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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: jimmyboy on February 08, 2016, 07:23:05 PM

Title: Crystal oscillator perishable ?
Post by: jimmyboy on February 08, 2016, 07:23:05 PM
I have an M-Tec 1200 8MB RAM/FPU/RTC which was working when i packed it away years ago. Today its dead. Ive tried the ram in another card and its fine. Is it possible the crystal oscillator has died? Do the crystals wear out or perish?
Title: Re: Crystal oscillator perishable ?
Post by: mechy on February 08, 2016, 08:41:43 PM
Quote from: jimmyboy;803704
I have an M-Tec 1200 8MB RAM/FPU/RTC which was working when i packed it away years ago. Today its dead. Ive tried the ram in another card and its fine. Is it possible the crystal oscillator has died? Do the crystals wear out or perish?

They are pretty robust, but i have had a good few accelerator boards and a few amigas with dead oscillators.
Title: Re: Crystal oscillator perishable ?
Post by: paul1981 on February 09, 2016, 02:39:01 AM
Quote from: jimmyboy;803704
I have an M-Tec 1200 8MB RAM/FPU/RTC which was working when i packed it away years ago. Today its dead. Ive tried the ram in another card and its fine. Is it possible the crystal oscillator has died? Do the crystals wear out or perish?


Do you mean a seperate crystal oscillator for the fpu clock or the crystal for the RTC?
If you mean the square crystal oscillator, then I suppose you could try removing it and jumper the card to run off the Amiga's 14MHz clock.

If it was the RTC crystal, would it not just cause the clock to be frozen in time?
Title: Re: Crystal oscillator perishable ?
Post by: Damion on February 09, 2016, 04:35:41 AM
I would suspect a contact issue first (looks like a number of socketed stuff on that board), but I imagine you've checked that already. Very rare for an oscillator to fail, but it happens.
Title: Re: Crystal oscillator perishable ?
Post by: jimmyboy on February 09, 2016, 04:54:28 AM
Quote from: Damion;803726
I would suspect a contact issue first (looks like a number of socketed stuff on that board), but I imagine you've checked that already. Very rare for an oscillator to fail, but it happens.


Im doing maintenance on everything atm. Im going over contact points with a fibreglass pencil and continuity testing for dry solder or broken/cracked joints.
Title: Re: Crystal oscillator perishable ?
Post by: delshay on February 09, 2016, 09:21:09 AM
I have one here 60MHz. After say 10Mins drops to around 30MHz. Heat up the casing to around 300-350c. Let it cool down working again at correct speed 60MHz, but sooner or later back to around 30MHz.   ..short story faulty.