Hails to one and all,
I'm a collector of retro computer and video game hardware and have been creeping through these AA forums for years now. I was luck as a kid as I had almost all the major computers from the late 70's through the mid 80's that were released in N. America. Many have been lost in moves and what not over the past couple of decades. But I never stopped adding to my collections. The one major computer system I never had back in the day was the ST line. So since I got into doing retro MIDI stuff the past half year, I started looking into the ST line. Got my first one off ebay a few weeks ago and it was a 520 STm and came with an SM124 mono monitor, RF modulator line, and mouse (no floppy drive though). The system simply didnt work. I checked the PSU (with a Fluke 87v with a still valid cal) and its as strong as an ox. I reseated all the socketed chips, and still no go. Then tried the final bit of resoldering most of the contact points on the board. Still dead. No obvious signs of trouble of course, so something is just flat out dead in the unit. Chalk it up to profits and losses toss it in the spare parts closet.
So back I go to ebay, to look for another 520. I simply didnt want to deal with the 1040 because of the size, weight, and built in FD. I'd rather go external and keep it small so I can make it fit into limited space. I figured that I can always upgrade the ram to 1MB by hand and pretty much have a 1040 without the lame DB9 port placement ( and no need to buy DB9 extensions to deal with that lame placement). So I find another 520STm. Its listed as having RCA ports for audio and an svideo port. Of course I think that the seller is trying to say that the RCA based RF out is for audio and that the full size DIN jack is an svideo port. Low and behold, I get the unit (this one works by the way) and it really does have left and right RCA jacks and an svideo port. So I dont have any svideo cables (or I should say that I cant find any) to try it out. I still have to get a 314 floppy drive and I'm waiting for the new ultrasatan but it works like a charm on the SM124. I'll get an svideo cable to test the port this weekend. It also came with a mouse so now I have two. It has no yellow on the case, keys or mouse (thought the mose cable has yellowed a bit). It really looks brand new and the svideo port and RCA jacks were placed very well. I asked the seller about the mod and he said he bought it that way and used it on his TV but just didnt have room for it anymore.
So first thing I do is rip it apart to inspect the mod. I'm really impressed at whoever figured this thing out. Clearly it was not a simple solution for them. It has a couple filter caps and resistors inline with the different mod connections and the audio is leached off the monitor port. I love the fact the the modder just tossed out the worthless RF shield, lol. But on the whole it is very cleanly done with good solder work, and every thing just looks good. I cant seem to find much info about a mod like this on the ST line. I see a thread or two about why other methods are better, but that seems to say do go through all the trouble of this sort of mod. Well I dont have to worry about that as its already a done deal. I'm just curious as to how much is really know about this sort of mod and what noise issues (audio and video) I may need to keep a watch for.
Now seeing that mod makes me want to do a few other things to it as well. I guess I'm going try the 1MB thing, but I was wondering if timing is an issue. Should I try and use 60ns or 70ns dram's for the full 1mb or just stick on 512k of the stock 150ns to the current chips? Also is there any issues (or benefits) with ripping out the 68k and putting in a socket and 68010? Why stop with that? Are there any other popular mods for the 520STm?
***EDIT***
Also what are the advantages to the different TOS roms? I cant seem to find a clear picture on any of the forums about what works best with this or that and is it worth it. Any info on that would be nice as well.
I'm a collector of retro computer and video game hardware and have been creeping through these AA forums for years now. I was luck as a kid as I had almost all the major computers from the late 70's through the mid 80's that were released in N. America. Many have been lost in moves and what not over the past couple of decades. But I never stopped adding to my collections. The one major computer system I never had back in the day was the ST line. So since I got into doing retro MIDI stuff the past half year, I started looking into the ST line. Got my first one off ebay a few weeks ago and it was a 520 STm and came with an SM124 mono monitor, RF modulator line, and mouse (no floppy drive though). The system simply didnt work. I checked the PSU (with a Fluke 87v with a still valid cal) and its as strong as an ox. I reseated all the socketed chips, and still no go. Then tried the final bit of resoldering most of the contact points on the board. Still dead. No obvious signs of trouble of course, so something is just flat out dead in the unit. Chalk it up to profits and losses toss it in the spare parts closet.
So back I go to ebay, to look for another 520. I simply didnt want to deal with the 1040 because of the size, weight, and built in FD. I'd rather go external and keep it small so I can make it fit into limited space. I figured that I can always upgrade the ram to 1MB by hand and pretty much have a 1040 without the lame DB9 port placement ( and no need to buy DB9 extensions to deal with that lame placement). So I find another 520STm. Its listed as having RCA ports for audio and an svideo port. Of course I think that the seller is trying to say that the RCA based RF out is for audio and that the full size DIN jack is an svideo port. Low and behold, I get the unit (this one works by the way) and it really does have left and right RCA jacks and an svideo port. So I dont have any svideo cables (or I should say that I cant find any) to try it out. I still have to get a 314 floppy drive and I'm waiting for the new ultrasatan but it works like a charm on the SM124. I'll get an svideo cable to test the port this weekend. It also came with a mouse so now I have two. It has no yellow on the case, keys or mouse (thought the mose cable has yellowed a bit). It really looks brand new and the svideo port and RCA jacks were placed very well. I asked the seller about the mod and he said he bought it that way and used it on his TV but just didnt have room for it anymore.
So first thing I do is rip it apart to inspect the mod. I'm really impressed at whoever figured this thing out. Clearly it was not a simple solution for them. It has a couple filter caps and resistors inline with the different mod connections and the audio is leached off the monitor port. I love the fact the the modder just tossed out the worthless RF shield, lol. But on the whole it is very cleanly done with good solder work, and every thing just looks good. I cant seem to find much info about a mod like this on the ST line. I see a thread or two about why other methods are better, but that seems to say do go through all the trouble of this sort of mod. Well I dont have to worry about that as its already a done deal. I'm just curious as to how much is really know about this sort of mod and what noise issues (audio and video) I may need to keep a watch for.
Now seeing that mod makes me want to do a few other things to it as well. I guess I'm going try the 1MB thing, but I was wondering if timing is an issue. Should I try and use 60ns or 70ns dram's for the full 1mb or just stick on 512k of the stock 150ns to the current chips? Also is there any issues (or benefits) with ripping out the 68k and putting in a socket and 68010? Why stop with that? Are there any other popular mods for the 520STm?
***EDIT***
Also what are the advantages to the different TOS roms? I cant seem to find a clear picture on any of the forums about what works best with this or that and is it worth it. Any info on that would be nice as well.