Core R4c trouble

[Pennanhuo]

I can get the "upload request" or sing of life via midi. When i tested voltages shown in http://www.ucapps.de/howtodebug/mbhp_core_extract_measuring_vdd.gif i got 1.66 volts from most of them and litle less from some. I have an original c64 psu that works fine. And my soldersing seems to be OK.

I'm not experienced enough in electronics to know whats wrong

Please help :>

[TK.]

How did you connect the PSU?

Best Regards, Thorsten.

[smashtv]

I'm not experienced enough in electronics to know whats wrong

More info please.  ;)

Be sure to pull the PIC and optocoupler until your voltage tests good...don't put them at risk during power supply related testing.

Tell us how it's wired to the power supply, specific test point voltages, etc.....Details help get specific answers.  :)

Best

Smash

[Pennanhuo]

First with this http://www.ucapps.de/mbhp/mbhp_sid_c64_psu.pdf and then later also tried connecting straight to the 5.someting volt pins on the psu.

And I did the ungplugged tests too and even with the sid (board not the chip) connected and they were ok. And thats what's bugging me since I'm not sure if some of the ICs are broken.

[Pennanhuo]

I'll get some more accurate readings from the board today when I get home.

[Pennanhuo]

pic pin 1 - 12 1.90v

    pin 11-12 1.89v

    pin 32-31 1.89v

Ic2 pin 8 - 5  1.90v

These were somewhere around 5v when I tested the core right after finishing it. After that I brought it home from work and now it measures as above.

Can you tell me what's wrong?

[smashtv]

These were somewhere around 5v when I tested the core right after finishing it. After that I brought it home from work and now it measures as above.

Same power supply?

Can you tell me what's wrong?

Not without complete specific info....I can make this -guess- though: If supply is the same one that gave you a good reading, then gave you a bad reading after moving the stuff, you have probably shaken loose a bad solder joint or a connection that was almost shorted  and the shuffle did the deed.....

There is also the possibility that your regulator is now bad (as a symptom of another problem) and only able to kick out a few volts (unlikely)....

Are your electrolytic caps in the right way?

Just to eliminate another unknown variable: same meter?

Check your soldering, even if it looks fine check it again and reflow anythign suspect.

Best

Smash

[Pennanhuo]

It seems that the problem was the old c64 psu. I think it just gave up at some point. I tried with my mobile phone charger :D, got a bit more power out of the pins (around 4v) now i just need to find a new supply :(

Sorry if my writing is a bit incoherent, since I'm a beginner with electronics and don't know all the terms and stuff.

[smashtv]

It seems that the problem was the old c64 psu. I think it just gave up at some point. I tried with my mobile phone charger :D, got a bit more power out of the pins (around 4v) now i just need to find a new supply :(

Cool!  9vac, 200ma or more is the statistically proven best choice for feeding the Core power section.

Sorry if my writing is a bit incoherent, since I'm a beginner with electronics and don't know all the terms and stuff.

No worries man!  I don't mean to sound grumpy with my replies, just trying to spur self-teaching without burning up components.... :)

Best

Smash

[Pennanhuo]

I switched to a regular 11v 500ma transformer. I did the iniatial voltage check and it was ok. Then I plugged in the pic and the octocoupler and it still wouldn't send the upload request.

Testing according to this http://www.ucapps.de/howtodebug/mbhp_core_extract_measuring_vdd.gif I got these readings.

From pic

Pin 1=5.06 11=5.06 20=1.64 32=5.06 26=1.88 25=0.08(Does this mean that it's sending something but it isn't getting trough?)

octocoupler pin 8 5.06

Midi out 5.06

J1 vd 5.06

And testing with this http://www.ucapps.de/howtodebug/mbhp_core_extract_measuring_gnd.gif

From pic

Pin 12=5.04 14=3.77 31=5.01

octocoupler pin 5 5.03

ic3 pin 2 5.05

I checked my soldering as best as I could and to me every part seems to be correctly placed.

Can you see what I missed?

[smashtv]

I switched to a regular 11v 500ma transformer. I did the iniatial voltage check and it was ok. Then I plugged in the pic and the octocoupler and it still wouldn't send the upload request.

Your test values won't speak much to us if we don't know whether it was done with PIC or without....Again please set both chips off to the side until your voltages are correct!

It's a waste of my time to try to help when you are not listening.  :-\

Testing according to this http://www.ucapps.de/howtodebug/mbhp_core_extract_measuring_vdd.gif I got these readings.

From pic

Pin 1=5.06 11=5.06 20=1.64 32=5.06 26=1.88 25=0.08(Does this mean that it's sending something but it isn't getting trough?)

octocoupler pin 8 5.06

Midi out 5.06

J1 vd 5.06

These readings point to one fault with the chips in, and another if they are out......so I'll quit guessing here and wait for you to finish explaining what's in front of you. 

Best

Smash

[Pennanhuo]

I'll try to clarify myself.

I did these measurings described in core page as "Apply power to the module after all parts except the PIC and the optocoupler are mounted. Check the voltage levels between the most important pins with a multimeter (analog or digital doesn't matter) before plugging the PIC and the 6N138 into the socket: IC1:MCLR(1) - IC1:Vss(12) = 5V IC1:Vdd(11) - IC1:Vss(12) = 5V IC1:Vdd(32) - IC1:Vss(31) = 5V IC2(8 ) - IC2:(5) = 5V" were all at 0.03-0.14 above the 5v, which I thought was OK. So I inserted the chips and tested the board. When it didn't work I did the tests described in the two pictures that I linked to in my previous post. To me it seemed that in the picture the chip's are connected, since it's the chip in the picture and not the socket. So I did measurings with them both inserted.

So did I intreped the pictures wrong? Do you need to know something more? This is quite frustrating for me too :S

[smashtv]

This is quite frustrating for me too :S

No worries, you did fine....Don't worry no matter what the frustration level I won't give up on it and I expect you not to either.... :)

Now that we are on the same page let's take some very small steps one at a time with troubleshooting......

Lets get some colors in the mix!

Pin 1=5.06 MCLR

11=5.06 Vdd

20=1.64 RD1

32=5.06 Vdd

26=1.88 TX

25=0.08 RX

octocoupler pin 8 5.06 Vdd

Midi out 5.06 M-

J1 vd 5.06 Input voltage (Vd)

Lets start with pin 20, There are several things that could cause this, but since you have power to pins 11 and 32 we can eliminate most of those causes (Missing/open/through hole plate on R6,R9,R10)....Let's focus on R9, is it the correct value (10K)? Is there anything plugged into J8/J9? If so disconnect it and see if the reading on pin20 changes, if nothing plugged in look carefully for any solder bridges around pin 20 (like where that trace goes between pins 18 & 19), also look for solder bridges on J8/J9.

Let me know what you find and we'll move on from there.  :)

Best

Smash

[Pennanhuo]

I did that and noticed nothing wrong. I also checked R6 and R10. Without the pic pin 20 reads 5.06 and with the pic 1.74. And board is still not sending anything.

[smashtv]

I did that and noticed nothing wrong. I also checked R6 and R10. Without the pic pin 20 reads 5.06 and with the pic 1.74. And board is still not sending anything.

Ok considering pin 20 has the PIC ever been installed in the socket in the wrong direction?

Best

Smash