Deskpro EN Sff on ATX psu

[Mat Menzies]

I have a Compaq Deskpro EN SFF series computer (really small desktop PII
450)
which I would like to put in a standard ATX case.
I have assesed the power supply connector and determined the corrct pins on
the motherboard to work with a standard ATX power supply except for two
wires which are labelled on the cct board of the powersupply as "3.5v RS-"
(black) and 3.5v RS+ (brown)

If I dont connect anything to the motherboard connector where these would
normally go, both lights on the front just flash and the PC doesn't boot /
no picture.

I am *guessing* that these are related to the "power good" signal from a
standard ATX psu, as there is nothing labelled as such from the deskpro
power supply. The PC still doesn't boot if only the RS+ position is
connected to the 'power good' signal from a standard ATX psu.

Can anyone supply the information req'd to make a COMPAQ Deskpro EN SFF PC
boot from a standard ATX psu?

Can anyone tell me what 3.5V RS+ and 3.5V RS- might be?

Mat

 

[Rod Speed]

Mat Menzies <mat.nospam@south.com.au> wrote
in message news:3fbbef8c$1@dnews.tpgi.com.au...

I have a Compaq Deskpro EN SFF series computer (really small
desktop PII 450) which I would like to put in a standard ATX case.

Makes a lot more sense to just cut to the chase and replace both
the case and the motherboard and move everything else over.

A good second hand or unused ATX motherboard
that can take that cpu will cost peanuts off ebay etc.

Or pay only peanuts more for a socket 370 Celeron 450 too.

Compaqs of that era are more trouble than they are worth.
Some are just plan utterly bizarre on the fine detail.

I have assesed the power supply connector and determined
the corrct pins on the motherboard to work with a standard
ATX power supply except for two wires which are labelled
on the cct board of the powersupply as "3.5v RS-" (black)
and 3.5v RS+ (brown)

If I dont connect anything to the motherboard connector
where these would normally go, both lights on the front
just flash and the PC doesn't boot / no picture.

I am *guessing* that these are related to the
"power good" signal from a standard ATX psu,

Given the labelling, its much more likely that they are
3.5V remote sense, one for each side of the 3.5V rail.

as there is nothing labelled as such from the deskpro power
supply. The PC still doesn't boot if only the RS+ position is
connected to the 'power good' signal from a standard ATX psu.

Can anyone supply the information req'd to make a COMPAQ
Deskpro EN SFF PC boot from a standard ATX psu?

Can anyone tell me what 3.5V RS+ and 3.5V RS- might be?

Bet they're remote sense.

 

[Mat Menzies]

after taking note of your ideas ..

Bet they're remote sense

what would they be "remotely sensing"?
If I knew what the m/b was looking for I could possibly find that in a std
ATX or reproduce it artificially.

Mat


"Rod Speed" <rod_speed@yahoo.com> wrote in message
news:bph4np$1munh9$1@ID-69072.news.uni-berlin.de...

Mat Menzies <mat.nospam@south.com.au> wrote
in message news:3fbbef8c$1@dnews.tpgi.com.au...

I have a Compaq Deskpro EN SFF series computer (really small
desktop PII 450) which I would like to put in a standard ATX case.

Makes a lot more sense to just cut to the chase and replace both
the case and the motherboard and move everything else over.

A good second hand or unused ATX motherboard
that can take that cpu will cost peanuts off ebay etc.

Or pay only peanuts more for a socket 370 Celeron 450 too.

Compaqs of that era are more trouble than they are worth.
Some are just plan utterly bizarre on the fine detail.

I have assesed the power supply connector and determined
the corrct pins on the motherboard to work with a standard
ATX power supply except for two wires which are labelled
on the cct board of the powersupply as "3.5v RS-" (black)
and 3.5v RS+ (brown)

If I dont connect anything to the motherboard connector
where these would normally go, both lights on the front
just flash and the PC doesn't boot / no picture.

