Dear All,
I couldn't find much help on this topic, so I'm opening a new thread, hope is not duplicating anything already existing.
I have a NeXTstation mono, everything worked fine until last time I've tested it.
Today, however, I've found out by chance that the floppy is apparently totally dead, to the point is not even recognised by the system.
Any test I've tried is just suggesting that the drive is not installed. Of course it is and the ribbon cable is OK (already checked). The diagnostic at start up is giving no error, so I assume the mother board (recently re-capped) is also OK.
I can only speculate the issue is in the drive, model is "MP-F40W-1X".
No matter what I do, there's no sign of life at all.
Neither the pick up motor, nor the main motor and not even the eject motor seems to be alive, despite there some current flowing through the board.
I've measured some voltages and they seem to be consistent, reading 5V wherever it should.
By lifting the board, to the eye everything looks OK, however there's one electrolytic capacitor (47 muF / 6.3 V) and 2 other through hole components I can't identify (one looks like a transistor, but the designator reads "PS", the other one I have no clue at all and is designated "X1").
Unfortunately, I don't have any other NeXT hardware around I can use for swapping components, I only have a Cube 030 which has no floppy.
I have many Apples, though.
Hence my questions:
1) is there any way to tell whether the motherboard is OK, is there any connector pinout reading one can check the board against?
2) is there any document about the floppy (recently I've brought back to life a 400 k floppy from a Mac 512k and I could use some schematics available on line as reference)
3) is there any best practice for checking the floppy functionality by attaching it to some other hardware (Apple? With another ad hoc made cable, of course).
4) same for the motherboard?
5) any idea about the pass through components on the floppy board (beside the capacitor)?
Any suggestion on how to test and, in case, repair the floppy drive is more than welcome.
Thanks in advance for your feedback!
The NeXT diagnostics "dvt040" can also check the floppy. Have a look at
http://www.nextcomputers.org/NeXTfiles/Software/Diagnostic_Utilities/68040_manual.pdf. dvt040 must be in the root directory of a boot drive (not neccesarily a floppy).
You can find schematics of the turbo slabs here:
http://www.nextcomputers.org/NeXTfiles/Docs/Hardware/Schematics/Turbo_slab/ - maybe you can draw conclusions from that.
It might be that the floppy itself has defective caps...
Quote from: "paolo.bertolo"Dear All,
I couldn't find much help on this topic, so I'm opening a new thread, hope is not duplicating anything already existing.
I have a NeXTstation mono, everything worked fine until last time I've tested it.
Today, however, I've found out by chance that the floppy is apparently totally dead, to the point is not even recognised by the system.
Any test I've tried is just suggesting that the drive is not installed. Of course it is and the ribbon cable is OK (already checked). The diagnostic at start up is giving no error, so I assume the mother board (recently re-capped) is also OK.
I can only speculate the issue is in the drive, model is "MP-F40W-1X".
No matter what I do, there's no sign of life at all.
Neither the pick up motor, nor the main motor and not even the eject motor seems to be alive, despite there some current flowing through the board.
I've measured some voltages and they seem to be consistent, reading 5V wherever it should.
By lifting the board, to the eye everything looks OK, however there's one electrolytic capacitor (47 muF / 6.3 V) and 2 other through hole components I can't identify (one looks like a transistor, but the designator reads "PS", the other one I have no clue at all and is designated "X1").
Unfortunately, I don't have any other NeXT hardware around I can use for swapping components, I only have a Cube 030 which has no floppy.
I have many Apples, though.
Hence my questions:
1) is there any way to tell whether the motherboard is OK, is there any connector pinout reading one can check the board against?
2) is there any document about the floppy (recently I've brought back to life a 400 k floppy from a Mac 512k and I could use some schematics available on line as reference)
3) is there any best practice for checking the floppy functionality by attaching it to some other hardware (Apple? With another ad hoc made cable, of course).
4) same for the motherboard?
5) any idea about the pass through components on the floppy board (beside the capacitor)?
Any suggestion on how to test and, in case, repair the floppy drive is more than welcome.
Thanks in advance for your feedback!
Hello Paolo and Forum members: I have new old stock NeXT Mono 68040 25Mhz Motherboards for $30 or used working Motherboards for $20 and New Old Stock NeXT Floppy Drives for $15 or used working $10, it may be the easiest route if you can't repair! I would test both to make sure they work but they are in original packaging . Shipping for floppy USPS Priority mail is $34.95 or First Class is $20 ... Shipping for Motherboard and floppy $65.50 to Europe. best Regards Rob
best regards Rob Blessin
Dear Rob, dear Bobo,
thanks for the prompt feedback.
Before ordering a spare drive, first of all I want to understand what is wrong with my disk drive or mainboard for what it matters.
I won't have time to go through the documents for some days to come, I will then investigate and decide accordingly. I will surely share my findings for other people in this great Community to benefit from this minor, yet unfortunate situation.
Paolo
Gents,
does anyone have high res pictures / schematics of the NeXTstation mono (original one) logic board, showing the specs of all surface mounted capacitors?
