RE: Identifying vacuum tube module

[rar via cctalk]

I have some very similar (but not identical) tube modules in my IBM 519 
Reproducing punch
Mine are the same form factor, but the resistors are lengthwise.

I'll attach the image which Kyle will get, but I doubt they will make it on to 
the list





Bob Roswell
brosw...@syssrc.com
410-771-5544 ext 4336

Computer Museum Highlights


-Original Message-
From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Kyle Owen via 
cctalk
Sent: Sunday, March 25, 2018 3:34 PM
To: General Discussion: On-Topic and Off-Topic Posts 
Subject: Identifying vacuum tube module

Anyone knows what these go to?

https://imgur.com/a/CpxLs

Thanks,

Kyle

Re: PATA hard disks, anyone?

[Guy N. via cctalk]

On Mon, 2018-03-26 at 11:18 -0700, Chuck Guzis via cctalk wrote:
> I'm surprised that your sysadmin is allowing this to happen.  Many large
> outfits have a policy of sending any hard disk, regardless of content to
> the industrial shredders.

The advantages of working for a small company... the sysadmin is a
long-time employee who's just moved into that role, he and I are good
buddies.  And there's not anything worth $$$ data recovery on them
anyway.

I hate seeing perfectly good working equipment reduced to low-value
scrap, so I'm wiping these drives at home on my own time to prevent
that.

Re: PATA hard disks, anyone?

[Tomasz Rola via cctalk]

On Mon, Mar 26, 2018 at 07:44:58PM +0200, Liam Proven via cctalk wrote:
> On 26 March 2018 at 19:34, Tomasz Rola via cctalk  
> wrote:
> >
> > I have heard good things of MHDD diagnostic/repair program in the
> > context of low level format and generally checking health of spinning
> > disks.
> 
> That's a new one on me.
> 
> I have occasionally used, and often recommend, DBAN -- Darik's Boot And Nuke.
> 
> https://dban.org/

Interesting. But judging from descriptions, mhdd is very different
tool/beast. Not that I can recommend one over another, having no
experience (when in trouble, I just ran dd over the disk or parts of
it).

http://hddguru.com/software/2005.10.02-MHDD/

-- 
Regards,
Tomasz Rola

--
** A C programmer asked whether computer had Buddha's nature.  **
** As the answer, master did "rm -rif" on the programmer's home**
** directory. And then the C programmer became enlightened...  **
** **
** Tomasz Rola  mailto:tomasz_r...@bigfoot.com **

Re: R: PATA hard disks, anyone?

[Bill Gunshannon via cctalk]

On 03/26/2018 05:58 PM, Ali via cctalk wrote:
>> NSA has been successful enough that the concept "DOD Wipe" as was found
>> in programs like Gformat from Ghost no longer exists.
> Bill,
>
> Are you saying that the NSA can recover data from a HDD that has been erased 
> and been written over multiple times?
>
>

That's what we were told when I was still with DOD.  No number of overwrites
made it impossible.  No disk that ever contained classified information 
could
ever be let out of containment.  Other than melting them down the only 
method
I ever heard of or saw that could truly erase a disk was passing them 
through
the ship deguasser at the Navy Yard.  And, after that the disk was not 
only clean,
it was unusable.

bill

Compaq 9000 Series Rack Screws

[Ali via cctalk]

Ok, 

A bit too new for this list but still hoping someone can help me out:

I am in need of at least six (prefer 10) Compaq 9000 Series OEM Rack screws
to mount a side panel. I believe these are M6 screws. On the side that had
the panel already mounted the OEM screws are star screws approximately 0.5"
long. 

I have looked online and on some of the rack accessory suppliers and have
found M6 screws which I believe are from HP racks. Aside from the fact that
the OEM is a Philip's head (not a big deal - security is not a huge issue)
the HP ones are just a tad bigger.

The length of the HP screws should be okay (I think). However, the flange is
just a bit too big and it catches on the side panel so you can't screw the
screw in all the way (w/o damaging the side panel). The OEM star screws do
not do this.

If anyone has any spares they can part with or knows where I can order some
(and definitely get the OEM ones vs. the after market/HP ones) I would
appreciate it. Thank you!

