Alienkid H5 C1 build

[alienkidmj12]

wow, all these issues :(

where did the dry joints come from lol

[alienkidmj12]

to be honest i had doubts about the donor board which was given for free. it was just a mess :( depends if i can get those chips at a good price or not. i really dont want to shelling out loads lol


thanks so far, theres no way id of found those issues :( i made tripple checks when i put the ic's into the sockets too :( so not entirely sure how a leg was broken

[PhilC]

A quick update.

The cart port is now working, it had a couple of pins that needed attention. So now I've been able to diagnose what's wrong with the floppy.

When carrying out the floppy test the drive appears to format fine but when its reading the data back there is a mismatch between what is read and what should have been written.

This will take a bit longer to diagnose due to the buffer chips etc being in the circuit. I'll probably have to build an adaptor of some kind so that I can have access to the floppy pins on the drive as well as the wd1772 to compare the data as everything seems OK.

[Icky]

@PhilC - try another 1772 in the socket. See if it's the chip as the DMA and GLUE had issues, you never know if the 1772 is also not functioning correctly. I had a similar issue with a 1772.

[PhilC]

@PhilC - try another 1772 in the socket. See if it's the chip as the DMA and GLUE had issues, you never know if the 1772 is also not functioning correctly. I had a similar issue with a 1772.

Yeah I'd already tried that and another DMA, it was fault F6, which said check floppy disk first, then floppy drive, then 1772 and finally DMA.

I think its an issue with the 1772 RD and WD lines

[alienkidmj12]

wowzers, i had no chance :( ive not been heavy handed or anything with this, im surpised it has so many issues :(

[PhilC]

wowzers, i had no chance :( ive not been heavy handed or anything with this, im surpised it has so many issues :(

It's easily done, the two dodgy chips from your donor board and that fake ds1315 didn't do you any favours. Its possible you'd have got it to boot if they worked but would still not be able to boot a floppy.

Just chalk it up to experience, then leave it alone :P :lol:

[alienkidmj12]

wowzers, i had no chance :( ive not been heavy handed or anything with this, im surpised it has so many issues :(

It's easily done, the two dodgy chips from your donor board and that fake ds1315 didn't do you any favours. Its possible you'd have got it to boot if they worked but would still not be able to boot a floppy.

Just chalk it up to experience, then leave it alone :P :lol:

Leave it alone.... ! :)
I need to pick stuff up, only way to learn, just didnt have the tools :)

[PhilC]

Today's update.

Tracing connections from the data lines to the DMA are ok.
Checking connections between the DMA and WD1772 look OK.
Checking signals from WD1772 to the floppy and annoyingly there appears to be an identical signals at either end.

Using the floppy exerciser on the rom cartridge everything pulses as it should although I have noticed a couple of anomalies on the WD1772 that I need to check out on another H5.
Pins 20,21 and 22 on the WD1772 appear to do what they should but voltage max is 4vdc instead of 5vdc.

Everything else on this H5C1 seems to work but the floppy.

[alienkidmj12]

again, i totally appreciate you looking at this for me

thanks again

dave