From nothing to 2 working SIDs?? (mono6581 and MB6582)

[cosmosuave]

Just a small thing worth mentioning: Sockets are not to be ignored. When you test a PIC pin's connection to a trace, there are actually a few points you should test:

• The joint where the trace solders onto the socket pin
  
• The pin on the other side of the joint (underneath the plastic part of the socket)
  
• The pin on the top side of the socket (where the PIC pin plugs in, above/inside the plastic part of the socket)
  
• The PIC pin inserted into the above
  

Not only should you test for continuity, but if things seem a bit weird (which they do here) also test for resistance. It should be very low (theoretically it would be zero), and the same every time you test it. If it's a bit higher than other joints, or if it changes, you have a bad joint.

Sorry to interrupt, just wanted to make sure you're testing it right... Keep following Wilba's instructions :)

Good point... I had issues with the pin sockets on my build which caused some issues... Some of the pin sockets were not making contact with the chip pins...

[Wilba]

ahhh... that might explain intermittent "Ready" message also...

Please ignore suggestion to replace C1_CORE2,C2_CORE2... I totally forgot that you once had a "Ready" message on Core 2, so now I've changed my mind  on what's wrong... it is most likely not a dead crystal or dead capacitors since you did say that the "Ready" message was intermittent, so it DID work at least once... and therefore highly unlikely that either crystal or capacitors died since then.

Intermittent "working" strongly suggests an intermittent connection between things that should be connected, but also possibly intermittent connection between things that should not be connected. You'll need to check for both, in the simplest case, just check no two adjacent pins of the PIC are shorting between each other.

First, what I probably should suggest is, taking the PIC out and putting it back into the IC socket, and making sure it is pushed into the socket as far as it can go. If that doesn't work... it's back to looking for a bad solder joint or some other bad contact between PIC pins and PCB. You should test continuity between a PIC pin (and I mean the actual pin coming out of the IC) and pads it should be connected to (in the case of 5V/ground this is easy, for others it means finding the connected lead of a resistor). Use the PDF as a guide.

[jooks]

I will roll up my sleeves and hook up the test pins ;) I´m so glad for all the help here. I would have no chance at all solving this on my own! I got the "ready" message 4 start ups in a row after maybe 4 "black bar" start ups. After that no more "ready" message...

I have already tested resistance for socket pins and they were all 0.01-0.02 (on lowest setting, can´t remember what it is now) but I will do it again since I was in a bit of hurry.

It would be great if it´s not the crystal or caps :)

[jooks]

I got my last 3 6582´s today :) Thanks Wilba! Hope I will be able to use all of them at the same time...

I´m all dizzy after testing...

Intermittent "working" strongly suggests an intermittent connection between things that should be connected, but also possibly intermittent connection between things that should not be connected. You'll need to check for both, in the simplest case, just check no two adjacent pins of the PIC are shorting between each other.

Found no shorts between PIC pins. Pin 11 and pin 32 are connected but that´s how it´s supposed to be I think.

First, what I probably should suggest is, taking the PIC out and putting it back into the IC socket, and making sure it is pushed into the socket as far as it can go. If that doesn't work... it's back to looking for a bad solder joint or some other bad contact between PIC pins and PCB. You should test continuity between a PIC pin (and I mean the actual pin coming out of the IC) and pads it should be connected to (in the case of 5V/ground this is easy, for others it means finding the connected lead of a resistor). Use the PDF as a guide.

- I put the PIC in the socket as far as I could and tested continuity between inserted PIC#2 and IC-socket solder joints/pads. No problems discovered.

- Continuity for all pins and the pads they are connected to (as in the pdf guide). I also tested for shorts at the pads they connected to. No shorts found. I got no continuity for pin 14 to ground J4 but that was the case for all U1_COREs so I guess no problem.

