User avatar
Olem
Norway

Posted Sun Jan 26, 2020 9:02 am

Here's a handy little thingy for reading the serial output, send mr. Arana an email and get him to solder one for you:
https://www.arananet.net/pedidos/produc ... m-to-wifi/

User avatar
grshaw

Posted Sun Jan 26, 2020 9:29 am

So - I redid the solder around the rom socket. That appears to have resolved that problem. Now I am seeing a green screen. This indicates a RAM fault apparently. I guess I may have to re-flow some more soldering. :D Another thing which is worth investigating is the RAM chips which I bought off eBay. Perhaps these are dodgy? I had 512K from the Amiga 500. however, I need 1024 K, so I bought some more .
if you get one of the color codes, you're quite close to getting it to work
I am only seeing the colour for a second or so on initial boot. Then the screen goes black. Is this normal for colour codes or should I expect the colour to remain? Perhaps the colour disappearing is indicative of another issue?
The 500++ is nearly done BTW, just waiting for some jumper caps for the df select, of all things. Will post some images when I get the last few bits, in a week or two!
Yes - that would be awesome. I am always keen to see what other people are up to.

User avatar
Olem
Norway

Posted Sun Jan 26, 2020 9:51 am

Progress! I've seen green/black flashing before when there's a RAM problem. Not sure what green and then solid black means...have you connected the case lights? Do the diodes flash? This is supposed to be good RAM, according to the A500++ team over at discord :D
https://www.aliexpress.com/item/3304386 ... b201603_53

User avatar
grshaw

Posted Sun Jan 26, 2020 11:43 am

No - I haven't connected the case lights. I have some RAM from a spare A2000. I know thats good. So I will try swapping that onto the newly built motherboard. If this works, then that would suggest that the soldering is good and it's the eBay RAM chips that are at fault. Conversely, if the good RAM does not work then I will need to re-flow the soldering round the RAM chips. In the former case, I may well buy some more chips from that Ali Express link. Thanks.

What worries me is that the switching to black after the red flash may be an indication that there is something else wrong. Perhaps there is something wrong with the the video display. Ah well. I will try to fix one problem at a time I guess.

User avatar
Olem
Norway

Posted Sun Jan 26, 2020 2:16 pm

Good luck! Hope you get it sorted soon; keep us posted.

User avatar
obitus1990
New Orleans, LA, USA

Posted Mon Jan 27, 2020 8:50 am

I see you're using machine pin sockets on some of the ICs while using dual wipe DIP sockets on others. Make sure your chip pins are not perfectly straight when using those machine sockets. They need to flare out from the sides of the IC a little bit to put tension on the socket, else poor contact will result. I hate those things, and, in my opinion, they should only be used with machine pin headers since that's what they're designed for. This is use of a "square pin in a round socket" as far as I am concerned. I had a 68000 CPU in an A500 I thought was bad recently, but, it was just making poor contact to a machined pin socket that had been placed in there during what I assume was some previous repair.

User avatar
eugenenine

Posted Mon Jan 27, 2020 7:14 pm

obitus1990 wrote:
Mon Jan 27, 2020 8:50 am
, they should only be used with machine pin headers since that's what they're designed for.
be careful, this isn't quite true. Yes there are some that are designed for round headers but there are others designed for IC pins, you need to check the spec sheet to see which is which. If you use the wrong one, then yes they might not make a good connection, but if you sue the right one then the connection is better since you have > 1 wiper.

User avatar
nadoom

Posted Fri Jan 31, 2020 5:57 pm

I've started building my a2000 mobo now. 🙂 Hopefully it will work first time so I don't have to learn how to fix it 😂 . @grshaw when I built an a500++ last year I got a green screen also one of the ram chips was not firmly seated. Worked fine once I made sure they were firm.

User avatar
grshaw

Posted Sun Feb 02, 2020 6:01 am

Well - firstly - I would like to thank you guys for your advice.
obitus1990: I see you're using machine pin sockets on some of the ICs while using dual wipe DIP sockets on others. Make sure your chip pins are not perfectly straight when using those machine sockets. They need to flare out from the sides of the IC a little bit to put tension on the socket, else poor contact will result. I hate those things, and, in my opinion, they should only be used with machine pin headers since that's what they're designed for. This is use of a "square pin in a round socket" as far as I am concerned. I had a 68000 CPU in an A500 I thought was bad recently, but, it was just making poor contact to a machined pin socket that had been placed in there during what I assume was some previous repair.
Well - it's quite possible that the problems I am seeing are indeed because of a poor socket connection.

I compared the picture that you posted of your build vs. mine. I have in fact got turned pin sockets on four locations where you have dual wipe DIP sockets. Specifically U102, U200, U201+ U800, i.e. the sockets for the four custom chips: Gary, Paula, Denise and Buster. I chose turned pin because I was having problems sourcing 48 pin dual wipe DIP sockets. The supplier that I used only has dual wipe DIP sockets with up to 40 contacts. I figured it would probably be okay. Looks like I may have been incorrect. :D I guess I will see if I can find any from a different supplier.
nadoom: I've started building my a2000 mobo now. 🙂 Hopefully it will work first time so I don't have to learn how to fix it 😂 . @grshaw when I built an a500++ last year I got a green screen also one of the ram chips was not firmly seated. Worked fine once I made sure they were firm.
Glad to hear it. :D I did try re-seating the RAM chips. I am wondering if the RAM I bought from eBay is not good. I will try taking out and replacing with some known good chips.
Olem: This is supposed to be good RAM, according to the A500++ team over at discord :D
https://www.aliexpress.com/item/3304386 ... b201603_53
Do you have a url for this discord server? I will join this if possible.

User avatar
nadoom

Posted Sat Feb 08, 2020 11:43 am

Hey @Grshaw

what did you do with C1 Cx/Rxx do you know what thats about?

Thanks!

Edit: its a cap and a resister in serial isnt it? I looked at your board and copied it :-P





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