So there have been some more updates on the irata.online code based on my work. Thom has taken on some more fine tuning with keyboard detection. I put in some Rasta bars and keyboard click as general UI improvements. They seems to have gone down well, the keyboard click was more of a burp. I think Thom has improved on my place holding burp, yet to see. My attempt to use the "click()" failed, guessing it needed a loop and calling a few times to kick the speaker. -dunno-
The Irata.online project is bounding forwards its admirable the force being thrown in to porting the code across systems. I ran through code with Thom for a few hours looking for an illusive bug. Issue with Talk and Bad passwords causing the cursor to mysteriously re position and over type causing no end of mess. I had a hunch about it being joined to the blank line process, damned if I could find my way through the code. Thom found it and the reference in the documentation to requiring a -15 being required to correct the position after clearing the line. Having only tested with the +3 I thought I should look at checking the Interface 1 RS232 code. There is a big assumption its just working. I had a scan through the assembly routines, there is very little in there probably calling ROM code (no comments can't tell!).
Next shot is Z80 from Gerton Lunter, I actually had a copy of this as shareware and is possibly the only shareware I upgraded to full version as a teenager. Serial port didnt work this time, but keyboard was fine. Given 3 emulators presented 3 different issues, I am giving up at this point. Fair to say a software defined port emulated and then using an actual buffered serial port is going to be a bust for testing. Even if it all worked, would it work on real kit?
After some contemplation I did the next silly thing. Jumped on ebay and found an IF1 for £38 including postage. No microdrives, just the interface. Not sure I would want and actual microdrive they like to chew tape too much, far to impractical. VDrive on the other hand... Well may be for Christmas?
Quick sanity check with the Spectrum group on Facebook. Peter Mulholland got it spot on with the cable being most likely at fault. Opening the PSU and testing at the board I found a nice 11V, slightly hot but with no load that is expected. Just need to cut the cable down and re-attach to the board. PSU actually looks to be in good condition. The casing looks to have warped a little, but I think that is from past problems. This old things had a repair or two over the years. Hopefully it will hold it together for the testing!
So with power under control next is a quick visual inspection on the old 48K. See if we have any leaking capacitors, bits of metal or other nasty surprises. The keyboard membrane looks to be in good condition, the ribbon on the right seems suspect. If a row of keys isn't working on one side I know what it will be. All in all it is looking good in the case. Once the PSU is fixed up, I will just need to pray to the gods of silicon heaven. And pray the soul doesn't come out the back of the machine on power up. Worst case its off to a repair shop, "paging Dr Ian" the frequent call on Facebook group.
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AuthorMe, slightly crazy engineer type. Generalist in nature, hardware or software with nonspecialist skill set. Archives
January 2020
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