- Tested resistance as suggested by stryd (solder joint to top side of IC-socket). With lowest setting (up to 200ohm) I got 00.1 for all pins but pin 2: 00.2 and pin 39: 00.2 (I guess this could be a measurment fault also). Resistance changed some depending on were on the joint I tested but that should be normal right? At one point I thought I´ve found the problem and that was when I discovered that there was a resistance of 1.7K between top side of pin 12 and solder joint pin11 and 600ohm top side pin11 and solder joint pin12 (This was also the case for pin 31 and pin 32). I then discovered I got the same results for the other U1_COREs so that should be ok since they work?

Is there anything in these results that can explain the intermittent "ready" message. Is there anything else I can test before replacing C1/C2_CORE2 and crystal?

Thanks!

Erik

[Wilba]

Is there anything in these results that can explain the intermittent "ready" message. Is there anything else I can test before replacing C1/C2_CORE2 and crystal?

From what you say, you seem to have been very thorough in testing for shorts and continuity... it's probably impossible for me to rule out a bad solder joint or short somewhere when I'm not the one testing it :)

Again, if I was facing the same symptoms, I would probably try to prove it's the crystal and C1_CORE2/C2_CORE2 caps at fault before desoldering them... I'd do this by getting a spare 40-pin IC socket and bending pins 13,14 out flat, then putting the PIC into this IC socket before putting both into Core 2, but after I'd connected those bent-out pins of the IC socket to pins 13,14 of an empty IC socket of another working Core (eg. Core 1). In other words, make the PIC work in Core 2 but using the crystal and caps of Core 1. You can solder a cut resistor lead (or capacitor/diode/etc. lead) to the end of a wire to make it go into an IC socket. You can probably just wedge the end of the wire between the PIC pin and the IC socket (the one in which you bent out pins 13,14).

I cannot guarantee that would even work! I would definitely keep the wires as short as possible.

Be careful when inserting the PIC+socket into another socket... you do not want to make contact between the pins 13,14 of the IC sockets... perhaps a piece of thin card or paper will ensure insulation... also make sure you insert the socket into the Core firmly, the pins of IC sockets are shorter and are not gripped well by the IC socket underneath. This is a neat trick to use if you are frequently moving a PIC around as you do not need an IC removal tool.

If finding a spare 40-pin IC socket is difficult, you can just carefully and gently bend out the pins 13,14 from the PIC and do the same kind of testing (avoid solder to the PIC pins!) and this would not harm the PIC if you bent it out and bend it back in only once.

These are the extremes I would go to just to avoid desoldering :)

Anyway, give it a try if you can... it can't hurt... but I'd suggest you try it between two known working Cores to prove the theory works (i.e. using crystal+caps from another Core).... wires between PIC and crystal may introduce some interference or affect the oscillation (beyond my knowledge there sorry) so I can't say for sure if this idea works.... but if it does work, it proves exactly where the problem is, or is not. You should also try the reverse, the PIC+socket in Core 1, connecting to crystal+caps of Core 2, to get more information. More information is good.

I hope I've made sense here, and that you understand both the process and intent of these tests... it's all about swapping parts of what works with what does not, to isolate the part that does not work.

[Futureman]

Hey there... just 5cents, but if you have a multimeter that can measure frequency, could you measure the freq's of the crystals in circuit?

[jooks]

I hope I've made sense here, and that you understand both the process and intent of these tests... it's all about swapping parts of what works with what does not, to isolate the part that does not work.

Thanks Wilba :) This make sense and I understand that desoldering is the very last thing to do....I will give this a try first although at first I got a little scared when reading about bending pic pins and such ;) But if it works without soldering any vital parts I should be ok. I think.

Hey there... just 5cents, but if you have a multimeter that can measure frequency, could you measure the freq's of the crystals in circuit?

Hm, no unfortunatly my multimeter can´t measure freq´s. I´ve done some reading on swedish electronic forums and it seems quite difficult to measure if a crystal/caps works the way it should or not even with a oscilloscope because you change the circuit doing this but maybe it would be enough to crosscheck values between working cores and non-working?

