Beeblebrox Posted January 12, 2023 Share Posted January 12, 2023 (edited) In addition to my earlier reply with the Fujinet thread I've just noticed you are getting corruption in the old firmware menu as well as the ROM error when it goes into self test. Check that the 28pin OS ROM Harting ribbon cable has continuity on all 28pins with the U1MB. Looks like a bad connection maybe causing issues. BTW just out of interest did I've been reading the replies regarding the 100pf cap addition to the U1MB. Did you happen to do it in the end? If so make sure you soldered it to the right points on the U1MB and also that you used the correctly rated cap. (It's just a thought... throwing suggestions out here. I'd imagine if you had installed it in the wrong place it probably wouldn't power up at all). Edit: remind me again... When power supply are you using? The original 9v Atari one or a modern switching type replacement? Edited January 12, 2023 by Beeblebrox 1 Quote Link to comment Share on other sites More sharing options...
+videofx Posted January 12, 2023 Author Share Posted January 12, 2023 I will add the Cap. I was reading that when you see corruption in the firmware it needs the cap. My power supply is the original Atari 9V Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted January 12, 2023 Share Posted January 12, 2023 (edited) 1 hour ago, videofx said: I will add the Cap. I was reading that when you see corruption in the firmware it needs the cap. My power supply is the original Atari 9V Sure.Take on board all the comments in this thread related to the adding of said cap also. Also make sure you ensure the legs of the cap are insulated from shorting out on any other pins. (I use little offcuts of shink wrap as per the image I posted the other day.) I still think it's worth double checking the OS rom socket Harting ribbon cable and continuity again. Make sure all pins are connecting and have a good connection. If you are using the old existing sockets there is a possiblity there is a bad socket/socket contact, etc due to age. Or a bad solder joint, trace/via in or around it. It happens. You can always re-flow the solder for the socket legs. Have you followed the Dual to single OS rom conversion instructions and everything checks out ok in that respect? Did you take the U1MB's 4 x signal hookups from the recommended pick up points on the board? Pop up a high res image or two of the install you like. Edited January 12, 2023 by Beeblebrox 1 Quote Link to comment Share on other sites More sharing options...
+videofx Posted January 13, 2023 Author Share Posted January 13, 2023 Is there anyone who can make me a longer 28pin OS ROM Harting ribbon cable? Mine just makes it and it's tight I will show all the connections Quote Link to comment Share on other sites More sharing options...
+videofx Posted January 13, 2023 Author Share Posted January 13, 2023 Here are photos of my install Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted January 13, 2023 Share Posted January 13, 2023 @videofx let us know if you had any luck re the cap, but thinking about it the OS ROM Harting ribbon cable shouldn't be particularly tight. The cable length is standard with u1mb and I don't recall mine being tight if you mounted it in the same place. If you still have issues my money is still on the 28pin socket. (Either the cable or the socket itself). If the way you have it is pulling on the cable there may be a bad connection. Can you show a wider shot of the whole board? Make sure nothing under the U1MB pcb is shorting anything. Quote Link to comment Share on other sites More sharing options...
+videofx Posted January 13, 2023 Author Share Posted January 13, 2023 I know its not the socket since I can you any eprom or ROM in the socket and it works. I will put on the cap and try it with there is a short. Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted January 13, 2023 Share Posted January 13, 2023 26 minutes ago, videofx said: I know its not the socket since I can you any eprom or ROM in the socket and it works. I will put on the cap and try it with there is a short. Sure, hopefully it's the addition of the cap in this instance that will fix it. There can still be issues with the socket even if it seems ok when you pop ICs in them. As I say if you are finding the ribbon cable tight it may well be pulling at the connector and/or the socket that could potentially mean the Harting cable pins don't have an optimal connection on one side. If the socket is a double wipe type and decades old you can't necessarily rule anything out. Just a thought. AFAIK the cable shouldn't be a tight fit if you installed the U1MB in the same place as the videos and the cable is folded right. Here is mine from an old pic where IIRC the 28pin cable was fairly slackish Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted January 13, 2023 Share Posted January 13, 2023 (edited) I agree, it's been of note that cable issues at the connectors has been an issue as well as bad sockets. The capacitor issue also of note. Definitely the trinity of trouble for the 1200XL mods. Edited January 13, 2023 by _The Doctor__ Quote Link to comment Share on other sites More sharing options...
