PROTRACK 20B (KJ3) STORE PROBLEM

Started by TRADMARK-X, July 12, 2023, 08:12:08 AM

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TRADMARK-X

Hi Al1234,

You are lucky to find one I think....

I will keep an eye out.

Cheers,
Mark...

TRADMARK-X

Hi Ai1234,

Yes, I am certainly enjoying it & have made some pretty patterns on it to demonstrate the superior definition on a CRT as opposed to a 'digital' or LCD screen! Sometimes using the right thing for the purpose should outweigh popular trends.
It makes a pretty flower across pin's 2 & 14 on a 7404 logic chip that reminds me of some of the images in Jerobeam Fendersons' Oscilloscope music, as can be seen, (Look on Google to download his scope music as interesting)...
The trace on the Workstation software is a squiggly mess compared to the CRT trace - which demonstrates why I would prefer the older units with CRT over an LCD one, it's simply just better at the task.

Have Fun!

Mark...

admin

Testing with Vcc as the common reference will sometimes result in unstable signatures when compared to using ground especially with CMOS devices.
The most important troubleshooting tool is your eyes.

TRADMARK-X

I only did this to demonstrate how a CRT can show more fine detail.
I just used pins that gave me a nice detailed trace, not an actual test as such....

admin

I must admit that when using a Tracker manually I prefer a CRT as well.  ;D
The most important troubleshooting tool is your eyes.

TRADMARK-X

Hi All,

Well the Omron G3VM-61VYT(TR) solid state relays have turned up.
I will fit one (with appropriate ballast resistor) in the next few days & let you know the outcome.

Cheers,
Mark...

TRADMARK-X

Hi All,

Fitted the solid state MOS-FET relay (see pictured), & all is well now.
Nice pulse waveform on pin#1 of the PROM now & it switches the 12V off properly so power glitches etc. should not cause any errors being written to the PROM.

Still wish I could explain why all reed relays fitted stuck closed here - a mystery!

Cheers,
Mark...

admin

Interesting solution. Glad that it works.
The most important troubleshooting tool is your eyes.