[*ZX81*]

Since a few days I own a 6 years old Ti2 Desktop in well maintained condition.

As I've no experiences with the TI, I started to check the unit using the build-in demo song (TIOS 5.1.7.0).

Many times that demo runs w/o issues in a loop before it's crashing randomly. Then it stops playing the demo with a very loud, buzzing + permanent sound.

Sometimes, when the demo starts again (loop), one can notice that suddenly any instrument of the demo got missing or sounds wrong. It's needed to switch OFF the 12V power adapter to solve that.


I've done a look inside: Mainboard is of revision D25, DSP is 2x DSPB56367AG150 with Freescale logo (there are some mainboard pictures/videos of D24 PCB revisions out there, populated with 2x DSPB56367PV150 and Motorola logo, but also D24's with DSPB56367AG150, again Freescale logo)

Not sure, if these Freescale/NXP DSPs are as good as the origin Motorola ones ...

Anyway ... can't see any demage inside, everything looks very good.

So far I've done this:

Renewed the battery and changed the 12V power adapter for a better one with >2A (later I found out, that the unit just consumes 0.5A max)

Performed a reset via ARP EDIT while connecting 12V
Down/upgraded TIOS

=> No success, again crashes after a while.


In addition, I think there is a SW bug in 5.1.7.0 to a special button sequence, what leads to a crash with the same buzzing sound as sometimes I get with the demo song:

Power ON the unit
Switch TI2 into Single or Multi mode (doesn't matter)
Hold SHIFT + SEARCH ( = AUDITION) >3s for keep playing the selected Program
Press PROGRAM +
Press PROGRAM -
Hold SHIFT + SEARCH >3s again
Hold SHIFT + SEARCH one more time -> TI2 does crash

I guess it's similar to that behaviour GV1UK posted on 04.03.2011

Can anyone replicate that on his own TI2?