sideburn
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Posts posted by sideburn
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12 minutes ago, Beeblebrox said:
@sideburn Great, good job.
Yup, those sockets are commonplace on those socketed A8 boards.
They aren't the best and they are called single wipe sockets.
Double or dual wipe, (metal on both sides) are better and then you have the precision round or turned socket types.
Double/Dual wipe:
Precision round/turned:
Ahh didn’t know the names. Dual wipe installed. Still going strong
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I think we are good to go now!
I cleaned all the pins on the ROM, swapped out the socket, dexoxited al the other sockets, rinsed the board in isopropyl, and blew it dry with an air gun.
You can't even tell I swapped out the socket
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I think I got it. It's either the ROM or the socket. I noticed the ROM tests are failing (red bars) when it starts acting up.
I cleaned the pins and re-seated it but at an angle in the socket and so far so good.
** just swapped out the socket and i noticed the originals are those crappy ones with the metal tabs only on the insides so it doesn't grab the chip pins from both sides
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32 minutes ago, Beeblebrox said:
@sideburn It could be one of the new RAM chips have gone bad again/is starting to fail.
When you experience the onscreen glitches have you carefully pressed down on the main 40pin ICs (CPU, ANTIC, GTIA), perhaps 4050, delay line, MMU and RAM chips one at a time in turn with the power on? I once found a weakness relating to an Antic IC socket by observing the reaction of doing so. Also are all the IC's pins definitely sitting in their socket recesses, (eg none bent albeit still engaging)?
It could also be a less than perfect solder connection between a socket pin(s) and the via(s) on the PCB that as the board heats up and expands under certain ICs, (eg like Antic), causes weak connection.
Also all the RAM chips replaced, are they all the same NS rating?
Just throwing some things out here.
I dont think its the Ram the ram tests are passing while the screen is going bonkers and i swapped out the new ram with the old and back.
Yeah I reseated the chips many times and inspected the board. Its clean. New...
I found an old 800xl in storage maybe the chips are socketed.. Sometimes when i power up it goes straight into the ram test.
When it powers up my Atarimax and unocart work flawlessly.
The only failures are the self test pages go whacky on the screen and it occasionally booting directly into the self test. if it doesn't it works perfectly consistently.
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Well I Deoxited every chip on the board. The problem is totally random. comes and goes so I don't think it is the shield (its off for now until I sort it out) nor a bad connection. it has a life of its own so I think its a bad chip. I need to get some canned air and freeze the chips and see if that affects anything.
** I found another clue... if I let a test run for a while like the memory test, the flickering gets worse and worse over time like the sprites are flying all over the place on the screen and then when i force the screen to redraw by returning to the main menu it draws the screen perfectly and then starts messing up again. This might explain why games are working ok because the screen is redrawing a lot.
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So the good news: The new cable got here today and it is 1,000 times better. Now the picture is how I remember it being.
And the bad news: Today is also the day the 800xl decided to start acting up again... goes directly into self test and the screen is bonkers (but looks much better with the new cable! lol)... Time to get the Deoxit out...
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28 minutes ago, _The Doctor__ said:
the shield is normally tightened with it aligned to the front of the Atari, if any pcb mask is damaged you can put fresh on the pcb or tape like was mentioned. the back side an 800XL normally has some protection at the PBI port.. nothing a piece of electrical tape or masking tape didn't take care of back there... I prefer Kapton/polymide tape though.
Yeah kapton would be best for that I think. If it starts acting up again I’ll take it apart again, inspect the shielding, kapton insulate, and Deoxit the sockets. I’ve always been using my 130xe and left this 800xl in the box since it’s it such NOS condition but now I think I’m going to start using it instead. I forgot how much nicer they are.
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1 hour ago, cwilbar said:
I had a real problem with the shield in one 800XL I was working on. If the sides of your metal shield can move around (not affixed to the top of the shield at the front of the shield, then the right side can move inward a bit and short against resistors that are there.
You can put some electrical tape around the bottom front of the right side of the shield to stop this problem.
It does sound like same issue I had, and if so, it is at least an easy fix.
I have run into one other 800XL that used the same shield construction, but on that one the sides were soldered on the inside near the top front to keep the sides from moving and hitting components due to the flexibility of the sides with that shield design.
I have a feeling that might have been what happened after I replaced the ram and it still wasn’t working. I had the bottom sheiks under the board just loose.
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1 hour ago, alortegac said:
Almost sure the problem was the bad ram. The rest of the issues are probably just due to moving things around, pulling chips, etc. It only takes one pin on one of the sockets to cause all the strange behavior.
it can be also be a cold joint somewhere.
Happy it is working now, as suggested above, you can spray deoxit on the sockets. You may not want to remove the chips again, but spray it with them on and let it dry.
@ _The Doctor_ is the real expert here, he has helped me several times and I learned a lot from him….hats off!