I am *guessing* that these are related to the
"power good" signal from a standard ATX psu,

Given the labelling, its much more likely that they are
3.5V remote sense, one for each side of the 3.5V rail.

as there is nothing labelled as such from the deskpro power
supply. The PC still doesn't boot if only the RS+ position is
connected to the 'power good' signal from a standard ATX psu.

Can anyone supply the information req'd to make a COMPAQ
Deskpro EN SFF PC boot from a standard ATX psu?

Can anyone tell me what 3.5V RS+ and 3.5V RS- might be?

Bet they're remote sense.

 

[Rod Speed]

Mat Menzies <mat.nospam@south.com.au> wrote in
message news:3fbc234f$1@dnews.tpgi.com.au...

after taking note of your ideas ..

Bet they're remote sense

what would they be "remotely sensing"?

Sorry. Thats the usual way to describe measuring the voltage
supplied by that rail, at what is powered from the rail, in this
case the motherboard. Thats better than measuring the rail
voltage at the power supply because remote sense allows
for the voltage drop in the wires for that rail.

The AT and ATX power supply design never used remote sense.
ATX basically uses a different approach, the 12V rails are regulated
on the motherboard to the voltages that need to be accurate there.
Thats the reason for the extra 12V lines with the ATX system.

If I knew what the m/b was looking for
I could possibly find that in a std ATX

Nope. It was never part of the ATX standard.

or reproduce it artificially.

Or that, when the ATX standard doesnt even have a 3.5V rail at all.

And it makes absolutely no sense anyway, the mother board
in those system is a steaming turd and should be binned. If you
must, you can move stuff like the cpu to a different motherboard,
but like I said, it makes more sense to use a socket 370 cpu
for peanuts, literally. Celeron 466s go for $20 on ebay.

"Rod Speed" <rod_speed@yahoo.com> wrote in message
news:bph4np$1munh9$1@ID-69072.news.uni-berlin.de...

Mat Menzies <mat.nospam@south.com.au> wrote
in message news:3fbbef8c$1@dnews.tpgi.com.au...

I have a Compaq Deskpro EN SFF series computer (really small
desktop PII 450) which I would like to put in a standard ATX case.

Makes a lot more sense to just cut to the chase and replace both
the case and the motherboard and move everything else over.

A good second hand or unused ATX motherboard
that can take that cpu will cost peanuts off ebay etc.

Or pay only peanuts more for a socket 370 Celeron 450 too.

Compaqs of that era are more trouble than they are worth.
Some are just plan utterly bizarre on the fine detail.

I have assesed the power supply connector and determined
the corrct pins on the motherboard to work with a standard
ATX power supply except for two wires which are labelled
on the cct board of the powersupply as "3.5v RS-" (black)
and 3.5v RS+ (brown)

If I dont connect anything to the motherboard connector
where these would normally go, both lights on the front
just flash and the PC doesn't boot / no picture.

I am *guessing* that these are related to the
"power good" signal from a standard ATX psu,

Given the labelling, its much more likely that they are
3.5V remote sense, one for each side of the 3.5V rail.

as there is nothing labelled as such from the deskpro power
supply. The PC still doesn't boot if only the RS+ position is
connected to the 'power good' signal from a standard ATX psu.

Can anyone supply the information req'd to make a COMPAQ
Deskpro EN SFF PC boot from a standard ATX psu?

Can anyone tell me what 3.5V RS+ and 3.5V RS- might be?

Bet they're remote sense.

 

[Mat]

Sorry. Thats the usual way to describe measuring the voltage
supplied by that rail, at what is powered from the rail, in this
case the motherboard. Thats better than measuring the rail
voltage at the power supply because remote sense allows
for the voltage drop in the wires for that rail.

OK thanks.
But from that description, I understand that its the powersupply that is
gathering information from RS +/-.
In that case it would seem that the motherboard wouldn't care what was
present on those two points and theoretically wouldn't be the reason it
doesn't boot.

