somacast Posted May 18, 2021 Share Posted May 18, 2021 hi, I boughg an Atari 65xe from someone who claimed its working but it wasn't, its giving black screen all the time opened it apart and its fairly clean, removed randomly 2 or 3 caps tested,they have low esr despite the usual old caps behavior with higher capacitance than rated. tried booting up with options depresed,no use , no beeps.. now the funny part is ... when i tried moving the keyboard while computer is on, the screen flickered and gave some colors and few letters tried that again never happened again also noticed that pressing reset while computer is switched off , gives black screen on !!!! again switch is off !! removed the keyboard totally, and i noticed it turns on and off while switch is off !!! can't visually see any short circuits also i kept my finger while computer is switched on on the n.p. caps , when i do so and press any buttons in keyboard i hear noisy beep in tv !! whats going on here please? thnx Quote Link to comment Share on other sites More sharing options...
Sugarland Posted May 18, 2021 Share Posted May 18, 2021 (edited) Are there cracked solder joints around the power switch area or elsewhere? Post clear closeup photos of the motherboard please. Edited May 18, 2021 by Sugarland 1 Quote Link to comment Share on other sites More sharing options...
somacast Posted May 18, 2021 Author Share Posted May 18, 2021 31 minutes ago, Sugarland said: Are there cracked solder joints around the power switch area or elsewhere? Post clear closeup photos of the motherboard please. thnx , here are the photos https://ibb.co/fXW3yy5 https://ibb.co/bNK8Zkt https://ibb.co/WWQbJYC https://ibb.co/Hxrxtdp https://ibb.co/ysdPD03 https://ibb.co/16f9mpb https://ibb.co/BsMjxfx https://ibb.co/XpTP8pw in fact its close to new condition motherboard no cracks not even rust, if i show you some of my commodore or msx you would call this brand new.. Quote Link to comment Share on other sites More sharing options...
Sugarland Posted May 18, 2021 Share Posted May 18, 2021 If stored reasonably well, many Atari's still look brand new inside. Do you have a local shop that can repair it? I suggest that firstly. If not, then try some contact cleaner in the power switch. It looks a little dirty or rusty..? With power unplugged to the 65XE, operate the switch back and forth with the contact clear in there to help clean it. Do you have anti-static brushes designed for electronics? Give the board a good clean with them with a good quality IPA. If all that fails, contact from whomever you bought it for a return. 1 Quote Link to comment Share on other sites More sharing options...
TGB1718 Posted May 18, 2021 Share Posted May 18, 2021 That power switch looks well corroded, and possibly rust between 2 of the pads, they need cleaning and maybe reflow with fresh solder. If you have some contact cleaner, that switch looks like it needs a good cleaning too 1 Quote Link to comment Share on other sites More sharing options...
+x=usr(1536) Posted May 18, 2021 Share Posted May 18, 2021 Interesting... From the photos, the motherboard identifies it as a 65XEN, which were the Arabic-language models sold in Saudi Arabia and Egypt by Najm. @somacast, I'm sharing your images here to make it easier for people to see them - I know that your post count won't let you do that yet 1 2 Quote Link to comment Share on other sites More sharing options...
somacast Posted May 18, 2021 Author Share Posted May 18, 2021 34 minutes ago, Sugarland said: If stored reasonably well, many Atari's still look brand new inside. Do you have a local shop that can repair it? I suggest that firstly. If not, then try some contact cleaner in the power switch. It looks a little dirty or rusty..? With power unplugged to the 65XE, operate the switch back and forth with the contact clear in there to help clean it. Do you have anti-static brushes designed for electronics? Give the board a good clean with them with a good quality IPA. If all that fails, contact from whomever you bought it for a return. I am good with electronics, its my hobby for the past 25 years, the switch legs are corroded but it works, i will give it a good contact cleaner or even replace it, but again, how will that a bad switch which is partially connected in off position contribute to black screen?? thnx 8 minutes ago, TGB1718 said: That power switch looks well corroded, and possibly rust between 2 of the pads, they need cleaning and maybe reflow with fresh solder. If you have some contact cleaner, that switch looks like it needs a good cleaning too thnx , same answer above 6 minutes ago, x=usr(1536) said: Interesting... From the photos, the motherboard identifies it as a 65XEN, which were the Arabic-language models sold in Saudi Arabia and Egypt by Najm. @somacast, I'm sharing your images here to make it easier for people to see them - I know that your post count won't let you do that yet many thanks for uploading, yes I am from Bahrain and its atari Najm 65xe, bought from a cheater on instagram who calls everything (well tested and all buttons works), i grew up a commodore person, however did and maybe still do own an 800xl , it looked nice 2 Quote Link to comment Share on other sites More sharing options...
