3 Bombs...yes again...

[nama]

Hi all,

This is my first post in the ST forum, so please be gentle.

I recently picked up a 520STfm. It was pretty grubby, and is missing a key. I pulled the machine apart and gave it a good scrubbing. Keyboard is presently in a million bits ready for cleaning.

After reassembling (except for the keyboard which is totally pulled apart, and I'm hoping someday I'll get a replacement key... so for now it's un attached), I was able to boot the machine to TOS, no mouse or keyboard means no way to navigate, but I was happy the machine seemed to work fine.

I then decided to make some floppies. I used floimgd (Floppy Image & file transfer program) from here http://atari.8bitchip.info/floimgd.php.

I used some DD (not HD) disks and after some mucking around I was able to create a Crazy Cars disk. Initially I got the thee bombs, but after some time (I'm assuming after the machine warms up) I could boot to the attract screen. Success!...or so I thought. Of course with no keyboard or mouse I couldn't test further... I'm assuming a keypress is needed to advance the game. And I couldn't hear any music and looking at some you tube vids it seems that music should be playing. However this morning I was not able to boot the disk at all...three bombs all the time. I even remade the Crazy Cars disk to no avail. I also let the machine warm up for about 10+ mins.

I tried making some other disks with limited success. Some may have worked, but don't auto boot like Crazy Cars did. After an initial crack screen I end up at the TOS or TOS with various other windows open and some icons showing.

I pulled the machine apart again, and reseated the ROMs and the 2 square IC's (I forget what they are). All other chips are not socketed.

The PSU looks good, no bulging Caps, or visible damage. Voltages coming from the PSU are ~5 and ~12.4 (is that a little high?)

I can still get to TOS with no obvious issues at all.

Anyway, sorry for the long explanation. I've searched and read a lot about 3 bombs, but none of the descriptions seem exactly the same as I have.

Wondering if anyone could point me in a direction for testing. I'm hoping to clean the keyboard and have it together this weekend, and maybe then I can try to run a RAM test program to check the memory.

Thanks for listening.

Phil

[Zogging Hell]

I think having the keyboard unplugged may cause a problem even if its not the cause of the three bombs. There is a clock in the keyboard and a processor (it's basically a mini computer in its own right). Crazy Cars will also need the joysticks, so not having a response from the keyboard controller processor may cause an error. Get that keyboard back in before anything else

[nama]

Ok, thanks.

I was wondering if having the keyboard removed may be mucking some things up.

 

Will plug it in tonight and see how it goes.

Cheers

 

P

Edited May 1, 2017 by nama

[nama]

Just an update.

I plugged in the half disassembled keyboard in last night. The good news is the keyboard works, although it still did not allow me to get further with booting programs the I did before.

 

After a While of mucking around I decided to pull the Gotek/HxC from my BBC Micro, and plug it into the 520STfm. Instantly I was able to boot Star Wars. It's the only disk image I've tried so far. I'll make some more images today, and test them out tonight.

 

So I'm going to guess the issue with booting from the original floppy is either:

- A funky drive

- The power supply providing power to the drive (maybe 12v Line as the Gotek does not use this line)

- Something not working perfectly with how I'm actually making physical disks

 

Any thoughts?

If I can't get the original drive to boot reliably, I'll probably get another Gotek/HxC and use that instead.

 

Cheers

Phil

[tjlazer]

check to see if you have a DSDD or SSDD drive! Yes I have a 520STfm with a SSDD drive. (360k) So you will not be able to use DSDD disks on it! (720k)

 

You can try working with some 360k or 400k disk images and see if those boot good.

Edited May 3, 2017 by tjlazer

[nama]

Checked the drive last night..It's 720K.

Anyway, decided to move to the Gotek as I now have it working with the HxC manage, and it is a pleasure to use.

 

Art from the missing key, I think the 520STm has a clean bill of health.