First of all, I want to rule out that I've made gross mistakes while recapping it. Should not be, since I normally pay a lot of attention in such an activity and all hardware checks are passed, but you can never known...
Thanks in advance,
Paolo
I can take some pictures next weekend. Most probably the caps are:
47uF, 16V, SMD type
220uF, 25V, 105 C, HFQ, radial type
Quote from: "bobo68"I can take some pictures next weekend. Most probably the caps are:
47uF, 16V, SMD type
220uF, 25V, 105 C, HFQ, radial type
Those are the only 2 types of electrolytics. The number of 47uF is dependent on the board revision of which there are at least 3 for the mono slab. The floppy controller chip should be right under the drive. If there is a problem with the board I would start there. I suspect it's the drive itself causing the issue.
Dear All,
thanks for your feedback.
This week end I will check the board, but I'm pretty sure it has been properly re-capped, I've only replaced the SMD capacitors with tantalum ones, all of them 47uF 16 V. The radial ones still look like new.
I also suspect it's the floppy. Will investigate and let you know.
Hello Gents,
So I took some time for investigating the floppy issue.
Honestly, I could not collect sufficient evidence for identifying the root cause, but I suspect it's something with the power management board section of the floppy drive, I guess something has blown off.
Running the diagnostics, all test are successfully passed, except the one about the floppy, so I'd speculate the logic board is OK.
https://db.tt/yafaQ5TiOnly thing I don't like, the fact that the solder looks "altered" for one of the pins in the connector on the motherboard side.
I got the same clue one an Apple 400k floppy I've recently fixed and in that case it was clear sign that the transistor connected to that very pin was gone.
But here it's just a junction pretty far away to any power component, so I could not link it to any visibly damaged component.
Surely, not a good sign, but for me it's hard to tell more.
https://db.tt/ztJW4bsYSo, I've focussed my attention on the floppy drive.
Honestly, everything looks OK, no sign of damage whatsoever, at least at a superficial visual inspection.
There are just three through hole components, one capacitor and two I was not able to identify (see pictures).
One look like a transistor (and could be suspect number one), but the designator is reading something different and, unfortunately, very generic.
https://db.tt/vBSn7EXdhttps://db.tt/BqjOzYeaJust for the sake of it, I replaced the capacitor on the floppy board, but, as expected, brought no results, the floppy is still completely dead.
On the B side of the board, there's a clear designator of a fuse / circuit breaker, but that's all I could understand.
https://db.tt/peeYk176I could measure 3.0 V where 5.0 V should be, so I suspect something has blown off, but I'm not able to tell what.
If someone is able to identify a replacement part for the other two components, I will replace them too, just to say I've done all I could possibly do with a soldering iron and a tester.
Otherwise, I guess I will give up and get a spare drive from our friend Rob.
The melted solder on the pin of the mainboard floppy connector looks fishy to me. Which pin is it? The floppy connector is the usual 34-pin floppy connector. Have a look at
http://www.nextcomputers.org/NeXTfiles/Docs/Hardware/Schematics/Turbo_slab/CSlab33-12.pdf to identify what the pin is for.
My guess on the X 1 part is that it is indeed a fuse. X usually denotes a fuse or lamp holder on a pcb. I've seen this kind of part but cannot remember what it is. Can you lift the white cap?
Of course just changing the fuse (if it is one) will normally not help because there must be a reason why it blew. Maybe the pin with the melted solder is an indication.
Did you verify 5v at the system logic board? Also I wouldn't be too worried about the solder pad having extra solder. You see this type of variation all the time with these machines.
Quote from: "bobo68"....
My guess on the X 1 part is that it is indeed a fuse. X usually denotes a fuse or lamp holder on a pcb. I've seen this kind of part but cannot remember what it is. Can you lift the white cap?
Its a Crystal Oscillator. It will show open when tested for resistance. It can be hard to test even high impedance oscilloscope or RF counter, as the extra capacitance or resistance could inhibit the oscillation.
QuoteDid you verify 5v at the system logic board?
Yes, on the logic board side I can read 5 V on the powered pins. It seems as though the current is being cut off at some stage on the floppy board. I guess it's the circuit breaker / fuse that blew off.
QuoteMy guess on the X 1 part is that it is indeed a fuse.
QuoteIts a Crystal Oscillator.
I also think it's an oscillator: however, all I could figure out is that it's 3 pin component. Not much. Googling the name led to no match.
Same for the other component that looks like a transistor (designator on the board is PS01, "PS" power supply, in theory). However, the B side of the board is actually indicating the symbol for a fuse, but everything is so dense that telling what is what is really hard.
My (null) skills end here, even thought I have the feeling that it's just one or two components that has to be replaced, I'm not planning to spend more time on this, higher level of knowledge is required in order to track down the issue in a professional way.
All I can do is replace pass through components that look damaged and only in case a spare is identified, which doesn't seem to be the case. Or at least I can't make any progress on my own.
However, if you have suggestions or ideas, I'm more than open to test them in order to create a first record for future cases.
