Underclocking...

Ok.

I've had a few problems with my Amiga, as I think some will know. I have managed to get the basic system to boot up to the purple screen every time without the accelerator in and hdd unplugged, which is good progress as far as I am concerned.

I also have the Accelerator virtually working. It may take 3 or 4 reboots, or the odd power cycle, but it does spring to life.

However, it does get a bit toastie inside there. It is running at 50mhz, and has a co-processor at equal speed. They appear to be sharing the same crystal via a kynar wire. If I do a long CPU intensive task (I recently unzipped about a gig of data), the system will crash.

So, could I just replace the 50mhz crystal with a similar 40mhz, losing a bit of speed, but gaining a bit of stability? Would I gain anything by using 2 crystals of the same value instead of the current shared setup?

The card in question is featured here in the bboah:

http://www.bboah.com/index.php?actio...965&artlang=en

Sorry for all the questions... but :bowdown:

:thumbsup:

Chinners

If the CPU and FPU are rated at 50Mhz then you shouldnt be getting that much heat from it especially from a Blizzard of all cards! There's no reason why you cant just bung a 40Mhz crystal in there but it seems somewhat of a waste of such a decent accelerator.
There could be something wrong with your card because it shouldnt be anything more then a bit warm TBH.

I have read a lot about these accelerators getting overly warm, too hot to touch, so didn't really think much of it. It did give me an excuse to buy a no-contact thermometer to play with though! Unfortunately, the markings on top of the CPU are worn away, so I cannot verify if it is a true 50mhz 030, or an overclocked [insert lower speed here] mhz 030.

But anyway, the card gets hot. No two ways about it. It's only recently that I have noticed it crashing on long cpu intensive operations though (perhaps something to do with just turning on the central heating?). I do have the trapdoor shut and the case closed, which is obviously preventing airflow.

t.b.h. I don't use the Amiga for much more than WHDLoad, and perhaps a bit of protracker, so I don't mind under clocking to try keep the temperature down. As I doubt anything uses the FPU, I have thought of popping that out too.

But back to the crystals. What type of crystal do I need, and is it safe to use just the one to clock both FPU and CPU, or would 2 be better?

:bowdown::thumbsup:

Chinners

Having a look if that is your card there seems to be no crystal or socket for one so the frequency will be fixed at whatever rate it is now (50Mhz presumably). But like I say rather then underclocking (if you could that is) I would investigate as to why it's getting warm in the first place. Sadly my knowlage is low on the Mk.II but I hope someone here can help you a little better then me.

Are there any jumper settings? I know theres one for FPU speeds.

Failing all of the above you could invest in heatsinks though this would most likely require you to leave the door off and depending on the depth, raise the whole machine up.

It is very intrusive, but I retroFit a fan into the broad side of my xbox360, so why not try it out in your Accelerator? You could probably find a dead (modern) PC and pull the heatsink and fan or simply buy one. But like I said, it would be more intrusive than what you would want for such a beauiful machine. How about liduid cooling? :p

Quote:

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Originally Posted by tokyoracer

Having a look if that is your card there seems to be no crystal or socket for one so the frequency will be fixed at whatever rate it is now (50Mhz presumably). But like I say rather then underclocking (if you could that is) I would investigate as to why it's getting warm in the first place. Sadly my knowlage is low on the Mk.II but I hope someone here can help you a little better then me.

Are there any jumper settings? I know theres one for FPU speeds.

Failing all of the above you could invest in heatsinks though this would most likely require you to leave the door off and depending on the depth, raise the whole machine up.

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The picture on bboah isn't very good. The two central "chips" are actually socketed crystals... at least on my card they are sockets, with 1 crystal installed.

I have installed a couple of 1.7cm fans inside the case to keep air moving, but these are a bit noisy (11,000rpm!!!) I am going to get some trimmers to slow them down a tad, the slower the better. I don't want to mod the case more than necessary. I would rather run it @33 than hack the case up.

---------- Post added at 15:38 ---------- Previous post was at 15:36 ----------

Quote:

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Originally Posted by Jazzmarazz

It is very intrusive, but I retroFit a fan into the broad side of my xbox360, so why not try it out in your Accelerator? You could probably find a dead (modern) PC and pull the heatsink and fan or simply buy one. But like I said, it would be more intrusive than what you would want for such a beauiful machine. How about liduid cooling? :p

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I have thought of getting a bigger fan in there - but NOT one of those beasts :)
I could try liquid cooling & run it in a bucket of distilled water. :D

Your turbo board is probably fine.
It's your Amiga or PSU getting worse.

Added:
Have you tried this turbo on another Amiga?

Quote:

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Originally Posted by stachu100

Your turbo board is probably fine.
It's your Amiga or PSU getting worse.

Added:
Have you tried this turbo on another Amiga?

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Hi stachu,

I don't have another Amiga.
I don't have any near-by friends with Amigas.

I have tried 2 different PSUs, and after I have broken down my old PC, will adapt that to work in the Amiga.

But would a poor PSU cause the heat?

Thanks (and thanks to everyone else who has chipped in - I always forget those sort of pleasantries :) )

Ok. Back at home.
Pictures say more than words.

The "crystals" What do I need to do to replace this with a 40mhz part? Would 2 be better than 1?
Attachment 19659

The CPU - can these hieroglyphs be decoded?
Attachment 19658

The whole underside of the card.
Attachment 19657

i can make out 03050 on that chip :)