osiweb.org

ronin47 wrote: ↑Mon May 13, 2024 12:27 pm I must admit I was fighting with mine to read the pulse width until I realised it was up there all along at the top of the screen

Haha I bet that will be the same case on mine too. I guess hunting it down on there will be easier than trying to do it on the old analog scope.

Sideburn wrote: ↑Mon May 13, 2024 12:37 pm

ronin47 wrote: ↑Mon May 13, 2024 12:27 pm I must admit I was fighting with mine to read the pulse width until I realised it was up there all along at the top of the screen

Haha I bet that will be the same case on mine too. I guess hunting it down on there will be easier than trying to do it on the old analog scope.

Yes, I expect it will

In addition I could adjust R57 and see the pulse width changing on mine.

OMG. What a beautiful build!

megardi wrote: ↑Mon May 13, 2024 3:52 pm OMG. What a beautiful build!

Thanks your reproductions are amazing as well! https://hackaday.io/project/186956-osi- ... production

ronin47 wrote: ↑Mon May 13, 2024 8:05 am

The service manual gives this as the way to adjust R57:


Screenshot 2024-05-13 at 09.03.23.png


It's what I've done for mine, getting it somewhere in the middle of the range, though I haven't yet confirmed my cassette in/out is working properly.

Just did the pulse calibration.

Didn’t get this right?

Sideburn wrote: ↑Tue May 14, 2024 6:16 pm

ronin47 wrote: ↑Mon May 13, 2024 8:05 am

The service manual gives this as the way to adjust R57:


Screenshot 2024-05-13 at 09.03.23.png


It's what I've done for mine, getting it somewhere in the middle of the range, though I haven't yet confirmed my cassette in/out is working properly.

Just did the pulse calibration.

Didn’t get this right?

IMG_8387.jpeg

Looks very like mine, so I think so

Thats with the pot pretty much maxxed out. If I turn it all the way up then it gets just a tiny bit wider. So 500us is about as good as I can get.

Sideburn wrote: ↑Tue May 14, 2024 8:41 pm Thats with the pot pretty much maxxed out. If I turn it all the way up then it gets just a tiny bit wider. So 500us is about as good as I can get.

Interesting, I can easily get up to near 600uS with mine.

ronin47 wrote: ↑Tue May 14, 2024 10:13 pm

Sideburn wrote: ↑Tue May 14, 2024 8:41 pm Thats with the pot pretty much maxxed out. If I turn it all the way up then it gets just a tiny bit wider. So 500us is about as good as I can get.

Interesting, I can easily get up to near 600uS with mine.

And you are measuring the top of the waveform like I am?

If I max the POT out then i can get it goes to where the green arrow is (actually about half that far):

OH wait is that 600?

If you want to increase that pulse width beyond 500 microseconds, would it not make sense to increase R53 from 10k to 12 or 15k?

I'm thinking 12k would give a maximum pulse width of 550 us, and 15k would give 625 us, since the series resistance of R57+R53 would be increased by 10 or 25 percent.