Good job! Enjoy your machines!btw, are you still having the issue of the blue color on the 130xe?
I agree. I bet it was only the ram. Yeah, I may pull it back apart and spray all the sockets. I’ve already got plenty of Deoxit. I love that stuff! I should have thought of that when I was re-seating all the chips.
Yes, still issues with the 130xe convergence but it’s looking the 800xl video is about the same so I’m leaning towards it being the cable. I hooked RF to the 800xl and it looked much better. Still need to try that on the 130xe.
Still got two more machines to fix. An Amiga 2000 that I don’t know what the heck happened to it, but it had major issues. Bad ram, blown Agnus and CIA chips, corroded battery & leakage, and more. I’ve finally got that working except for the hard drive. The disk activates and then solid HD activity LED.
A Vectrex with a board that suffered bad corrosion. It’s now got a clock but that’s about it.
Also an Apple ][ plus with bad ram that I just fixed.
All of these have been in storage for a few years. In the same location. It’s interesting that all of them have / had bad ram and were all in working order before I boxed them up back then…
I should probably get rid of a bunch of this stuff so I’ll have fewer broken things to fix every day and be forced to get some real work done! ?
*The Ataris ain’t goin nowhere though. I still have all my floppies and programs from when I was 13 for those puppies.
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That’s what I did. I think I’m good to go. Looks like it might have been a bad connection with the rom and a couple bad ram chips.
thanks for the help everyone.
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3 minutes ago, chevymad said:
None of my machines have the shields anymore. Possibility for display noise, but I've never seen a difference on mine.
I think I got it. I think the shield thing was just a coincidence. I re-seated the ROMs and so far so good. Time will tell…
I’d ditch the shields but this one is brand new. Rather keep it in mint / stock condition.
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OK the plot thickens... All the sudden it got really bad and powers up straight into self test and the screen is going nuts...
I take the whole thing apart again, remove the metal shield of the top and the bottom and set the board down on the workbench, power it up and its working flawlessly... self test page is nice and clean and passing all tests.. What gives! when i pu the thing back together it goes whacko on me..
Tempted to not put the damn shield on. what a PITA!
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OK I got that RAM and this was weird.
I swapped all 8 out and no change, black screen.
I then swapped the only socketed chip I had in mu 130XE, the GTIA and no change..
I then try powering up again and boom its working!
So I'm not sure if maybe the metal shield on the bottom was shifted and shorting something or what but it's working now.
I then swapped the original rams one chip at a time and found two bad rams.
The only issue now is the self test pages start going bonkers on the display but they are working properly. Only the display starts jittering around like crazy.
Everything else works perfectly, I put my UNO cart in and ran a bunch of games and demos and they all work fine.
So I am not sure why the Self Test screen is whacky...
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20 minutes ago, alortegac said:This is a reputable seller. Good quality cables. Above link to cable with S-Video For your 130Xe. You need to have a monitor or tv with S-video input.This other cable is good for your 800xl. Composite input in your tv or monitor. Your 130xe will also work with this cable, composite only.
Have you tried testing your computer with the rf cable? If your screen display correctly, then you know it is something wrong with the cable or composite circuit (socket, cold joint or a capacitor)
I ordered that exact xe cable from them yesterday.
I have not tried RF. Good idea, I will try that next.
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I will keep you posted once they arrive.
on a little off topic side note, my 130xe’s video convergence is way off. Especially the blue layer. Could that be my composite video cable or is it something else. I tested on a crt monitor, and lcd monitor, and a tv and it’s bad on all of them. -
34 minutes ago, alortegac said:
According to the link, appeared to have ordered 4164’s. They are exactly what you need.
Great. Fingers crossed.
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2 hours ago, cwilbar said:
I believe this is 16K DRAM (common # 4116). It is not compatible with the 800XL.
If your Rams are MT, one is very likely bad. They are 64x1, data line is pin #2. If you have a logic probe, try powering on the Atari and check pin 2 on each DRAM. If one of them is stuck low or stuck high, then the chip could be dead (other things can cause this too but often it is the RAM). 64x1 is still easy to get (4164).
If you find a bad one and your XE has socketed RAM (doubtful), and it is 4164 or 4264 (or equivalent 64k x 1 chip), then you can borrow one to try in the XL. But I would not take a soldering iron to a working XE, it isn't worth it considering all the chips are still available and it is not worth it to mess with it.
Oh no I ordered them already. Crap.
oh you mean the apple ram.
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22 minutes ago, alortegac said:
I would Just buy a set of new ram chips from the website I shared (reputable seller). It is worth the gamble.
I wouldn’t mess with the 130xe. Most XE boards aren’t socketed. De-soldering good IC’s for testing sake is unnecessary and risky. It may cost you much more in the end.
Ok I just ordered 8 of these--> https://twistywristarcade.com/ram/47-4164-ram.html
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3 minutes ago, alortegac said:
I would Just buy a set of new ram chips from the website I shared (reputable seller). It is worth the gamble.