Or that, when the ATX standard doesnt even have a 3.5V rail at all.

I'll consider that the 3.3V from a std ATX is not high enough to cater for
the 3.5V previously supplied to the m/b as a reason it wont boot .. however
I considered it within a tolerable range.

And it makes absolutely no sense anyway, the mother board
in those system is a steaming turd and should be binned. If you
must, you can move stuff like the cpu to a different motherboard,
but like I said, it makes more sense to use a socket 370 cpu
for peanuts, literally.

Celeron 466s go for $20 on ebay. <-- there's a reason for that!


My reasons for wishing to use the existing motherboard are:
I originally used one as a filesever on my home network, where it had 95 on
it and served up a couple of printers. The need for that purpose is far less
now with the size of HD's, so I put 98 on it and used it as a GPL online
race server. It worked fantastically cos that game works much better on a
PII (even a slow one) than it does on (even a fast) Celly, 98 picks up all
the hardware perfectly, the onboard v/c runs pretty much any GPL track in
software mode without a hitch, it has onboard Intel 10/00 LAN and it was all
very easy. I have just never had any problems with these things at all. (Not
sure why you dont like the motherboards, except that they are frustratingly
non-std). Plus I have a number of these deskpros in varying uses around
here and at work.
However, they dont have CD drives in them. They require expensive slim CD
drives to suit the cases, and if I could successfully move them to std cases
I would pop a CD in them all. My kids use a couple and they are increasingly
requiring CD's too.
Yes, its not expensive or difficult to grab a second hand m/b, but to get
one with on-board everything I wouldn't get decent chipsets, s/h quality
would be a worry, and to go for s/h Intel chipset boards to replace all my
deskpros would be a bit too pricey, and I'd have to buy new NICs & V/Cs (&
possibly sound).
For me, it'd be great if I could just get them to run on a std ATX supply,
and put them into some new $12 ATX cases along with a cheap CD

Mat

 

[Rod Speed]

Mat <mad_mat*remove*@tpg.com.au> wrote in
message news:3fc052d2$1@dnews.tpgi.com.au...

Sorry. Thats the usual way to describe measuring the voltage
supplied by that rail, at what is powered from the rail, in this
case the motherboard. Thats better than measuring the rail
voltage at the power supply because remote sense allows
for the voltage drop in the wires for that rail.

OK thanks.
But from that description, I understand that its the
powersupply that is gathering information from RS +/-.

Correct.

In that case it would seem that the motherboard
wouldn't care what was present on those two points

Correct.

and theoretically wouldn't be the reason it doesn't boot.

Correct. BUT most likely the problem is that the motherboard
expects 3.5V and since the ATX supply only supplys 3.3V,
thats the reason it doesnt boot, the supplied voltage is too low.

Or that, when the ATX standard doesnt even have a 3.5V rail at all.

I'll consider that the 3.3V from a std ATX is not high enough to cater
for the 3.5V previously supplied to the m/b as a reason it wont boot ..
however I considered it within a tolerable range.

Sure, but unless you actually try supplying it with 3.5V and see what
happens when its getting 3.5V instead of 3.3V, you cant be sure.

And it makes absolutely no sense anyway, the mother board
in those system is a steaming turd and should be binned. If you
must, you can move stuff like the cpu to a different motherboard,
but like I said, it makes more sense to use a socket 370 cpu
for peanuts, literally.

Celeron 466s go for $20 on ebay. <-- there's a reason for that!

Just that they are so common that they arent worth much now.

It'll perform just as well as that current motherboard/cpu.
And wont have the stupid quirks that motherboard has either.

My reasons for wishing to use the existing motherboard are:

I originally used one as a filesever on my home network, where it had 95
on it and served up a couple of printers. The need for that purpose is far
less now with the size of HD's, so I put 98 on it and used it as a GPL
online race server. It worked fantastically cos that game works much
better on a PII (even a slow one) than it does on (even a fast) Celly,

Then get a slot 1 motherboard and PII cpu for about the same price.