BTW pictures and measurements can be found in this thread on VCF: 

http://www.vcfed.org/forum/showthread.php?62877-WTB-OEM-Compaq-9000-Series-R
ack-Screws=507884#post507884

-Ali

Re: DTC 3250

[Chuck Guzis via cctalk]

On 03/26/2018 01:26 PM, Fred Cisin via cctalk wrote:
> I just stumbled on a DTC3250, & "Installation Guide"
> 8 bit ISA SCSI + 4 floppy
> 
> Firmware: "GSH53A"
> 
> The floppy interface MIGHT work for HD on a 5150/5160?
> (with appropriate software)
> 
> Condition unknown
> 
> Anybody need one?

Fred, I used to have one of those--great little cards.  If you don't get
any takers, let me know and I'll flog it on the vcfed forum for you.

--Chuck

RE: R: PATA hard disks, anyone?

[Ali via cctalk]

> NSA has been successful enough that the concept "DOD Wipe" as was found
> in programs like Gformat from Ghost no longer exists.

Bill,

Are you saying that the NSA can recover data from a HDD that has been erased 
and been written over multiple times? 

-Ali

DTC 3250

[Fred Cisin via cctalk]

I just stumbled on a DTC3250, & "Installation Guide"
8 bit ISA SCSI + 4 floppy

Firmware: "GSH53A"

The floppy interface MIGHT work for HD on a 5150/5160?
(with appropriate software)

Condition unknown

Anybody need one?

--
Grumpy Ol' Fred ci...@xenosoft.com

Re: RL02 Question

[allison via cctalk]

On 03/26/2018 04:08 PM, Aaron Jackson via cctalk wrote:
>>> So, from what I can see, the drive should spin up correctly, but for
>>> some reason it goes into fault mode. I am right in thinking that upon
>>> load, the heads should continue moving forward until the first track is
>>> found, right? I should not have to perform a seek manually from the PDP?
>>> If this is not the case, perhaps there is something else wrong.
>> I’m not an RL02 hardware expert at all, just a daily user back in the
>> day. I’m reading this assuming that at all times the drive is
>> correctly hooked up to an RLV12 in a running PDP with the correct
>> cable and termination present on the drive? If it isn’t you’ll get a
>> fault condition instead of ready after spin up.
>>
>> A
> No worries, your input has been valuable, so thank you.
>
> For anyone else who might have an idea:
ON fault the heads are retracted and will not load till cleared.
Least mine behaves that way.

Most common problems are wrong drive address, cable issues, no terminator.
Others include head lock not removed or the auto unlock style of
headlock has
the tab broken.

> It seems to be hooked up correctly. When it is in the weird flashing
> ready state, the boot loader says "Read error" or "Device error"
> randomly. The heads oscillate back and forth very slightly as if it is
> trying to align itself better on the first track, which doesn't exist
> because it hasn't moved far enough into the pack.
IF in fault its resetting to retracted on every try.
If not something else is wrong.

> I'm beginning to think the heads are bad which will be far too expensive
> so I may end up giving up.

Heads are not that expensive...  However you could have a wrong pack
or one that has been erased and has no servo tracks.   You must start with
a known good pack and cleaned heads.


Allison

Re: PATA hard disks, anyone?

[TeoZ via cctalk]

Only somebody working for the NSA would bother trying to do that. Going from 
theory to practice can be VERY expensive and time consuming.


-Original Message- 
From: Ethan via cctalk

Sent: Monday, March 26, 2018 3:26 PM
To: Chuck Guzis ; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: R: PATA hard disks, anyone?


Certainly, but it's fruitless to use logic in cases such as these.
Chances are that someone once read the paper from the 1990s that said it
was possible to recover overwritten data from a drive using, IIRC, an
STM--at a rate of what was it? 1 kbit per hour?


AFAIK there has been a bounty out to recover data with a single wipe that
hasn't been collected. I thought it was all theory and never done in
practice?


--
: Ethan O'Toole


---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

Re: R: PATA hard disks, anyone?

