Search found 759 matches

by Peter
Wed Mar 20, 2019 8:12 am
Forum: Hardware
Topic: Poll: CPU choice
Replies: 45
Views: 1474

Re: Poll: CPU choice

Thanks Dave and Nasta. I somehow expected the full outline of the connector on the silkscreen, because that was the case for D-SUB etc., too. Sorry for the confusion. I really want this QL mainboard replacement, and my personal taste would be very classic, re-using the original chips. Like a very la...
by Peter
Tue Mar 19, 2019 10:15 pm
Forum: Hardware
Topic: Poll: CPU choice
Replies: 45
Views: 1474

Re: Poll: CPU choice

Forgive me, but I still don't see the normal ROM port contacts. Will they be there or not?
by Peter
Mon Mar 18, 2019 9:05 pm
Forum: Hardware
Topic: Poll: CPU choice
Replies: 45
Views: 1474

Re: Poll: CPU choice

I noticed the PCB picture has no contacts for the ROM port. Intended?
by Peter
Mon Mar 18, 2019 8:14 am
Forum: Hardware
Topic: SGC successor brainstorming
Replies: 89
Views: 7224

Re: SGC successor brainstorming

Another useful improvement would be a 5+ year battery clock As mentioned at the start of this thread, if a SGC successor was designed by me, it would come with a re-chargeable buffer. That would most likely be a supercap like on the Q68, just larger. It would probably not hold time for 5 years if t...
by Peter
Thu Mar 14, 2019 12:40 pm
Forum: Hardware
Topic: Two peripherals attached to Q68 fried at the same time. Coincidence ?
Replies: 9
Views: 452

Re: Two peripherals attached to Q68 fried at the same time. Coincidence ?

What the Q68 sees is a delay on reset/power good for the FPGA, video is given a little noise for a few ms (but this isn't visible as video hasn't even started yet). The 47u cap on the Q68 wasn't low ESR, and the calculated impedance during this period was 154 ohms. Off topic remark: The damping is ...
by Peter
Wed Mar 13, 2019 12:19 pm
Forum: Hardware
Topic: Two peripherals attached to Q68 fried at the same time. Coincidence ?
Replies: 9
Views: 452

Re: Two peripherals attached to Q68 fried at the same time. Coincidence ?

But this particular time, I was careless, (though it should not have been a problem) - Powered up the PSU - I did not disable the output - I keyed in the maximum voltage first i.e. 5 volts To be more clear: This is a problem, and has the potential to damage sensitive circuitry, especially with seve...
by Peter
Wed Mar 13, 2019 11:00 am
Forum: Hardware
Topic: Two peripherals attached to Q68 fried at the same time. Coincidence ?
Replies: 9
Views: 452

Re: Two peripherals attached to Q68 fried at the same time. Coincidence ?

[*]SD card went bust (due to whatever reason) and started to draw significant current. Sh*t happens. If I understood correctly, François powered the overall system including SD card by sort of a "80 mA current supply" - this has a good chance to produce wildly oscillating internal supply ...
by Peter
Wed Mar 13, 2019 8:52 am
Forum: Hardware
Topic: Two peripherals attached to Q68 fried at the same time. Coincidence ?
Replies: 9
Views: 452

Re: Two peripherals attached to Q68 fried at the same time. Coincidence ?

The 5V of the power supply connector goes directly to the keyboard, no Q68 components involved except the PCB traces. So if the keyboard was damaged, I'd have no idea what the Q68 could have contributed. What exactly can happen to a complex mix of electronics if a current-limited supply is attached ...
by Peter
Tue Mar 12, 2019 11:44 am
Forum: Hardware
Topic: Poll: CPU choice
Replies: 45
Views: 1474

Re: Poll: CPU choice

This board has a really precise target. People who have and use a BBQL with maybe a (S)GC and a couple of extras like QubIDEs, etc. It's just a board to allow a person to keep their original case, keyboard and expansions hooked up to a "true" QL. Issue 5 owners would see some performance ...
by Peter
Mon Mar 11, 2019 10:10 pm
Forum: Hardware
Topic: Poll: CPU choice
Replies: 45
Views: 1474

Re: Poll: CPU choice

Hi Dave, I find this mainboard a good idea, if it can still run an unchanged historical OS, keeping the timings for games, network and microdrives intact. Do all three choices support unchanged timings? Peter PS: I think this mainboard should look & feel as "retro" as possible - otherw...

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