Search found 65 matches

by guus.assmann
Thu Jul 05, 2018 7:09 pm
Forum: Hardware
Topic: F030 RTC/NVRAM replacement kit
Replies: 17
Views: 1507

Re: F030 RTC/NVRAM replacement kit

Hello, A short while ago, I replaced the RTC on 4 Falcons. The RTC's came from Mouser and were sure to be new and good. But on 2 boards they didn't work, the boards would not boot with the new Clock. When the old IC was put back, it worked just fine again. However, a solution was found. The Falcon w...
by guus.assmann
Sat May 12, 2018 1:31 pm
Forum: Hardware
Topic: Broken monitor tube (glass end)
Replies: 3
Views: 689

Re: Broken monitor tube (glass end)

Hello,

To test, just switch it on.
If it's ok, then it will work. (Obviously) :)
If the vacuum is gone, it just won't work.
Mostly, the front won't look nice and even if the vaccum is gone.

BR/
Guus
by guus.assmann
Thu Feb 08, 2018 8:52 pm
Forum: Hardware
Topic: Upgrading serial port for higher speed / more midi stability
Replies: 118
Views: 10086

Re: Upgrading serial port for higher speed / more midi stability

Hello Foxie, What I can see in the schematics is that the LDS signal is used as a clock to 74F74 FF's. A signal called SEM is delayed by one extra FF that's also clocked with the LDS. So it looks like the complete access cycle is delayed to give the Midex a bit more time to finish a cycle. Maybe slo...
by guus.assmann
Wed Feb 07, 2018 8:46 pm
Forum: Hardware
Topic: Upgrading serial port for higher speed / more midi stability
Replies: 118
Views: 10086

Re: Upgrading serial port for higher speed / more midi stability

Hello Foxie,
Yes, I did figure out (for a bit) what it does.
It inserts an extra wait-state in the handling of a command.
BR/
Guus
by guus.assmann
Mon Feb 05, 2018 8:46 pm
Forum: Hardware
Topic: Upgrading serial port for higher speed / more midi stability
Replies: 118
Views: 10086

Re: Upgrading serial port for higher speed / more midi stability

Hello, Does anyone have the MROS files from Steinberg that work on a Falcon? I've tried to modify a Midex+ to run on a Falcon. But the testprogram keeps telling it cannot find a file in the MROS folder. The modified Midex doesn't work on a Mega ST anymore. (But can be made switchable real easy.) BR/...
by guus.assmann
Sat Jan 20, 2018 8:59 pm
Forum: Hardware
Topic: Upgrading serial port for higher speed / more midi stability
Replies: 118
Views: 10086

Re: Upgrading serial port for higher speed / more midi stability

Hello Foxie, The full schematics in a four sheet PDF, sometimes a bit hard to read, but ok. And the Jedec files for the main GAL, as well as the data to create this GAL. (20V8) And the Jedec file for the SMTP-Gal, a 16V8 So in my opinion, enough to recreate a Midex+ expander. Just let me know an E-M...
by guus.assmann
Sat Jan 20, 2018 10:46 am
Forum: Hardware
Topic: Upgrading serial port for higher speed / more midi stability
Replies: 118
Views: 10086

Re: Upgrading serial port for higher speed / more midi stability

Hello, Would a Steinberg Midex+ interface do the right job? As it happens, I do have a lot of data on that. There's the schematic diagrams, GAL files and data for the modification. (Originally the Midex has PAL's) And there's a document for a Falcon mod. (That I've not tried yet) Also, I have test p...
by guus.assmann
Thu Dec 14, 2017 8:42 pm
Forum: Hardware
Topic: PAK68/3 and FRAK/2 schematic
Replies: 18
Views: 3328

Re: PAK68/3 and FRAK/2 schematic

Hello Artik-wroc,
Have a look at the cabling for the power supply.
Specially the minus needs to be very big, large surface.
Memory creates spikes in supply voltages.
BR/
Guus
by guus.assmann
Thu Dec 14, 2017 8:40 pm
Forum: Hardware
Topic: PAK68/3 and FRAK/2 schematic
Replies: 18
Views: 3328

Re: PAK68/3 and FRAK/2 schematic

Hello Olverg,
It is possible to use FPU or CPU at lower speed. Also at different speed.
Like CPU @ 33Mhz and FPU @50Mhz or even 66Mhz, overcolcing a FPU is often no problem.
And the 68000 family is A-Syncronus, so no problem.
BR/
Guus
by guus.assmann
Sat Sep 30, 2017 7:11 pm
Forum: Hardware
Topic: Pardon me for asking...
Replies: 3
Views: 930

Re: Pardon me for asking...

