PCB Build - Progress - Post your Pics here :-)

Post by **exxos** » Sun Sep 16, 2018 10:20 pm

So I obviously got confused with those 3 Hsync lines

The fix is simple to do.. Lift pin 8 out of the socket on the LS04 U51 (or cut it off) .. and wire link on the bottom of the socket pins 8 & 9... so that will bypass that inverter...

: d1.JPG (49.49 KiB) Viewed 5074 times

PaulJ · Post by **PaulJ** » Mon Sep 17, 2018 4:31 pm

Its going to a while before I get all the parts together to build my board.. still waiting for the board to make the trip across the pond and parts I have ordered. So if processor signals look good I think I would plug in the diagnostic cartridge and a 9600 baud terminal (terminal emulator) to the serial port. There's a better chance to get a meaningful interaction out of the serial port. Do not need board video or keyboard to have an a interaction. Big issue would be if a good serial setup was present in the 6850. Just a thought..

Post by **exxos** » Mon Sep 17, 2018 4:36 pm

But the serial port has had a total re-design, it hasn't been tested either

rpineau · Post by **rpineau** » Mon Sep 17, 2018 5:50 pm

And the serial port on the ST is done by the MFP, not the ACIA (they are use for MIDI and Keyboard).

Post by **exxos** » Mon Sep 17, 2018 6:21 pm

I've boxed up my board and bits to send off tomorrow for assembly.. Don't really know how long that will take, maybe a couple of weeks I guess..

I guess we really need to see if someone else as this video sync fault or not.. I mean really even a broken system should still output stable video frame..

Post by **PhilC** » Mon Sep 17, 2018 6:55 pm

Will do the video mod soon, I did notice that there were two inverted signals on the monitor port but then we had a power cut, so didnt get a chance to note which ones.

I did see 15Khz and 60Khz out of the Glue.

Hopefully have more time later on or tomorrow.

Post by **exxos** » Mon Sep 17, 2018 7:03 pm

Forgottenmyname wrote: Mon Sep 17, 2018 6:55 pm Will do the video mod soon, I did notice that there were two inverted signals on the monitor port but then we had a power cut, so didnt get a chance to note which ones.

I did see 15Khz and 60Khz out of the Glue.

The inverters are not actually used (well shouldn't be) there were for the modulator... just I didn't notice there was 3 HSYNC signals going on.. but the monitor port goes syncs go direct to the GLUE without buffering... so I might actually add buffers on those on a later revision (if it doesn't break something that is).

All other signals come from the shifter directly.. so monitor output should be good.. at least it has a black screen and white border, so looks like the RGB buffers I re-designed are working.. so that is at least something...

troed · Post by **troed** » Mon Sep 17, 2018 7:28 pm

Forgottenmyname wrote: Mon Sep 17, 2018 6:55 pm I did see 15Khz and 60Khz out of the Glue.

Assuming you have a PAL TOS, that means TOS didn't execute and/or the machine is being kept in RESET. One of the first things it does is to set 50Hz.

It does mean GLUE is working as it should

Post by **exxos** » Mon Sep 17, 2018 7:34 pm

troed wrote: Mon Sep 17, 2018 7:28 pm
Forgottenmyname wrote: Mon Sep 17, 2018 6:55 pm I did see 15Khz and 60Khz out of the Glue.
Assuming you have a PAL TOS, that means TOS didn't execute and/or the machine is being kept in RESET. One of the first things it does is to set 50Hz.

It does mean GLUE is working as it should

That is a good point actually... I sent out PAL versions of the ROM.. Peoples monitors really need to support 50 & 60Hz.. mine does

I'm checking around the video and don't see any other mistakes anywhere..

Post by **PhilC** » Mon Sep 17, 2018 7:39 pm

See, I learn something new every time I turn this board on, which is one of the reasons I got it

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