XM501 B/W (Breakout) Solid White w/ Lightning Show on Anode Lead

Scucci

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XM501 B/W (Breakout) Solid White w/ Lightning Show on Anode Lead

I've already ordered the capacitors for it, so I'm going to start on that when they get here in a few days.

But other than the cap kit... because I'm not 100% sure it's going to really fix the main issues with the monitor (but that's where I always start at)... what else could/would be causing my issues?

The screen is solid white, but I do have some control of the brightness... contrast does nothing. B+ is adjusted to 73V on the dot.

 
The light show looks normal to me, I see the same thing on my xm's. For the white screen a cap kit would be a good start. Here's a snippet from Atari the Book for some more ideas. I've seen the same thing happen when one of those transistors go bad
 

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The light show looks normal to me, I see the same thing on my xm's. For the white screen a cap kit would be a good start. Here's a snippet from Atari the Book for some more ideas. I've seen the same thing happen when one of those transistors go bad

Thanks for checking that for me (the light show)... that's what I was more worried about, but if it's common/normal then I'm not going to sweat it.

The capacitors should be getting here either today or tomorrow and I'll replace them ASAP. I saw some post about someone else having the same issue with a solid white screen and having brightness control and they said their issue was C6. ... so, hopefully it'll be the same deal with me. If not I have a lot of spare diodes and transistors here as well, so I should have all my bases covered.

FWIW, I've never seen anything use so many odd-ball capacitors (uF values) before. IE: 50uF over 47uF? ... just weird.
 
yeah that's the problem with working on these Motorola it seems like almost every part is now obsolete and you have to cross reference everything.
 
yeah that's the problem with working on these Motorola it seems like almost every part is now obsolete and you have to cross reference everything.

For the caps, I lucked out and found all their uF values... I had to go up a little in voltage for a couple of them, but I was just happy to find the right uF. Mouser wasn't much help, neither was Digikey or Jameco... but oddly enough Newark had them all for the "right price" (read as cheap)... so, that's where I got them from. I checked with Bob's kit and from what I read the values he sends work, but aren't the exact same as what it there originally... and I'm just anal like that.

The biggest PITA part to find (for cheap) was the 6000-8000uF filter cap on the Breakout board... Newark again. For my other cap kits and crap, I'll probably stick with Mouser, but the oddball stuffs like those caps, I'll be checking Newark. Hell, they even had the 2N3716 and 2N3792's for my Battlezone monitor! ... plus the 5V regulator for Breakout... I was REALLY impressed with their stock... So if it ever comes up again, I'd give them a shot for any older stuffs. Bob is still cheaper, but I was ordering in a bunch of ICs to and I snagged up everything I needed while I was there because I hate paying shipping.
 
The values used in some old monitors and power supplies are obsolete. No need to replace with the exact value, remember that the tolerance on these parts wasn't very tight to begin with. Usually, you go up to the next standard value, but for something like 50uf, 47uf is fine. For filter caps, feel free to go a lot larger than the original.

-Ian
 
Replaced all the caps I could easily replace (didn't bother with the sound card or the one under the monitor frame). Also, they sent a 1uF 16V NP cap instead of what I wanted (and thought I was ordering) so I'll have to round a 1uF up later from my parts pile and slap it in.

Anywho, the monitor is back up and going fine*. I can't adjust it down to the same size it was out of the factory (the color films won't line up), I can only adjust the coil down so much before it starts getting bigger again. So I'll just adjust it to how I like it, then redo the color films. Easier and I'll end up with something I like better anyways (there's a 1.5"+ gap at the top and bottom of the screen... I don't like wasted space). I'll have to put the bezel back on and make sure the score and ball text that's on there doesn't get in the way... but I think I'll be okay with making the screen a little bigger and then redo'ng the color films.

*there's a little bit of "snow" on the screen. It's not a connection issue on the board, so I'll just deal with it for now.

 
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Regarding adjusting it down.....have you tried adjudting the rings at the back of the yoke?

Edward
 
Regarding adjusting it down.....have you tried adjudting the rings at the back of the yoke?

Edward

Yeah, that's how I got it centered and where it is now. I can adjust it down where the blocks are on their colors, but then the paddle will be below the blue.

I really need to just take the films off and put them back on where I see fit. I also want to adjust them to my height, but since everyone else that plays the game is a full 4-5" shorter than me, I'm not sure if I should adjust the films for me, or for "everyone else".
 
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