I´ve also read that a crystal probably will be damaged if dropped to the ground from more then 10cm (I don´t think this is the case here but you never know). I´ve also read about similar problems due to faulty ceramic caps (but they are apparantly hard to damage by heat)... more testing before replacing though. I´ll be back next week with some results and hopefully a working core2 :) Good thing I´m not in a hurry with this and I´m also learning alot from the troubles (always look at the bright side of life ;))

[stryd_one]

I will give this a try first although at first I got a little scared when reading about bending pic pins and such ;)

I think you should read Wilba's post again - DON'T bend PIC pins! Put the PIC in a socket and bend the socket pins!

[jooks]

If finding a spare 40-pin IC socket is difficult, you can just carefully and gently bend out the pins 13,14 from the PIC and do the same kind of testing (avoid solder to the PIC pins!) and this would not harm the PIC if you bent it out and bend it back in only once.

It was this quote I refered to but I have a 40-pin socket source in town so I´ll leave my PIC pins as they are  :)(which I´m quite happy to!)

[jooks]

Finaly had some spare time today and tried Wilbas suggested method of testing the core crystal/caps. I used the proved working pic #2 and put it in proved working CORE3 with crystal/caps (pin 13 and 14) of CORE4. I got a "ready" message and was very :) the method worked! Then tried non-working CORE2 with crystal/caps of CORE3 and got a "ready" message!! So at this point I thought the problem was solved. Bad crystal and/or caps in CORE2. But for a final test I tried to put the pic in CORE1 and use the crystal/caps of CORE2 just to prove this theory. And of course I got a "ready" message.....and I tried several times just to be sure it wasn´t intermittent. So all cores work if I use pin13 and 14 of another core..... :( And I don´t want to do that! Unfortunatly I didn´t have the time to do any more crosstesting but I will this evening (try another pic maybe)

[stryd_one]

So this highlights that the problem is not with the xtal or caps, but with the connection between the PIC in that socket, and the xtal and caps for that core.... Did you do the resistance testing I suggested? What are the results at each point?

[Wilba]

Actually that's cool... the idea worked, AND you proved you didn't need to desolder the caps/crystals on Core 2 AND you showed pics so I believe you :)

It seems the only difference is the way the PIC is "seated" in the Core 2 socket...

Let's assume you were very wise and bought more than one extra 40-pin IC socket :) now try to put the PIC in this loose IC socket and then put both into Core 2. So basically the same as the second picture, but without the bent pins/wires. If that makes things work (and based on your results so far, that's just as unbelievable but still possible) then you've narrowed things down even more.

I am approaching the point of being stumped.... not quite there yet, I can still come up with some more tests to do, but running out of ideas. At least we know the parts are good, and it really is only a contacts/joints problem.

[jooks]

I´m very surprised the connection proved to be better with my bent socket pins/wire thingy. The extra socket was really bad quality also and didn´t sit well in the mounted socket (I even thought I would have to press it down while testing)

Did you do the resistance testing I suggested? What are the results at each point?

I tested resistance (pad/joint - ic-socket on top)for all pins and it was 00.1ohm for all pins except pin2 and pin 39 that had 00.2ohm. I also tested continuity with the pic mounted and I got a "beep" for both pin 13 and 14 (and all other pins)

Actually that's cool... the idea worked, AND you proved you didn't need to desolder the caps/crystals on Core 2 AND you showed pics so I believe you

I´m very glad I don´t have to desolder :) It was a great and very creative idea  (thanks Wilba :))to try this cause it was ALOT easier then resoldering and that would only have led to more confussion since it would still not work!

Let's assume you were very wise and bought more than one extra 40-pin IC socket  now try to put the PIC in this loose IC socket and then put both into Core 2. So basically the same as the second picture, but without the bent pins/wires. If that makes things work (and based on your results so far, that's just as unbelievable but still possible) then you've narrowed things down even more.

