Spontaneous reboots due to overheating?

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Spontaneous reboots due to overheating?

After a couple of hours of Pascal work on my //e, it starts to spontaneously reboot. After the first reboot, you can sit there, doing nothing, and it will reboot at 5-10 minute intervals.

It seems to run fine with the lid removed, so I suppose it could be a heat related problem. My system has:

-- Applied Engineering RAMWorks III card with 1MB RAM
-- Applied Engineering Transwarp accelerator
-- Super Serial card
-- Mouse card
-- Disk II controller card

The lid of the computer was noticeably warm when the reboots started, and the interior seemed warm, although nothing like the burn-your-finger temperatures inside a modern machine.

Still, I suppose some cooling is in order.

A System Saver external fan is the classic solution, but looking at the way the inside of the computer is arranged and the way the inside lip of the case comes down almost to the top of the power supply, I can't believe any significant air flow would make it in through the side vents.

I suppose I could mount a small fan somewhere in the chassis. Is there a preferred solution?

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Re: Spontaneous reboots due to overheating?

Not sure, but check your power supply. Does that get "hot"?

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Re: Spontaneous reboots due to overheating?

It's probably heat. I have a similar setup that is unstable after long hours during the summer months, but runs just fine during these winter months.

Is there a preferred solution?

Operate your Apple IIe in a refrigerated room.

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Re: Spontaneous reboots due to overheating?

I've seemingly run my II+ and //e at temperatures like you describe for long periods without issue. Weeks. I used a single SystemSaver and had fantastic results.

Perhaps there actually is some chip or socket in substandard condition. Maybe you are in the mood for removing cards one at a time and seeing if you get longer run times?

If you do fans, why not get a few small low-rpm jobbers and place them between the keyboard area and card area. Then run your system saver as usual. The airflow would be L-shaped and more than sufficient.

Remember a Transwarp card is essentially another computer. Now you've got two mainboard's equivalent dissipation AND 16 times the original memory added in. That's a tall order for stock passive cooling.

Run the system with the lid off and see what happens.

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Re: Spontaneous reboots due to overheating?

Hello dramsey,
it´s a common problem in the entire Apple II series starting from model II till up to the IIGS.....
Apple always has weak powersupplies - calculated for simple small loads.... - RAMworks card drives load on +5 Volt nearly to the permitted limit and that drives the powersupply in heat-limits.... there are several solutions:
first most common used is to add fan-power to the computer ... but if the lid is shut the heat won´t get out fast enough....
second better solution: using a so called "heavy load" power supply like that one from AE ...
the normal power supply is "at limit with a load of 4,8 Amperes .... the one from AE permits load up to 7,3 Ampere in the +5 Volt branch.... the same problem rises when attaching larger drives to the Apple ....
2 drives with 640 kB or a Harddisk gives the same problem... that´s the reason that nearly every third party manufacturer calculates external powersupply .... 1 Ampere at +12 Volt branch is rather poor....

just for short explanation... some of the switching supplies have heatprotection and switch off power when touching temperature limit - that causes reboot.....

if you don´t want to collect for resale but rather use system then a view to:
http://www.harrowalsh.de/Elektronik/APPLEBOX/powersupply_upgrading.htm
might give you an idea how to solve the problem...

sincerely speedyG

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Re: Spontaneous reboots due to overheating?

Since I've been running 6 out of 8 slots in my IIe Platinum, I have been leaving the lid off and using a System Saver. Before, I noticed more heat than I thought I should have, but now she seems to run fine.

You could always get another 12V Fan and run it from the power supply. I did this with my Darth Vader II Plus. It worked fine.
Or you could get another System Saver and mount it on the other side of the housing.
That way you would get almost double the flow.

Or if you would rather not try any of those, you could get a small house fan to set next to the housing with the lid open.

Just a few options. Smile

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Re: Spontaneous reboots due to overheating?

The power supply was definitely warm, but neither it nor any of the components I touched were more than hand-warmer warm. Still, it seems likely the either heat or low voltage is to blame.

I've seen several solutions for this:

-- Find an old AE or other upgraded power supply
-- Use an external PC-style power supply (I've a bunch of those, but where the find the 6-pin connector for the Apple motherboard? I'd prefer not to cut the connector off an existing power supply)
-- Buy a Lite On PE-5221-08 and put its guts in the shell of the Apple power supply.

