Blizzard MK4

Sim085 · 05 October 2017, 11:39

Hello, I just received a blizzard mk4. The motherboard I have is the Rev 2B. Without the mk4 installed I boot from a CF card normally. With the blizzard mk4 installed I get a dark screen with the power LED on. The power LED is not that bright when the card is connected. I have kickstart 3.1.

Does anyone know what might be wrong?

Daedalus · 05 October 2017, 16:41

The LED staying dim like that shows that the CPU isn't running. First off, do you have another A1200 to try the board in? Try running the card without any RAM or other extras installed. This can be simply a matter of a bad connection, try gently cleaning both sides of the A1200's trapdoor connector as 25 years of gradual contamination build-up won't be helping.

Check the accelerator's connector for any bent or misshapen pins that would cause problems.

Also, the A1200's metal shield might possibly be shorting against the solder joints of the Blizzard's connector. If the A1200 still has its upper shield in place, it might be wise to at least bend it so that it can't possibly touch the accelerator. The shield can also be removed if desired.

Finally, the connector isn't a perfect fit and can sometimes need a little wriggle to get it to fit properly. Try pull it out by 1mm or so to see if that helps.

Sim085 · 05 October 2017, 17:01

Hi Deadalus,

Thanks for the reply. I managed to get it working. It was real silly! It seems you need more than a 250W PU! I read how people said that the A1200 PU was not good enough however I thought this was not my issue as I had an ATX PU. I put a 500W PU and it booted.

I still followed your advise with the connector as it seems like it dangles, so at the moment I am holding it with some plastic.

Quote:

Originally Posted by Daedalus

The LED staying dim like that shows that the CPU isn't running. First off, do you have another A1200 to try the board in? Try running the card without any RAM or other extras installed. This can be simply a matter of a bad connection, try gently cleaning both sides of the A1200's trapdoor connector as 25 years of gradual contamination build-up won't be helping.

Check the accelerator's connector for any bent or misshapen pins that would cause problems.

Also, the A1200's metal shield might possibly be shorting against the solder joints of the Blizzard's connector. If the A1200 still has its upper shield in place, it might be wise to at least bend it so that it can't possibly touch the accelerator. The shield can also be removed if desired.

Finally, the connector isn't a perfect fit and can sometimes need a little wriggle to get it to fit properly. Try pull it out by 1mm or so to see if that helps.

Daedalus · 05 October 2017, 17:06

Quote:

Originally Posted by Sim085

Hi Deadalus,

Thanks for the reply. I managed to get it working. It was real silly! It seems you need more than a 250W PU! I read how people said that the A1200 PU was not good enough however I thought this was not my issue as I had an ATX PU. I put a 500W PU and it booted.

Well, there might be some other issue then - perhaps the 250W PSU wasn't working properly, or was marginally low on the 5V line, because an A1200 with a Blizzard only needs maybe 20W of power. Dirty contacts on the power lines can also cause voltage drops that add up - ATX connector, Amiga motherboard connector and trapdoor slot connector all introduce small drops that together may have been too much for the Blizzard with one PSU but by coincidence ok with the other.

Quote:

I still followed your advise with the connector as it seems like it dangles, so at the moment I am holding it with some plastic.

The trapdoor lid is designed to hold it nice and snug, so you should really use that if you can.

Sim085 · 05 October 2017, 17:10

At first I tried to put it in without removing the casing but it was quite difficult. So I decided to remove everything out of the case. I noticed those plastic slots you mention so will now try to put everything back in.

Quote:

Originally Posted by Daedalus

The trapdoor lid is designed to hold it nice and snug, so you should really use that if you can.

Hmm... this is worrying; so either I have a fried PU (which was enough for the A1200 alone but not with Blizzard too) or I have problems on the A1200 ...

I'll check the PU with a multi-meter...
There is the recapping I still have to do to the A1200, hope is nothing related to that (I did not see any stains on the mb to be honest)

Quote:

Originally Posted by Daedalus

Well, there might be some other issue then - perhaps the 250W PSU wasn't working properly, or was marginally low on the 5V line, because an A1200 with a Blizzard only needs maybe 20W of power. Dirty contacts on the power lines can also cause voltage drops that add up - ATX connector, Amiga motherboard connector and trapdoor slot connector all introduce small drops that together may have been too much for the Blizzard with one PSU but by coincidence ok with the other.

Daedalus · 05 October 2017, 17:15

It shouldn't be related to the recapping, but it's worth measuring both PSUs when running the Amiga to see the difference. Try measure the +5V at the floppy power connector to get an idea. The first PSU might not be fried, it could simply be that it outputs 5.0V whereas the other outputs 5.2V, and that's enough of a difference that when power gets to the Blizzard, it's 4.8V instead of 4.6V.

Sim085 · 05 October 2017, 17:42

Do you have a picture on which is the +5V pint and which is the ground pin? Unfortunately I don't know such basics.

