A3660 cold boot issues

chrisw · 30 April 2020, 11:22

Hi everyone,

I've just acquired an A3660 for my A4000 and it's all working perfectly apart from one odd issue.

It will not boot during the first 3 minutes of being turned on.

Symptoms:
* Power light bright
* No IDE activity
* Black screen
* Responds to Ctrl-Amiga-Amiga
* CAPS lock LED responds to about 5 presses before getting stuck

If I leave it on for 3-minutes then either Ctrl-Amiga-Amiga or cycle the power it boots. It will then behave perfectly (surviving reboots and power cycles) until I switch it off again for a prolonged time.

Motherboard has been recapped. Only other installed hardware is a CF IDE adapter and a FlickerMagic.

Any suggestions what I should check first? Instinct says probably PSU? (It's an original and I don't know if it's been recapped).

Thanks,
Chris

22dave66 · 30 April 2020, 12:21

My A3000 only recognizes 4mb of the 16mb fast ram on cold startup and works fine apart from Amiga Explorer transfer errors. Cycle power after 10mins and the full 16mb is there and no Explorer problems, i think mine is a heat/bad connection issue. Have you tried re-seating the A3660?

alexh · 30 April 2020, 15:43

If it isn't the PSU here are a few ideas :

Bad connection? Could be the CPU edge connector? Are you using the correct size stand-offs? Try putting pressure on the edge connector when cold?

A dry joint. Could be anywhere on the A3660 or motherboard. Try a different accelerator card?

The A3660/A3640 uses a delay line which will perform differently at different temperatures. Are you running at the default speed?

chrisw · 01 May 2020, 10:26

Thanks both. Tried reseating the card and pressing down on the connector during boot - still the same behaviour. Same with DiagROM too. Running with a 50Mhz oscillator.

An ATX PSU adapter arrived today so will give that a try later.

chrisw · 04 May 2020, 22:12

Happy news - finally had a chance to test the ATX PSU and the machine boots perfectly from cold with it.

Now the big decision, recap the original PSU, replace the innards with a modern PSU's guts, or replace the whole PSU?

30 April 2020, 11:22	#1
chrisw Registered User Join Date: Apr 2020 Location: United Kingdom Posts: 4	A3660 cold boot issues Hi everyone, I've just acquired an A3660 for my A4000 and it's all working perfectly apart from one odd issue. It will not boot during the first 3 minutes of being turned on. Symptoms: * Power light bright * No IDE activity * Black screen * Responds to Ctrl-Amiga-Amiga * CAPS lock LED responds to about 5 presses before getting stuck If I leave it on for 3-minutes then either Ctrl-Amiga-Amiga or cycle the power it boots. It will then behave perfectly (surviving reboots and power cycles) until I switch it off again for a prolonged time. Motherboard has been recapped. Only other installed hardware is a CF IDE adapter and a FlickerMagic. Any suggestions what I should check first? Instinct says probably PSU? (It's an original and I don't know if it's been recapped). Thanks, Chris

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30 April 2020, 12:21	#2
22dave66 Registered User Join Date: Apr 2020 Location: Hertfordshire, uk Posts: 16	My A3000 only recognizes 4mb of the 16mb fast ram on cold startup and works fine apart from Amiga Explorer transfer errors. Cycle power after 10mins and the full 16mb is there and no Explorer problems, i think mine is a heat/bad connection issue. Have you tried re-seating the A3660?

30 April 2020, 15:43	#3
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,448	If it isn't the PSU here are a few ideas : Bad connection? Could be the CPU edge connector? Are you using the correct size stand-offs? Try putting pressure on the edge connector when cold? A dry joint. Could be anywhere on the A3660 or motherboard. Try a different accelerator card? The A3660/A3640 uses a delay line which will perform differently at different temperatures. Are you running at the default speed?

01 May 2020, 10:26	#4
chrisw Registered User Join Date: Apr 2020 Location: United Kingdom Posts: 4	Thanks both. Tried reseating the card and pressing down on the connector during boot - still the same behaviour. Same with DiagROM too. Running with a 50Mhz oscillator. An ATX PSU adapter arrived today so will give that a try later.

04 May 2020, 22:12	#5
chrisw Registered User Join Date: Apr 2020 Location: United Kingdom Posts: 4	Happy news - finally had a chance to test the ATX PSU and the machine boots perfectly from cold with it. Now the big decision, recap the original PSU, replace the innards with a modern PSU's guts, or replace the whole PSU?

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