Finding an AE/other replacement supply seems simplest and there are several available on eBay. Do these generally work well?

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Re: Spontaneous reboots due to overheating?

I have an Apple IIe with the original power supply in it running the following:

0 – Microsoft Premium CP/M
1 – Apple Super Serial
2 – Echo II Speech
3 – AE Transwarp
4 – AE Timemaster II
5 – Apple Disk Controller with DuoDisk
6 – Empty / Prototype Card
7 – CFFA3000

I have never had any heat issues related problems. I thought the CFFA3000 would push the box over the edge but.....

Do you have similar problems running DOS or PRODOS?
Remove the Transwarp card, this will reduce the loading. Does the problem go away???
I am wounding if you have a marginal power supply or thermal run away on a piece of silicon.

Do you have access to an oscilloscope? Check the ripple on the four voltages under full load (filter caps).

I have one major complaint against the Apple II supply, NO ventilation. You can always drill several vent holes in the power supply but this is not as simple as it would seem.

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Re: Spontaneous reboots due to overheating?

The main issue to the powersource is the RAMworks....
the pull from the 32 RAMchips at the +5Volt is nearly 70 mA to 80 mA per chip depending to used type
=> little more than 2,1 Ampere to 2,5 Ampere !....
together with the rest of the chips and resistor networks the total amount can get up to 3 Ampere !!!

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Re: Spontaneous reboots due to overheating?

I'm buying a 60W clone power supply from a member here; perhaps that will help.

Alternatively I can repurpose one of my PC power supplies and use it externally, although I'd really like to find that Apple MB 6 pin connector so I don't have to cut one off an existing power supply. Does anyone know if this is a standard part that can still be obtained?

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Re: Spontaneous reboots due to overheating?

I'm buying a 60W clone power supply from a member here; perhaps that will help.

Due to the fact that that clone supply has 60 Watt it´s weaker than the original supply.... that makes things worse...
the enhanced powersupply from AE has 95 Watt.... that´s nearly 50% more than the original....
with the RAMworks inside your supply should be able to deliver at least 6,5 to 7 Ampere at the +5 Volt branch....

Alternatively I can repurpose one of my PC power supplies and use it externally, although I'd really like to find that Apple MB 6 pin connector so I don't have to cut one off an existing power supply. Does anyone know if this is a standard part that can still be obtained?

in fact powersupplies are repeatingly offered at ebay....
acsurplus offered a bunch of them just 2 or 3 months ago....
the plugs are same difficult to get like the connectors... in normal case you just can extract them from damaged boards or damaged supplies....

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Re: Spontaneous reboots due to overheating?

I'm buying a 60W clone power supply from a member here; perhaps that will help.

Due to the fact that that clone supply has 60 Watt it´s weaker than the original supply.... that makes things worse...

Um...no. I'm looking at the power supply from the Platinum //e that was giving me the problem. It's a silver metal case with ventilation holes, made by Dyna Comp but with Apple labeling. IIRC these are 45 watt power supplies. The specs on the sticker are:

+5V: 4A (so, 20 watts there)
+12V: 1A (1.8 peak) (so max of 21.6 watts)
-5V: 0.25A (1.25 watts)
-12V: 0.25A (3 watts)

That comes to 45.85 watts.

The specs on the 60 watt supply are:

+5 at 5.5A
+12 at 2A
-5 at 0.5A
-12 at 0.5A

So, not a huge improvement, but still significantly better than stock.

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Re: Spontaneous reboots due to overheating?

Alternatively I can repurpose one of my PC power supplies and use it externally, although I'd really like to find that Apple MB 6 pin connector so I don't have to cut one off an existing power supply. Does anyone know if this is a standard part that can still be obtained?

Is this the 6 pin power supply cable your looking for:

http://www.ebay.com/itm/APPLE-IIe-e-II-WIRE-HARNESS-FOR-EXTERNAL-POWER-S-D-I-Y-ASSEMBLE-SOLDER-/321021811139?pt=US_Vintage_Computing_Parts_Accessories&hash=item4abe6419c3

Same guy also has 150 watt power supplies:

http://www.ebay.com/itm/Heavy-duty-Under-table-External-power-supply-for-Apple-IIe-II-Choice-of-2-units-/321045213049?pt=US_Vintage_Computing_Parts_Accessories&hash=item4abfc92f79

Hope this helps.