[Bill Gunshannon via cctalk]

On 03/26/2018 04:09 PM, Fred Cisin via cctalk wrote:
>>> Certainly, but it's fruitless to use logic in cases such as these.
>>> Chances are that someone once read the paper from the 1990s that 
>>> said it
>>> was possible to recover overwritten data from a drive using, IIRC, an
>>> STM--at a rate of what was it? 1 kbit per hour?
>
> On Mon, 26 Mar 2018, Ethan via cctalk wrote:
>> AFAIK there has been a bounty out to recover data with a single wipe 
>> that hasn't been collected. I thought it was all theory and never 
>> done in practice?
>
> NSA (No Such Agency) at Fort Meade, Maryland, does not discuss how 
> much success they have had with their extensive research into data 
> recovery.
>

NSA has been successful enough that the concept "DOD Wipe" as was found
in programs like Gformat from Ghost no longer exists.

bill

Re: R: PATA hard disks, anyone?

[Fred Cisin via cctalk]

Certainly, but it's fruitless to use logic in cases such as these.
Chances are that someone once read the paper from the 1990s that said it
was possible to recover overwritten data from a drive using, IIRC, an
STM--at a rate of what was it? 1 kbit per hour?


On Mon, 26 Mar 2018, Ethan via cctalk wrote:
AFAIK there has been a bounty out to recover data with a single wipe that 
hasn't been collected. I thought it was all theory and never done in 
practice?


NSA (No Such Agency) at Fort Meade, Maryland, does not discuss how much 
success they have had with their extensive research into data recovery.


It is hard to make the data unrecoverable.
It is easy to make the recovery cost exceed the value of the data.

--
Grumpy Ol' Fred ci...@xenosoft.com

Re: R: PATA hard disks, anyone?

[Chuck Guzis via cctalk]

On 03/26/2018 12:26 PM, et...@757.org wrote:

> AFAIK there has been a bounty out to recover data with a single wipe
> that hasn't been collected. I thought it was all theory and never done
> in practice?

Here's the Gutmann paper that many people cite:

https://www.usenix.org/legacy/publications/library/proceedings/sec96/full_papers/gutmann/index.html

This may be applicable to early hard drives, but probably not practical
with later hard drives.  However, like a bad penny, the legend has
persisted and IT management has, ever since, been irrationally paranoid.

--Chuck

Re: RL02 Question

[Aaron Jackson via cctalk]

>> So, from what I can see, the drive should spin up correctly, but for
>> some reason it goes into fault mode. I am right in thinking that upon
>> load, the heads should continue moving forward until the first track is
>> found, right? I should not have to perform a seek manually from the PDP?
>> If this is not the case, perhaps there is something else wrong.
>
> I’m not an RL02 hardware expert at all, just a daily user back in the
> day. I’m reading this assuming that at all times the drive is
> correctly hooked up to an RLV12 in a running PDP with the correct
> cable and termination present on the drive? If it isn’t you’ll get a
> fault condition instead of ready after spin up.
>
> A

No worries, your input has been valuable, so thank you.

For anyone else who might have an idea:

It seems to be hooked up correctly. When it is in the weird flashing
ready state, the boot loader says "Read error" or "Device error"
randomly. The heads oscillate back and forth very slightly as if it is
trying to align itself better on the first track, which doesn't exist
because it hasn't moved far enough into the pack.

I'm beginning to think the heads are bad which will be far too expensive
so I may end up giving up.

Thanks,
Aaron.

Re: RL02 Question

[Adrian Graham via cctalk]

> 
> So, from what I can see, the drive should spin up correctly, but for
> some reason it goes into fault mode. I am right in thinking that upon
> load, the heads should continue moving forward until the first track is
> found, right? I should not have to perform a seek manually from the PDP?
> If this is not the case, perhaps there is something else wrong.
> 

I’m not an RL02 hardware expert at all, just a daily user back in the day. I’m 
reading this assuming that at all times the drive is correctly hooked up to an 
RLV12 in a running PDP with the correct cable and termination present on the 
drive? If it isn’t you’ll get a fault condition instead of ready after spin up.

A

Re: R: PATA hard disks, anyone?

[Ethan via cctalk]

Certainly, but it's fruitless to use logic in cases such as these.
Chances are that someone once read the paper from the 1990s that said it
was possible to recover overwritten data from a drive using, IIRC, an
STM--at a rate of what was it? 1 kbit per hour?


