How to: recapping the Mega STe power supply

[mikro]

One is a REV-A1 which has the cut track and the centre post is isolated with cloth tape. This one the opto isolator is a CNY17-3Z and it is from an Atari TT REV H.

The other a REV-02 which does not have the cut track and the centre post is not isolated. This one has the PC111 opto isolator and is from and Atari MegaSTE.

For me it was the other way around: "-002" had the cloth tape (not sure about cut track) and PC111, "-001" had 5 screws and CNY17-3Z.

[Icky]

Just digging through my photos and found the cut track board. That saved me opening the machines back up again.

IMG_2618.jpeg

[exxos]

One is a REV-A1 which has the cut track and the centre post is isolated with cloth tape. This one the opto isolator is a CNY17-3Z and it is from an Atari TT REV H.

The other a REV-02 which does not have the cut track and the centre post is not isolated. This one has the PC111 opto isolator and is from and Atari MegaSTE.

For me it was the other way around: "-002" had the cloth tape (not sure about cut track) and PC111, "-001" had 5 screws and CNY17-3Z.

:dizzy:


I think we need to take into consideration is a few things here.

1) what is stamped on the power supply lid.
2) what the PCB version actually is
3) what version of OPTO it has
4) if it has a cut track or not.
5) if the middle screw is insulated or not.

I'm going to make a preliminarily assumption that the cut track may be relating to the Opto used, and the cut track is basically doing the same thing as isolating the middle screw..

[czietz]

Just digging through my photos and found the cut track board. That saved me opening the machines back up again.

It's maybe worth noting that the cut also "only" breaks a loop but doesn't fully disconnect something from something else:

psm5341_cut.JPG

This connection isn't even there in the first place on the PCB that @Pacman an posted:

psm5341_unconn.JPG

The issue with the opto-coupler (why you should have a PC111 or CNY-17F and not a CNY-17) is something else entirely, imo. E.g., I have two -001: one had the "bad" CNY-17 optocoupler, the other one a PC111.

[mikro]

I have to correct my previous statement, too. My situation is:

First MegaSTE:

• C302074-001 (on lid)
• S/N S10201717A3 (on lid)
• REV A1 (on PCB)
• 5 screws, nothing insulated
• nothing to cut
• PC111

Second MegaSTE:

• C301379-001 (on lid)
• S/N M04700353A2 (on lid)
• REV A1 (on PCB)
• 5 screws, nothing insulated
• nothing to cut
• PC111

TT:

• C302074-002 (on lid)
• S/N xxxxxxxxxxx (on lid) (TODO: check)
• REV A2? (on PCB) (TODO: check)
• 4 screws, insulated with cloth tape
• cut PCB? (TODO: check)
• CNY-17

I don't have all the information about the TT because I can't find the energy to open it again. :-)

It's interesting that Icky's REV-A1 did have the track cut while both my MegaSTEs + Pacman's don't have anything to cut at all. @Icky isn't there a chance you have mistaken those two? For instance, you keep referring to yours as "02" while the photo clearly shows it is "A2".

Also, I don't think it is a coincidence that a cloth tape is used, this must by factory, i.e. another hint that Icky's PSU with track cut was in fact A2, same as in my TT. His "A1" was from a TT, had track cut and CNY-17 opto.

[Icky]

It's interesting that Icky's REV-A1 did have the track cut while both my MegaSTEs + Pacman's don't have anything to cut at all. @Icky isn't there a chance you have mistaken those two? For instance, you keep referring to yours as "02" while the photo clearly shows it is "A2".

Also, I don't think it is a coincidence that a cloth tape is used, this must by factory, i.e. another hint that Icky's PSU with track cut was in fact A2, same as in my TT. His "A1" was from a TT, had track cut and CNY-17 opto.

It's possible I got them mixed up @mikro - It was a long time ago as you mention I dont have the will to go and open them all up.

[Icky]

Damn, I couldn't leave it alone. Actually glad I popped it open there was a lot of dust in there.

My TT PSU is:

• C302074-002 (on lid)
• S/N S20207127A7 (on lid)
• REV A1 (on PCB)
• 4 screws, insulated with cloth tape on 5th centre pillar
• Cut in PCB
• PSU Metal frame # 63029-289 REV C

And no they physically are not mixed up as I performed the PSU re-caps at different times and never had the two out together.

[mikro]

OK, now my curiosity got sparkled again, this is really puzzling. Maybe mine is A1, too.

[mikro]

TT:

• C302074-002 (on lid)
• S/N xxxxxxxxxxx (on lid) (TODO: check)
• REV A2? (on PCB) (TODO: check)
• 4 screws, insulated with cloth tape
• cut PCB? (TODO: check)
• CNY-17

I can't edit the post anymore, so here it is:

C302074-002 (on lid)
S/N S20207006A7 (on lid)
REV A1 (on PCB)
4 screws, insulated with cloth tape on 5th centre pillar
cut in PCB
CNY-17
PSU Metal frame # 63029-289 REV C

So it would seem that the only A2 PSU has been found in @Icky's MegaSTE and our TT PSUs are virtually the same. And as @czietz mentioned, the opto-coupler is entirely different issue as PC111 has been found in my A1s and also in Icky's A2.

[pixelpusher]

I recently got a MSTE and on inspection found that in the PSU the R23 resistor is cut out (the wires of it are still soldered) - it looks like on the picture from the first page of this thread (while the unit shown on exxos last update PSU page does contain the resistor).

Does anyone know why it was cut out in later revisions of the PSU (according to the enclosure it's still a 001 variant, though it looks different and also has a different opto than earlier 001 versions)?

Best,