Thanks
Quote from: "paolo.bertolo"
QuoteIts a Crystal Oscillator.
I also think it's an oscillator: however, all I could figure out is that it's 3 pin component. Not much. Googling the name led to no match.
wa2flq is right, it is most probably a crystal oscillator. Found a similar piece described as part of another Sony floppy drive:
http://matthieu.benoit.free.fr/101.htm. Also the symbol underneath the component seems to designate an oscillator.
There is a drive select switch (S101). Is it properly set (seems to be between 0 and 1)?
Quote from: "bobo68"Quote from: "paolo.bertolo"
QuoteIts a Crystal Oscillator.
I also think it's an oscillator: however, all I could figure out is that it's 3 pin component. Not much. Googling the name led to no match.
wa2flq is right, it is most probably a crystal oscillator. Found a similar piece described as part of another Sony floppy drive: http://matthieu.benoit.free.fr/101.htm. Also the symbol underneath the component seems to designate an oscillator.
If the crystal has been damaged, that would certainly kill the unit. Since its a three pin device, ignore my earlier comment about load, its not just a crystal but a integrated oscillator. The inputs are +5 and gnd, and output is the clock. From the photo's I suspect it will the middle pin and you should be able to put a scope or counter on the pin.
QuoteFound a similar piece described as part of another Sony floppy drive
Very interesting link, thanks.
However, even though the naming of the "transistor" is quite similar (N 5 G and N 5 M here respectively), I must confess I have doubts it's about a transistor we're speaking about. I have de-soldered it and there are just 2 pins (should be 3 of them, right?).
https://db.tt/u6nSGg9LBesides, even on the A side, underneath the component (PS01) there's a symbol looking like a circuit breaker.
https://db.tt/e3fBtUSoAnyhow, either way, with this component not in place, the voltage readings are not changing, so either it's neutral or, since it's damaged, in place or not makes no difference.
QuoteThe inputs are +5 and gnd, and output is the clock. From the photo's I suspect it will the middle pin and you should be able to put a scope or counter on the pin.
There are no +5V, that's why I suspect the damage is before the oscillator.
In those places where I should read 5 V, in fact I see some 3 V only.
https://db.tt/JBtXvKRAThanks to All who are contributing to this discussion.
(By the way, how the hell can I include the author in the quoted text?)
Quote from: "paolo.bertolo"
However, even though the naming of the "transistor" is quite similar (N 5 G and N 5 M here respectively), I must confess I have doubts it's about a transistor we're speaking about. I have de-soldered it and there are just 2 pins (should be 3 of them, right?).
Maybe I'm too simplistic here but:
semiconductor with 3 legs -> transistor
semiconductor with 2 legs -> diode
Theory 1:
It is a current limiting diode in an unusual packaging. If you are brave you just short the contacts on the pcb and see what happens... Of course this could end in smoke and destruction.
Theory 2:
The wave symbol stands for AC and the diode is a simple rectifier. Do you measure AC across the contacts?
P.S. to put a name in the quote use quote="<name>". The blog software should do this automatically.
Quote from: "bobo68"Quote from: "paolo.bertolo"
However, even though the naming of the "transistor" is quite similar (N 5 G and N 5 M here respectively), I must confess I have doubts it's about a transistor we're speaking about. I have de-soldered it and there are just 2 pins (should be 3 of them, right?).
Maybe I'm too simplistic here but:
semiconductor with 3 legs -> transistor
semiconductor with 2 legs -> diode
Theory 1:
It is a current limiting diode in an unusual packaging. If you are brave you just short the contacts on the pcb and see what happens... Of course this could end in smoke and destruction.
Theory 2:
The wave symbol stands for AC and the diode is a simple rectifier. Do you measure AC across the contacts?
I would splice in a quick blow fuse, say 1/8 amp in place of the N5G device. Is the N5G open (check it with diode test on a VOM)? Do not just short it. I cannot find a similar device in that form factor. The symbol for Fuse and AC are similar, but I would never expect to see the AC symbol across the component (on both sides of the PCB!).
For the "Crystal Oscillator", I also cannot find similar 3 pin package for this. The pcb symbol is typical for crystal, but it looking around it is possible that it may be a ceramic filter. My background in floppy signal recovery is practically nil, so I cannot speculate if this would be a reasonable component for this design. See
http://www.radio-electronics.com/info/rf-technology-design/receiver-selectivity/ceramic-if-rf-bandpass-filters.php The symbols are usually different for a ceramic filter.
Thanks guys for the prompt feedback, I will try to check everything according to your instructions over the next week end, I will keep you posted!
PS01 is an "Integrated Circuit Protector" device (probably a sort of fuse, but who knows). N code stands for the TO92 packaged type and the 5 code says it is 250mA rated. M probably is the manufacturer code, and it actually has no meaning in device functionality.
NTE distributes these as NTE15019E. Also you can find them as generics using "N5 TO92 ICP" keywords at google.
Not every thing that comes as TO92 package is actually transistor, or even a semiconductor.
It's good when somebody just knows stuff. :) Thanks for the clarification.