Dopy25

Do you have a Sega model 1 power supply? I can send you an adapter for the cost of shipping.

Added some RF cables and adapters. Removed stuff that's gone.

Out of curiosity, what would it mean if it flickers when you press the fire button? Is that an issue, or a common feature bug?

Pm sent

Moved temp prices to main post.

Awesome. Mine went well. Take it slow with the ST ram chips. Best way I found was to lay the board flat, and use a heat gun from the bottom. I have a pair of angled tweezers that I set under the ram to let the tweezers do the work once the solder was hot. The light weight of the tweezers will pop the ram up. After that you can use a desoldering unit to pull the solder out. Luckily you only have to clear the top 2 rows holes for all but 2 slots. I chose not to use a switch for a9 because I don't even know what software malfunctions with 4MB vs 1MB yet. It's all new to me. When I can find a piece of software that causes an issue, I will decide at that time. Everything I am running is from masteries SD card solution right now and I think anything that runs from SD has already been modified and will most likely work with 4MB. The issue in my last post was interference. Every board worked well after I moved the MMU lines away from whatever was causing it not to boot. It had to be too close to one of the other connections on the board somehow. I posted more about it under hardware:

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It's hard to believe I am the first to leave feedback in this sub forum for this seller. I've seen so many positive comments in masteries sales threads. I picked up a low cost SD card solution for my Atari 520ST and it is amazing. Mine was basic so I had to upgrade the RAM before I could play most of the software, but after upgrading the onboard ram from 512k to 4MB, it runs like a champ. masteries is great if you have any questions. He helped me pinpoint a few issues I was having that were unrelated to the device but caused it to have issues for me. Even the shipping was pretty good considering the location. He in Spain, I in the US. I am sure this is all dependent on the time of year as well so be aware. I would not hesitate to buy anything from masteries in the future.

Great buyer. No issues at all! Would definitely sell to again. Boneheadimus is a treasure to the community.

2 sold, 2 left.

Update: I have 2 left. Update: last 2 are pending. ALL SOLD I only needed one, but since 5 boards was the minimum order, I bought enough to make 5. I figured instead of throwing away 4 blank boards, I would buy enough RAM and SMD components to finish all of them and part with the rest. I won't do it again so the 4 remaining are up for grabs and that's it. All have been tested in YAART. If you have a preference on how many passes you want me to run, I will redo it. Just let me know. This board will provide your Atari 520ST (an possibly others with a similar 512k layout) with 4MB of ram, or 1MB if you ground the a9 line. You can also use a switch to change between 1MB and 4MB. That would be on you to figure out. This board was designed by agranlund and the PCB was posted on his GitHub. You can build your own if you have the patience and knowledge. This particular board design was "fixed". By a user (snarkdluG on AA) and posted in a thread here on AA. It does not require a bodge on the ram board, and the CAS & RAS solder points are correctly labeled. They are swapped on the original design. You must remove your old RAM and put this board in their place. You cannot use sockets as it will not provide enough clearance for the RF or keyboard to sit inside the case. Feel free to Frankenstein it if you want but I warned. Not all pins are required to be soldered in place. It is labeled as such on the board. Therefore only 2 boards have 2 rows of pins across the top, and 2 have pins only where a connection is needed. You may also need to remove the header pins for the lines that go to MMU. They were there for testing. Feel free to specify which you would like (until I only have one style left) Cost is $35 plus shipping on PayPal. If you can send Venmo friends & family payment, cost is $30 plus shipping. Please feel free to ask any questions.

No problem at all. I'm glad you asked. Maybe a potential buyer had the same concern. I remember when we got Cozmo. He was such a blast. But kids grow up and have the attention span of a goldfish these days. Honestly if I can find a way to trade someone anything else for a PS4, I'd trade my son for Cozmo just to keep him. haha

@-^CrossBow^- I was finally able to get my son to spend some time testing Cozmo. I told him someone wanted to know, and that he should do it sooner than later but since it's his, I didn't push too hard. Cozmo works fine without any sort of internet connection and we do not have a subscription. He picked up a cube and enjoyed it for a few minutes it before my son put him back in the box. No subscription, no issues. I can send you a short video of him working and playing if you like.

Or you might need to replace some capacitors. I know there are some green "chiclets" on the board that are responsible for video clarity. https://console5.com/store/22uf-100volts-film-capacitors-5-atari-chicklet-replacement.html Hmm. It says they're responsible for RF interference. I guess those might not be the issue but it might be worth looking into.

Yes. Remove all the old RAM and solder the board in their place (most of their place), and you make 4 connections to the MMU.

SUCCESS!! The issue was the routing of the wires to the MMU. Something interfered with them. Not sure what it was but I had an idea to move the wires away from the edge and to again so I placed a spacer between the board and cabling and tried again and it booted! The other 3 assembled boards also work.

No longer need ST RAM.

New want

I did have those. Unfortunately adding that in made no change. It's still pink and black bars only. I even tried a third set of board/chips with the exact same outcome. This board had never been installed, and the pins never bridged, or at least powered while bridged. At this point I'm wondering if I have the wrong chips. It's odd to me that they would all have the same outcome. Guess I'll try to revert everything unless there are other ideas. I'll be looking for replacement chips in the meantime. Thanks for the advice.

It did in fact work before the mod, yes. The issue is that I started by clipping the legs off the old RAM chips before remembering I could use my heat gun. Hence the overheating in the middle of the rows of RAM chips. I suppose I could remove the 6 pin sockets and install full sockets, and buy more RAM, but I think that would be more work than I want to do, considering it *did* work before any modifications. Although if I can't figure anything else out, I guess that will be my only option 🤷🏼‍♂️. Ugh.

Looks like they should be 220nF based on the 224 above what you can see in the pic. The whole label reads: CGW 224 Z5J 8327 (OR 8321) Looking up this info it seems the most likely is 220nF. Unfortunately I do not have this value or anything remotely close to it. Looks like I will order a few and hope any extra eyes will help in the meantime.

Here are a few more pics of the Atari board. I'm still not sure those old ceramic caps are necessary but can anyone tell me what would be an acceptable replacement for the caps located at c36, c37, c38? When I first tried to remove the old chips, I used too much heat in this area and burned the old caps. One even fell apart. I didn't think they were necessary because the positive side no longer comes into contact with the new pins but I could be wrong. I double checked continuity in this area as well and everything still seems ok. Also uploaded a pic of the caps that I put too much heat on. 2 have the same label (3127) but the third ends in 3121. I don't know the difference and I can't seem to find a component list that includes c36-c38.

Here are some pics of the board and RAM. After checking the diagram for this ram, I'm pretty sure I did not bridge vcc. I think I bridged pins 2&3 on one chip and somewhere around 15-17 (not all pins, just 2 of them) I could also be mixing it up as I didn't take notes on which were bridged, not even mentally. I just was kinda like "oh those shouldn't be there" and used a wick to get rid of it. I guess I could have bridged the other side and maybe it was around pin 37 which says it's VSS. I'm guessing that might not be a good thing either. I do have 2 boards that are not fully assembled yet, and 4 chips that have been completely unused. I'll finish assembling them and check for bridged pins before supplying power this time. It's just kinda weird to me that they all have the same result so far with those pink and black bars.

If you shit yourself every now and again, you could see brown drawers more often.

Holy crap are the EP units really worth $500?