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Re: Spontaneous reboots due to overheating?

I saw those auctions, but I'll see how well this 60 watt internal unit works first.

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Re: Spontaneous reboots due to overheating?

In what can only be called Kismet, a friend called while I was in San Jose to say that his father, who had thrown out an office full of Apple II equipment about ten years back, had found one overlooked item: a Kensington System Saver. Did I want it?

It works, although it does add an undesired sonic signature. I picked up two 40mm fans that I may try: they fit just between the top of the keyboard and the baseplate, with enough friction to keep them in place. They don't move much air but then you don't need much movement to dissipate 45 watts.

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Re: Spontaneous reboots due to overheating?

I saw those auctions, but I'll see how well this 60 watt internal unit works first.

hello dramsey,

the posting #11 explains the difference in discussion.....
you have been talking about Watt in netto output instead of Watt brutto input.....
it´s nearly close to the explenation in posting #7 in the thread :
http://www.applefritter.com/content/apple-power-requirments

in fact the powersupllies are defined by Input - not Output ( at least by the manufacturers )....
so in fact the powersupply you claim to be 60 Watt - is in fact the "heavy duty" supply - with 90 Watt in a black case ( if it is in the original case.... )

and together with the fans the trouble should have now turned to become history.....

"if things happen, that fit to life - some call it fate...." ( arthur schoppenhauer )

sincerely speedyG

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Re: Spontaneous reboots due to overheating?

I have worked in the computer industry for some decades now and have never heard of power supply ratings by input power rather than output power. That doesn't seem to make any sense because what I or anyone else would be looking for is output power.

I don't know how efficient power supplies were supposed to be back in the day, but 90 watts input for 60 watts output is horribly inefficient...only about 66%, and that at full load! A modern power supply will be over 85% efficient at full load and many "Platinum" certified supplies can reach 95% efficiency.

All that said, I have installed the new supply and added a couple of 50mm DC fans; I'll post a picture as soon as I figured out how. Clicking the Image icon only inserts the string "[inline:attached_image_#]" in the message.

UPDATE: I have uploaded my photo, but see no way to reference it in a forum posting. Searches on the boards reveal nothing. Hints, anyone?

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Re: Spontaneous reboots due to overheating?

Hello dramsey,

you need to know the very correct url where the picture has been uploaded to....
then within the text you should insert in a new line the following tag:

[_img _]_http://example.com/screenshot.jpg_[_/img_]

in case the picture is in a subdirectory of course that has to be inserted in the tag too....
i had to insert understrokelines to avoid the tag getting valid and then not displayed...
so the understrokelines must be removed from the tag without replacement...

sincerely speedyG

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Re: Spontaneous reboots due to overheating?

Oh, well, in that case it's easy: I'll upload the photo to my own server and use that URL. So:

IMAGE(http://neko.com/~dramsey/images/apple_cooling_small.jpg)

These fans work and are quieter than the System Saver, although still more audible than I'd like. Although they don't move much air, case temperatures are much lower. They're held in place simply by friction; the 50mm height is just enough to "wedge" them between the bottom of the keyboard PCB and the base plate, with the help of a paper shim. If I had a Makerbot I'd fabricate a bracket.

I'm wondering now if a low-speed 120mm fan laying flat on top of the vents in the bottom of the case, blowing are up against the keyboard PCB, would work. Perhaps enough airflow would deflect off the angled PCB to the back of the case...might try that since the large fan would be quieter.

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Re: Spontaneous reboots due to overheating?

It looks as if it was definitely overheating. With the new clone power supply, the system will still spontaneously reboot after it gets warm.

With the two 50mm fans installed and running, it doesn't.

Perhaps it's a marginal chip on the AE RAMWorks card, or something else. But moving a little air sure fixes things right up.

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Re: Spontaneous reboots due to overheating?

Cool! Smile

What is your power source for your fans?

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Re: Spontaneous reboots due to overheating?

If you look at the corner of the Apple II motherboard, between the speaker and the fans, you'll just see the two wires I soldered to the pads there.

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