DoG's Hx Mongrel build attempt

[DoG]

Looks like your keyboard connector is on backwards. Missing pin should be second from the front, not second from the rear.

Thank you! I just held up the connector from the keyboard. Didn't check that at all. I even have a original motherboard beside me. Clumsy.

[DoG]

...When will power up be ?

Now!

Well, it's working... but I got no floppy. I also got very faint red or missing red in display. Have to look into that tomorrow.

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No red.jpg (17.31 KiB) Viewed 4744 times

Audio is working and Blitter is working. Got 4Mb of ram and it's working. HDD/satandisk is working. External port. So ran GemBench:

GB with blitter.jpg (89.2 KiB) Viewed 4744 times

[exxos]

Looks like you got a bit or 2 in the red line somewhere not contacting.

I assume you did all the fixes to the board and got all jumpers correct ?

[DoG]

Looks like you got a bit or 2 in the red line somewhere not contacting.

You were right about a bit missing. First I checked all my soldering and they seemed fine. So I measured all the stuff on the red side of shifter, DAC and mux. I found that pin 27 (R2) of the shifter didn't have contact with pin 11 on the mux. I found that I got a missing trace on my board so did a little bodge wire and now it is working.

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Desktop with all colours.jpg (47.31 KiB) Viewed 4722 times

[exxos]

You were right about a bit missing. First I checked all my soldering and they seemed fine. So I measured all the stuff on the red side of shifter, DAC and mux. I found that pin 27 (R2) of the shifter didn't have contact with pin 11 on the mux. I found that I got a missing trace on my board so did a little bodge wire and now it is working.

Good find! wow those boards are all supposed to be checked for continuity as well.

[DoG]

Ordered a few DMA buffer fix pcb from coronaland and some 1 channel converters since @kodak80 have mention it is working now.

I haven't got a chance to check any further, what is faulty with my floppy drive access yet. Measured all of the resistor pack that is 10k around that area. Seems that I got 8k on one of the resistors in RP9. Ordered some new 10k bussed RP. I have also checked continuity of tracks without luck finding anything to get floppy working. I have changed DMA and 1772 chip. No change. Since Satandisk is working I'm hoping that it's the resistor pack that needs changing. I have not soldered in the external port so haven't tried that but I don't see any point of doing that. Anyone got any tip to proceed of finding the fault?

[exxos]

Have you done this mod ? https://www.exxosforum.co.uk/forum/viewt ... 893#p31893

[DoG]

Have you done this mod ? https://www.exxosforum.co.uk/forum/viewt ... 893#p31893

Yes, already done that. Didn't help.

[exxos]

Checked 1772 has 8Mhz clock ?

[DoG]

Checked 1772 has 8Mhz clock ?

Just bought a LA so haven't checked that. I also thought that I had checked all the traces but when i measured between pin 18 on the 1772 and R905 I had no signal. It was a very small scratch mark on the trace. So solder a small wire and now I got floppy drive access.

So thanks for leading me to check the 8Mhz pin