Quote:

Originally Posted by Daedalus

It shouldn't be related to the recapping, but it's worth measuring both PSUs when running the Amiga to see the difference. Try measure the +5V at the floppy power connector to get an idea. The first PSU might not be fried, it could simply be that it outputs 5.0V whereas the other outputs 5.2V, and that's enough of a difference that when power gets to the Blizzard, it's 4.8V instead of 4.6V.

Sim085 · 05 October 2017, 17:43

Nothing nothing ... I was looking at the data pins not the power pins which are next to the led pins!!

Ok .. let me check!

Quote:

Originally Posted by Sim085

Do you have a picture on which is the +5V pint and which is the ground pin? Unfortunately I don't know such basics.

Sim085 · 05 October 2017, 18:40

Not sure if I am doing it correctly,

I use one of the middle pins as ground and the right most pin for the voltage.

I get 12.19 with the old PU.
and 12.30 with the new PU.

Quote:

Originally Posted by Sim085

Nothing nothing ... I was looking at the data pins not the power pins which are next to the led pins!!

Ok .. let me check!

Daedalus · 05 October 2017, 21:40

Well, it's the 5V line that's important for the chips like the CPU. The two middle pins are ground and the outer pins are 5V and 12V, so you need to check the leftmost pin...

Sim085 · 06 October 2017, 17:55

I have checked the 5V line with accelerator card connected.

With 500W PU I had 4.58V, A1200 booted all ok
With 250W PU I had 4.34V, A1200 did not boot and LED was dim.

Both look to be under 5V... is it normal?

Quote:

Originally Posted by Daedalus

Well, it's the 5V line that's important for the chips like the CPU. The two middle pins are ground and the outer pins are 5V and 12V, so you need to check the leftmost pin...

Daedalus · 06 October 2017, 21:50

Nope, they're far too low - the 4.58V one is just about getting away with it, but you have some voltage drops somewhere, or else poor regulation. What is the +5V measuring at the ATX connector? Usually black and red wires, and you should be able to measure them while the machine is powered up from the back of the connector.

Sim085 · 06 October 2017, 22:03

With the machine switched on, if I take a reading from an unused molex (the ones usually used for hard disks) the reading is 5.20V. If I take the reading from the molex used to switch the A1200 the reading is 4.98V.

Do I need to take reading from some other place?

Quote:

Originally Posted by Daedalus

Nope, they're far too low - the 4.58V one is just about getting away with it, but you have some voltage drops somewhere, or else poor regulation. What is the +5V measuring at the ATX connector? Usually black and red wires, and you should be able to measure them while the machine is powered up from the back of the connector.

E-Penguin · 06 October 2017, 23:46

ATX supplies are designed to regulate the 12v line, and the others are divided from that. You need more load on the 12v line to make it regulate better.

Source (forgive my paraphrasing) :

http://www.ianstedman.co.uk/Amiga/am...su.html#ATXPSU

Daedalus · 07 October 2017, 01:07

Yep, it could be that there's not enough load, or it could be that there are losses elsewhere. If you're measuring 5V at the ATX connector but 4.6 at the motherboard, there's a big drop somewhere, most likely the main power connector to the Amiga. They do tend to get dirty and tarnish over time, increasing resistance and causing a voltage drop. See about cleaning both the plug and the socket and see if that helps. The floppy port on the motherboard should be measuring very close to the ATX connector - 0.4V drop is too much.

Sim085 · 07 October 2017, 01:09

How can I do that? How can I increase the load on the 12v line? I just plug the Amiga to the PSU based on instructions here:
http://ianstedman.co.uk/Amiga/amiga_..._supplies.html

Quote:

Originally Posted by E-Penguin

ATX supplies are designed to regulate the 12v line, and the others are divided from that. You need more load on the 12v line to make it regulate better.

Source (forgive my paraphrasing) :

http://www.ianstedman.co.uk/Amiga/am...su.html#ATXPSU

E-Penguin · 07 October 2017, 13:26

From Stedy's website :
25W, 12 ohm resistors added to provide the required load and either a suitable heatsink or cooling fan to dissipate the heat.

Daedalus · 07 October 2017, 15:23

Alternatively, if you have some old hard drives lying around, try plugging a couple of them into the unused connectors. These will use 12V for their motors and should be enough of a load for most power supplies.

Sim085 · 07 October 2017, 15:44

Connected two hdds but still get same reading of 4.58...

Could it be rust on the power connector?
I had to use a rust remover substance on the back connectors as these had rust when I got this a1200.

How can I take a reading from the power connector on the Amiga? (if voltage is already dropped at that point then I believe the mystery would be solved).

Quote:

Originally Posted by Daedalus

Alternatively, if you have some old hard drives lying around, try plugging a couple of them into the unused connectors. These will use 12V for their motors and should be enough of a load for most power supplies.

Daedalus · 07 October 2017, 16:00

Hmmm, it's looking like the connector alright. Well, you can measure at the floppy drive power connector. Unless the traces or solder joints are damaged, that should be the same voltage as the main power connector itself. What you can do is measure *between* the two supplies. So, multimeter black lead to the +5V at the floppy connector, red lead to the back of the ATX connector. The reading there is the voltage drop between the two, and shouldn't really be more than 0.2V. On a heavily expanded A500 here, the drop across that setup is around 0.15V.

