Mesa 7i95 ssr bug / damage?

Bocho
Topic Author
Offline
New Member

5 years 4 months ago #211236 by Bocho

Mesa 7i95 ssr bug / damage? was created by Bocho

Hello,

Please can someone explain strange behavior of ssr outputs?
Asserting ssr active signal on any 1-3 channel simultaneously turns on channels 3 4 and 5
Hal scope shows correct values (only selected channel is on) however ssr LEDs on mesa board for channels 3 4 5 become active.

Code:

bit   IN          FALSE  hm2_7i95.0.ssr.00.out-00
bit   IN          FALSE  hm2_7i95.0.ssr.00.out-01 <== tool-open-out
bit   IN          FALSE  hm2_7i95.0.ssr.00.out-02
bit   IN          FALSE  hm2_7i95.0.ssr.00.out-03
bit   IN          FALSE  hm2_7i95.0.ssr.00.out-04
bit   IN          FALSE  hm2_7i95.0.ssr.00.out-05
u32   IN     0x000F4240  hm2_7i95.0.ssr.00.rate

Thanks

Please Log in to join the conversation.

PCW
Offline
Platinum Member

5 years 4 months ago #211237 by PCW

Replied by PCW on topic Mesa 7i95 ssr bug / damage?

That indicates a damaged 74ACT04 chip on the 7I95, most likely from 5V overvoltage

Please Log in to join the conversation.

Bocho
Topic Author
Offline
New Member

5 years 4 months ago #211247 by Bocho

Replied by Bocho on topic Mesa 7i95 ssr bug / damage?

PCW wrote: That indicates a damaged 74ACT04 chip on the 7I95, most likely from 5V overvoltage

Fears were confirmed by the oscilloscope - the IC is dead.
Outputs 3-5 work fine, enough for the current setup.
Ordered 74ACT04 for resoldering.
Thank you!

Please Log in to join the conversation.

Time to create page: 0.077 seconds