exxos's Atari, Amiga & retro forum

well, apparently even after removing the clock load CAPACITOR, it still doesn't work.

terriblefire wrote: 23 Mar 2022 22:38 If you dont get any clock at the jumper then your crystal is dead. Or your jumper is bad.

I've checked continuity at the jumper, and it seems fine. Also, probing the clock pin with a multimeter gives me half of 3.3v, which kind of implies that it's working, even though the logic probe says otherwise.

GadgetUK164 wrote: 23 Mar 2022 23:44 Check your crystal output is not grounded, and then check all the pins on the 68K socket to make sure only the grounds are connected to ground.

Did that, all the pins seem to be fine, no shorts to ground.

gumorr wrote: 24 Mar 2022 00:25 well, apparently even after removing the clock load CAPACITOR, it still doesn't work.

terriblefire wrote: 23 Mar 2022 22:38 If you dont get any clock at the jumper then your crystal is dead. Or your jumper is bad.

I've checked continuity at the jumper, and it seems fine. Also, probing the clock pin with a multimeter gives me half of 3.3v, which kind of implies that it's working, even though the logic probe says otherwise.

GadgetUK164 wrote: 23 Mar 2022 23:44 Check your crystal output is not grounded, and then check all the pins on the 68K socket to make sure only the grounds are connected to ground.

Did that, all the pins seem to be fine, no shorts to ground.

Ok please check what I’m asking. Is there a clock signal on the jumper. I don’t care about what it has continuity with. Do you see a square wave

terriblefire wrote: 24 Mar 2022 16:13 Ok please check what I’m asking. Is there a clock signal on the jumper. I don’t care about what it has continuity with. Do you see a square wave

Unfortunately I don't own an oscilloscope so I can't be sure if there's a square wave, but a logic probe on the jumper says it's completely low.

Well, I gave some of the components a reflow, and the behavior has now changed. Diagrom is now outputting data on the serial port, however it seems to be mostly garbage. It either pumps out garbage characters, "IA", or a few 'U's.

Please recheck your com port settings and your cable:
https://sites.google.com/one-n.co.uk/am ... ial-output

gumorr wrote: 24 Mar 2022 22:38

terriblefire wrote: 24 Mar 2022 16:13 Ok please check what I’m asking. Is there a clock signal on the jumper. I don’t care about what it has continuity with. Do you see a square wave

Unfortunately I don't own an oscilloscope so I can't be sure if there's a square wave, but a logic probe on the jumper says it's completely low.

Measure between that centre pin and ground - make sure the clock output is not grounded. if its just low, it's either shorted to ground or the XTAL is bad / not powered.

Maximilian wrote: 25 Mar 2022 11:33 Please recheck your com port settings and your cable:
https://sites.google.com/one-n.co.uk/am ... ial-output

Both my cables and settings are good. I just tested it with the old processor just to make sure.

GadgetUK164 wrote: 25 Mar 2022 16:33 Measure between that centre pin and ground - make sure the clock output is not grounded. if its just low, it's either shorted to ground or the XTAL is bad / not powered.

The center pin isn't shorted to ground. I've also checked voltages on the clock, and it's receiving 3.3v.

At this point, I'm not sure the clock is the issue. My logic probe may just be acting up (it's some $20 probe I bought off amazon, it probably isn't the greatest in terms of quality). On top of this, the screen seems to flash random colors, and it manages to brighten the power led, so I think the clock is actually fine. I'm just gonna try to reflow everything and see if that helps more.

Could you give us some high quality pictures from the top and the bottom of the board?

gumorr wrote: 24 Mar 2022 00:08 Well, after a bit of looking around I realized something. I put a capacitor instead of a resistor for the clock load resistor. :headbang:

You dont need anything there. its not listed on any BOMs.

Maximilian wrote: 26 Mar 2022 13:36 Could you give us some high quality pictures from the top and the bottom of the board?

I know I got the wrong regulator, but it still works. :oops:


Starting to wonder if this is something related to signal impedance, because it never acts the same way whenever I boot...