I wouldn’t mess with the 130xe. XE boards are never socketed. De-soldering good IC’s for testing sake is unnecessary and risky. It may cost you much more in the end.
I edited my post: apple rams are TMM416D-3
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1 minute ago, alortegac said:
I would Just buy a set of new ram chips from the website I shared (reputable seller). It is worth the gamble.
I wouldn’t mess with the 130xe. XE boards are never socketed. De-soldering good IC’s for testing sake is unnecessary and risky. It may cost you much more in the end.
Ok cool. Yeah I don’t want to mess with it. It’s the only working atari I have
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1 hour ago, Beeblebrox said:
@sideburn Well good news - your board is socketed.
Flip over the casing and on the underside the label should state made in Hong Kong.
This makes it a whole lot easier.
FYI yours is a standard 800XL with a delay line (eg no Freddie chip).
Anyways you'll be best off sourcing the 16-pin 4164 Dram mentioned by Alortegac earlier. Get either 120ns (12n) or 150ns (15n) RAM. Make sure it's 64Kx1Bit.
Incidentally what Apple Drams do you have? Pop the chip number/details here and maybe it'll be compatible.
for example: https://www.ebay.co.uk/itm/334004379230
EDIT: I realise quickly reading a few of the earlier posts just now you obviusly are aware this is socketed. (The last few posts talked about soldering so I'd naturally assumed is wasn't a socketed board until now.)
Anyways - I'd definitely invest in some new DRAM, whip out the current ones and replace them all and hopefully that'll sort it. You can always keep the old ones as spares.
I highly recommend getting a Sys Check II btw.
Yea I noticed the Hong Kong label when I had it apart. Do you know if my 130xe has socketed ram? Or do I have to open it up to find out.
apple rams are TMM414D-3
I’ll look at that syscheck.
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1 hour ago, Mclaneinc said:
I don't have stuff like the Hakko gear, just cheapo Aliexpress gear, but I'm not a repair guy except to my own stuff, so a Hakko would be overkill for the work it would get used for. If I win the lottery, then maybe I'll upgrade
Always wished I'd got a Vectrex back then, silly prices now..
I know. It was hard to justify buying the hacko but after 30+ years getting angry at those damn spring loaded suckers I just folded and bought one and I have to say, when you DO need to desolder something it’s awesome!
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37 minutes ago, Mclaneinc said:
A socketed machine is a huge plus especially if it's the ram, on the C64 it's pretty much a must as they are blighted by MIT rams which are awful. Of course, not a job for a soldering beginner, as mentioned earlier, these old machines can lift traces with unsettling ease if any force or too much heat is used. The last thing you want is a machine full of bodge wires, looks awful, and says to a buyer that it wasn't treated well.
I hear ya on the pads lifting and bodge wires. I am also repairing a vectrex and it was bodge wire city all day yesterday! This board is nasty corroded and impossible to not lift traces.
But aside from that, usually there’s not a problem, I have a hacko desoldering gun, heat gun, flux, wick, etc. been soldering since I was a kid in the 80’s but I certainly do not have Louis Rossman surgery skills ?
For ram donor boards I have 130xe, commodore sx-64, apple ][ plus with ram expansion cards, Amiga A1000, and Amiga 2000. I don’t know if my xe has socketed ram or not. The others do. I’ll have to open the xe up and have a look.
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1 hour ago, Beeblebrox said:
@sideburn Not had time to read all the thread in detail so just skim read it, but number one cause is highly likely one or more bad ram chips causing the black screen. MMU (C061618) is worth checkng, then Bad CPU, Antic and OS rom next. Delay line chip also.
My money is on one or more bad ram chips.
The SAMS guides linked earlier have troubleshooting guides. RAM is relatively cheap.
I use my excellent Sys Check II module most of the time to ascertain which chips are bad.
It could be a number of other things and there is chance if you could resolve one thing another will be revealed. I've had this happen countless times and have been sent down rabbit holes mant times.
If you have the skills then worth socketing all the ram IMHO. I do this with most of my A8s initially.
You can swap a good number of chips between an XE and 800XL. I've done this many times with my 65XE which I use when fixing other A8s. Both machines have the same OS ROM chip yes.
BTW do you know if you have a stock 800XL or one with the Freddie chip (an XLF)?
Hopefully he ram on my XE is socketed. All ram on 800xl is socketed. Does the 800xl need all the ram or can I pull 4 out and see if it boots?
I have an Apple ][ as well, can I use that ram by chance?
Not sure if I have the Freddy version. I uploaded a pic of the board.
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Atari 800 XL black screen
in Atari 8-Bit Computers
Posted
Did you check all the chips for continuity. Put one lead on the pins on the chip and then the other lead on the solder connection on the other side of the board. The problem with my black screen issue was ram and bad connections with the chip because the stock sockets are pretty crappy.