Search found 135 matches

by tzok
Fri Sep 20, 2019 9:09 am
Forum: Hardware
Topic: STE repair
Replies: 22
Views: 610

Re: STE repair

Jumpers are needed because ~OE, A15 and A16 on ROMs have different locations depending on used chips (Mask ROM/27C1000/27C010). ~OE is hard wired to GND, and two most significant address lines are connected respectively to the Atari A16 and A17 address bus lines (as Atari address bus starts at A1, w...
by tzok
Thu Sep 19, 2019 9:09 pm
Forum: Hardware
Topic: STE repair
Replies: 22
Views: 610

Re: STE repair

Bikerbob wrote:Thanks but what do these points refer to?
To the Address Bus lines A16 & A17 on MC68000.
by tzok
Thu Sep 19, 2019 2:00 pm
Forum: Hardware
Topic: STE repair
Replies: 22
Views: 610

Re: STE repair

Your "e-pads" are configuration jumpers. They could be read at some I/O address. I think only one of them has any use of all, and is used to inform TOS 2.x that the machine is equipped with a HD floppy.
by tzok
Sun Sep 15, 2019 9:58 am
Forum: Hardware
Topic: Overheating chip on Atari STE plugged into socket U405--is it normal?
Replies: 10
Views: 712

Re: Overheating chip on Atari STE plugged into socket U405--is it normal?

Oh yes, I missed that. Pin 4 is mono detection and is left floating. As for pull-ups I believe it is a design flaw, and despite of chip version being used, there should be a pull-up resistors on both monitor input pins (3 & 4). It is not recommended to leave input pins floating. BTW this is a ge...
by tzok
Sat Sep 14, 2019 7:10 pm
Forum: Hardware
Topic: Overheating chip on Atari STE plugged into socket U405--is it normal?
Replies: 10
Views: 712

Re: Overheating chip on Atari STE plugged into socket U405--is it normal?

It is better to fit there a 74F254. Mono detection already has a 4k7 pull-up (R472).
by tzok
Fri Sep 13, 2019 12:02 pm
Forum: Hardware
Topic: Diode choice
Replies: 2
Views: 145

Re: Diode choice

Try with BAT42 or BAT43, these are true Shottky diodes, while all your propositions are small signal switching silicon epitaxial planar diodes. https://www.vishay.com/docs/85660/bat42.pdf https://www.vishay.com/docs/81857/1n4148.pdf https://www.vishay.com/docs/85523/1n4151.pdf https://www.vishay.com...
by tzok
Fri Sep 13, 2019 11:43 am
Forum: Hardware
Topic: UltraSatan clears SD card on Atari power off
Replies: 10
Views: 606

Re: UltraSatan clears SD card on Atari power off

The ultimate solution of the problem was replacing the ACSI bus buffers (U302 & U307).

Strangely on the old buffers there were no problem with the Megafile 60 nor with the ACSI-CF adapter (both ACSI #0).
by tzok
Sun Sep 08, 2019 3:33 pm
Forum: Hardware
Topic: UltraSatan clears SD card on Atari power off
Replies: 10
Views: 606

Re: UltraSatan clears SD card on Atari power off

Card works just fine after reformatting. What is even more interesting - I've changed ACSI ID of USatan from 0, 1 to 1, 2 and the card is no longer erased. On ACSI 0, keeping reset button pressed during powering off also helps. Don't know if it is normal, but I can't boot to TOS 2.06 without a card ...
by tzok
Sun Sep 08, 2019 10:15 am
Forum: Hardware
Topic: UltraSatan clears SD card on Atari power off
Replies: 10
Views: 606

Re: UltraSatan clears SD card on Atari power off

After replacing MC68000 with MC68HC000 I no longer experience any "bad DMA" symptoms. This issue doesn't seem to be directly connected with a "bad DMA". The card is cleared not corrupted, and only at Atari power-off, never on reset or read/write access.
by tzok
Sat Sep 07, 2019 9:15 pm
Forum: Hardware
Topic: UltraSatan clears SD card on Atari power off
Replies: 10
Views: 606

Re: UltraSatan clears SD card on Atari power off

If I could get a "good DMA" I'd certainly replaced it. But as the card doesn't get corrupted, but completely deleted it doesn't seem to be DMA problem. It only happens after powering off the Atari, never on reset. I've tried both CMOS (HC) and NMOS CPUs, I've added 4k7 pull-ups to the DMA ...
by tzok
Sat Sep 07, 2019 10:03 am
Forum: Hardware
Topic: STe - Bad DMA Chip
Replies: 175
Views: 40530

Re: STe - Bad DMA Chip

Have anyone read this: We received trouble reports from a few STe's used in combination with a hard drive. The problem that arose was the mutilation of data, directories or the presence of faulty sectors during the work. These effects result from the fact that some brands of SIMM's can influence the...
by tzok
Thu Sep 05, 2019 10:15 am
Forum: Hardware
Topic: UltraSatan clears SD card on Atari power off
Replies: 10
Views: 606

UltraSatan clears SD card on Atari power off

Like in the topic, whenever I turn off my STe and there is a SD card in the UltraSatan slot, the card is blank. Activity LED turns on on UltraSatan for a few seconds immediately after powering off the Atari, and I know that card is clear at this moment. Afterwards some cards have just 0x00, others h...
by tzok
Wed Sep 04, 2019 7:48 am
Forum: Hardware
Topic: Netusbee by Lotharek, plugin orientation?
Replies: 7
Views: 528

Re: Netusbee by Lotharek, plugin orientation?

