Search found 82 matches

by guus.assmann
Sun Jun 28, 2020 11:41 am
Forum: CHAT FORUM
Topic: New BENQ BL702A arrived (hopefully solving my monitor issues.)
Replies: 36
Views: 1055

New BENQ BL702A arrived (hopefully solving my monitor issues.)

And then you're still of by a whopping 5Hz. ;)
Actually it's 15,625 Hz.
Even more difficult to say I guess.

BR/
Guus
by guus.assmann
Wed Jun 10, 2020 8:53 pm
Forum: 8 BIT CORNER
Topic: 65XE boot issues
Replies: 34
Views: 2319

65XE boot issues

Hello Ziggy, Good to see that. Also good you didn't give up. Now you can also consider to expand the memory to more than 128K. The memory error must be a defect in the address lines. So check the lines between the Freddy chip and the address-lines of the Ram. Also, the address lines from CPU to Fred...
by guus.assmann
Wed Jun 10, 2020 3:42 pm
Forum: 8 BIT CORNER
Topic: 65XE boot issues
Replies: 34
Views: 2319

65XE boot issues

Hello, Good to read that I'm contributing. If it's not solved with the MMU, then we'll keep rethinking. I'm positive that it's possible to get the board 100% again, it's working for a big part anyway. Pitty that UK and NL are so far apart and postage is not so cheap. Anyway, keep up the good work. I...
by guus.assmann
Tue Jun 09, 2020 7:04 pm
Forum: 8 BIT CORNER
Topic: A little bit of 8 Bit: 65XE upgrade to 128k RAM
Replies: 24
Views: 5632

A little bit of 8 Bit: 65XE upgrade to 128k RAM

Good that you found the problem. :D Soldering jobs are not always as easy as they look. This may not be a reset problem but a totally different one. To check that theory, take a game cartridge. Switch off, plug the cartridge and switch on. The cartridge should run. Now switch off, pull the cartridge...
by guus.assmann
Tue Jun 09, 2020 6:54 pm
Forum: 8 BIT CORNER
Topic: 65XE boot issues
Replies: 34
Views: 2319

65XE boot issues

Sure I know I don't have to answer fast. But I do know how frustrating it can be if a computer problem eludes you. The problem on this one seems to do so. My next point of action would be to desolder the MMU. But for me that's not such a big deal, I've done it many times. And I hate to destroy possi...
by guus.assmann
Mon Jun 08, 2020 6:41 pm
Forum: 8 BIT CORNER
Topic: A little bit of 8 Bit: 65XE upgrade to 128k RAM
Replies: 24
Views: 5632

Re: A little bit of 8 Bit: 65XE upgrade to 128k RAM

Hello, Did you leave pin 7, 8, 9, 12 and 13 from the GAL out of the board and bend them up? They shouldn't make any connection to the MB. The redish screen usually means a Ram fault or the CPU not running. To test the standard part, remove R111 at the side that's not connected to pin 15 of the Ram a...
by guus.assmann
Mon Jun 08, 2020 6:17 pm
Forum: 8 BIT CORNER
Topic: 65XE boot issues
Replies: 34
Views: 2319

65XE boot issues

Hello again, Sorry it took a while. I'm not in the habit of checking a Forum very often. The value on pin 8 of MMU seems a bit low. This is a line from the cartridge connector to the MMU and has a 1K resistor to GND. And nothing more. It's the line RD5 and a cartridge may use that to disable Ram (an...
by guus.assmann
Sun Jun 07, 2020 12:50 pm
Forum: 8 BIT CORNER
Topic: 65XE boot issues
Replies: 34
Views: 2319

65XE boot issues

Yes, you're right its only 20 pins for the MMU. OK, some more TTL logic. All voltages between 0 and 0,8V are logical zero. And depending on the exact logic family, anything abouve 3,5V is logic one. (Mostly, >4,8V is more common) In between is "not determined". (Can also be an active signal or a flo...
by guus.assmann
Sat Jun 06, 2020 6:12 pm
Forum: 8 BIT CORNER
Topic: 65XE boot issues
Replies: 34
Views: 2319

65XE boot issues

Hello Ziggy, Don't worry, to learn one needs to ask questions. And you're right, a lot of this stuff is easy for me. I've been repairing the 600XL and 800XL since they were introduced in Netherlands. (As an Atari employee) Moreover, the MMU file I sent is in German. That may complicate matters. So f...
by guus.assmann
Fri Jun 05, 2020 5:08 pm
Forum: 8 BIT CORNER
Topic: 65XE boot issues
Replies: 34
Views: 2319

Re: 65XE boot issues

Hello, Please also see the schematics. And the Gal-design file has some comment with the controll pins. For basic, I did mean an alternative for removing the chip, by just interrupting the signal to pin 18. It's possible to "fool" the MMU by activating the pin that enables the self-test. If the cart...

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