events you get are not “encoder” events and more like button press events, which can only happen with garbage from U20, i.e. from garbage data going into U16, not from false triggering from U16’s input pins which connect to the CS PCB.