98 picks up all the hardware perfectly,

Does that with the vast bulk of motherboards of that era too. And
adding an appropriate driver is a lot less farting around than attempting
to run that fucked motherboard off a standard ATX power supply.

the onboard v/c runs pretty much any GPL
track in software mode without a hitch, it has
onboard Intel 10/00 LAN and it was all very easy.

Plenty of socket 370 motherboards do all that fine, for peanuts now.

I have just never had any problems with these things at all.

Just as true of any decent socket 370 motherboard.

(Not sure why you dont like the motherboards,
except that they are frustratingly non-std).

And fucked by design. One of them, if you want to add a video
card, you have to cycle the power repeatedly until eventually
it decides to use the addon video card. Fucked by design.

Plus I have a number of these deskpros
in varying uses around here and at work.

Pity they're fucked by design and cant be easily
moved to a better case, as you have just discovered.

However, they dont have CD drives in them. They
require expensive slim CD drives to suit the cases,
and if I could successfully move them to std cases

And you have just discovered that they're fucked by design on that.

I would pop a CD in them all. My kids use a couple
and they are increasingly requiring CD's too.

Yep, those small format Deskpros are fucked by design.

Yes, its not expensive or difficult to grab a second hand m/b, but
to get one with on-board everything I wouldn't get decent chipsets,

Bullshit. And even brand new socket 478
integrated motherboards are dirt cheap now.

s/h quality would be a worry, and to go for s/h Intel
chipset boards to replace all my deskpros would be
a bit too pricey, and I'd have to buy new NICs

There's hordes of very decent 10/100 NICs on ebay for peanuts.

& V/Cs (& possibly sound).

There's plenty of very decent socket 370
motherboards with all of that for peanuts.

I just paid $25 for one to replace an older socket 7 based system
in the kitchen, just to get instant on which is handy for that situation.

For me, it'd be great if I could just get them to run on a std ATX supply,
and put them into some new $12 ATX cases along with a cheap CD

Pity it aint that easy, because they are fucked by design.

 

[Mat Menzies]

Points taken .. I'll rethink it all.
Thanks for your help.

Mat

"Rod Speed" <rod_speed@yahoo.com> wrote in message
news:bpr67f$1q6nqs$1@ID-69072.news.uni-berlin.de...

Mat <mad_mat*remove*@tpg.com.au> wrote in
message news:3fc052d2$1@dnews.tpgi.com.au...

Sorry. Thats the usual way to describe measuring the voltage
supplied by that rail, at what is powered from the rail, in this
case the motherboard. Thats better than measuring the rail
voltage at the power supply because remote sense allows
for the voltage drop in the wires for that rail.

OK thanks.
But from that description, I understand that its the
powersupply that is gathering information from RS +/-.

Correct.

In that case it would seem that the motherboard
wouldn't care what was present on those two points

Correct.

and theoretically wouldn't be the reason it doesn't boot.

Correct. BUT most likely the problem is that the motherboard
expects 3.5V and since the ATX supply only supplys 3.3V,
thats the reason it doesnt boot, the supplied voltage is too low.

Or that, when the ATX standard doesnt even have a 3.5V rail at all.

I'll consider that the 3.3V from a std ATX is not high enough to cater
for the 3.5V previously supplied to the m/b as a reason it wont boot ..
however I considered it within a tolerable range.

Sure, but unless you actually try supplying it with 3.5V and see what
happens when its getting 3.5V instead of 3.3V, you cant be sure.

And it makes absolutely no sense anyway, the mother board
in those system is a steaming turd and should be binned. If you
must, you can move stuff like the cpu to a different motherboard,
but like I said, it makes more sense to use a socket 370 cpu
for peanuts, literally.

Celeron 466s go for $20 on ebay. <-- there's a reason for that!