+x=usr(1536) Posted May 18, 2021 Share Posted May 18, 2021 9 minutes ago, TGB1718 said: That power switch looks well corroded, and possibly rust between 2 of the pads, they need cleaning and maybe reflow with fresh solder. If you have some contact cleaner, that switch looks like it needs a good cleaning too There is also what appears to be damage (corrosion, missing pad, etc.) on the underside of the board. 1 Quote Link to comment Share on other sites More sharing options...
somacast Posted May 18, 2021 Author Share Posted May 18, 2021 53 minutes ago, x=usr(1536) said: There is also what appears to be damage (corrosion, missing pad, etc.) on the underside of the board. i will go through them right away , thnx 1 Quote Link to comment Share on other sites More sharing options...
+CharlieChaplin Posted May 18, 2021 Share Posted May 18, 2021 Hey now, hey now now, sing show this corrosion to me Hey now, hey now now, sing show this corrosion to me Hey now, hey now now, sing show this corrosion to me (The Sisters of Mercy - This Corrosion) 1 Quote Link to comment Share on other sites More sharing options...
+x=usr(1536) Posted May 18, 2021 Share Posted May 18, 2021 34 minutes ago, CharlieChaplin said: Hey now, hey now now, sing show this corrosion to me Hey now, hey now now, sing show this corrosion to me Hey now, hey now now, sing show this corrosion to me (The Sisters of Mercy - This Corrosion) Funnily enough, that started going through my head as well while I was looking at the photos Quote Link to comment Share on other sites More sharing options...
somacast Posted May 18, 2021 Author Share Posted May 18, 2021 1 hour ago, x=usr(1536) said: There is also what appears to be damage (corrosion, missing pad, etc.) on the underside of the board. well , most of them were not corrosion, it was stain of old flux from factory, only corrosion was in the mid oval circle and removed old solder, cleaned and resoldered, same black screen now i was wondering if this was done at factory, i mean looks like a non completed trace, intentionally maybe ? anyone has a photo to share of bottom side of a 65xe ? https://ibb.co/LpKb0VL 1 Quote Link to comment Share on other sites More sharing options...
+x=usr(1536) Posted May 19, 2021 Share Posted May 19, 2021 5 hours ago, somacast said: well , most of them were not corrosion, it was stain of old flux from factory, only corrosion was in the mid oval circle and removed old solder, cleaned and resoldered, same black screen Well, at least you now know Definitely check into cleaning the power switch, though. BTW: what are you measuring at the power supply's output end? You may want to take a look at these search results - it appears as though other people have run into similar issues in the past with their Najm XEs, so there may be something useful in there. Good luck with figuring it out - these are one of the machines I'd like to eventually add to the collection because they're so unique, but that will have to wait until everything else is fixed first. It's good to know that one more may be about to be saved. 1 Quote Link to comment Share on other sites More sharing options...
somacast Posted May 19, 2021 Author Share Posted May 19, 2021 5 hours ago, x=usr(1536) said: Well, at least you now know Definitely check into cleaning the power switch, though. BTW: what are you measuring at the power supply's output end? You may want to take a look at these search results - it appears as though other people have run into similar issues in the past with their Najm XEs, so there may be something useful in there. Good luck with figuring it out - these are one of the machines I'd like to eventually add to the collection because they're so unique, but that will have to wait until everything else is fixed first. It's good to know that one more may be about to be saved. thanks for your efforts, well the switch is clean and fine now so its out of checklist voltage is 5.1 volts , which is good i will see the older topics, thnx again 1 Quote Link to comment Share on other sites More sharing options...
Mathy Posted May 19, 2021 Share Posted May 19, 2021 Hello guys Maybe we need @tf_hh to have a look at this. Sincerely Mathy 1 1 Quote Link to comment Share on other sites More sharing options...
somacast Posted May 19, 2021 Author Share Posted May 19, 2021 39 minutes ago, Mathy said: Hello guys Maybe we need @tf_hh to have a look at this. Sincerely Mathy thanks , would appreciate any advices Quote Link to comment Share on other sites More sharing options...
somacast Posted May 21, 2021 Author Share Posted May 21, 2021 any other suggestions Quote Link to comment Share on other sites More sharing options...
