A1200 Blizzard 1230IV - MAPROM causing crash (magenta screen) on soft reboot

[Boing-ball]

Hey everyone!

Hoping someone might have a suggestion on what I can try next to identify the cause of this strange issue.

I have an A1200 (recently recapped) and a Blizzard 1230IV with 64MB fast RAM. The Blizzard with fast RAM was purchased online recently.

This is all running like a dream - very stable, performing nicely, passing Amiga Test Kit tests and meeting expected benchmarks in SYSINFO.

I noticed though, that the seller sent the Blizzard with one jumper and it was placed in the most poorly-optimised possition - to disable MAPRAM. There was no jumper on the RAMSPEED, thus setting 70ns even though the RAM can handle 60ns (I found this based on the chip markings: https://ram-co-shop.de/64-MB-EDO-RAM-72-pin-Simm-non-Parity-60-ns-5V-Chips-8x-8X8E-43VDW-SS_1).

Strange right? So I moved the jumper to enable MAPROM and set RAMSPEED to 60ns.

Amiga booted well, I ran SYSINFO and got the expected boost to around 9.8MIPS for the RAMSPEED change to 60ns. Ran memory tests and all good. Fast RAM reading reduced to 63MB as expected from MAPROM. Happy days I thought.

Unfortuantely, there is the issue in the title; any soft reboot with MAPROM enabled will lead to crash, pretty much immediately (before the flashing blue lines for the Blizzard would show) with a bright magenta screen!

I've tried many things, including reseating the Blizzard and the fast RAM, but unfortunately not having any luck to solve. It happens on any soft reboot whenever it is done, even if I boot without the hard drive connected. It means I can't use Blizkick so it is bothering me... I really want to to determine if the issue is definitely with the Blizzard before I try to return (as it was sold as tested and fully working), becasue I'm really liking it otherwise.

Any help appreciated, thanks!

Have a look here to download the manual:

https://bigbookofamigahardware.com/bboah/product.aspx?id=151

Secondly, download and run AmigaTestKit and check the RAM is okay on the card. Also try switching back the jumper for the 60NS to 70ns just incase.

AmigaTestKit can be downloaded here:

https://github.com/keirf/amiga-stuff/releases

[Boing-ball]

Have you checked the jumper pins for any oxidisation? Like wise on the Blizzard 1230 pins that connect up to the A1200 expansion connector?

Other thing to check is the Power supply has correct voltages.
Which revision is the A1200 motherboard? If it is a 1D4 or 2B, did you have the timing fixes done when it was recapped?