AFAIK there has been a bounty out to recover data with a single wipe that 
hasn't been collected. I thought it was all theory and never done in 
practice?



--
: Ethan O'Toole

Re: RL02 Question

[Aaron Jackson via cctalk]

I have turned up the amplitude just a little higher than I think it
should be. Instead of going into fault mode after loading a pack, the
READY light flashes about quickly. With the scope hooked up I can see
that it hasn't managed to find the first track yet. Not really sure what
it thinks it is doing...



Aaron Jackson via cctalk writes:

> Hi Andrea,
>
> Thanks for your suggestions.
>
> Checking the amplified output from the r/w heads is one of the first
> things I did. The voltages are within normal range, but only after I
> push the head a bit further into the pack.
>
> Although, I did not set the jumper to try the other head (I suppose I
> was always looking at head 0), so I've just tried this now. There does
> indeed appear to be servo burst data coming from both heads once I've
> manually loaded them fully. So I am not sure if this is the problem. I'm
> really hoping that the pack is not bad since I paid for a tested pack.
>
> I also checked the sector transducer output last night. The individual
> waves (i.e. from trough to peak) seem to be twice as fast, but the
> timings between two peaks is correct.
>
> The survo busts are correctly aligned with the sector pulses.
>
> So, from what I can see, the drive should spin up correctly, but for
> some reason it goes into fault mode. I am right in thinking that upon
> load, the heads should continue moving forward until the first track is
> found, right? I should not have to perform a seek manually from the PDP?
> If this is not the case, perhaps there is something else wrong.
>
> Thanks again for your input,
> Aaron.
>
>
>
> shad via cctalk writes:
>
>> Hello,
>> I'm not an absolute expert, but I successfully fixed a couple of RL02 in
>> the past.
>> Adjustment to the head is only useful for azimuth, I think. The radial
>> position will be adjusted continuously using the servo tracks, so there's
>> no absolute position adjustment at all.
>> If the drive fails during spinup, I would check at least the following:
>> - the presence of spindle sector signal after digital conversion of pulses
>> from analog signal coming from the pickup.
>> - having disabled the servo linear motor (there's some jumper to setup,
>> check the maintenance manual), perform the motor spinup, then load slowly
>> the heads on the disk by hand, until you find the servo tracks.
>> - with an oscilloscope check the presence of analog signal of the servo
>> tracks on both heads, and it's digital counterpart after amplification and
>> threshold detection (expected level values in the manual). If you see
>> something strange, e.g missing or too short pulses, try to adjust the gain
>> with the trimmer on the head board
>> - enable again the servo, then load again
>>
>> My 2 cents.
>> Andrea


-- 
Aaron Jackson
PhD Student, Computer Vision Laboratory, Uni of Nottingham
http://aaronsplace.co.uk

Re: R: PATA hard disks, anyone?

[Chuck Guzis via cctalk]

On 03/26/2018 11:23 AM, Mazzini Alessandro wrote:
> Well, but with dban and/or other certified software the drives are as well as 
> new. The only issue would be the time/cost to sanitize them in house.

Certainly, but it's fruitless to use logic in cases such as these.
Chances are that someone once read the paper from the 1990s that said it
was possible to recover overwritten data from a drive using, IIRC, an
STM--at a rate of what was it? 1 kbit per hour?

--Chuck

Re: RL02 Question

[Aaron Jackson via cctalk]

Hi Andrea,

Thanks for your suggestions.

Checking the amplified output from the r/w heads is one of the first
things I did. The voltages are within normal range, but only after I
push the head a bit further into the pack.

Although, I did not set the jumper to try the other head (I suppose I
was always looking at head 0), so I've just tried this now. There does
indeed appear to be servo burst data coming from both heads once I've
manually loaded them fully. So I am not sure if this is the problem. I'm
really hoping that the pack is not bad since I paid for a tested pack.

I also checked the sector transducer output last night. The individual
waves (i.e. from trough to peak) seem to be twice as fast, but the
timings between two peaks is correct.

The survo busts are correctly aligned with the sector pulses.

