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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: PiR on January 28, 2004, 06:40:01 PM
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Listen to my very interesting story about the way I fried my BPPC card two days ago.
People willing to play with the Power can learn some from this.
Well, I have problem with power from the very beginning of my BPPC. During startup my Amy freezes before full WB getts started, at random moments. Luckilly for me after the temperature getts higher after some time it, starts working quite stable.
But this startup was getting on my nerves! :madashell:
When the mashine froze I could hear the fan getting slower. Yeah, deffinetly power problem.
I did some tests with multimeter. Strange thing - I've discovered that on 5V from the PSU to the PCB I was loosing 0,14V, while from the PCB entry to froppy connector I was loosing only 0,07V. So till floppy power connector I have over 0,2V dropping, but most of the power is somewhere inside cable + socket (???) BTW: I have strong PSU from Micronik, and Amy still in desktop.
On Sunday I decided - I'll connect the cables to the fan connector of BPPC! I connected GND and +5V from the main power socket. Started up. Well, it worked! :-D
On Monday I figured that fan is not working. I got nervous. I took out my freshly bought 128MB SIMM and HOLLY COW! What a mess did I find! :-o
Some chips exploded, covering everything with black dust, and plastic desktop case has a burned out hole in the place it sticks to BPPC. What a nightmare. :-(
Yesterday I picked my poor card. First thing was - well, it IS working! :-) Only fan is not moving...
Closely placed tracks looks not touched. :-)
Only those connected to those exploded thingies...
And those thingies are surface soldered resistors, mayby hard to fix, but not a big intelligence afterall... And the only thing they seemed to be connected to is the fan.
I picked up some cables and connected the fan to the floppy power supply. The trick worked! :-) I put everything together again.
So, I still have this trouble with power again. Till my Miggy gets warm it freezes on startup. And funny thing - I can still hear the fan getting slower at that moment. But now it is connected to floppy power supply, not to BPPC, so the drop down is global for whole Amy and I thought that this edge connector can be big trouble.
Still I have to wait until I can do anything. But I'm extremally happy my BPPC works at all. 8-) I don't understand what happend and why. The most damaged resistor is on the track closer to GND than +5V.
I won't mess around with my BPPC any more. But only the Devil knows whats happening inside my PSU cable + socket... :-(
And they lived happily ever after.
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You mean......you blew up your Bliz and it kept on working???
My god....A1200's really are frankenstein machines :-D.
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@PiR:
As the fan is still going slower when it is directly connected to the power supply, I would suggest that your power supply is a bit dodgy.
/Patrik
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pir: are you 100% sure you connected it correctly and that it was 5+ Volt ?.
if you mix this then u will get problems ...
anyway i am glad to hear it still works but there was some parts in your post i didnt understand, want to try explaining it again?
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Could it be that what exploded wasn't a resistor, but a capacitor you had feeded
a wrongly polarized voltage in by your trick ?
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@Patrik
The dropping is only on Amy board I've checked the voltage inside PSU and its quite over 5V.
@lempkee
I've checked several times several things. I was not going to risk my precious! I've checked the voltage, when on-power, I've checked the resitance from one point to the other when off-power... I've checked the direct voltage (+5V and GND) and cross voltage (one pin from one point and the other from the other....)
What can I clearify more?
My checking points:
PSU (+12, GND, +5) : never under 5V
Amy Power socket on MoBo (+12, shield, GND, +5, -12) : hard to reach... Made shortcut once during tests... My PSU works tricky now after such experience ;-)
floppy power connector on Amy MoBo ( +12, sheld, GND, +5) easiest place to check; 4,8 when it's working, can drop till 4,65 on freezing...
BPPC fan connector (+5, GND): whats the difference? Its even further to PSU than floppy...
@Kronos
I could be better in present electronics, but I'd bet capacitor of valuable size should be bigger... Well, every guy with BPPC can check three thingies next to BPPC fan, on the other side.
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Thats serves you right manuel says tower case only it probaly got to hot in a desktop.
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@PiR:
I dont mean the voltage drops caused by the resistance in the cables and the motherboard power supply lines. When you hear the fan loose rpm temporarily when it is connected directly to the power supply it cant be the cables. The resistance in cables could only cause a constant lowering of the voltage and alas fan rpm.. and a cable with great enough resistance for that when powering a little 5V fan would probably have to be as thin as 0.01mm. What I am trying to say is that it definately sounds like your power supply is acting wierd and I would urge you to try another one... if it doesnt sound like a good idea to you, atleast consider doing it just for the sake of it.
/Patrik
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If you have a 060 PPC you might get away with only pouring power into the system at one point. If you have an 040 PPC you absolutely must put extra power to the system via the floppypowerconnector of the A1200 board.
Is sure look ugly as hell haveing an extra powercord going into the machine through a crack in the desktopcase, but thats the only way to get a stable system.
So better put it in a Tower anyway.
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What Lemmink just said is the absolute 100% correct way to run a B PPC card in a A1200.
And I'd only add that making a tower solution could solve many heat/power problems.
I made my own with a big old AT server case and it
worked out great. You just need some beer, dremel tool, ultra violence, heat, friction, a bit of cussing and
bleeding (you will cut open your hand) and soon you'll emerge on the other side, A1200Tower land.
