Atari 400 PSU - Help needed

Any 8bit repairs, images, cool things, upgrades etc.
Tomswork
Posts: 571
Joined: Fri Nov 22, 2019 10:05 pm

Re: Atari 400 PSU - Help needed

Post by Tomswork » Mon Oct 04, 2021 6:58 pm

Are you sure c202 is in correctly? it is backwards in the schematics relative the the other caps also it looks big is it a 470uf cap

Tom

@PuddyTat

Tomswork
Posts: 571
Joined: Fri Nov 22, 2019 10:05 pm

Re: Atari 400 PSU - Help needed

Post by Tomswork » Mon Oct 04, 2021 7:20 pm

Just a question how are you getting the video out of this atari 400 with the rf removed? Maybe the inductors for the rf modulator should be lifted from the circuit for testing l201 and l203

Tom

Tomswork
Posts: 571
Joined: Fri Nov 22, 2019 10:05 pm

Re: Atari 400 PSU - Help needed

Post by Tomswork » Mon Oct 04, 2021 9:38 pm

Another question are you holding the lockout switch down when checking?


Tom

PuddyTat
Posts: 15
Joined: Tue Jun 23, 2020 8:23 pm

Re: Atari 400 PSU - Help needed

Post by PuddyTat » Mon Oct 04, 2021 10:52 pm

Hi @Tomswork ,
Thanks for the feedback.

CR201 is in with band to the right as per the diode I removed (towards the center of the board). All three of the diodes there (CR201-CR203) are marked the same way). CR202 & CR203 are 1N5391 same as the bridge rectifier circuit.

C201 & C202 are Vishay 470uf 25v caps and polarity is marked on the circuitboard with the -ve to the left edge (pointing away from the center).

S202 is being held down for testing to ensure the power LED lights (which is does), however the RF Modulator is not currently installed for testing as should be redundant. This is a bare PSU only (no load) as I'm unwilling to fit it yet with the tested voltages being so badly off.

Post Reply

Return to “8 BIT CORNER”