Recent content by A4000Bear

I have a Rev 5, and it has three GAL chips. Some time ago, I removed the GALs and attempted to read them, but they were protected. The reason was that a friend also has this board and he had damaged it by putting 12V where it shouldn't be. My board still works well, although not with an A4091...

I was able to overclock my CSPPC/MK3 to 80MHz, using a Rev 6 060. I also have an earlier version, with different firmware that couldn't quite get to 80 MHz, though it was good at 75. It should be noted that the board does get very hot, even with extra cooling, so in the end I chose to fit a...

That is correct, I purchased it from a retailer here in Australia. I did mention the retailer, but it was removed as I had also quoted the price in the same sentence, which I shouldn't have done. I don't know when it was released, but there is a copyright date of 2022 on the box. Looking at the...

Apologies. I didn't know that applied to items I wasn't selling.

I found a couple of new currently available monitors that support 15KHz. Philips 221S9 (21") and 241S9 (24") both support 15kHz PAL & NTSC RGB through the VGA connector. Both monitors also have HDMI input, and can be set to display 4:3. Interestingly, the listed specs show a minimum frequency of...

Saw this post a bit late, and it is unclear what your configuration is, but there is an incompatibility with OS3.1 on a Warp Engine with any 68060 that has an FPU. Is your Rev 5 an EC or LC version? If so, that is why it works. In order to get a full 060 with FPU to work on a Warp Engine, you...

This site lists three different FPUs that work on a clock doubled A2386 SX with 486SXLC2 CPU: https://a4000bear.neocities.org/overclock/A2386/A2386

I know this reply is very late, but it still may be of interest. Yes, the G50 version of the TI486SXLC2 is rated at 3.3V nominal power. According to the datasheet, the maximum rated voltage is 5.5V. I'm not aware of differences between earlier and later G50 variants. I have had my G50...

You didn't mention what model Amiga you have, but assuming you have a rev 6 A2000, the modification is here: http://members.iinet.net.au/~davem2/overclock/A2000-2MB-chip.html If you have a Rev 6 A500, this image had the modification you need: It appears you have the wrong kind of RAM. You...

I had an A4000T that refused to work with Zorro III cards. Fault was traced to one of the 74FCT16646 bus transceiver chips. The A4000D uses 74FCT646 and 74F245 chips for this application.

Normally computer power supplies are identical between their 120V and 230V versions, except for a single wire jumper (sometimes a switch) that rearranges the configuration of the rectifier circuit. For 230V it is wired as a conventional bridge rectifier. For 120V it is wired as a voltage doubler...

I must confess I didn't know that those 486SXLC2 chips came in a 3.3V version. I soldered one onto my Bridgeboard over 20 years ago. It's been running on 5V happily since then, and I even overclocked it to 62MHz. I did put a fairly large heatsink with fan on it as it did get quite warm, even at...

After digging around in my documentation, the modification I mentioned previously was described in the 'enhancements' section of this document The added chip was a 74F00, and it improved cache flushing specifically for the TI486SXLC2. While the document was specifically for the Commodore 386...

I did a similar hack to a Commodore A2386 bridgeboard many, many years ago using the TI version of this chip. From my very vague memory, the added TTL logic chip was used to inhibit caching of certain problematic memory locations, which would otherwise have to be done by software during booting...

I have two SCSI2SD V6 boards. I updated one of them perfectly, the other fails, just like the original poster. I have no idea why, I would assume there is a fault, even though the board works fine otherwise.