BTW, my fan blew up too, everything still works perfect without it.
:-D
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Hi thanks for such a big feedback, I didn't expect it. :-)
@amigamad:
I know that sounds crazy, but I observed, that when my Amy is cold it won't work. When it gets warmer it starts working. I think that for some reason on the higher temperature either resistance or power consumption reduces.
So what is the purpose of increasing cooling, again? :-)
@patrik:
That would be insane if just a cables had that big resistance. But what can you tell about the socket? I was trying to test it but it is too hard for me to access it (I mean internal parts of it). On the other hand this is the only thing that sounds logical to me. I've measured the voltage just at the other side of the power socket and observed the poor result, while having good values in soldering places in PSU. So either unlikely cable, or this stupid socket.
I have my original PSU. Also here I don't trust this socket, but that can be my self-sugestion, mayby I'll investigate it more deeply.
@Lemmink
Yes, it is 60. But read yourself and tell me - I'm insane and the Amiga power socket cannot be the source of the troubles... Attaching power to floppy connector is just omitting this socket.
@TheGoose
Did you blow your fan too? Do you also have 60? Mayby this is the rule - you just shouldn't do it for 60?
Am I wrong, or 60 in BPPC works under 3,3V, while 40 really uses 5V? Hmmm....
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Belive it or not but since the BPPC draws way more power then the A1200 expansion connector was originall build for you just have to give some extrajuice to the board via the floppypowerconnector. On the way from the A1200 Powerconnector to the expansionconnector some power is lost, depending on the shape the board is in it will be more or less.
Feeding power to the board by two ends increases the amount of power that actually reaches the expansionconnector.
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I had an A1200 desctop with BPPC040 and it worked sortof with a converted 200W AT PSU. If the CPU load was higher than idle the mouse pointer graphic would start jumping like crasy and if I accessed both internal and external diskdrive att the same time my 3.5" HD that i had inside would spin down and upp again. I soldered a "male HD power" connector directly on the motherboard where where the powerplug is and plugged in one of the powerplugs from the PSU and it worked like a charm, guess the floppypowerplug is just as good but not as good looking.
For my BPPC I had added an extra coolingplate and fan for the 040 and cut out holes for both coolingplates in the trappdoor aswell as added feets to lift ut the computer some (fan stuck out about 1cm underneath the computer).
Now the hole lot is going into a tower though. :-D
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Hi
@Lemmink
I know, I know... But:
If you look at my first entry you'll see that I'm losing much more power (more less twice as much) on the way from PSU to MoBo (cable+socket) than really inside MoBo. Anmd belive me - I've checked it really carefully a lot of times as I couldn't belive it.
And now my fan is juiced from floppy connector and behaves EXACTLY THE SAME as when it was connected originally to BPPC. So, again also huge surprize for me - edge connector is not the main player.
To be honest - Amiga power socket was also designed for different power consumption, so 'is allowed' to cause troubles...
I have a board ver.2B, and my HD had to go off the desktop case exacly the same day my BVision arrived - unluckilly no place for both inside the case.
Luckilly for me, my Micronic PSU, appart from normal Amiga power connector has additional HD-like power conectors, so I powered HD and CD from there, not from MoBo. Frankly - this was also the most comfortable place to measure the voltage produced by PSU. And I don't have any troubles with either HD or CD.
@Brian
In my case I have a feeling that much VRAM manipulations can cause my machine to freeze (screen opening, Window moving - squares of data to copy, when machine is very cold at the beginning even text manipulations can be risky).
No, I won't add any cooling to the system... I want it to get hot and operational as soon as possible (mayby even extra heating at startup? ;-) )
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@PiR:
Atleast give lemminks suggestion a try even if you dont think it will help. If it for some reason wouldnt do any good, it wouldnt make things worse.
/Patrik
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Good that your box survived! But you should really look into a more powerfull PSU... This powervariations is definitely not healthy for the hardware.
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I'm assembling a spare A1200T system which will consist of an 040 BPPC. Some good info in this thread, I must say. I'll definitely take seriously the power issue suggestions and hook up the PSU floppy power connector to the motherboard floppy power pins.
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If you really want to see what the power supply is doing, don't use a multimeter, as it gives you an AVERAGE reading.
I.E. it might say 4.9V which should be fine, but there might be ripple as low as 4.2V which will definately cause problems.
The correct way to measure the stability of a power supply is to use a decent oscilloscope, or some recording multimeters can capture fast peaks/dropouts.
Sounds like you've helped the BPPC board by giving it a more stable supply. The components which blew up are probably tantalum capacitors.
They have a very low ESR (series resistance) which makes them good at smoothing power supply noise, but means when they charge up as the system is turned on, the current flow can be many 10s of amperes. Occasionally this causes the tantalum dielectric to break down, the device short circuits, then if the current flow is great enough, it explodes.
I've seen it quite a bit, mainly with leaded components rather than SMD ones.
The additional resistance of the motherboard power tracks would have helped to limit the inrush current to the capacitors, so made the dielectric less likely to break down.
