STE video synchronisation problem
Re: STE video synchronisation problem
Lift one end of R470 and see if GCLK comes back up ? Also check CCLK both sides of C427.. and R489.
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Re: STE video synchronisation problem
I've tried removing R470, and after removing - input of R489 (it's R469, I believe though) 4.6V, after R469 - 2.6V, on input of C427 it's 2.6V and on the side connected to pin 17 of 1377 it's same 5V.
Re: STE video synchronisation problem
So just a flat DC voltage there, no signal ?Number_Nine wrote: ↑Sun Oct 01, 2017 7:52 pm I've tried removing R470, and after removing - input of R489 (it's R469, I believe though) 4.6V, after R469 - 2.6V, on input of C427 it's 2.6V and on the side connected to pin 17 of 1377 it's same 5V.
So to recap, input to R469 has the clock, but the output does not ?
Also with the IC end of R469 lifted, do you still see CCLK on both sides of the resistor ?
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
Re: STE video synchronisation problem
This is what I get "left side input" of R469..
3V p-p. Bias 0v.
Output side of R469 (IC side).
about 0.2V p-p (200mV) with 0.4V (400mv ). DC offset.
3V p-p. Bias 0v.
Output side of R469 (IC side).
about 0.2V p-p (200mV) with 0.4V (400mv ). DC offset.
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
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Re: STE video synchronisation problem
Yep, no signal, I was blaming that from the beginning, but then I've checked on a good Atari and that was the same flat signal.exxos wrote: ↑Sun Oct 01, 2017 9:36 pmSo just a flat DC voltage there, no signal ?Number_Nine wrote: ↑Sun Oct 01, 2017 7:52 pm I've tried removing R470, and after removing - input of R489 (it's R469, I believe though) 4.6V, after R469 - 2.6V, on input of C427 it's 2.6V and on the side connected to pin 17 of 1377 it's same 5V.
So to recap, input to R469 has the clock, but the output does not ?
Also with the IC end of R469 lifted, do you still see CCLK on both sides of the resistor ?
Both input and output of R469 have clock, output has it much weaker (~300mV), though, regardless of the IC side soldered or desoldered.
On schematics R469 is 5.0K, but on the board it's almost 6K, but I don't think that matters as I've tried shorting it out and got no difference.
And what's more interesting - it's all absolutely the same on my second Atari.
Re: STE video synchronisation problem
I think you need to switch to 100mV on your scope and re-check, as you probably won't see the signal else. See my previous images, if I use 5V/div It would appear flat also on my scope.Number_Nine wrote: ↑Sun Oct 01, 2017 10:00 pm
Yep, no signal, I was blaming that from the beginning, but then I've checked on a good Atari and that was the same flat signal.
Both input and output of R469 have clock, output has it much weaker (~300mV), though, regardless of the IC side soldered or desoldered.
On schematics R469 is 5.0K, but on the board it's almost 6K, but I don't think that matters as I've tried shorting it out and got no difference.
And what's more interesting - it's all absolutely the same on my second Atari.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
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Re: STE video synchronisation problem
You need to be in x10 mode with your probe, and 100mV/div on scope...
I don't think you will see it with the modes you are using.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
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Re: STE video synchronisation problem
Sorry, I meant flat 5V on 17 pin of 1377 (well, it's also a pulse-ish, but with 5V bias and p-p some very few mV).exxos wrote: ↑Sun Oct 01, 2017 10:07 pmI think you need to switch to 100mV on your scope and re-check, as you probably won't see the signal else. See my previous images, if I use 5V/div It would appear flat also on my scope.Number_Nine wrote: ↑Sun Oct 01, 2017 10:00 pm
Yep, no signal, I was blaming that from the beginning, but then I've checked on a good Atari and that was the same flat signal.
Both input and output of R469 have clock, output has it much weaker (~300mV), though, regardless of the IC side soldered or desoldered.
On schematics R469 is 5.0K, but on the board it's almost 6K, but I don't think that matters as I've tried shorting it out and got no difference.
And what's more interesting - it's all absolutely the same on my second Atari.
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- Joined: Tue Sep 19, 2017 1:48 pm
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