Just that they are so common that they arent worth much now.

It'll perform just as well as that current motherboard/cpu.
And wont have the stupid quirks that motherboard has either.


My reasons for wishing to use the existing motherboard are:

I originally used one as a filesever on my home network, where it had 95
on it and served up a couple of printers. The need for that purpose is
far
less now with the size of HD's, so I put 98 on it and used it as a GPL
online race server. It worked fantastically cos that game works much
better on a PII (even a slow one) than it does on (even a fast) Celly,

Then get a slot 1 motherboard and PII cpu for about the same price.

98 picks up all the hardware perfectly,

Does that with the vast bulk of motherboards of that era too. And
adding an appropriate driver is a lot less farting around than attempting
to run that fucked motherboard off a standard ATX power supply.

the onboard v/c runs pretty much any GPL
track in software mode without a hitch, it has
onboard Intel 10/00 LAN and it was all very easy.

Plenty of socket 370 motherboards do all that fine, for peanuts now.

I have just never had any problems with these things at all.

Just as true of any decent socket 370 motherboard.

(Not sure why you dont like the motherboards,
except that they are frustratingly non-std).

And fucked by design. One of them, if you want to add a video
card, you have to cycle the power repeatedly until eventually
it decides to use the addon video card. Fucked by design.

Plus I have a number of these deskpros
in varying uses around here and at work.

Pity they're fucked by design and cant be easily
moved to a better case, as you have just discovered.

However, they dont have CD drives in them. They
require expensive slim CD drives to suit the cases,
and if I could successfully move them to std cases

And you have just discovered that they're fucked by design on that.

I would pop a CD in them all. My kids use a couple
and they are increasingly requiring CD's too.

Yep, those small format Deskpros are fucked by design.

Yes, its not expensive or difficult to grab a second hand m/b, but
to get one with on-board everything I wouldn't get decent chipsets,

Bullshit. And even brand new socket 478
integrated motherboards are dirt cheap now.

s/h quality would be a worry, and to go for s/h Intel
chipset boards to replace all my deskpros would be
a bit too pricey, and I'd have to buy new NICs

There's hordes of very decent 10/100 NICs on ebay for peanuts.

& V/Cs (& possibly sound).

There's plenty of very decent socket 370
motherboards with all of that for peanuts.

I just paid $25 for one to replace an older socket 7 based system
in the kitchen, just to get instant on which is handy for that situation.

For me, it'd be great if I could just get them to run on a std ATX
supply,
and put them into some new $12 ATX cases along with a cheap CD

Pity it aint that easy, because they are fucked by design.

 

[amstereo - matt2]

hook up the orig psu, messure the voltages on the RS pins, and supply with
near exact voltages +-10% .

some of the atx connectors have bizzar voltage allocations to the pins (same
pin count/fit but diff voltages to different pins)


"Mat Menzies" <mat.nospam@south.com.au> wrote in message
news:3fbbef8c$1@dnews.tpgi.com.au...

I have a Compaq Deskpro EN SFF series computer (really small desktop PII
450)
which I would like to put in a standard ATX case.
I have assesed the power supply connector and determined the corrct pins
on
the motherboard to work with a standard ATX power supply except for two
wires which are labelled on the cct board of the powersupply as "3.5v RS-"
(black) and 3.5v RS+ (brown)

If I dont connect anything to the motherboard connector where these would
normally go, both lights on the front just flash and the PC doesn't boot /
no picture.

I am *guessing* that these are related to the "power good" signal from a
standard ATX psu, as there is nothing labelled as such from the deskpro
power supply. The PC still doesn't boot if only the RS+ position is
connected to the 'power good' signal from a standard ATX psu.

Can anyone supply the information req'd to make a COMPAQ Deskpro EN SFF PC
boot from a standard ATX psu?

Can anyone tell me what 3.5V RS+ and 3.5V RS- might be?

Mat