Hello clh333, Normally, removing all the screws that are in a "square hole" will enable you to take an Atari computer apart. For the Mega ST, lift the back as far as you can and try to slide the plastic to the front. This will enable you to move it past the front of the floppy drive. It he...
by guus.assmann
Thu Aug 24, 2017 12:34 pm
Forum: Hardware
Topic: Yet another dumb ST to VGA adaptor, take 2
Replies: 9
Views: 1878

Re: Yet another dumb ST to VGA adaptor, take 2

Really nice.
I want to buy one.
For some reason the PM's I write are still in the outbox and apear bot to be sent.
Can you please try to contact me?
Thanks.
by guus.assmann
Sat Feb 18, 2017 5:09 pm
Forum: Hardware
Topic: Need help with PAK 68/2
Replies: 28
Views: 4438

Need help with PAK 68/2

It may help to replace the 74LS244 and 74LS373 by a couple of F-types.
This makes the access to Ram a bit faster and often more reliable.

The PAK always needs the ROM's in the MB to start.
It uses the reset vector in these.

BR/
Guus
by guus.assmann
Fri Sep 02, 2016 4:02 pm
Forum: Hardware
Topic: Booster 020 by Jean Conter
Replies: 22
Views: 4887

Booster 020 by Jean Conter

My 4 CPU's:
68020RC16B 2A70N8633
68020RC12B 2A70N8747
These 2 work fine in the booster20

68020RC16B 2A70N8807
68020RC12B 2A70N8633
Don't work in the Booster20 but are ok in the Pak68/2
BR/
Guus
by guus.assmann
Thu Sep 01, 2016 7:40 pm
Forum: Hardware
Topic: Booster 020 by Jean Conter
Replies: 22
Views: 4887

Re: Booster 020 by Jean Conter

The Booster020 works fine with a blitter. I have two 020's and tested in 5 individual MegaST boards. These are of various revisions, 1MB, 2MB, 4MB with different chips. Also with IMP chips. Maybe the combination with 16Mhz is not ok for the blitter? And not all CPU's work fine. Out of 6, I only had ...
by guus.assmann
Wed Aug 17, 2016 8:57 pm
Forum: Hardware
Topic: PPera/Popsel IDE interface Gal speed
Replies: 1
Views: 931

PPera/Popsel IDE interface Gal speed

The PCB's are ready, I just need to program and mount the Gal's.
What speed is needed for these?
I have 16V8 in 25nS, 15 nS and 7nS.
Can I use the 25nS ones or do they need to be faster.

BR/
Guus
by guus.assmann
Mon Aug 15, 2016 8:21 am
Forum: Hardware
Topic: Atari TT Real time clock precision
Replies: 3
Views: 1084

Re: Atari TT Real time clock precision

Hello Guilaume, Just now, I've checked the schematics for the TT. It uses the MC146818 clock chip. And an external clock generator, using a 4069 chip, U402. Only 2 gates A and B are used. Using this C-Mos chip gives a lower power consumption than having the MC146818 do the oscillator. (It can) The c...
by guus.assmann
Mon Aug 15, 2016 7:56 am
Forum: Hardware
Topic: Atari TT Real time clock precision
Replies: 3
Views: 1084

Re: Atari TT Real time clock precision

It may very well be that it can be adjusted. On the much older MegaST, there's an adjustable capacitor. And the same on a MegaSTE. For these 2, I have a bare board and had a look. For the TT, I'm not sure. But it can very well be the case. (Check the schematics) If you can't find it, let me know and...
by guus.assmann
Fri Aug 05, 2016 4:39 pm
Forum: Hardware
Topic: PAK68/2 PCB Project ...
Replies: 109
Views: 43423

PAK68/2 PCB Project ...

