AtariFox STFM service blog

Blogs & guides and tales of woo by forum members.
User avatar
Steve
Posts: 505
Joined: Fri Sep 15, 2017 11:49 am

Re: AtariFox STFM service blog

Post by Steve » Tue Sep 08, 2020 11:41 am

AtariFox wrote:
Tue Sep 08, 2020 3:28 am
Steve wrote:
Mon Sep 07, 2020 2:39 pm


One small anomaly I just noticed is this: On the STFM KIT DUAL TOS kit that is installed (with ube chip) The ube has not been connected to pin 16 of CPU, the bank select jumper is on bk2, but TS is bridged! Which according to your instructions, could mean the ube chip is damaged. I know this probably has nothing to do with the floppy. But I might unsolder the TS blob, and test the other TOS bank.
The UBE chip isnt used nor connected.

It reads ToS 1.04 and has done since i first got the upgrade, i' have not needed to mess with it as i just want it to run 1.04 and i just switch the jumper if i want tos 1.02.
Steve wrote:
Mon Sep 07, 2020 7:13 pm
Okay I added a DMA sip 10k resistor pullup and it's a little better. Managed to load yaart off floppy. Will do more testing tomorrow.
So you think i must have done something to the DMA chip? I can't believe I caused so much of an issue with just the soldering thing i messed up with.

I must have really buggered up something for it to need all this.
Don't worry I'm not connecting or enabling the UBE chip, I just noticed that TS was bridged, which according to the installation instructions could blow the UBE chip. I just mentioned it in the blog in case it was relevent to the floppy issues.

As for the DMA chip pull-ups, reason I did this is because the DMA is intrinsic for floppy and ASCI operations, and on this forum it has helped others with similar issues in the past.
Repairs & Servicing for Atari & Amiga machines (and any other retro computers) Located in the West Midlands UK. PM me if you require assistance.
www.solidstatesociety.co.uk

User avatar
Steve
Posts: 505
Joined: Fri Sep 15, 2017 11:49 am

Re: AtariFox STFM service blog

Post by Steve » Tue Sep 08, 2020 8:05 pm

END OF SERVICE BLOG
---------
Unfortunately I have been unable to completely solve the floppy issue, but I have improved it somewhat. I have managed to load Gembench and YAART to run through testing, but it seems to be inconsistent and other times it won't load. But economically for AtariFox I cannot spend more time on the unit, as I've already spent quite a few days trying my best to solve the problem, I have to call it a day.

* Socketed & installed WD chip & resistor mod
* Tested new WD chip
* Installed DMA resistor pullup mod
* Replaced 6 x bus data resistors on motherboard
* Cleaned floppy heads
* Re-flowed solder on floppy header connector
* Re-flowed solder on major chips on the board
* Pulled, cleaned and re-installed both PLCC chips & sockets
* Direct wired ram bypass to 4700 cap
* Replace c68 and test
IMG_20200908_192455.jpg
IMG_20200908_192455.jpg (442.26 KiB) Viewed 327 times
IMG_20200908_130748.jpg
IMG_20200908_130748.jpg (393.86 KiB) Viewed 329 times
IMG_20200908_130741.jpg
IMG_20200908_130741.jpg (508.96 KiB) Viewed 329 times
Repairs & Servicing for Atari & Amiga machines (and any other retro computers) Located in the West Midlands UK. PM me if you require assistance.
www.solidstatesociety.co.uk

User avatar
PhilC
Moderator
Moderator
Posts: 3483
Joined: Fri Mar 23, 2018 8:22 pm

Re: AtariFox STFM service blog

Post by PhilC » Tue Sep 08, 2020 8:47 pm

Nicely done @Steve . Just a thought, have you tried floppy head alignments?
If it ain't broke, test it to Destruction.

User avatar
exxos
Site Admin
Site Admin
Posts: 11861
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
YouTube: https://www.youtube.com/user/exxosuk
Contact:

Re: AtariFox STFM service blog

Post by exxos » Tue Sep 08, 2020 8:59 pm

Don't see if you actually tried a different floppy drive ? Most of the original ones are pretty busted these days :(
https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.

User avatar
Steve
Posts: 505
Joined: Fri Sep 15, 2017 11:49 am

Re: AtariFox STFM service blog

Post by Steve » Tue Sep 08, 2020 9:37 pm

PhilC wrote:
Tue Sep 08, 2020 8:47 pm
Nicely done @Steve . Just a thought, have you tried floppy head alignments?
exxos wrote:
Tue Sep 08, 2020 8:59 pm
Don't see if you actually tried a different floppy drive ? Most of the original ones are pretty busted these days :(
Phil: I actually don't know how to do that to be honest
Chris: The only spare floppy drive I have is my TT's Epson SMD340. It is a high density drive but I figured it would just work in DD mode if I tried it out. I did try it and it worked as well as his stock DD drive, same issues.
Repairs & Servicing for Atari & Amiga machines (and any other retro computers) Located in the West Midlands UK. PM me if you require assistance.
www.solidstatesociety.co.uk

User avatar
AtariFox
Posts: 77
Joined: Wed Aug 07, 2019 6:13 pm

Re: AtariFox STFM service blog

Post by AtariFox » Wed Sep 09, 2020 12:27 am

Thanks so much for all your hard work @Steve

I dont know if the drive is misaligned, since you used your Atari TT 030's one and it did the same thing.

I might buy a new DMA chip then, I can buy one of those and do it, if you'd socket the existing chip for me. or up to you if you want to outright replace and see.

Otherwise, thank you so much for the time and effort in doing all this amazing work on it for me.

User avatar
Steve
Posts: 505
Joined: Fri Sep 15, 2017 11:49 am

Re: AtariFox STFM service blog

Post by Steve » Wed Sep 09, 2020 11:26 am

No worries I'm just sorry I couldn't completely solve the problem. I don't know whether replacing the DMA would help, usually with digital systems they either work completely or not at all. That's the thing though it can become an endless rabbit hole of fault finding.
Repairs & Servicing for Atari & Amiga machines (and any other retro computers) Located in the West Midlands UK. PM me if you require assistance.
www.solidstatesociety.co.uk

User avatar
exxos
Site Admin
Site Admin
Posts: 11861
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
YouTube: https://www.youtube.com/user/exxosuk
Contact:

Re: AtariFox STFM service blog

Post by exxos » Wed Sep 09, 2020 2:28 pm

Maybe just a bad cable ? You could put a socket there instead.. But of course more work...
https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.

User avatar
Steve
Posts: 505
Joined: Fri Sep 15, 2017 11:49 am

Re: AtariFox STFM service blog

Post by Steve » Wed Sep 09, 2020 2:50 pm

exxos wrote:
Wed Sep 09, 2020 2:28 pm
Maybe just a bad cable ? You could put a socket there instead.. But of course more work...
True true... I will put it to him see what he would like to do.
Repairs & Servicing for Atari & Amiga machines (and any other retro computers) Located in the West Midlands UK. PM me if you require assistance.
www.solidstatesociety.co.uk

User avatar
AtariFox
Posts: 77
Joined: Wed Aug 07, 2019 6:13 pm

Re: AtariFox STFM service blog

Post by AtariFox » Wed Sep 09, 2020 7:30 pm

Steve wrote:
Wed Sep 09, 2020 2:50 pm
exxos wrote:
Wed Sep 09, 2020 2:28 pm
Maybe just a bad cable ? You could put a socket there instead.. But of course more work...
True true... I will put it to him see what he would like to do.
You mean a new socketed floppy cable? I mean i guess you could try that.

Post Reply

Return to “MEMBER BLOGS”