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Old 19 June 2019, 22:42   #1
Becks
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GVP A1230 crystal oscillator issue

Heya,

I've swapped out the 68EC030 @ 40MHz on my GVP A1230 Turbo+ Series II (Jaws II) accelerator card with a new 68030RC50C. To make it run at the correct 50MHz speed, I replaced the original 40MHz FOX electronics oscillator with a Pletronics branded one. Same specs aside from the faster clock speed.
I fired up the system and powered it on, and voila, it booted right up, SysInfo benchmark showed the faster speed. Perfect. So, job well done, I turned it off, screwed the system back together and flipped the power switch. Nothing. No sign of life at all. Opened it back up, swapped back to the old crystal (still with the new cpu) and it is all working fine.
Tried the 50MHz one again, and no go.

So, for the last few days, I've just been underclocking my cpu.

Anyone got any good theories? I AM using the original stock psu, so I have been playing with the idea of it simply struggling with the extra power draw of higher clock speeds and the MMU, but seeing as it is a last revision 68030, I kinda imagine it should be pretty kind in regards to power consumption.

I am waiting for a new PSU from amigastore, so time will tell, but in case of the PSU not being the problem, where do I start?

I have much more experience with x86 than with Amiga, sadly.
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Old 19 June 2019, 22:52   #2
hooverphonique
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Is the voltage rating for the 50MHz correct?
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Old 19 June 2019, 23:56   #3
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Yes, both are 5V (+/- 10%).
I just managed to find the datasheet for the FOX (40MHz) oscillator now, and it lists it has having and input current of 70mA, but it seems the Pletronics one is listed as 50mA. Any chance that would affect things? I mean, effectively that just means the 50MHz one has lower power draw. Could the A1230 be picky about such things?
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Old 20 June 2019, 11:06   #4
hooverphonique
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Osc current consumption is unlikely to be the issue. Without a schematic I'd say there's an osc startup issue, or it has failed permanently for some reason.
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Old 20 June 2019, 16:52   #5
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Right. Who knows what the problem was, but I just installed my new 68882 and the new "clock-in-a-can" and thought "what the hell" and popped the 50MHz crystal back in as well. Booted right up. Turned it off and back on to make sure. No problems. Put all the screws back in and now it is working just fine.
I guess I will just call that a win.
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Old 27 June 2019, 01:05   #6
slackenby
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Hi, please can I ask where you sourced your clock-in-a-can? I have the same board and have struggled to find anywhere to get them from.
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