Today I put a socket in a MegaST 2.
For the rest it's standard and has the IMP Shifter, MMU, Glue and DMA.
I've left the Tos 1.04 in it.
The PAK68/2 works just fine. I've tested with Gembench 6 and 4.03
That's 3 different boards they do work in. (I have 2 peices)
BR/
by guus.assmann
Wed Aug 03, 2016 7:38 pm
Forum: Hardware
Topic: Mega ST4 CPU stuck in HALT Condition
Replies: 31
Views: 5931

Re: Mega ST4 CPU stuck in HALT Condition

My diagnostics card is most likely the same. But it you also have some short between data lines, I guess it may go wrong. Or there's been another failure on my MB. I know that I only fixed the memory to get it working again. But I had the good luck of starting out with a MegaST 1 that was working be...
by guus.assmann
Wed Aug 03, 2016 7:30 pm
Forum: Hardware
Topic: PAK68/2 PCB Project ...
Replies: 109
Views: 43423

Re: PAK68/2 PCB Project ...

So I've been testing. Either Tos 1.04 or 2.06 do get the PAK68/2 started. But is made no difference if JP2 is on or off. It should I guess. And it's always the German Tos, not the UK one in the MB. Removing JP4 does make the board see the FPU. And I tested with 16, 40 and 56 Mhz. There's a differenc...
by guus.assmann
Wed Aug 03, 2016 1:21 pm
Forum: Hardware
Topic: PAK68/2 PCB Project ...
Replies: 109
Views: 43423

PAK68/2 PCB Project ...

This evening I will try to have the PAK68 boot from the MB-Tos and report the result.

If you put JP8 to JP11 on 2/3, then slow Eproms are ok.

Q: If you put a regular 68000 in the MB, with any Tos, will it boot ok?

BR/
by guus.assmann
Wed Aug 03, 2016 9:49 am
Forum: Hardware
Topic: Mega ST4 CPU stuck in HALT Condition
Replies: 31
Views: 5931

Re: Mega ST4 CPU stuck in HALT Condition

When I've been working on expanding the memory on 2 MegaST boards, the diagnostics would not start either, also not with the serial port. To start, about 200 bytes (if my memory serves right) of Ram need to work. I've swapped RAS and CAS between the banks and then it would start. So I initially had ...
by guus.assmann
Wed Aug 03, 2016 9:19 am
Forum: Hardware
Topic: PAK68/2 PCB Project ...
Replies: 109
Views: 43423

Re: PAK68/2 PCB Project ...

Finally, I started reading the article again. As I should have done better from the start. On some point it clearly states that the Roms on the board are needed to fetch the reset vector. And the JP2 will determine what's used. When it's connecting 1-2, then the PAK68 (ep)roms are used. No jumper on...
by guus.assmann
Wed Aug 03, 2016 6:56 am
Forum: Hardware
Topic: PAK68/2 PCB Project ...
Replies: 109
Views: 43423

Re: PAK68/2 PCB Project ...

Yesterday evening, I did spend a little time in testing. Both Tos2.06 in a special board, but also Tos1.04 in the sockets do allow the PAK68 to start. No Tos means that PAK68 will not start at all. The jumper setting is a Frank has written. And now I also see why the FPU doesn't work. JP4 is set. Th...
by guus.assmann
Tue Aug 02, 2016 2:24 pm
Forum: Hardware
Topic: PAK68/2 PCB Project ...
Replies: 109
Views: 43423

Re: PAK68/2 PCB Project ...

Hello joska, I have observed the same behavior. Some activity and then nothing. But now, both cards are working. Again, I'd done the same and bought a 2nd card from Frank. Both are working now. I put a Tos 2.06 card in my MegaST. The PAK68 sits on top of this card. It boots fine, either with J3 jump...

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