05 October 2017, 11:39	#1
Sim085 Registered User Join Date: Apr 2009 Location: N/A Posts: 962	Blizzard MK4 Hello, I just received a blizzard mk4. The motherboard I have is the Rev 2B. Without the mk4 installed I boot from a CF card normally. With the blizzard mk4 installed I get a dark screen with the power LED on. The power LED is not that bright when the card is connected. I have kickstart 3.1. Does anyone know what might be wrong? Last edited by Sim085; 05 October 2017 at 16:29.

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05 October 2017, 16:41	#2
Daedalus Registered User Join Date: Jun 2009 Location: Dublin, then Glasgow Posts: 6,334	The LED staying dim like that shows that the CPU isn't running. First off, do you have another A1200 to try the board in? Try running the card without any RAM or other extras installed. This can be simply a matter of a bad connection, try gently cleaning both sides of the A1200's trapdoor connector as 25 years of gradual contamination build-up won't be helping. Check the accelerator's connector for any bent or misshapen pins that would cause problems. Also, the A1200's metal shield might possibly be shorting against the solder joints of the Blizzard's connector. If the A1200 still has its upper shield in place, it might be wise to at least bend it so that it can't possibly touch the accelerator. The shield can also be removed if desired. Finally, the connector isn't a perfect fit and can sometimes need a little wriggle to get it to fit properly. Try pull it out by 1mm or so to see if that helps.

05 October 2017, 17:15	#6
Daedalus Registered User Join Date: Jun 2009 Location: Dublin, then Glasgow Posts: 6,334	It shouldn't be related to the recapping, but it's worth measuring both PSUs when running the Amiga to see the difference. Try measure the +5V at the floppy power connector to get an idea. The first PSU might not be fried, it could simply be that it outputs 5.0V whereas the other outputs 5.2V, and that's enough of a difference that when power gets to the Blizzard, it's 4.8V instead of 4.6V.

05 October 2017, 21:40	#10
Daedalus Registered User Join Date: Jun 2009 Location: Dublin, then Glasgow Posts: 6,334	Well, it's the 5V line that's important for the chips like the CPU. The two middle pins are ground and the outer pins are 5V and 12V, so you need to check the leftmost pin...

06 October 2017, 21:50	#12
Daedalus Registered User Join Date: Jun 2009 Location: Dublin, then Glasgow Posts: 6,334	Nope, they're far too low - the 4.58V one is just about getting away with it, but you have some voltage drops somewhere, or else poor regulation. What is the +5V measuring at the ATX connector? Usually black and red wires, and you should be able to measure them while the machine is powered up from the back of the connector.

06 October 2017, 23:46	#14
E-Penguin Banana Join Date: Jul 2016 Location: Darmstadt Posts: 1,213	ATX supplies are designed to regulate the 12v line, and the others are divided from that. You need more load on the 12v line to make it regulate better. Source (forgive my paraphrasing) : http://www.ianstedman.co.uk/Amiga/am...su.html#ATXPSU

07 October 2017, 01:07	#15
Daedalus Registered User Join Date: Jun 2009 Location: Dublin, then Glasgow Posts: 6,334	Yep, it could be that there's not enough load, or it could be that there are losses elsewhere. If you're measuring 5V at the ATX connector but 4.6 at the motherboard, there's a big drop somewhere, most likely the main power connector to the Amiga. They do tend to get dirty and tarnish over time, increasing resistance and causing a voltage drop. See about cleaning both the plug and the socket and see if that helps. The floppy port on the motherboard should be measuring very close to the ATX connector - 0.4V drop is too much.

07 October 2017, 13:26	#17
E-Penguin Banana Join Date: Jul 2016 Location: Darmstadt Posts: 1,213	From Stedy's website : 25W, 12 ohm resistors added to provide the required load and either a suitable heatsink or cooling fan to dissipate the heat.

07 October 2017, 15:23	#18
Daedalus Registered User Join Date: Jun 2009 Location: Dublin, then Glasgow Posts: 6,334	Alternatively, if you have some old hard drives lying around, try plugging a couple of them into the unused connectors. These will use 12V for their motors and should be enough of a load for most power supplies.

07 October 2017, 16:00	#20
Daedalus Registered User Join Date: Jun 2009 Location: Dublin, then Glasgow Posts: 6,334	Hmmm, it's looking like the connector alright. Well, you can measure at the floppy drive power connector. Unless the traces or solder joints are damaged, that should be the same voltage as the main power connector itself. What you can do is measure between the two supplies. So, multimeter black lead to the +5V at the floppy connector, red lead to the back of the ATX connector. The reading there is the voltage drop between the two, and shouldn't really be more than 0.2V. On a heavily expanded A500 here, the drop across that setup is around 0.15V.

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