Where to find GLUE and MMU chip ?

[rubber_jonnie]

The HALT and RESET sound fine. Have you checked GND for continuity to the all the ROMs. That was one of the problems I had.

When my Mega 4 had 2 bad data lines, I got the same readings.

You should check the address and data lines for continuity if you haven't already done so.

[Tomswork]

Interesting frame with noise is this in hi res or low

Tom

[San-A]

Interesting frame with noise is this in hi res or low

Tom

I suppose low which is the default mode.

[Tomswork]

Are you able to check the clock voltage and frequency.

Tom

[San-A]

Are you able to check the clock voltage and frequency.

Tom

I have a multimeter PM18C measuring up to 10MHz (not sure of the quality).
Where to measure the clock ?

[San-A]

Are you able to check the clock voltage and frequency.

Tom

I have a multimeter PM18C measuring up to 10MHz (not sure of the quality).
Where to measure the clock ?

I have 8MHz on the pinout 15 of the 68000.
I don't know where to measure the clock for other chips.

[Tomswork]

Does your meter give the peak voltage. Maybe ask exxos were to check the clock at others spots I think the master crystal is under the cover with the shifter.

Tom

[DoG]

Lots of schematics and other stuff can be found at https://docs.dev-docs.org/

[PhilC]

Just had a quick look at the screenshot. I've got 3 NEC multisync monitors and that screen pattern can be achieved by having the horizontal size set too small.

Do you know what frequency the monitor screen is presently displaying? 60 or 50hz?

Presuming you've got a PAL Atari, the screen will be 50hz once the computer has decided it can at least try to read from the rom

Have you tried a diagcart in the computer?

Btw, you might need to use an oscilloscope to diagnose the faults easier.

[San-A]

Just had a quick look at the screenshot. I've got 3 NEC multisync monitors and that screen pattern can be achieved by having the horizontal size set too small.

Do you know what frequency the monitor screen is presently displaying? 60 or 50hz?

Presuming you've got a PAL Atari, the screen will be 50hz once the computer has decided it can at least try to read from the rom

Have you tried a diagcart in the computer?

Btw, you might need to use an oscilloscope to diagnose the faults easier.

I have a STE working perfectly on my NEC. So I presume that the pb is on my STF. Anyway I will check the frequency of the NEC.
Yes I used a diagnostic card. With the STE my PC displays the test menu. However with my ST my PC receives nothing. Of course I paid attention to switch the diagnostic card from STE to STF mode.