When ST sits on a table you really can't plug it in any other way... it also has rubber feet on the bottom.
by tzok
Wed Aug 28, 2019 1:54 pm
Forum: Hardware
Topic: NetUSBee USB drivers download
Replies: 88
Views: 16751

Re: NetUSBee USB drivers download

I use BIGDOS to access bigger flash drives, it has to be loaded before netusbee drivers. I don't think usbtool is able initialize mouse, if it was not recognized during boot. I guess the problem is the voltage on USB port of the netusbee.
by tzok
Wed Aug 28, 2019 1:43 pm
Forum: Hardware
Topic: Frustrating Display Issue 520ST
Replies: 2
Views: 261

Re: Frustrating Display Issue 520ST

My STfm sometimes starts normal, sometimes like this... but I can't help you more.
by tzok
Wed Aug 21, 2019 3:21 pm
Forum: Hardware
Topic: Non-working Mouse/Joy buttons on 520STF keyboard
Replies: 5
Views: 495

Re: Non-working Mouse/Joy buttons on 520STF keyboard

Most USB mouse adapters ignore the fact, that in the Atari ST the right mouse button is hardwired with the joystick 1 fire button. Becouse of this, both the fire button, and mouse buttons signals must be of open collector type. There are pull-up resistors on these lines. None of these lines can have...
by tzok
Mon Aug 19, 2019 9:32 am
Forum: Other emulators & tools
Topic: Gotek Vs. HD 1.44 images
Replies: 3
Views: 1790

Re: Gotek Vs. HD 1.44 images

You can create a special HFE images for DSDD drives, up to 3,42MB using a HxC Floppy Emulator Software.
by tzok
Sat Aug 17, 2019 3:17 pm
Forum: Hardware
Topic: STe - Bad DMA Chip
Replies: 175
Views: 40530

Re: STe - Bad DMA Chip

This demo was working fine on my STe with HC CPU. I've got a slightly older M/B revision (CA4003290), with 2 small ICs under SIMM slots, and a 3rd IC mounted as a "backpack" on one of the existing.
by tzok
Mon Aug 05, 2019 6:07 pm
Forum: Hardware
Topic: Screen sometimes going momentarily black when using a RGB->SCART cable - An attempt of an explanation
Replies: 11
Views: 1439

Re: Screen sometimes going momentarily black when using a RGB->SCART cable - An attempt of an explanation

siriushardware wrote:I wonder if there are some variants of ST (where the Hsync and Vsync may come directly from TTL-level IC outputs) where the Hsync and Vsync outputs may not be able to drive loads as low as 75R.
Actually these serial resistors are present only in STe, in ST/f/fm H/VSync are driven directly.
by tzok
Sun Aug 04, 2019 4:20 pm
Forum: Hardware
Topic: Screen sometimes going momentarily black when using a RGB->SCART cable - An attempt of an explanation
Replies: 11
Views: 1439

Re: Screen sometimes going momentarily black when using a RGB->SCART cable - An attempt of an explanation

In STe the HSync & VSync also have a 33R series resistor. Whats more, the diode introduces further voltage drop out. It should be Shottky diode to ensure minimal voltage drop. 1N4148 is not ideal (won't work with my STe & Sony TV).
by tzok
Sat Aug 03, 2019 10:33 am
Forum: Hardware
Topic: PSU restoring; Recapping all my Atari PSUs
Replies: 9
Views: 1184

Re: PSU restoring; 12v rail too low!

However, considering that the 12 V rail isn't used by much in the ST (older floppy drives, serial port, possibly modulator), I wouldn't worry too much. Nope, STf/fm/e use 12V solely for the FDD motor drive (and even not all units, newer units with Sony FDD don't use it at all). It is only present (...
by tzok
Sat Aug 03, 2019 10:26 am
Forum: Hardware
Topic: 1040STfm boot failure -> white screen/stripes [solved]
Replies: 21
Views: 2015

Re: 1040STfm boot failure -> white screen/stripes [solved]

On some TV sets it won't work, whatever you'd done... you may try to use voltage divider and use signal from pin 8 (12V) instead of rectifying the VSync, but it has very low output current.
by tzok
Tue Jul 30, 2019 1:43 pm
Forum: Hardware
Topic: 520 ST+ anyone know what this mod is?
Replies: 4
Views: 822

Re: 520 ST+ anyone know what this mod is?

On the 1st photo there is an battery backed-up RTC. The blue thing is a Ni-Cd battery, probably needing a replacement, then there is an original TOS EPROM (1 of 6), some generic logic chips, a GAL, and a RTC 58321A (by Seiko). On the remaining photos there is a factory installed 512kB RAM expansion ...
by tzok
Mon Jul 22, 2019 5:43 am
Forum: Hardware
Topic: Atari STFM dead
Replies: 3
Views: 575

Re: Atari STFM dead

12V is only for floppy, STf itself will run fine just on 5V.
by tzok
Mon Jul 15, 2019 9:55 am
Forum: Hardware
Topic: ST TOS ROMs - what is the speed of stock ROMs
Replies: 16
Views: 2123

Re: ST TOS ROMs - what is the speed of stock ROMs

Ok, so on stock ST, I'm "completely safe" using 200ns EPROMs. Thank you!

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