The way I fried my BPPC card.

[patrik]

@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

[Tomas]

Good that your box survived! But you should really look into a more powerfull PSU... This powervariations is definitely not healthy for the hardware.

[x56h34]

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.

[Castellen]

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...
 

[Chunder]

@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...

[PiR]

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

[Castellen]

@ 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.

[PiR]

@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.

[Karlos]

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....

[PiR]

[jonssonj]

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

[darksun9210]

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.