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Need help pointing to strange video problem on SE/30
- Thread starter 68kbits
- Start date
onlyonemac
Well-known member
Isn't that why we have a wiki? I'm sure the "advanced problems" threads are going to clutter up the main forums as badly as uniserver's "Caps!" threads did a while back. That was a nightmare!
uniserver
Well-known member
Again - OOM - You keep trying to moderate every thread? do you have a control complex?
Why would anyone give a FLYING F**K About what you have to say?
I do not care about your feelings, you are the most annoying SOB i have ever seen.
Ya offer nothing. Just flapping lips every single time.
Hell, a little while back, I even felt sorry for you and offered you ( for free ) a 32meg stick of ram, and I offered you a Great working 80meg IBM SCSI drive
and you told me to SHOVE it because i would not ALSO pay for the $12.95 shipping to you. I feel sorry for the guy i meet in public one day that reminds me of anything like you.
Blinkenlightz
Well-known member
>
Seriously??The man puts huge effort into what has become both a very needed warning and valuable resource, and you whine about clutter?? Whilst yourself offering very little of value??
As far as I'm concerned, the "Caps!" threads should be stickied -- but that's not my call to make.
My apologies for the thread-jack here, but I couldn't just let that one fly - carry on the discussion on SE/30 bizarreness.
techknight
Well-known member
Well, in the modern world of computing we call those "trolls"
CC_333
Well-known member
I don't want to get too involved here, but...
I don't think he's totally a "troll", but there's definitely some things he's said that are probably, shall we say, somewhat adversarial, in my opinion, and he should try to be more tactful if he wants to continue being a member here (it seems, judging by some unpleasant exchanges between he and several other members here, that he is somewhat close to being banned).
Whew! That is one long sentence!
Please feel free to quote this all you like. I am trying to share some objective observations, and you are all welcome to pass them along.
OK, I'm done now |)
c
Edit: Here's what Wikipedia says about the term "troll". Without more information on my end, I'd say that techknight is on to something, unfortunately :-/
I don't think he's totally a "troll", but there's definitely some things he's said that are probably, shall we say, somewhat adversarial, in my opinion, and he should try to be more tactful if he wants to continue being a member here (it seems, judging by some unpleasant exchanges between he and several other members here, that he is somewhat close to being banned).
Whew! That is one long sentence!
Please feel free to quote this all you like. I am trying to share some objective observations, and you are all welcome to pass them along.
OK, I'm done now |)
c
Edit: Here's what Wikipedia says about the term "troll". Without more information on my end, I'd say that techknight is on to something, unfortunately :-/
onlyonemac
Well-known member
I've read about the "troll" matter on Wikipedia and would say with all honesty that I do not intend to cause trouble, but rather that uniserver takes everything I say in a very strong manner. I would be inclined to think that he is "trolling" me moreso.
techknight
Well-known member
Can we just move forward? and forget all the crap?
CC_333
Well-known member
Agreed 1000%!
Let's just move along and be polite, shall we? Arguing and being rude gets people NOWHERE!
Did anybody come up with a solution to the video problem?
c
p.s. Also, I'd like to put in a good word or two for uniserver, for what it's worth; He's always been polite to me, and he has been very reliable and honest. I would be rather disappointed to see him get banned because of this.
uniserver
Well-known member
Last night I received CC_333's SE/30 parts board. ( thank's man
Used my heatgun, and swapped chips.
ITs still doing the SAME pinstripe effect, I am pretty sure my issues are related to original OP's issue.
My next task is to go over the Schematics and do a Pin by pin, chip to chip continuity check.
( as Techknight Suggested )
Of corse this is going to take some time.
But it has to be done obviously.
One question, you know how some people make a jumper that goes from C6, 1uf 50v cap to the sound chip?
I thought that cap had something to do with the video?
It does show what bypassing a bad trace would look like.
( picture from the parts se/30 )
I will admit I am more of an R&R kind of guy, the troubleshooting part can be way too time consuming for my liking.
Maybe as I go along, I'll be able to shot gun more common SE/30 VIDEO issues.
College of hard knocks.
Used my heatgun, and swapped chips.
ITs still doing the SAME pinstripe effect, I am pretty sure my issues are related to original OP's issue.
My next task is to go over the Schematics and do a Pin by pin, chip to chip continuity check.
( as Techknight Suggested )
Of corse this is going to take some time.
But it has to be done obviously.
One question, you know how some people make a jumper that goes from C6, 1uf 50v cap to the sound chip?
I thought that cap had something to do with the video?
It does show what bypassing a bad trace would look like.
( picture from the parts se/30 )
I will admit I am more of an R&R kind of guy, the troubleshooting part can be way too time consuming for my liking.
Maybe as I go along, I'll be able to shot gun more common SE/30 VIDEO issues.
