STE - 5.25V?

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coonsgm
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STE - 5.25V?

Post by coonsgm »

So been working a fair amount with my STE and have found that if the 5V line is between about 5V and 5.15V I have stability issues. From 4.8V to around 4.95V, it's pretty darn stable, but the screen is dimmer than my other ST's. The sweet spot seems to be around 5.2V - 5.25V

Here it's rock solid stable and the video out is normal brightness.

My question here is....is this a normal thing? This is my only STE and I haven't experienced this on any of my other ST's....

Thoughts?
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exxos
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Re: STE - 5.25V?

Post by exxos »

Sounds like you need to do the mandatory fixes.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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People should find solutions to problems, not find problems with solutions.
coonsgm
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Re: STE - 5.25V?

Post by coonsgm »

Sorry, I didn't mention that I've already done the mandatory fixes along with the video ghosting fix. :D
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exxos
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Re: STE - 5.25V?

Post by exxos »

coonsgm wrote: Fri Nov 05, 2021 2:57 am Sorry, I didn't mention that I've already done the mandatory fixes along with the video ghosting fix. :D
The bus fixes ? Recapped PSU ? HC CPU ?

Seems odd. I've ramped the voltage right up on machines in the past while messing about. Normally if all the fixes are done things are a lot more stable.

There is a clock buffer chip which if it is a "S" version can cause issues.74S257chip for U405. Should be a F version.
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.
coonsgm
Posts: 152
Joined: Sat Jan 30, 2021 1:30 am

Re: STE - 5.25V?

Post by coonsgm »

Bus fixes = yes
New PSU = RD-50a (just did today) the previous PSU had been recapped a couple years ago...but I hadn't done it myself, so I wasn't sure of the quality of caps / work.
HC CPU = yes

Clock buffer chip....I'll take a look and see which version I have.
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