Amek Big timecode reader issues (TRG card)

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franklinh

Well-known member
Joined
Aug 18, 2004
Messages
89
Location
Troy, NY USA
Hello all,

Sorry that it's been a while for me. I'm so thankful that this place still exists. Here's one for the Amek folks!

Here's my quandary - I have a customer with a studio based around an Amek Big console. The timecode reader/generator card or "TRG" as its referred to, stopped being recognized by the automation computer, which will now show the message "TRG not found!" upon starting up.

After investigating, my findings are:
Automation computer is otherwise communicating with the console normally, all other computer controlled functions are working, it "sees" the faders and mutes, the Virtual Dynamics are working.
The card has +5vdc power as it should, spot checked at V+ pins on many but not all ICs
The clock generator on the card appears to be functioning (was unable to count frequency, it looked like a saw wave on my 15MHz scope)
Using the automation software to send a test query we hear a relay click on the IBM interface card (joins the automation PC to the console)
U7 on the TRG is receiving RS232 data in the form of a steady -8vdc with pulses
The same U7 passes this data through a buffer/inverter and I see a steady +5vdc at its output with the pulses inverted
The pins on U7 that receive the reply from the TRG don't show any activity when the test query is sent.
Replaced U7 with no change in behavior.

Schematic attached. Any insights greatly appreciated!
 

Attachments

  • TRG Schematic.pdf
    3.8 MB · Views: 3
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