JGRAHAM2

February 16

1 hour ago, orpheuswaking said:

If it's got a Bkey then upgrade it. You've already changed the machine (albeit reversibly).

B-Key was one of the things I really wanted in the early 80s. I never really got serious about programming until I got my 800XL. I bought this with the keyboard for nostalgic reasons. I actually bought my original machine because I thought the keyboard was futuristic looking and cool.

February 16

4 hours ago, bob1200xl said:

Dig up an Atari 48K upgrade - the Mosaic looks complex compared to the 48K factory kit.

Bob

It requires some cutting traces, removing capacitors, soldering 6 points, replacing RAM, plugging in a board in place of an ic and connecting to the motherboard with a press on connector. I did it and it partially works. I get a black screen. On reset I get BASIC, but PRINT FRE(0) gives the wrong free memory 39,000+ instead of 37,000+ and it freezes. List produces zeros. Star Raiders works, but other carts do not. I think I have some bad RAM. I’ll try other chips and recheck my wiring tomorrow.

February 16

36 minutes ago, Allan said:

@JGRAHAM2

Could you possible scan the Mosaic manual?

Yes, I’ll upload here sometime this week.

February 15

3 hours ago, Rybags said:

Wrong photo?

I had a B-key from new. Sure, more usable than the membrane default but in the modern day for a collectable I'd say original all the way.

I’m talking about the Mosaic 48k upgrade. I think someone bought it back in the day and after reading the instructions, they decided not to try it.

February 15

3 hours ago, mimo said:

Keep as is imo.

I removed a third party keyboard from mine and installed a nos original keyboard.

It looks and feels like a 400 now.

I only play games on it though

I’ve got 3 others with the old keyboard and a set of extra boards, so I’m good there.

February 15

What do you think? Install in my B-Key 400 or keep as it is?

February 14

2 hours ago, flashjazzcat said:

The signals are labelled on the U1MB board itself which you can match up with any readily available Sally pinout; you can take all of them from the CPU if you don't want to hunt around for vias.

https://lotharek.pl/productdetail.php?id=56

There's a clickable link on that page which shows the hook-up points on the CPU.

Got it, thanks!

February 14

On 2/8/2021 at 5:25 AM, Dinadan67 said:

Take a look at flashjazzcat's video. This is my machine and i am very happy with it. Of course it runs Bomb Jack!

https://www.youtube.com/watch?v=JZ0gm6YLDX4

Are the exact pickup points for the U1MB documented somewhere?

February 7

This is an old post, but who has tried this upgrade?

February 1

I have 2 of these I’m working on. They are dirty, but for the most part are in working order. The issue with both was the little micro switches under the Start, Option, Select, etc. I tried contact cleaner. Don’t do that. It quite effectively stopped all from working. Taking them apart, they are about as cheap of a device they could source. A rubber cup with a conductive coating shorting 2 tiny pads. I was able to resurrect them using CaiKote 44, but lesson learned. Try one first. I tried using a pencil to restore the conductive layer, but no deal. I had the CaiKote to fix a C128 keyboard. Anyway, on to my question. See the picture. Have you seen a XEGS case top warp like this? Any suggestions on straightening it? I have another and it is not like this. Also, I think the composite video out of this computer is pretty good, so I use my UAV for another one.

January 26

10 hours ago, _The Doctor__ said:

remember to run a screw threw it (in and out) when wet to prevent the glue from filling the threads and splitting again when you re assemble... the magnet wire/speaker wire reinforcement works 'very' well.

Too late for that unfortunately. I will reinforce it and then use a tap perhaps. Thanks.

January 26

This is what I’ve done so far, plus glued the ones holding one side of the keyboard. More will have to be done to reinforce it. I’ll use some of the suggestions above.

January 25

7 hours ago, Faicuai said:

Agree 100%.

By looking at the posted pictures, I would say those guid-posts broke off due to a) impact and/or b) fatigue caused by over-torque.

Unit may have been dropped accidentally, for instance.

It happened when they shipped it to me. I’ve had a couple vintage computers damaged in shipment, most of the time due to poor packaging and sometimes due to poor handling.

January 25

1 hour ago, Faicuai said:

You will never be happy about this. Deep inside you know it...

...But there IS a solution. Thanks God your problem is with the top-half. Just chase all open deals on e-Bay, until you find a decent 800, listed for parts or clearly undervalued. Just go grab it, and get a whole new top-cover. Color match it by just exposing it periodically to the sun, if a bit darker/ yellow. If not, you will be all set, plus a whole stash of fresh parts for your future endeavors. They will come handy.

Trust me, you will sleep better... Do it right!

I actually have 2 800s. Since I am installing an Incognito in this one, I will probably switch cases and defer fixing this one until later. I have about 6 projects going right now, most waiting on parts to come in.

January 24

I just took apart an 800 that I bought some time ago. I noticed a little chip out of the case back then, but when I took it apart, I found it is much worse. Any ideas on what to do about this? These cases must be like porcelain.
Other than that, I found that it has an Axlon 128K RAMDISK, which is kind of cool.

January 23

This was the DMA chip. I replaced it with one from an old 520ST and it is functional again. Thanks everyone.

January 20

I did burn this to an EPROM, but I haven’t tried to do anything useful with it. It seemed to work just like the original for what I did do. The lot I purchased had two highly used computers, a 800XL with 256K and a 130XE with 512K. It also came with 2 modified 1050s. He must have found something it was good for. Unfortunately, I don’t have any of his disks and his son really didn’t know much about it.

January 17

12 hours ago, ParanoidLittleMan said:

It may be DMA chip, but may be floppy drive too. So, for start disconnect floppy drive and try so.

Removing DMA is not big deal - but you need desoldering vacuum pump and good soldering iron. Of course, not putting there other DMA chip, but solder socket for first.

And there are smaller chances that it is something other, not DMA chip.

Thanks, I do have a desoldering station and am practicing on an old board. I’ll probably do this soon. I’ve tried a couple working drives with no luck.

January 17

I just got a 1040STe in great condition, but it will not access the floppy or boot from an Ultrasatan (or my MegaFile30 for that matter.) It sounds like it is reading the disk when it boots up, but comes up with the error in the attached picture when it is accessed. (“Your output device is not receiving data.”) I’ve heard a bad DMA can cause this and there are other remedies for general issues in some of the forums I’ve read. I brought this up on Facebook as well. Has anyone seen this exact behavior or have any ideas? I have a couple DMA chips from old 520ST boards that are socketed, so I could just try that, but as you know, removing one from an STe can be risky.

January 14

9 hours ago, JGRAHAM2 said:

I found a 130XE from the same lot with this OS and 512GB of RAM, switchable down to 128.

512GB 🙂 I wish! 512K of course

January 14

I found a 130XE from the same lot with this OS and 512GB of RAM, switchable down to 128.

January 12

On 1/6/2021 at 11:22 PM, doctor_x said:

BBS operations????

Could be. I got the computer in a lot from someone who inherited it from his father. It included a Happy modified 1050.

January 12

Just a note that you hold select when you boot up to get to the menu. It doesn’t load from disk unless you go through this menu. To load from a disk drive instead of the RAM disks, just hit return and answer with the drive number you want to load from. It will then load normally.