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Posted: **Mon Apr 01, 2019 8:17 pm**

Thank you Kindly

Posted: **Mon Apr 01, 2019 11:55 pm**

I have an original 610 and there is no trace, but mine has a jumper wire between them.

Posted: **Tue Apr 02, 2019 5:47 am**

Steve Gray wrote: ↑Mon Apr 01, 2019 11:55 pm I have an original 610 and there is no trace, but mine has a jumper wire between them.

Context?

Posted: **Tue Apr 02, 2019 10:45 am**

Klyball wrote: ↑Tue Sep 29, 2015 12:01 am Can some one check there 610 board if there is a connection between pin 9 of U10 and pin 1 of U11,
my 610 is missing the trace so the replica is also missing this trace.

OSI_610-7.jpg

Thanks

Context :0). It's from a post farther up this thread.

Posted: **Tue Apr 02, 2019 10:23 pm**

waltermixxx wrote: ↑Tue Apr 02, 2019 10:45 am
Klyball wrote: ↑Tue Sep 29, 2015 12:01 am Can some one check there 610 board if there is a connection between pin 9 of U10 and pin 1 of U11,
my 610 is missing the trace so the replica is also missing this trace.

OSI_610-7.jpg

Thanks
Context :0). It's from a post farther up this thread.

I have a short term memory problem. 3 posts and I’m fresh again

. I think it’s called “age”.

Posted: **Tue Apr 02, 2019 10:38 pm**

He He...

Posted: **Sat Feb 10, 2024 7:26 am**

Hi all,
I'm (finally) just finishing off my 610 board.
I have it all hooked to my 600 and I can see the extra RAM that I have added...which is great!

Today I wanted to try and hook it up to a drive, so I set about tuning in the timing (as described in this tread by Jeff). I was able to tune in R18, R9, R10 (with jumper between pin 9 of J3 to pin 10 of J3)...but when I got to R19 (with jumper between 9 of J3 to pin 11 of J3) no amount of turning the trimpot makes any difference to the timing signal. It's always at about about 8us, and I want to get it to 6us. I also saw that Jeff changed out R20 to 10k, so I did the same, unfortunately there was no change at all turning the 10k trimpot has no effect at all.

So I'm a bit stumped on how to move forward, and was hoping someone may be able to share a few ideas.

Thanks in advance.

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Posted: **Sat Feb 10, 2024 7:35 am**

I should add that I have checked the trimpot, and it seems to be functioning fine.

Posted: **Sat Feb 10, 2024 4:40 pm**

I'm guessing you are turning the wrong trimpot (not that I have never done that

). Aside from verifying that the TOTAL R varies between 10K and 20K when you turn the trimpot maybe the C value is incorrect. There's not much else unless there is flux on the board in that IC circuit.

Posted: **Sun Feb 11, 2024 12:21 am**

Hi, Thanks for the reply.
I'm pretty sure I'm turning the correct trimpots. And I've had a good look round the board for any shorts or flux etc.
I've found the instruction on how to tune the timing here within this thread, but also in the SAMs manual and also on Marks site (although his site has a mistake that could cause much confusion).

I broke out my digital scope to tune things more accurately. I tuned U68 pin 13 and pin 12 to 400ns (see images).
I tuned U70 Pin 5 (with jumpers between J3 pin 9 and pin 10) to 1us (see image)
...but now when I look at U70 pin 4 (with jumpers between J3 pin 9 and pin 11) I don't see any pulsing at all and the signal is at 5v !!!

I also checked that with the jumper in place that a pulse is arriving at U70 pin 2 and it is. Removing the jumper on J3 and the signal on pin 4 drops to GND.

*please note that R20 is still changed out for 10k as per the suggestion in this thread.