343S0120 (0120) voltage monitor IC (LC, Color Classic, Classic II) replacement

[mmu_man]

I've been distracted from EGRET woes by that small chip next to it…

I've since figured out the pinout and characteristics, and found a potential candidate for replacement. But of course it doesn't have the same pinout, and of course it's also SOIC-8, because the smaller TSSOP version is actually kind of vaporware. So I started designing a small PCB to interpose it…

 

[mmu_man]

I got a routed PCB, but so tiny it'd probably wouldn't be accepted by fabs… luckily it seems possible to do your own cuts for castellated PCBs, which means panelizing them manually would make them larger and probably easier to pass the validation. I should try that soon.

 

[mmu_man]

If only my ISP would accept the account validation mail from PCBWay…

 

[mmu_man]

I received the PCBs and *finally* some chips, after a 3rd order (1st never shipped, 2nd never arrived…).
Looks promising:

 

[mmu_man]

Seems to work in this LC-III…

 

[mmu_man]

And it's actually not that hard to solder, just needs some flux. Seems to work fine.
If I use RoHS solder for the IC it should be even quite easy to remove it in one piece if needed.

 

[RetroViator]

And it's actually not that hard to solder, just needs some flux. Seems to work fine.
If I use RoHS solder for the IC it should be even quite easy to remove it in one piece if needed.

Impressive work finding a suitable solution! I appreciate those that can take on this level of research and add creativity. Are you planning on posting the details on how to obtain the IC and PCB?

 

[mmu_man]

Impressive work finding a suitable solution! I appreciate those that can take on this level of research and add creativity. Are you planning on posting the details on how to obtain the IC and PCB?

I'll probably sell a few batches first but yeah.

 

[RetroViator]

I'll probably sell a few batches first but yeah.

Sure, selling them is great. As long as cool solutions get out there.

 

[badferday]

What is the benefit of this mod?

- Katrina

 

[mmu_man]

Well it allows replacing broken chips (they are close to caps usually) with known good chips because they are new chips still in production, not some "new old stock" that possibly got de-soldered from a battery-bombed logic board that might work or not for who knows how long.

 

[badferday]

Ohhh gotcha. Yeah, I'm researching that kinda stuff for my Mystic project.

 

[ImmortanJoe]

Do you have any information on the characteristics available? Even a truth table or something? I'm trying to fault find on a 5200CD with some weird issues stopping it from powering on and I've got no reference for a 0120 to work out if it's behaving normally. Depending on results, any idea when you'd be selling some?

 

[mmu_man]

Do you have any information on the characteristics available? Even a truth table or something? I'm trying to fault find on a 5200CD with some weird issues stopping it from powering on and I've got no reference for a 0120 to work out if it's behaving normally. Depending on results, any idea when you'd be selling some?

The pinout is linked to in the first post.
Basically Vout = max(Vin, Vbatt) (with some threshold effects though) ; /RST OUT is 0 if Vcc < 4.2V or /MR is down ; /PFO is down if PFI < 4V or so.

I've been busy with other stuff, I need to finish the test gear then hopefully I can get some shipped.

 

[ImmortanJoe]

The pinout is linked to in the first post.
Basically Vout = max(Vin, Vbatt) (with some threshold effects though) ; /RST OUT is 0 if Vcc < 4.2V or /MR is down ; /PFO is down if PFI < 4V or so.

I've been busy with other stuff, I need to finish the test gear then hopefully I can get some shipped.

Thanks for that. This is actually a really big help. I had the pinout but needed the behaviour because the 0120 does something but I couldn't determine if it was the correct thing under certain conditions.