I´m not that wise (yet ;)) but will get another tomorrow and try it out.

am approaching the point of being stumped.... not quite there yet, I can still come up with some more tests to do, but running out of ideas. At least we know the parts are good, and it really is only a contacts/joints problem.

I hope we won´t come to this :o If it works with an extra ic socket I guess I have to live with that...

[stryd_one]

I tested resistance (pad/joint - ic-socket on top)for all pins and it was 00.1ohm for all pins except pin2 and pin 39 that had 00.2ohm. I also tested continuity with the pic mounted and I got a "beep" for both pin 13 and 14 (and all other pins)

It would pay to do all of those tests....

[Wilba]

I´m very surprised the connection proved to be better with my bent socket pins/wire thingy. The extra socket was really bad quality also and didn´t sit well in the mounted socket (I even thought I would have to press it down while testing)

That is to be expected, because the IC socket pins are not as long as an IC and not designed to mount into another IC socket. It is a much looser connection, which is why I use this "double socket" when I'm moving a PIC between a PIC burner and a Core; it's easy to put in and out, no need for an IC removal tool, and no wearing out of the IC socket.

After a bit of thinking, my best hypothesis is that somehow there's a difference between the PIC pins in Core 2's IC socket and your wires... and it may not be the pins connecting to the crystal, it could be any of the Vdd/Vss pins or pin 1 (reset pin) which by being bad/intermittent, cause the PIC not to boot up properly. Even if you test this in-situ with a PIC installed, an intermittent contact on the crystal pins might cause the PIC not to get a good oscillation and thus not boot up.

You might want to try a few other tests - like inserting a known good PIC into Core 2 only half-way, test, then try pushing it in down very firmly, test again. Perhaps also check how you've bent the pins on the PIC, that they're all aligned the same, it's symmetical, they all angle slightly inwards instead of outwards (like they are when "fresh") or exactly vertical. You want them to go neatly into the IC socket pins, that the ends of the PIC pins align with the place the two sides of the IC socket pin touch each other. If they're bent too far inwards or outwards, it makes inserting the PIC difficult and might cause a bad contact.

The other alternative theory is, perhaps the IC socket pins have been damaged or widened too much and do not have enough grip on the PIC pins... let's say for example it's the crystal pins, those IC socket pins work when there's your wire plugged into them but not when there's a PIC pin... perhaps the wire is wider and makes a better contact. Inversely, perhaps the other IC socket pins make a better contact into the IC socket than the PIC pins.

At some point, you might have to just replace Core 2's IC socket, which is time consuming but not too hard if you cut between the socket's pins and remove them one at a time.

[jooks]

Got another 40 pin socket today and made some tests. Used PIC#1 in core2 and it worked! Then tried PIC#1 without the extra socket...and it worked! Tried again, worked. Put in all the other PICs in their cores and core2 still worked :)

So....question is if this is solved now? It might be that my reheating of "perhaps dodgy" solderjoints made the necessery different? Then again it didn´t work after I did that but my core2 maybe just needed some extra attention and pampering before it decided to work :P I don´t know. Time will tell I guess if it´s still intermittent or not. So far so good. But many many thanks for the help Wilba!! Beers on me ;) Thanks stryd and everyone else who contributed and supported through this hard time in my mb6582 building :)

Now back to upload mb582 apps and test with sids!

[Wilba]

Hmmm... so the problem fixed itself, or perhaps you didn't run tests again after reheating joints... I suppose it doesn't matter, you will know soon enough if Core 2 starts to fail again.

But many many thanks for the help Wilba!! Beers on me ;)

That problem is easily fixed.... just click on the under my name :)

**edit** LOL you already did....

[jooks]

Hmmm... so the problem fixed itself, or perhaps you didn't run tests again after reheating joints... I suppose it doesn't matter, you will know soon enough if Core 2 starts to fail again.

Yeah, I´m not 100% sure what tests I did after reheating and I think I might have went over it again afterwards...I´ve done so much testing I can´t remember....

I forgot to mention I also tested with the PIC halfway seated like you suggested and it worked like that also.

