Speed issue with Blizzard 1220/4

[A1200]

Hi I have a Blizzard 1220/4 board which was working well and you can see a screengrab of the sysinfo speed etc. here:

Link to post on my blog

However recently I noticed the clock speed recognised by Sysinfo and Which Amiga is 15.3MHz, not the 30.6MHz sysinfo used to report, or even 28MHz which the CPU on the card should be clocked at.

I cleaned the contacts etc. but then I noticed on every image of this board I could find, only my board has a missing passive oscillator indicated on pic of someone else's pic below (I have circled the part).

Blizzard 1220 Osc

So my questions are, how did it work at 30ish MHz in the 1st place, and can anyone who has this board let me know the frequency written on this part? I would assume 28MHz but not sure as there might be a multiplier somewhere, which actually makes sense but I thought it ran a multiple of the A1200's own clock.

In any case, if attaching this crystal or replacing another part doesn't work (open to suggestions for another fix), I am left with a 14MHz 020 board with 40MHz FPU and 4MB RAM. Machine is still twice as fast as the stock A1200 but not that long ago it was 4x the speed.

Any guidance/ideas would be useful.

Thanks,

Mike
(A1200)

[A1200]

I have now ordered another Blizzard 1220/4 to restore my spec and to learn about the board in order to potentially fix the other.

[Sandro]

Originally Posted by A1200

Hi I have a Blizzard 1220/4 board which was working well and you can see a screengrab of the sysinfo speed etc. here:

Link to post on my blog

However recently I noticed the clock speed recognised by Sysinfo and Which Amiga is 15.3MHz, not the 30.6MHz sysinfo used to report, or even 28MHz which the CPU on the card should be clocked at.

I cleaned the contacts etc. but then I noticed on every image of this board I could find, only my board has a missing passive oscillator indicated on pic of someone else's pic below (I have circled the part).

Blizzard 1220 Osc

So my questions are, how did it work at 30ish MHz in the 1st place, and can anyone who has this board let me know the frequency written on this part? I would assume 28MHz but not sure as there might be a multiplier somewhere, which actually makes sense but I thought it ran a multiple of the A1200's own clock.

In any case, if attaching this crystal or replacing another part doesn't work (open to suggestions for another fix), I am left with a 14MHz 020 board with 40MHz FPU and 4MB RAM. Machine is still twice as fast as the stock A1200 but not that long ago it was 4x the speed.

Any guidance/ideas would be useful.

Thanks,

Mike
(A1200)

I have a "Tra1200" turboboard, 020/28mhz+8mb ,very similar to the blizzard 1220 but supports up to 8mb fast via standard sim

this turboboard seems is clocked by the motherboard itself using the 28 mhz crystal because the turboboard have not any oscilator but there is a socket to install one if you plan install a fpu
According to the manual, you can install up to 50mhz fpu

SYSinfo 4.0 recognize the 68020 but not recognize how many MHZ is running on, so don't worry about it

[A1200]

Hi Sandro, the Blizzard 1220 in my case is definitely not right. I have before and after speed results, plus I bought a new board which shows the higher speed, plus there is countless screenshots on a google image search of the proper speed of this board.

Update:

I bought another card identical to see what I could see as I noticed the little cylindrical oscillator was missing. Anyway to cut a long story short, I can't repair this one.

It works fine, 100% stable as a ram card @ 14MHz, the battery backed clock (RTC) is fine and the 68882 FPU rated and clocked at 40MHz is also good. So if you just need extra ram, a battery backed clock and an FPU this is the card for you.

I soldered on a timing crystal and also attempted to redo some solder joints. I also noticed some caps that were present on my replacement not on this one so I tried a solder bridge as I didn't have any SMD caps. This prevented the A1200 booting so I removed them, but a solder pad did come off (see pics).

So, I am selling this as-is - 4MB RAM board, FPU, RTC. As it DID work without the watch crystal and any other components its probable that someone who knows more than me could fix it but with my amount of resoldering, it does look cosmetically a little tatty - but hey inside the Amiga who cares? It is still 2x faster than a standard A1200, being a ram board and all.

eBay link: http://www.ebay.co.uk/itm/262178929756

Pics of dodgy card and related info:
http://www.amiga600.net/wp-content/u.../12/bench1.jpg
http://www.amiga600.net/wp-content/u.../12/bench2.jpg
http://www.amiga600.net/wp-content/u.../12/board6.jpg
http://www.amiga600.net/wp-content/u.../12/board5.jpg
http://www.amiga600.net/wp-content/u.../12/board4.jpg
http://www.amiga600.net/wp-content/u.../12/board3.jpg
http://www.amiga600.net/wp-content/u.../12/board2.jpg
http://www.amiga600.net/wp-content/u.../12/board1.jpg

[jbenam]

Hmmm, I love a challenge, so I might just register an eBay account...

[A1200]

I suspect this is a rouge board or a rare revision as I cannot find another image of one without the components missing where this one has missing components.