So, from what I can see, the drive should spin up correctly, but for
some reason it goes into fault mode. I am right in thinking that upon
load, the heads should continue moving forward until the first track is
found, right? I should not have to perform a seek manually from the PDP?
If this is not the case, perhaps there is something else wrong.

Thanks again for your input,
Aaron.



shad via cctalk writes:

> Hello,
> I'm not an absolute expert, but I successfully fixed a couple of RL02 in
> the past.
> Adjustment to the head is only useful for azimuth, I think. The radial
> position will be adjusted continuously using the servo tracks, so there's
> no absolute position adjustment at all.
> If the drive fails during spinup, I would check at least the following:
> - the presence of spindle sector signal after digital conversion of pulses
> from analog signal coming from the pickup.
> - having disabled the servo linear motor (there's some jumper to setup,
> check the maintenance manual), perform the motor spinup, then load slowly
> the heads on the disk by hand, until you find the servo tracks.
> - with an oscilloscope check the presence of analog signal of the servo
> tracks on both heads, and it's digital counterpart after amplification and
> threshold detection (expected level values in the manual). If you see
> something strange, e.g missing or too short pulses, try to adjust the gain
> with the trimmer on the head board
> - enable again the servo, then load again
>
> My 2 cents.
> Andrea


--
Aaron Jackson
PhD Student, Computer Vision Laboratory, Uni of Nottingham
http://aaronsplace.co.uk

Re: SGI Indy power supply: identify this diode?

[Camiel Vanderhoeven via cctalk]

4B would be a 2.2V zener; 4A would be a 2.0V zener, so that’s odd indeed...

Camiel

On 3/24/18, 9:47 PM, "cctech on behalf of Pete Turnbull via cctech" 
 wrote:

After a recent power cut and a series of glitches as the power was
restored, one of my Indys suffered a PSU failure.  It's a Sony APS-81 
171W unit, SGI P/N 060-0008-001.  I've found half a dozen damaged parts, 
and I've identified a 150R 1W metal film resistor (R135), two trannies 
(Q105, a 2SC4304 and Q106, a 2SC2785) and a couple of small diodes.  One 
of them (D116) appears to be a 6.2b2 (6.2V 1/2W) zener.

The other one I'm not sure about.  On the PCB it's labelled D113, and
it's adjacent to the 2SC2785.  It's very small, with a green band at the
cathode end, and the legend "4B" in green - photos at 
https://www.flickr.com/photos/pnt103/albums/72157667056183978

Oddly, another Sony PSU I looked at had a diode there that looked
identical except it's marked "4A".

I have an idea what it might be but if anyone actually knows what family
or type/value this is, I'd be grateful for any insight.

-- 
Pete
Pete Turnbull

R: PATA hard disks, anyone?

[Mazzini Alessandro via cctalk]

Well, but with dban and/or other certified software the drives are as well as 
new. The only issue would be the time/cost to sanitize them in house.

-Messaggio originale-
Da: cctalk [mailto:cctalk-boun...@classiccmp.org] Per conto di Chuck Guzis via 
cctalk
Inviato: lunedì 26 marzo 2018 20:18
A: Guy N. via cctalk
Oggetto: Re: PATA hard disks, anyone?

On 03/25/2018 07:32 PM, Guy N. via cctalk wrote:
> The new sysadmin at work is clearing out closets full of junk^H^H^H^H 
> cool old stuff accumulated by the previous sysadmin.  There's a big 
> carton full of PATA hard disks.  Most of them are in the 4.3 GB - 20 
> GB range, a few larger, a few smaller.
> 
> Anyone have any use for these?  You can have them for the cost of 
> shipping, or free for local pickup in Bothell, WA.  They're going to 
> be recycled as scrap if I don't find a home for them.

I'm surprised that your sysadmin is allowing this to happen.  Many large 
outfits have a policy of sending any hard disk, regardless of content to the 
industrial shredders.

