Horizontal lines - help with power supply repair

[tmppro]

My Model 1 Saturn recently started acting up. If I reset the console after about an hour of playtime, I get horizontal lines/bars rolling over the image.
I read up about the problem and the common fix seems to be to replace the TOP202YAI and/or add a capacitor.

So I've ordered some replacement TOP202YAIs from China, and installed one. Immediately after powering it on the fuse went off.
I don't have much experience in repairing power supplies, so any advice what to do next would be helpful. Are my new TOP202s bad?
They have slightly different markings and are made in Philippines instead of Malaysia, but that can't be relevant, right?
Thanks.

[mattius]

Jun 5, 2017 11:44:34 GMT tmppro said:

My Model 1 Saturn recently started acting up. If I reset the console after about an hour of playtime, I get horizontal lines/bars rolling over the image.
I read up about the problem and the common fix seems to be to replace the TOP202YAI and/or add a capacitor.

So I've ordered some replacement TOP202YAIs from China, and installed one. Immediately after powering it on the fuse went off.
I don't have much experience in repairing power supplies, so any advice what to do next would be helpful. Are my new TOP202s bad?
They have slightly different markings and are made in Philippines instead of Malaysia, but that can't be relevant, right?
Thanks.

Was the capacitor on the PSU?

[tmppro]

No, I only replaced the TOP202, nothing else.
My guess was that adding the capacitor would only cure the symptoms of a failing TOP202 (noisy output).

[mattius]

I highly doubt adding a single capacitor would blow the fuse through stress. Sounds like you caused a short with soldering. Recheck all the connections. If worst comes to the worst, I have a Saturn model II (PAL) we might be able to do a deal on. Before that check the connections, and get new fuses.

[tmppro]

Sure, I'm just saying the capacitor can't be it because I didn't add one
I'm quite experienced with soldering so that shouldn't be a issue, here are some pictures:



Here's the old TOP202 compared to the new ones

[zyrobs]

The components you ordered may have been faulty or fake. That kind of chip hasn't been produced for a while, it was succeeded by a newer line. You should only order parts like that from reliable sources, not random Chinese ones! That or you may have shorted something out while soldering - it happened to me once as well.

The modern replacement part is the TOP224YN or TOP234YN (latter has higher wattage rating).

Note that if you blown the fuse (and most likely the varistor next to it), then you will need to replace those as well.

[mattius]

Jun 5, 2017 12:41:15 GMT tmppro said:

Sure, I'm just saying the capacitor can't be it because I didn't add one
I'm quite experienced with soldering so that shouldn't be a issue, here are some pictures:



Here's the old TOP202 compared to the new ones

The biggest solder point looks to be covering a trace. 

[tmppro]

The trace in the middle is joined to the heat sink, that's ok.

I don't get why anybody would fake ICs like that, but it's the only thing I changed. They were very cheap though. (I've checked that all capacitors were discharged before soldering, so even shorting anything by accident shouldn't damage a component.)

What's a reliable (and cheap) source to get the TOP224YN or TOP234YN from?
The big component distributors like Mouser and DigiKey have very expensive shipping costs.
Do any of you guys have one that I can buy?

The varistor looks fine visually, is there any way to test it?
Before I can do any further testing I have to order a couple of fuses though.

[mattius]

Jun 5, 2017 13:44:30 GMT tmppro said:

The trace in the middle is joined to the heat sink, that's ok.

I don't get why anybody would fake ICs like that, but it's the only thing I changed. They were very cheap though. (I've checked that all capacitors were discharged before soldering, so even shorting anything by accident should damage a component.)

What's a reliable (and cheap) source to get the TOP224YN or TOP234YN from?
The big component distributors like Mouser and DigiKey have very expensive shipping costs.
Do any of you guys have one that I can buy?

The varistor looks fine visually, is there any way to test it?
Before I can do any further testing I have to order a couple of fuses though.

This is way above my level of expertise for Saturn mate. Try asking on the assembler games forums. 

[zyrobs]

Jun 5, 2017 13:44:30 GMT tmppro said:

I don't get why anybody would fake ICs like that

Money.

What's a reliable (and cheap) source to get the TOP224YN or TOP234YN from?
The big component distributors like Mouser and DigiKey have very expensive shipping costs.
Do any of you guys have one that I can buy?

I use Farnell and TME.eu. They have reasonable shipping, to where I live anyway.

The varistor looks fine visually, is there any way to test it?

I think it should pass a continuity test. The point of the varistor is that it blows up if there's a big problem, before the over voltage can damage the rest of the circuitry. So if it looks fine then it probably wasn't damaged.

[tmppro]

Alright, I ordered a TOP202YAI and a TOP224YN from a reputable German shop.
I will report back in a couple of days when the parts arrive.
Thanks for your help so far

[mattius]

Jun 5, 2017 16:48:46 GMT tmppro said:

Alright, I ordered a TOP202YAI and a TOP224YN from a reputable German shop.
I will report back in a couple of days when the parts arrive.
Thanks for your help so far

Good luck mate.

[zyrobs]

You don't need a top202yai, the 224yn is newer/better.

[tmppro]

It's been a while, the shop took more than a week to ship the parts and after that I've been busy with other things.

But I've installed the TOP224YN today and the PSU is working again. And even better, it's been running for about 5 hours now and no sign of horizontal lines or other image problems so far

[Gunstar]

Awesome that you got it fixed! Also handy info in this thread about the TOP224YN.