LED lightcurtain / christmas tree lights

[N_Cook]

KAM LED lightcurtain control box dropped and now no function.
DC rails are right , not yet checked crystal and 555 sub cct function
This has 4 channel output , 20V drive to an array of coloured LEDs. Assuming
the NXP micro is defunct, and the owner does not use the DMX or mic input or
even speed variation , just simple unvarying sequence, would it be possible
to salvage the curtain and use a christmass tree LED lightstring controller
?

 

[N_Cook]

555 working. 16M Crystal osc working, but the only other pin with any
activity is an unused external timing pin of divided clock f.
Caps check ok, forcing a reset no change, as sprung pin socket for the NXP
P89V51 micro added an intermediary 40pin turned pin socket. Any more last
rites before consigning to the big dumpster?
I've not checked the SN75176 DMX serial chip yet for perhaps latched o/p
condition.

I suppose using the variable 555 output to clock a 4 stage shift register
and couple to the existing 4x TIP122 buffers would be sufficient for the
owner's purposes rather than trying to find a suitable chrismass tree set

 

[N_Cook]

Pulling the micro and trying a 4013 clocked by the 555 and feedback between
the 2 flip-flops gives quite a pleasant pseudo-random sequencing to the 4
strings. Just have to hope it does not have a latch up state - I've
forgotten how to determine that, clocked through a few hundred cycles
without hickup.
For anyone else , in the future, where to put the ouput of the mic amp to
give a beat sync to the lights?

 

[N_Cook]

I suppose for sound syncing, or'd with the 555 clock would be ok if the mic
amp gives L to H transistion on the beat