Sugarland Posted May 21, 2021 Share Posted May 21, 2021 You need to socket many of the chips and swap them into a known-working computer. You still have your 800XL? It's risky putting good chips into a non-working computer. I would start with the CPU, then GTIA. 1 1 Quote Link to comment Share on other sites More sharing options...
somacast Posted May 21, 2021 Author Share Posted May 21, 2021 3 hours ago, Sugarland said: You need to socket many of the chips and swap them into a known-working computer. You still have your 800XL? It's risky putting good chips into a non-working computer. I would start with the CPU, then GTIA. ok good idea , i ordered a kit of sockets, regarding the cpu i remember seeing a YouTube video saying that its written part# on it is wrong, any known significant part number to search for? just in case . thnx Quote Link to comment Share on other sites More sharing options...
+tf_hh Posted May 22, 2021 Share Posted May 22, 2021 On 5/19/2021 at 11:53 PM, Mathy said: Maybe we need @tf_hh to have a look at this. Sorry, wasn´t online some days here. Interesting find with the "gap" in the power trace, but it seems to be standard for this board revision: This is the same 65XEN mainboard and it also have this gap. I checked it against the schematics and reason is the seperation of +5V from standard to the 4050 buffer and video amp stage. There´s a coil between to filter the 5 volts. I´m pretty sure the developer saw the wrong routing after the final production mask was made and scratch these gap by hand from the mask. However, IMHO the first problem is the power switch itself regarding your posts here. I´ve often have had bad power switches. So exchange them first or solder for test a permanent bridge and plug/unplug the power. Now the black screen behaviour should be constant. The board you have is a PAL mainboard with PAL chips on it. You didn´t set your location in your profile, so if you´re living in NTSC areas, a black screen is normal. More typical is a red/brownish screen (PAL) or greenish (NTSC) when the computer has memory failures. Black scren - when T.V. norm is capatible - is more something around bad CPU, bad ROM, bad DRAM logic. 1 1 Quote Link to comment Share on other sites More sharing options...
somacast Posted May 22, 2021 Author Share Posted May 22, 2021 34 minutes ago, tf_hh said: Sorry, wasn´t online some days here. Interesting find with the "gap" in the power trace, but it seems to be standard for this board revision: This is the same 65XEN mainboard and it also have this gap. I checked it against the schematics and reason is the seperation of +5V from standard to the 4050 buffer and video amp stage. There´s a coil between to filter the 5 volts. I´m pretty sure the developer saw the wrong routing after the final production mask was made and scratch these gap by hand from the mask. However, IMHO the first problem is the power switch itself regarding your posts here. I´ve often have had bad power switches. So exchange them first or solder for test a permanent bridge and plug/unplug the power. Now the black screen behaviour should be constant. The board you have is a PAL mainboard with PAL chips on it. You didn´t set your location in your profile, so if you´re living in NTSC areas, a black screen is normal. More typical is a red/brownish screen (PAL) or greenish (NTSC) when the computer has memory failures. Black scren - when T.V. norm is capatible - is more something around bad CPU, bad ROM, bad DRAM logic. thank you very much, very helpful sorry Don't usually fill all info in forums profiles, iam in a Pal region , Bahrain but great info regarding the trace, and possible bad ics as well thnx 1 Quote Link to comment Share on other sites More sharing options...
+CharlieChaplin Posted May 22, 2021 Share Posted May 22, 2021 On 5/18/2021 at 9:46 PM, somacast said: [snip] yes I am from Bahrain and its atari Najm 65xe, [snip] Quoted from post #7 here... according to Google, Bahrain uses PAL standard. Ooops, Somacast was faster... 1 Quote Link to comment Share on other sites More sharing options...
somacast Posted May 22, 2021 Author Share Posted May 22, 2021 I do have a further question please is the cpu here just a common 6502 ? i hear its the same thing of all c64 , apple ii , atari xe , etc ? also which one is the d-ram ? thnx Quote Link to comment Share on other sites More sharing options...
Mathy Posted May 22, 2021 Share Posted May 22, 2021 Hello somacast 4 hours ago, somacast said: is the cpu here just a common 6502 ? i hear its the same thing of all c64 , apple ii , atari xe , etc ? No it is not! Sincerely Mathy 1 Quote Link to comment Share on other sites More sharing options...
somacast Posted May 23, 2021 Author Share Posted May 23, 2021 thanks alot Quote Link to comment Share on other sites More sharing options...
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