1.44 floppy mod install help

[rubber_jonnie]

Also the soldering bridges DS0 + DS1

This is incorrect, the drive can be DS0 or DS1, it is a drive ID, you can't have both soldered at the same time.

Which jumpers are you specifically referring to, those on the drive itself or D0 and D1 on the small PCB?

[exxos]

I order a new 1,44 board with gal. Then we see

There shouldn't be any need.. The GALs are all tested, so unless it was plugged in backwards should be fine.

If you have a scope then you should check the 1772 clock.. you should see 8Mhz there with D0,D1 soldered.. This verifies the GAL is working and the 1772 is getting the correct clock.

I would also make sure you have no shorts on the mod board anywhere. Also flux and solder all connections. Clean GAL and 1772 and all connections connections with IPA wipes.

There was a modification you should maybe do, is that 1K resistor, there is another 1K next to it, should be changed for 470R. I need to make a note in the docs actually about that. But 99% of the time, 1K is fine anyway.

[bbisi]

ok
i do it and send a message

is it correct that the gal only data begins from address 05835 to 0592


thank you

[exxos]

is it correct that the gal only data begins from address 05835 to 0592

I don't know.. but I also don't know why you need to know ? All the GALs are code protected, you can't read its contents anyway.

[bbisi]

ok
you have a circuit diagram

[exxos]

You need to check CLK on the 1772

1772.png (22.15 KiB) Viewed 2652 times

There is no schematic, but similar circuit exists in the H5 schematics.

Capture.PNG (50.8 KiB) Viewed 2651 times

[bbisi]

hi
I measured all the circuit paths and found no errors.
no short circuits.....
i don't find anything

[exxos]

What exactly have you measured ? Some pins on the 1772 goes via resistors or other logic, and there be no direct connection to measure, you should have at least found those surely ? How you know what to measure when I only posted the diagram a few seconds ago ?

I would suggest you find someone local to you who can help diagnose your machine for you.

[bbisi]

Hello ALL

I checked all the pins I knew of and found a defective pin 21 on the 1772.
I soldered in a new one, measured again, and installed everything on mainboard .
It seems to be working.
Using Elco-HD in autostart, I also managed to format it to 1.44.
Reading and writing 1,44 is ok
I'll keep testing and hope everything works.

[exxos]