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Atari still crashing after power supply recap.

Posted: Fri Oct 11, 2019 11:40 am
by Cosmic Puppet
My US Atari STFM started crashing after being powered on for long periods, so I had the power supply recapped. Now Notator crashes immediately. Is a full board recap required? Been at this since June and my resolve is weakening. :cry:

Re: Atari still crashing after power supply recap.

Posted: Fri Oct 11, 2019 11:45 am
by exxos
Can you post a image of your board ?

Also who recapped the PSU ? With what ?

Re: Atari still crashing after power supply recap.

Posted: Fri Oct 11, 2019 1:00 pm
by Cosmic Puppet
exxos wrote:
Fri Oct 11, 2019 11:45 am
Can you post a image of your board ?

Also who recapped the PSU ? With what ?
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My board has since had your TOS 1.04 upgrade and I've installed the 4MB Marpet successfully. It's acting odd as The frozen program will free up when left and then freeze again and the floppy drive tries itself. Do new caps need 'breaking in' Also, could my Dongle have an issue since other programs load?

Was a power recap service on Ebay.

p.s. Just noticed that the freeze undoes when the floppy drive sounds.

Re: Atari still crashing after power supply recap.

Posted: Fri Oct 11, 2019 1:14 pm
by exxos
Cosmic Puppet wrote:
Fri Oct 11, 2019 1:00 pm
I've installed the 4MB Marpet successfully.
Well, that is likely your first problem, as those things are unstable as hell to start with.
Cosmic Puppet wrote:
Fri Oct 11, 2019 1:00 pm
Do new caps need 'breaking in'
Nope. Though those capacitors look incredibly small, what values are they ??
Cosmic Puppet wrote:
Fri Oct 11, 2019 1:00 pm
Also, could my Dongle have an issue since other programs load?
Most likely yes. I am working on the mandatory fixes list, where you will need to replace the bus resistors with a lower value, such issues are aggravated with marpet and anything plugged in the cartridge port.
Cosmic Puppet wrote:
Fri Oct 11, 2019 1:00 pm
Was a power recap service on Ebay.
Who exactly was it ? does this person actually know how to service power supplies or have they just put the cheapest when low brand of wang-lo and job done service ?

If after getting the power supply things are worse, they just still suggest you have a power supply issue to me. Looking at those caps, there is no way they are more than 1,000uF 16V jobbies, the 16V 4700uF's I use are way larger than those.

It will be difficult to diagnose your machine as you have multiple problems going on. I really would suggest you remove the marpet and try the YAART program on your machine ( nothing plugged into the cartridge port) and leave it running the 24 hours to see if any problems appear And then take it from there and fixing your other issues.

Re: Atari still crashing after power supply recap.

Posted: Fri Oct 11, 2019 3:31 pm
by Cosmic Puppet
I've had the resistors soldered to the Capacitor to bypass the original 520 RAM so I'm stuffed. Is there an alternative to the Marpet as I just need this working so I can write music again? There's a shop in Haslingden I believe does Atari repairs so could arrange something as I have no skills in this area and the only computer place here is VERY busy. What is a YAAART? p.s. Other programs load okay. Main issue is with Notator.

Re: Atari still crashing after power supply recap.

Posted: Fri Oct 11, 2019 3:57 pm
by exxos
Cosmic Puppet wrote:
Fri Oct 11, 2019 3:31 pm
Is there an alternative to the Marpet as I just need this working so I can write music again? There's a shop in Haslingden I believe does Atari repairs so could arrange something as I have no skills in this area and the only computer place here is VERY busy. What is a YAAART? p.s. Other programs load okay. Main issue is with Notator.
YAART viewtopic.php?f=25&t=28

My 4MB kit replaced the marpet years ago... https://www.exxoshost.co.uk/atari/last/4MBMMU/index.htm

For repairs and upgrades I would contact Steve on here.. I don't know where either of you are in the world though.

If you want a reliable machine, then my 4MB kit + PSU is the way to go. Though your MB needs the resistor packs changing and marpet removing by the sounds of it.

At the very least you need a proper PSU recap and the resistor packs may get you along with the marpet, but its nothing I have tried personally.

Re: Atari still crashing after power supply recap.

Posted: Fri Oct 11, 2019 5:32 pm
by redhawk668
The first capacitor I spotted is the left one at the front, that one is 220uF, 200 Volt. I’ve recapped one of my SR98 PSU’s and that one was a 47uF, 400 Volt one. Exxos already mentioned it, the other capacitors look really small.....

Re: Atari still crashing after power supply recap.

Posted: Fri Oct 11, 2019 5:42 pm
by exxos
redhawk668 wrote:
Fri Oct 11, 2019 5:32 pm
The first capacitor I spotted is the left one at the front, that one is 220uF, 200 Volt.
Good spot! but wow :o :o ... if that PSU is running on 230VAC then that cap needs to be at least 350VDC... If that's the case its a wonder it hasn't exploded :shock: :shock: The rectifier must be taking a hammering with turn on surges on a 220uF cap as well. Whoever did that re-cap job needs to be banned from touching a soldering iron again.

Re: Atari still crashing after power supply recap.

Posted: Fri Oct 11, 2019 9:26 pm
by tzok
As I can see, this is a 120VAC (USA) PSU, so 200V cap is just fine.

Re: Atari still crashing after power supply recap.

Posted: Fri Oct 11, 2019 9:47 pm
by Cosmic Puppet
redhawk668 wrote:
Fri Oct 11, 2019 5:32 pm
The first capacitor I spotted is the left one at the front, that one is 220uF, 200 Volt. I’ve recapped one of my SR98 PSU’s and that one was a 47uF, 400 Volt one. Exxos already mentioned it, the other capacitors look really small.....
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Here is a pic of the original capacitors that were already on the 110v power supply.