+videofx Posted January 13, 2023 Author Share Posted January 13, 2023 OK, cap installed, makes no difference and BIOS is still garbage which I thought the cap fixed. No shorts, I put the board on its side. Now I am stumped Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted January 13, 2023 Share Posted January 13, 2023 (edited) Just the graphics at the top now? menus and functionality ok? I would place something to insulate in between the u1m and the main board while doing this work, that scares me... I think you have little to loose in updating the JED and flashing the u1m. You can do both externally if that helps ease your situation don't forget about the ribbon cables/connectors/sockets... I'd start with the cables. They turned up bad a time or two direct from the dealer, bad crimps intermittent connections and shorts Edited January 13, 2023 by _The Doctor__ Quote Link to comment Share on other sites More sharing options...
+videofx Posted January 13, 2023 Author Share Posted January 13, 2023 @_The Doctor__ Just the graphics on top is the same before and after the 100pf capacitor install. In the BIOS everything works correctly and I can choose and save and quit, but of course quit takes me to the built in self test. I will now test the cables. Does anyone sell the cables in case there is a problem ? Quote Link to comment Share on other sites More sharing options...
+videofx Posted January 13, 2023 Author Share Posted January 13, 2023 OK problem found! It is the 28pin cable. Is there anyone that sells them or can make me one? 1 Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted January 13, 2023 Share Posted January 13, 2023 (edited) Shame re the cap but some good suggestions from recent posts. Just wondering if it is also worth replacing the 74LS08 chip with the 74F08, (a common swap to improve stability in other A8s with U1MB installed. Be interested to see if re flowing the socket's solder and double checking them for continuity will help. The other thing which is a possible avenue if you have another A8 (say a socketed 800XL) is to transplant the U1MB installation into. Edit: Just seen your latest post. Ah, that's good news. How'd you work out it was the cable? You can source them from the reseller who sold you the U1MB usually. If it is faulty they should ideally replace it for free. Edited January 13, 2023 by Beeblebrox Quote Link to comment Share on other sites More sharing options...
+videofx Posted January 13, 2023 Author Share Posted January 13, 2023 I only have an 800 with Incognito so cant transplant. But since the pins on the 28 pin are either incorrect or shorted I need to buy a new cable Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted January 13, 2023 Share Posted January 13, 2023 16 minutes ago, videofx said: I only have an 800 with Incognito so cant transplant. But since the pins on the 28 pin are either incorrect or shorted I need to buy a new cable Sure, our messages crossed over hence why I edited in in light of you discovering the problem. As mentioned contact the reseller you bought it from if the cable is faulty. They should replace it. Quote Link to comment Share on other sites More sharing options...
+videofx Posted January 13, 2023 Author Share Posted January 13, 2023 I bought it from Lotharek and thought if I could get one here in the US I could get the cable faster Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted January 13, 2023 Share Posted January 13, 2023 (edited) Ah, the brewing academy in the US usually sells U1MB. They are sold out at the moment but might have some spare cables or may be able to make one up for you. Can't hurt to ask. https://thebrewingacademy.com/products/ultimate-1mb-upgrade-lotharek-jon-fjc-halliday-candle Alternatively you could get some ribbon cable yourself and some 28pin Harting connector and the other end connector and crimp your own as well. So what is exactly wrong with your cable? Was it obvious when you checked it out? Edited January 13, 2023 by Beeblebrox Quote Link to comment Share on other sites More sharing options...
+videofx Posted January 14, 2023 Author Share Posted January 14, 2023 Now that I look at the cable, the end of the cable that goes into the IDC connector is in crooked. Quote Link to comment Share on other sites More sharing options...
+videofx Posted January 23, 2023 Author Share Posted January 23, 2023 OK, I tried new cables and a new U1MB and still doesn't work. So I yanked the socket and will replace it. Hope that fixes it! Quote Link to comment Share on other sites More sharing options...
flashjazzcat Posted January 23, 2023 Share Posted January 23, 2023 (edited) On 1/12/2023 at 12:50 PM, videofx said: I was reading that when you see corruption in the firmware it needs the cap. Yes: the problem the cap specifically addresses is the text of the menu being replaced by reverse video tab characters (actually $FFs) because the 'IORAM' under the hardware registers is turned off by noise on the reset line after the U1MB BIOS already enabled it. Evidently the RAM in this region is perfectly functional on your system. Edited January 23, 2023 by flashjazzcat Quote Link to comment Share on other sites More sharing options...
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