College of hard knocks.
genie_mac
Well-known member
I had a similar problem with my SE30 (vertical bars) and luckily I managed to fix it. First thing I did was look at exactly what was going on on the the screen. It's a bit hard to see on the image posted above, but it looks like 7 good pixels and one bad (incorrect) pixel. Does that sound right? If you have a higher res picture then it will be easy to count the pixels.
That way I was able to figure out the most likely cause of the problem, which in my case was a faulty address line caused by a bad via. The use of a spreadsheet helped me visualise the problem but still took a few hours to figure out. Someone with lots of experience could probably pinpoint this straight away, but that would be too easy ha!
ps: Out of curiosity did you try checking continuity between pin 23 on UC6 and pin 14 on UE8 (the 74LS166)?
That way I was able to figure out the most likely cause of the problem, which in my case was a faulty address line caused by a bad via. The use of a spreadsheet helped me visualise the problem but still took a few hours to figure out. Someone with lots of experience could probably pinpoint this straight away, but that would be too easy ha!
ps: Out of curiosity did you try checking continuity between pin 23 on UC6 and pin 14 on UE8 (the 74LS166)?
I would like to update that I successfully fixed the original issue I started the thread with.
I first swapped all the removable chips one by one from another working se30, no luck.
Thanks to uniserver for keeping an eye out for the solution and asking for pictures.
It was a "simple" one wire fix.
http://s20.postimg.org/z1w7b8lpp/se30.jpg
See the original thread posting the photo here:
viewtopic.php?f=7&t=21005&p=202535#p202535
If anyone has a spare video rom for an se30 please contact me. I have a damaged one in a different compact from an unrelated incident.
I first swapped all the removable chips one by one from another working se30, no luck.
Thanks to uniserver for keeping an eye out for the solution and asking for pictures.
It was a "simple" one wire fix.
http://s20.postimg.org/z1w7b8lpp/se30.jpg
See the original thread posting the photo here:
viewtopic.php?f=7&t=21005&p=202535#p202535
If anyone has a spare video rom for an se30 please contact me. I have a damaged one in a different compact from an unrelated incident.
uniserver
Well-known member
following the schematic , between UE8 the VID lines to UC6 and UC7 just don't make sense, the only pins that really make continuity is pin 2 of UE8 and PIN 2 of UC7, and pin 3 of UE8 and pin 3 of UC7, none of the rest of the pins seem work(continuity) . may be I have a different revision or something.
witch seems strange because it appears only one pixel is out of the 7 data lines.
witch seems strange because it appears only one pixel is out of the 7 data lines.
genie_mac
Well-known member
My reasoning from my very limited understanding of the video system is that only the last pixel is incorrect, all other 7 are ok therefore the problem must be between RAM and shift register, assuming the RAM's are ok. If it were an addressing issued before the RAM's, it would be at least two faulty lines as the RAM is interleaved? Does that make sense to anyone? Now I'm not too sure myself anymore .
As the first 7 pixels are ok, VID0 to VID6 must be ok, so I assumed that there must be a problem with VID7. As VID7 on UC6 RAM (pin23) is only connected to VID7 on UE8 shift register (pin 14) I thought this would be the first place to look. As the thick line labelled VID(0-7) is in reality 8 individual tracks, the others shouldn't be connected, just as you say, so only corresponding VID numbers are connected (VID0 to VID0, VID1 to VID1 etc).
Hmm that could be it, probably too much to ask for though, is it?
.As the first 7 pixels are ok, VID0 to VID6 must be ok, so I assumed that there must be a problem with VID7. As VID7 on UC6 RAM (pin23) is only connected to VID7 on UE8 shift register (pin 14) I thought this would be the first place to look. As the thick line labelled VID(0-7) is in reality 8 individual tracks, the others shouldn't be connected, just as you say, so only corresponding VID numbers are connected (VID0 to VID0, VID1 to VID1 etc).
Hmm that could be it, probably too much to ask for though, is it?
The problem could also be in the shift register itself, I've had logic ICs fail in such a way that inputs were dead, as well as some interesting internal faults that caused the outputs to not behave the way I expected.
Occasionally I'll take a probe connected to Vcc or Gnd via a 100 ohm-ish resistor and touch it to various input pins to force them high or low and observe the effect on the circuit. If you force one of the shift register inputs high, I would expect a row of light or dark pixels. When you find the pin that affects the dead columns you are seeing, or discover that none of them do, that will give a pretty good clue as to where the problem is. A logic probe can be very useful for this sort of fault tracing too.
Occasionally I'll take a probe connected to Vcc or Gnd via a 100 ohm-ish resistor and touch it to various input pins to force them high or low and observe the effect on the circuit. If you force one of the shift register inputs high, I would expect a row of light or dark pixels. When you find the pin that affects the dead columns you are seeing, or discover that none of them do, that will give a pretty good clue as to where the problem is. A logic probe can be very useful for this sort of fault tracing too.