--Chuck

Re: RL02 Question

[shadoooo via cctalk]

Hello,
I'm not an absolute expert, but I successfully fixed a couple of RL02 in
the past.
Adjustment to the head is only useful for azimuth, I think. The radial
position will be adjusted continuously using the servo tracks, so there's
no absolute position adjustment at all.
If the drive fails during spinup, I would check at least the following:
- the presence of spindle sector signal after digital conversion of pulses
from analog signal coming from the pickup.
- having disabled the servo linear motor (there's some jumper to setup,
check the maintenance manual), perform the motor spinup, then load slowly
the heads on the disk by hand, until you find the servo tracks.
- with an oscilloscope check the presence of analog signal of the servo
tracks on both heads, and it's digital counterpart after amplification and
threshold detection (expected level values in the manual). If you see
something strange, e.g missing or too short pulses, try to adjust the gain
with the trimmer on the head board
- enable again the servo, then load again

My 2 cents.
Andrea

Re: PATA hard disks, anyone?

[Chuck Guzis via cctalk]

On 03/25/2018 07:32 PM, Guy N. via cctalk wrote:
> The new sysadmin at work is clearing out closets full of junk^H^H^H^H
> cool old stuff accumulated by the previous sysadmin.  There's a big
> carton full of PATA hard disks.  Most of them are in the 4.3 GB - 20 GB
> range, a few larger, a few smaller.
> 
> Anyone have any use for these?  You can have them for the cost of
> shipping, or free for local pickup in Bothell, WA.  They're going to be
> recycled as scrap if I don't find a home for them.

I'm surprised that your sysadmin is allowing this to happen.  Many large
outfits have a policy of sending any hard disk, regardless of content to
the industrial shredders.

--Chuck

Re: PATA hard disks, anyone?

[Liam Proven via cctalk]

On 26 March 2018 at 19:34, Tomasz Rola via cctalk  wrote:
>
> I have heard good things of MHDD diagnostic/repair program in the
> context of low level format and generally checking health of spinning
> disks.

That's a new one on me.

I have occasionally used, and often recommend, DBAN -- Darik's Boot And Nuke.

https://dban.org/


-- 
Liam Proven • Profile: https://about.me/liamproven
Email: lpro...@cix.co.uk • Google Mail/Hangouts/Plus: lpro...@gmail.com
Twitter/Facebook/Flickr: lproven • Skype/LinkedIn: liamproven
UK: +44 7939-087884 • ČR (+ WhatsApp/Telegram/Signal): +420 702 829 053

Re: PATA hard disks, anyone?

[Tomasz Rola via cctalk]

On Mon, Mar 26, 2018 at 06:22:04AM -0700, Guy N. via cctalk wrote:
[...]
> I have to wipe the drives before I ship them -- my word of honor to the
> sysadmin.  I have probably a couple dozen done now that I can ship right
> away.  The rest will trickle out a little bit slower after that.
> 
> When I said "big carton" I meant it.  There are plenty for everyone.

I have heard good things of MHDD diagnostic/repair program in the
context of low level format and generally checking health of spinning
disks. Strangely, I have never had a chance to use it, so far. It
seems like there is freeware version, able to boot from CD?

HTH

-- 
Regards,
Tomasz Rola

--
** A C programmer asked whether computer had Buddha's nature.  **
** As the answer, master did "rm -rif" on the programmer's home**
** directory. And then the C programmer became enlightened...  **
** **
** Tomasz Rola  mailto:tomasz_r...@bigfoot.com **

Re: SGI Indy power supply: identify this diode?

[Ethan via cctalk]

If only!  That question has been asked many times on SGI forums like 
nekochan, for the Sony PSU (like this one) and also the Nidec.  No-one has 
ever claimed to have seen one, and the chances are Sony wouldn't ever have 
released them.


Yea I was looking for the Nidec one for the Indigo, as mine constantly 
spits out a power lost error on the console of my R4000. IIRC Nidec said 
no, but Sony might be different. I think there is a private system that 
Sony repair shops can access that has schematics online.


I have thought about tracing out the relevant area of the circuit, but it 
would take a while as the components are fairly densely packed, and I've got 
several other tasks on the agenda.


I can imagine that would take a ton of time. And the parts list still 
wouldn't be official.



--
: Ethan O'Toole

Re: SGI Indy power supply: identify this diode?

[Pete Turnbull via cctalk]

On 26/03/2018 17:39, et...@757.org wrote:
I'm hoping I don't have to breadboard a 1kV supply and find a lot of 
multi-megohm resistors to try and estimate the breakdown voltage - and 
then guess at the forward current rating.


