Ultimate 1MB in a 600XL -- how to mount the pcb?

[+Larry]

I've been wrestling with this all morning, and I still have not found a good way/place to mount the board. There is so little room -- far less than an XE or 800XL. But I'd really like to avoid drilling the mobo. I've looked through the threads with a search of Ultimate 1 MB + 600XL, but have not found any real good pics of the mounting position.

 

Can anyone point me to a couple of good pics or take some if you've done this? I guess if there is no good way, I'll wait for Simius new 65816 + 4 MB upgrade.

 

Thanks,

Larry

[flashjazzcat]

I don't think you can mount it securely without drilling a couple of holes, but it's no big deal. I use two nylon standoffs screwed to 3mm holes drilled either side of the PBI connector:

 

 

 

Well - as you can see, one standoff is missing because the nylon washer was snagging something (you might do better than I did with the vacant hole by drilling it 1mm or so further from the board edge), but it's secure enough with just a single screw.

 

[+Larry]

Hi Jon!

 

Thanks. You've given me an idea, and I'll elaborate after I try some fitting. I won't have to drill, hopefully. And you even gave me the location of several of the VIAs for the signal pickups.

 

-Larry

[+Larry]

I ended up with your method -- drilling one hole in the PCB on the right side of the PBI. My idea was to make a mounting bracket that would allow the U1B to rest on it and allow more location flexibility. But that created some added issues. The only thing that I changed was to take a nylon screw and a pair of nylon nuts to make a second leg for the U1B at the other mounting hole. The "third leg" of the mounting is the battery resting on the OS (cable) connector. Got the top back on and fits quite good. Definitely 10 lbs in a 5 lb bag...

 

Operationally, this is the best so far. Not a spec of visible interference. Mine is a Lotharek V2. The Candle version (like your picture) would fit a little better. In this case, the 90-degree headers cause some space issues.

 

As always, thanks for the help!

 

-Larry

[flashjazzcat]

 

Operationally, this is the best so far. Not a spec of visible interference. Mine is a Lotharek V2. The Candle version (like your picture) would fit a little better. In this case, the 90-degree headers cause some space issues.

 

 

I love the Lotharek upgrades and I hate to nitpick, but I dislike the open, horizontally aligned pin headers for the OS ROM and MMU on the recent boards. They make the board unnecessarily wide and are a little more prone to inadvertent damage (when pulling out the IDC connector when removing the ribbon cable) than the enclosed IDC headers on the original Candle boards. While the open pin headers are cheaper, I assume the reason they were adopted was to avoid vertical clearance issues. However, having installed twenty or more U1MBs in various machines, I never encountered a situation where cables with strain relief clips plugged vertically into enclosed male IDC headers created a problem with clearance. Meanwhile, I once had to replace the headers currently used on a 130XE installation since the MMU header blocked the screw pillar at the top left of the motherboard - at least when U1MB is mounted in the recommended location.

 

Another tip about the 600XL: the one in the picture has the U1MB OS ROM transitional connector plugged into the BASIC socket since I couldn't otherwise find room for the Stereo Pokey board. The 600XL has vias for a 28-pin socket in place of the 24-pin socket put in at the factory, so I replaced it and plugged U1MB into that. Just had to change a couple of jumpers on the underside of the board.

Edited May 16, 2016 by flashjazzcat

[+Larry]

I swapped out the Lotharek U1MB today for my Candle version. This fits in the 600XL *much better*. Cables fit better; and more importantly, there is now 1/2" clearance between the U1MB pcb and the little adapter used with 600XL keyboards. (It was "crammed in" with the other U1MB.) And Candle's works equally well in this XL.

 

I didn't install it originally, because the MMU adapter pins would not fit in the precision socket -- they were "staggered" slightly from one bank of the header pins to the other. This would have been no problem in a regular socket, but too much out of alignment for my precision socket. Got out the Hakko desoldering gun and removed one bank of the header pins and then used a fixture (AKA a precision socket) to make sure the new pins were properly aligned. Easy fix, and it now fits like a champ.

[flashjazzcat]

Excellent. It's easy to see how obstructive the newer, horizontally aligned header pins are in a situation like this. The enclosed IDC headers on the older boards are vastly superior.

[Level42]

@flashjazzcat, I know you moved the OS ROM connector to the Basic spot and I successfully copied that, and I know you have Stereo Pokey and U1MB combined but do you also have U-switch installed ? I have a hart time trying to position the U1MB at the same place (over the PBI) as you did....

 

I'd love to see pics of the entire set-up you have.

[flashjazzcat]

@flashjazzcat, I know you moved the OS ROM connector to the Basic spot and I successfully copied that, and I know you have Stereo Pokey and U1MB combined but do you also have U-switch installed ? I have a hart time trying to position the U1MB at the same place (over the PBI) as you did....

 

I'd love to see pics of the entire set-up you have.

 

I think I have an old Mega-HZ stereo board in the 600XL and no U-Switch (the second POKEY is enabled all the time). If U-Switch doesn't fit in the normal position, I guess it might be possible to re-orient it or mount it via a cable to the stereo board.

[Level42]

Mmmmm, been looking a bit further and I think it will fit. I first thought It needed to be quite low but there actually is quite a bit of space in the height at that spot of the 600XL case. There is enough space to place the U1MB _OVER_ everything else, including the U-switch.

 

Waiting for the plastic supports to arrive...