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Re: Icky - Progress
Posted: Wed Oct 10, 2018 2:38 am
by PaulJ
Icky, I just checked my board and the 1772 pin 28 is connected to u32 pin 5 and pin 2 of rp1.. The net measures ~1k to +5 rain. I don't see a pull-up on the STFM schematic but it should still function. Is your resistance from pin 28 shorted to +5 or ground?. A question Exxos can answer is why INTR (RP1 pin 2, and u32 pin 5) is different designator (INTRQ) than 1772 pin 28? Electrically this net should work on my board.
I have order the wrap cables for the DIAG cart so I will find out if my DMA port works.
Re: Icky - Progress
Posted: Wed Oct 10, 2018 3:15 am
by PaulJ
Your missing:
- 1772IRQ.jpg (90.99 KiB) Viewed 3940 times
Ties it together.
Re: Icky - Progress
Posted: Wed Oct 10, 2018 6:36 am
by Icky
PaulJ wrote: ↑Wed Oct 10, 2018 3:15 am
Your missing:
1772IRQ.jpg
Ties it together.
Thanks PaulJ.
Too many late nights on this board. I’m starting to patch existing patches.
looks like the patch was already there on my board
As Exxos mentions it’s good to have many people building these boards to spot things and to keep us sane in my case.
Re: Icky - Progress
Posted: Wed Oct 10, 2018 7:30 am
by Icky
PaulJ wrote: ↑Wed Oct 10, 2018 2:38 am
I have order the wrap cables for the DIAG cart so I will find out if my DMA port works.
That’s a good shout to help diagnose. Where did you get those from?
Re: Icky - Progress
Posted: Wed Oct 10, 2018 8:39 am
by PhilC
Yeah I agree it's great to see the others involved. I've been so busy with work that I've not been able yo make much in the way of a contribution lately.
Good work guys.
Re: Icky - Progress
Posted: Wed Oct 10, 2018 10:18 am
by exxos
Icky,
When you checked IRQ & DRQ on the DMA, did you see switching ? As you would have to likely setup a trigger and access the harddrive to see the signals..
Also did you check this post out ? in particular the mods in the last 2 images at the bottom of the page ?
http://www.exxosforum.co.uk/atari/last/g ... /index.htm
I documented 2 issues,
If I remember right, U51 capacitor solves auto booting problems with the hard drive. The DMA (U31) solves problems with loading programs from the hard drive , typically from GEM desktop.
While I only saw this with gigafile.. Its possible this could now be a problem on the STF with other drives... It looked like there was noise causing the issue, but I don't know if that noise was generated from Giagafile or not. The capacitor clamped it.. but the capacitor also would add delay onto the signals..
In both cases, changing U51 for a non-ls type (7404) would do both jobs to a degree.. but likely very hard to find those chips these days. But adding capacitors 100pf at a time, is the only thing to try on both pins (one at a time) to see if it helps or not.
Re: Icky - Progress
Posted: Wed Oct 10, 2018 1:01 pm
by Icky
exxos wrote: ↑Wed Oct 10, 2018 10:18 am
Icky,
When you checked IRQ & DRQ on the DMA, did you see switching ? As you would have to likely setup a trigger and access the harddrive to see the signals..
Also did you check this post out ? in particular the mods in the last 2 images at the bottom of the page ?
http://www.exxosforum.co.uk/atari/last/g ... /index.htm
I documented 2 issues,
If I remember right, U51 capacitor solves auto booting problems with the hard drive. The DMA (U31) solves problems with loading programs from the hard drive , typically from GEM desktop.
While I only saw this with gigafile.. Its possible this could now be a problem on the STF with other drives... It looked like there was noise causing the issue, but I don't know if that noise was generated from Giagafile or not. The capacitor clamped it.. but the capacitor also would add delay onto the signals..
In both cases, changing U51 for a non-ls type (7404) would do both jobs to a degree.. but likely very hard to find those chips these days. But adding capacitors 100pf at a time, is the only thing to try on both pins (one at a time) to see if it helps or not.
Thanks Exxos. Will take a look at this. I have Megafile and Gigafile to test with. Will start reading and trying out these suggestions. After I recover from my embarrassing patching an existing patch moment last night
Re: Icky - Progress
Posted: Wed Oct 10, 2018 2:05 pm
by PaulJ
Icky,
I got the cables from Best Electronic who as I understand it purchased most of Atari's stock when they went belly up. They have a lot of the hard to get parts and they also make new replacement parts. I'm not very good at waiting and they ship quick. I usually get what I order in two or three days. They have a catalog you have to buy hat shows everything that was available for all the Atari products all though a lot of the items they don't have any longer. The bad part is they are only open 1:30 - 5:00 pm pst. I aways call, I guess you can order via email.
http://www.best-electronics-ca.com
Re: Icky - Progress
Posted: Wed Oct 10, 2018 2:17 pm
by PaulJ
It was an advantage to know all the patches up front instead of encountering them one by one. Also when you can plan the patches it makes them easier to implement. I think everything is working on my board but one never knows until it's exercised. It will be nice to have the wrap cables for the drag-cart, can pretty much check all the io. If you get the DMA port running before I get there that's ok too!
This spell checker aways wants to change DMA to dam! What does it know?
Re: Icky - Progress
Posted: Wed Oct 10, 2018 5:19 pm
by czietz
Icky wrote: ↑Wed Oct 10, 2018 7:30 am
That’s a good shout to help diagnose. Where did you get those from?
There is a second source:
http://gossuin.be/index.php/shop, search for "ATARI LOOP HARDWARE TEST for Test Kit Cartridge".