Six-Trak keeps hanging on boot

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AmpedVoltz
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Six-Trak keeps hanging on boot

Post by AmpedVoltz » Fri Jan 04, 2019 12:24 am

Hi,

anyone recognize this problem:
I have repaired several six-trak's, but this one is making the holidays hard It keeps hanging in the boot (all leds on and 00 on display). I have checked the reset-circuit and it's always +5V. So have checked the U113 and C1243 but the voltage at the negative-side of the cap drops from 5V to 0V in 1 sec... I have checked the diode 112, R124, and still drops. At the positive side of the cap there's a stable 5V...



Thanks in advance!

beam
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Re: Six-Trak keeps hanging on boot

Post by beam » Wed Sep 15, 2021 9:47 am

Hi,
Did you ever get this solved?
I have one in pretty much the same state.

synthchaser
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Re: Six-Trak keeps hanging on boot

Post by synthchaser » Fri Sep 17, 2021 8:01 pm

Besides the reset line going high the CPU also needs a working clock signal to execute instructions.

beam
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Re: Six-Trak keeps hanging on boot

Post by beam » Tue Sep 21, 2021 2:34 am

Reset high and solid clock at the Z80 on my unit. Although I have not checked the 200MHz & 200Hz clocks for the WAIT and interrupt.
On power up I get 20 in the Prog display and no response to buttons.
Looking at A11- A14 there is some activity for a few seconds after powerup then A14 sits high.
Planning to look at U125, the Memory Address Decoder to see if that is making sense.

beam
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Re: Six-Trak keeps hanging on boot

Post by beam » Thu Jan 20, 2022 1:12 am

Finally solved. After becoming reacquainted with a scope and paying for a decent scan of the tech manual, I ended up replacing the Z80 after checking out the easier replacement options.

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