That problem is easily fixed.... just click on the  under my name

**edit** LOL you already did....

Cheers ;) I´ll have one myself and celebrate tonight!

[stryd_one]

[me=stryd_one]does the "it's working" dance[/me]

Now if it will just stay that way............ ;)

[jooks]

Encouraged after celebrating the working mb6582 (thanks for the dance stryd_one!) I started working on the optimized 64 psu for the mono sid. I´ve been worried about doing this since day 1...with no prior skills do read a schematic and no knowledge about vero boards and such I´ve been really lost in my mind but finaly I felt that it was time for learning by doing (trial and error). My ordered parts looked ok except for the super big caps. They are apparently not ceramics (poly?) but does it matter (same specs)? Butchered the c64 to get the switch and dinplug (desoldering was ugly with more violance then you might expect in electronics).

I first made a sketch with all connections and where to jumper and cut and then just soldered away...6 jumpers on component side and 4 solder side (not the best layout I guess;-) but I´m very happy if it works!

I´m not finished yet since I still have to cut the tracks in proper places (need a drill or something) Here is the result so far:

still have to solder jumpers between pin 4-5 and gnd on the power in pins.

[TafterT]

Hey,

i built a similar optimised psu on vero board with a slightly different board layout, i was really chuffed the first time i powered it up and it worked here's a couple of pics

[jooks]

Nice compact design TafterT! And extra plus it worked. Mine didn´t....or sort of not. I got around 5.40V for all pins  but when measuring the dinplug pins on solderside I get around 5.40V for all pins there also. I have tested the psu before and got both 5 and 9 v out of it. But now 5.40V from pins 6 and 7 also...strange. I have another psu but a bit afraid of trying that if there is something on my homemade board that i wrong... don´t know what else to do either? It comes to mind that when testing my psu´s output pins I got some "lightning" one time (shortcut?), maybe that got it messed up? Hmmm...

edit: I got a clean 0.00V from pin 6 and 7 on the psu and 5.40V from pin 4. So the psu is dead. Question is if my opt psu killed it or if I killed it a couple of months ago when testing the output voltages..

[jooks]

Did some more measuring since I found out that I forgot to switch to AC on the multi :-[ So much to remember;-) Still no good results though. I got:

- 11.1VAC and 10.3VAC for pins 6 and 7 (solder side).

- 11.4VAC-5.5VDC after bridge rect (+ side)

- 11.3VAC-5.4VDCafter bridge rect (-side)

- 11.8VAC-5.4VDC just before voltage reg pin 1

- 0.00VAC-5.4VDC volt reg pin2

- 10.9VAC-5.36VDC volt reg pin3

- 10.9VAC at the 14VDC output pin??? 5.36VDC when set to DC....

- 5.36VDC at 5VDC pins

- 5.36VDC at power led pins (no led attached)

Conclusion: I have no idea why I get both AC and DC readings all the way in the 14VDC line except at the voltage regulatur pin2. ....very small changes in voltage also. voltage seems ok until the bridge rectifier but nothing changes after it. Not functioning? hm thinking about it it seems like this could be it. Bridge rectifier not working....but then again I have very little knowledge of these things so if anyone could confirm this thought in anyway I´d be greatful. 11.4VAC into the voltreg and 10.9 out....is this because it gets AC at pin1 and DC at pin2?

[joewhat]

wow this looks like we are stock with the same kind of trouble.. im building the same optimized_psu mine is acting almost the same way.. and i have no/limited knowledge like you.. its very annoying :0)

mine psu an c64-II psu makes the same kinda random voltage output from the supposed 9vAC output.. and i also get AC voltage on the other side of the bridge.. ://

[jooks]

Similar problem but my psu seems ok and give a steady 11-12VAC and 5.5VDC.

I went over the board again and found a short between the bridge rectifier - leg and ~leg. Fixed it but still the same problem with 10-12VAC almost everywhere....maybe the short have destroyed the bridge rectifier?