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Fix for glitchy / unreliable consoles


ckoba
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Both of my production consoles have been quasi-unreliable. Up until recently I've ascribed it to the heat expansion/contraction of the aging solder connections, along with not yet having removed the 4116s from the basement TI, when I realized something:

 

The console glitches when it gets bumped.

 

A bit of experimentation, and I narrowed it down to the power switch. The power switch is a dual-position dual-throw (DPDT) type mounted straight up on the power board, with a plastic actuator connecting it to the front slider.

 

After forty years, the bottom contact terminals have developed grooves, and a minor bump will momentarily interrupt power with catastrophic results. I opened one up to prove my hypothesis -- deeply grooved, which explained a lot.

 

I was not able to find an exact replacement with PCB mounts and the same wide footprint, but a similarly sized DPDT sliding switch will serve. The critical factors in choosing a switch are:

 

* will the bottom connectors line up vertically with the PCB?

* can I bend the bottom connectors out horizontally to make contact with the other power rail on the PCB?

* will the result be as tall as the original power switch?

* is the slide on the switch roughly the same size/shape?

 

Before writing off a glitchy console or going on a snipe hunt replacing RAM, try replacing the switch. Odds are the console will be much more reliable.

Edited by ckoba
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Interesting. What switch did you end up using? Any pics of the finished swap-out?

No pictures of the swapout, because I sealed the console before I'd thought about sharing this. I'll do the basement console tomorrow; perhaps I'll remember to take a photograph of the power board then.

 

Attached are photos of the switches in question. The left is the replacement, the right is the original. There are no manufacturing marks on the replacement -- it's probably a generic Chinese PoC, but it's in better shape internally than the origiinal.

 

With photos, you can see what I was talking about getting the replacement switch geometry right. The replacement can have lugs instead of pins, as long as they can be bent (with a pick, not pliers!) into the solder holes topside.

 

post-42172-0-95410700-1462793503_thumb.jpg

 

post-42172-0-21832800-1462793520_thumb.jpg

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Fur Ball must have many little bouncy things to bat around and enjoy. :) Humans are a good source of such things and must be punished when attempting to use them for projects other than those that enhance the happiness of the almighty Fur Ball. :)

 

I still remember a nice cat quote from a good friend many years ago: "It isn't a cat if you stick your hand out to it and the hand doesn't come back looking like hamburger."

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No pictures of the swapout, because I sealed the console before I'd thought about sharing this. I'll do the basement console tomorrow; perhaps I'll remember to take a photograph of the power board then.

 

Attached are photos of the switches in question. The left is the replacement, the right is the original. There are no manufacturing marks on the replacement -- it's probably a generic Chinese PoC, but it's in better shape internally than the origiinal.

 

With photos, you can see what I was talking about getting the replacement switch geometry right. The replacement can have lugs instead of pins, as long as they can be bent (with a pick, not pliers!) into the solder holes topside.

 

attachicon.gifIMG_20160509_202745.jpg

 

attachicon.gifIMG_20160509_202814.jpg

 

Yeah I need to do this for my "demo" console which randomly wont turn on when you slide the switch over. I have spare power boards should just swap it out.

 

Greg

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  • 2 weeks later...

There's always the solution I want to employ: Replace the entire power board with a single signal-level switch and replace the linear power supply with a switcher that is more efficient, runs cooler, and doesn't have 35 year old capacitors that might explode any minute now.

 

I'd considered doing this externally and just feeding the power switch signal back out, but it also comes to mind that a picoATX supply would more than serve the purpose and requires only a 12V brick. Since the TI doesn't need -5V, I kinda like this idea more and more actually.

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You may want to check again on that!

 

(Somewhere on here there's a thread with a link to a PS module that does have all the required output voltages)

 

You are right! I checked again, and it was -12 it didn't need. -5 it does need. That's probably why I didn't immediately jump on the picoATX power supply in the first place. Well, that's not going to work then is it? :)

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You are right! I checked again, and it was -12 it didn't need. -5 it does need. That's probably why I didn't immediately jump on the picoATX power supply in the first place. Well, that's not going to work then is it? :)

 

Yeah, I seem to recall that message thread, I thought that was what you were referring to in your post a couple back. Could you please post the link to that message? I need to be sure to write that down again. I have plans you see....

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You are right! I checked again, and it was -12 it didn't need. -5 it does need. That's probably why I didn't immediately jump on the picoATX power supply in the first place. Well, that's not going to work then is it? :)

 

You might be able to get away with a +5V/+12V external supply, and fit a small +5V --> -5V converter module in the console. Something like [http://uk.farnell.com/multicomp/mca05d05d/dc-dc-converter-1w-dual-o-p/dp/2079668].

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You might be able to get away with a +5V/+12V external supply, and fit a small +5V --> -5V converter module in the console. Something like [http://uk.farnell.com/multicomp/mca05d05d/dc-dc-converter-1w-dual-o-p/dp/2079668].

 

That little part would cost me $20 just to get it sent to me. *facepalm* What's really stupid about element14 (and the reason I am inclined to shop elsewhere when possible) is that this large multinational corporation or partnership or whatever the hell it is doesn't want to deal with end consumers in the United States. If you're not ordering 10,000 units of stuff on a regular basis, Newark doesn't want your business anymore. You have to go to MCM now. And MCM doesn't carry most parts you might be looking for. *sigh*

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Yeah, I seem to recall that message thread, I thought that was what you were referring to in your post a couple back. Could you please post the link to that message? I need to be sure to write that down again. I have plans you see....

 

Which message? (Also, I'm still rather new to this forum, don't really 100% know how to use it yet, and find forums in general to be clunky, cumbersome, and not very friendly for someone like me to operate. So I'll try, but it may take an attempt to two.)

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