Is it possible to get the schematics?


If only!  That question has been asked many times on SGI forums like 
nekochan, for the Sony PSU (like this one) and also the Nidec.  No-one 
has ever claimed to have seen one, and the chances are Sony wouldn't 
ever have released them.


I have thought about tracing out the relevant area of the circuit, but 
it would take a while as the components are fairly densely packed, and 
I've got several other tasks on the agenda.


--
Pete
Pete Turnbull

Re: SGI Indy power supply: identify this diode?

[Ethan via cctalk]

I'm hoping I don't have to breadboard a 1kV supply and find a lot of 
multi-megohm resistors to try and estimate the breakdown voltage - and then 
guess at the forward current rating.


Is it possible to get the schematics?


- Ethan
--
: Ethan O'Toole

set help

[Jörg Hoppe via cctalk]

Re: SGI Indy power supply: identify this diode?

[Pete Turnbull via cctalk]

On 26/03/2018 16:08, Camiel Vanderhoeven wrote:

4B would be a 2.2V zener; 4A would be a 2.0V zener, so that’s odd indeed...


That's the idea I had...

Except it's not a zener, or at least not anything like those.  I took 
one out of another (working) supply, and I can tell it has a forward 
voltage of 0.2V, so it's presumably a Schottky diode of some sort.  I 
can also tell it's not a low-voltage zener; the reverse breakdown 
voltage is more than 35V (the highest my bench supply goes up to).


I'm hoping I don't have to breadboard a 1kV supply and find a lot of 
multi-megohm resistors to try and estimate the breakdown voltage - and 
then guess at the forward current rating.



On 3/24/18, 9:47 PM, "cctech on behalf of Pete Turnbull via cctech" 
 wrote:

 After a recent power cut and a series of glitches as the power was
 restored, one of my Indys suffered a PSU failure.  It's a Sony APS-81
 171W unit, SGI P/N 060-0008-001.  I've found half a dozen damaged parts,
 and I've identified a 150R 1W metal film resistor (R135), two trannies
 (Q105, a 2SC4304 and Q106, a 2SC2785) and a couple of small diodes.  One
 of them (D116) appears to be a 6.2b2 (6.2V 1/2W) zener.
 
 The other one I'm not sure about.  On the PCB it's labelled D113, and

 it's adjacent to the 2SC2785.  It's very small, with a green band at the
 cathode end, and the legend "4B" in green - photos at
 https://www.flickr.com/photos/pnt103/albums/72157667056183978
 
 Oddly, another Sony PSU I looked at had a diode there that looked

 identical except it's marked "4A".
 
 I have an idea what it might be but if anyone actually knows what family

 or type/value this is, I'd be grateful for any insight.


--
Pete
Pete Turnbull

Re: PATA hard disks, anyone?

[Guy N. via cctalk]

I've had more replies to this offer than I expected!  I'll make a
general reply here, and contact everyone who responded off-list.

I think the simplest and most cost-effective way to ship these is a USPS
Priority Mail flat rate box.

I have to wipe the drives before I ship them -- my word of honor to the
sysadmin.  I have probably a couple dozen done now that I can ship right
away.  The rest will trickle out a little bit slower after that.

When I said "big carton" I meant it.  There are plenty for everyone.

Re: PATA hard disks, anyone?

[Liam Proven via cctalk]

>> On Sun, Mar 25, 2018 at 9:32 PM, Guy N. via cctalk 
>> wrote:
>>
>> The new sysadmin at work is clearing out closets full of junk^H^H^H^H
>> cool old stuff accumulated by the previous sysadmin.  There's a big
>> carton full of PATA hard disks.  Most of them are in the 4.3 GB - 20 GB
>> range, a few larger, a few smaller.
>
> On 26 March 2018 at 05:29, Adrian Stoness via cctalk  
> wrote:
>
> those are the ibm server ones right?

No. PATA means parallel ATA, that is, EIDE. It covered all EIDE
versions, original 40-wire 16 MB/s and the later 80-wire 33, 66, 100,
& 133 MB/sec standards.

In theory it also embraces pre-*E* IDE, that is, IDE, the old
sub-540MB non-LBA IDE drives.

-- 
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