Often they can handle high inrush current, but it would seem you had the unfortunate luck of one failing. It happens...
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@Castellen
Aha! That sounds familiar - my A2000 went a similar way (hideous smell, too! Ick!), although the components looked more like resistors (or perhaps diodes)...
Do you know if these capacitors can be replaced?
I'm not too sure how my BPPC is powered - it's safely tucked away in the middle of my Eyetech tower, and I've not opened the case for a long time! :-) Works OK, though...
/me touches some wood...
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Hi every1 again. :-)
@patrik
I don't asume if it will help or not. I can only experiment with weaker PSU, so there is not a real point. I could try to find myself even stronger PSU, but if I am right by any chance I'll just increase my collection of Amiga PSUs with the same behaviour.
I know it shouldn't make things worse, despite decrementing my bank account. :-D
@Tomas
Yeah, you can imagine how I do feel happy that it works. I'm affraid that working just on the edge of acceptable voltage can damage something one day.
But on the other hand I also think that if I push more power inside, my card will produce even more heat, and the heat is mayby even worse.
@x56h34 (is this alkohol or something? ;-) )
I experimented with attaching +5V ang GND to floppy connector, while having open desktop. Had no problems with it and observed almost 200mA current... (yeeeks, and this should have the same voltage on both sides...)
@Castellen
Yes, I assume some fluctuation at startup or shutdown. I think that adding a huge capacitor in paralel (in correct direction, of cource...) could serve as the BPPC overvoltage guard.
I also know that multimeter gives me only average value, but thats enough for me to know. Even on average I can se noticable average voltage dropdown in the very moment, when my machine getts frozen.
@Chunder
Mayby that solves the riddle.
I repeat - my electronic skills are more less on the level that I know that + is over - and GND is somewhere between both, but can really capacitor be so small to look, like surface soldered resistor?
But diode... Yes, diodes are another animals, that can be as little as resistors and are also observed to have ability to explode sometimes.
Or I just mixed things up. ;-)
Well, for me there is no more fun anyway, as those things' last action in their electric life was burnig out of my BPPC, the tracks they've been connected to...
Thanks for all
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@ Chunder:
Yes, they can be replaced. Anything is potentially repairable.
@PiR:
To the casual observer, many SMD components can look the same. Despite working in the professional electronics industry, I sometimes get small inductors, resistors and certain capacitors mixed up. Sometimes there is very little physical differences.
The huge capacitor idea would not really serve as an over voltage protection. Like if you accidentally put 12V instad of 5V onto the thing, you'll still get 12V across your equipment, but it make take an additional 100ms or so to rise to 12V.
It may serve to smooth power supply ripple to some extent, but you would want a capacitor with low series resistance for this. Ideally you need a number of capacitors in parallel on the power supply line.
Do remember that the multimeter gives a rough indication only, and may even lead you down the wrong path. I've seen many trainee technicians make the same mistake all too often. After spending hours chasing themselves around in circles, they eventually use the advice of using a scope for critical voltage measurement, which shows exactly what's happening.
You can either make assumptions and guesses, or you can find out exactly what's happening and do something about it.
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@Castellen
Anything is potentially repairable.
Potentially there is no reason why people aren't immortal either. :-D
I won't fix my burnt out tracks. :-(
Sometimes there is very little physical differences.
Ok. I belive. You know what you say, so those could be capacitors.
The huge capacitor idea would not really serve as an over voltage protection. Like if you accidentally put 12V instad of 5V onto the thing
And if you connect it to 24V or directly to 220V AC it won't help either - I know. Of course I meant only for this inrush, assuming you connect correct voltage.
But i was thinkig, if this startup inrush (by any chance) happend in the opposite diretion, huge capacitor in parallel could make things even worse...
Anyway, thanks for help.
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glib = on
Well, you could always shove 13A 240V AC direct through it. Then at least you'd know its beyond repair...
Worked for Will Shatner....
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Who owns the right to build them? Who have the schematics of these cards? What would it require to start building these cards again, in money? Tools? machines?
/Jörgen
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they are produced. but just in very small batches when DCE feel inclined.
thing is, the distibutors have to take the orders and money before hand, and when they have enuff orders to pay for DCE to do a production run, they'll do a batch. which is why vesalia and people like that can only offer one type out of the entire range. say the 060/210Mhz (note no scsi). for a month or so, then a batch of 240Mhz's couple of months after.
that leaves people like you and me possibly waiting a couple of months or so for 'new' cards
thing that bothers me is, unless we have some enterprising people out there willing to build something based on a G3/G4, how long till we run out of 060's (040's arn't around much anymore), 603's, and 604's?
[yes i am willing to bet money on the fact that the shark is vapourware and will never be released. it'd be a serious botch up if they did. 2 computers sharing the same PCI bus. the amiga side would be used to setup the system and initiallize the cards, then the shark would take over and shut down the 680x0, 60x, and most other functions. the amiga mainboard would then become an "amiga input device compatable PCI board" i guess.]
to only reason i'm not promoting peg or morph or what ever, is there is too much infighting as to what is best. so i'm going to stick with upgrading my classic machines till at least OS4 comes out and has a proper platform.