R205 100 ohm resistor in SR98 starting to get hot and smell

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Icky
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Re: R205 100 ohm resistor in SR98 starting to get hot and smell

Post by Icky »

exxos wrote: Fri Nov 16, 2018 12:34 pm
Icky wrote: Fri Nov 16, 2018 12:19 pm DONE - Recapped and re-metal filmed
:bravo:
Thanks - that was a fun easy relaxing Atari morning whilst waiting for half a dozen other jobs to finish :)
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Re: R205 100 ohm resistor in SR98 starting to get hot and smell

Post by PhilC »

It is funny how we can find some jobs stressful but others relaxing, even if they are more complicated.

My missus thinks I'm nuts fixing computers to relax.
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Re: R205 100 ohm resistor in SR98 starting to get hot and smell

Post by atari030 »

G'day, I've been reading, reading and more reading a bit about PSU's lately. And this thread popped up a few times. Couple of quick questions, if a modern floppy is used on an old PSU, can that cause issues? I'm starting to think it would cause some 12v drama and it might explain a few odd things I've been seeing with Mega PSU's and the like.
I am about to rebuild an STe PSU with the same hot resistor dramas.
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Re: R205 100 ohm resistor in SR98 starting to get hot and smell

Post by exxos »

12v isn't used on modern drives, only really old brick style type stuff. I would suggest you check out here https://www.exxosforum.co.uk/forum/viewforum.php?f=17
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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Re: R205 100 ohm resistor in SR98 starting to get hot and smell

Post by atari030 »

I did read some posts where you mentioned dummy loads on the Mongrel boards due to a lack of 12v on the floppy. I couldn't see that in your mandatory fixes though. I'll keep looking. Would that cause a PSU not to kick over?

I'm going to dump a 5w resistor in R205 on my STe PSU. The current 3w one is in burnt fingers territory. I might place D203 under the board as there is heaps of room to clear it from the PSU plate.
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Re: R205 100 ohm resistor in SR98 starting to get hot and smell

Post by exxos »

atari030 wrote: Sat Jan 18, 2020 10:41 am I did read some posts where you mentioned dummy loads on the Mongrel boards due to a lack of 12v on the floppy.
I think you must be confusing 3 subjects there... dummy loads are for testing the PSU. Resistors on the PSU are to load it while nothing is connected else it would probably explode otherwise. Mongrel 12V I was talking about trying to not use 12V at all, or a small step up converter from 5V.
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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.
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Re: R205 100 ohm resistor in SR98 starting to get hot and smell

Post by atari030 »

No, I understand that. If you use a standard STe (or FM) PSU with low or no 12v load, what would be the impact of that?

R205 I'm just doing while I recap the PSU as its roasting.
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Re: R205 100 ohm resistor in SR98 starting to get hot and smell

Post by exxos »

atari030 wrote: Sat Jan 18, 2020 11:30 am If you use a standard STe (or FM) PSU with low or no 12v load, what would be the impact of tha
No, it won't matter.
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.
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