zonaps2

Thanks Tursi, I see that I'll have to check out a lot of chips then Sent from my iPhone using Tapatalk

Hi, yesterday I got this TI-99/4A in nice cosmetic condition. It's a PAL version, 220V PSU. Modulator says VHF Channel 3. I plugged it in an old TV I have and I just got a black screen with a continuous beeeeeeep tone. I tried a different TV just in case and same problem. I've tried a cartridge (Parsec), with no luck. I have a bunch of old computers, commodore, amiga, etc, but I never owned a TI before. I've read the sticky post for new members and it say that this symptom could be anything on the board. I've already disassembled the machine, on a visual inspection everything looks good, I've re inserted the socketed chips. PSU voltages are: on pins 1-2 = 19.6V on pins 2-4 = 9.15V I see that these voltages are higher than specified on the PSU case, I guess it's because it's under no load? What things should I check? I have no idea beyond this. HERE is a video with the symptom.

Thanks!

Hi, I have these pictures and I would like to id these 3 Atari. Are they light or heavy sixers? I don't have other pictures. TIA

I've set the power supply to 7v and works. thanks! I've also made the composite video mod, and now the image is very clear! Thanks everybody for the help!!

Got it working!!!! I tried another power supply (the fourth one I tried), and now the Atari works. The power supply is a 'universal' one, it output different voltages, from 1.5 to 12 volts. and says 1000mA 18w. I put it to 9V and measured the tip and it read 15.2v I wasn't sure if plug it or not because I thought it was too high, but I did it anyway. Why does it works with this power supply and doesn't work with the other ones that are rated 9V? Will this power supply break the atari in long term? Now the image looks with a lot of noise, also the audio is not clear. what can I do to make the picture better? I've tried 2 TV's, one LED TV and a CRT one. two different RF cables and they all look the same. Will an A/V mod help? Thanks guys!

Hi, thank you all for your help, I really want to get this Atari working! Only top and bottom chip inserted measures 2.9v Sorry for my ignorance, but, do I have to remove the components for measuring them? Because if that's the case I could just replace them. (Assuming they are easy to get in any electronics shop). Is it possible to measure capacitors with my cheap meter? About the RF module, will it help with the problem if I do the A/V mod? No, I don't have one. As I undestand with the top and bottom chips measuring 2.9v, it means that the 3 chips are fine? I will ask in the electronic shop if they have the freezer spray, not sure if I want to do the bag and freezer thing. Thank again!!

Hi, the cable is fine, I've used it with a NES and is working. Also I've used another cable and the problem persist. The meter shows 0. Thank you for your help, very appreciated.

Hi, I've posted some days ago in the hardware section, but maybe this sub is a better place for this: http://atariage.com/forums/topic/241575-help-trying-to-fix-an-atari-2600/

The cartridge is inserted the right way, maybe it's confusing seeing the motherboard from the rear on top of the VCS case. Input socket with switch in the off position is 14v Regulator Input Voltage with inductor removed is 11v Regulator Output voltage with inductor removed is 5v Yes, it's 5V Here are the tests: only the top chip: 4.5v only bottom chip: 4.9v only middle chip 4.9v top and middle chip: 3.2v middle and bottom chips: 3.2v three chips: 2.0v I've attached a file with what are top, middle and bottom chips for me

I've measured again: Power input Atari ON: no cartridge 4.2v with cartridge 3.9v Power input Atari OFF: no cartridge 13.6v with cartridge 13.6v Yes, it does. I'm not sure if I'm measuring correctly, so I'm posting pictures of what I'm doing: Hi Stephen, I'll try this today when I have some time. Thank you for your help! EDIT: I've went frame by frame in the above video and right when you power on the atari you can see the game, in this case Combat was inserted. Don't know if this info is useful. Screenshots:

Hi Osgeld, thanks for your help! I've turned on the atari for like 5 minutes but nothing gets hot, only the regulator gets warm. I'm not sure if I've set my meter to the right setup, I've set it to 2000K ohms and measured first the middle leg with the top leg, then the middle leg with the bottom leg and it shows me 489 with the top leg and 004 with the bottom one, all this with the power disconnected. Maybe it's not the right regulator? it says L7805V and some other numbers. The guy at the electronic shop told me that's the same as the original I took it off. Here are the pics:

Hi, I'm trying to resurrect this Atari I bought long ago and was never able to get it working, When the power is on it shows black and white lines as in the video: VIDEO: I'm not very good at soldering, but I've tried these things without success: - cleaning motherboard with contact cleaner - remove and re inserted the 3 chips - change voltage regulator 7805 - resolder power input - Test another power supply (9V 500mA) - desolder, clean and place RF modulator Things I've tried with a cheap multimeter: - 9V power supply shows 13.5V in the multimeter without being plugged in. - when Atari is ON the voltage drops to 3.5v at the power input - the voltage regulator shows 3.6v and 2.1v in the two 'legs', I don't know what values are the right ones. Here there's a bunch of pics showing the tests I've done: New power supply: With Atari ON: Old regulator: NEw regulator: More pics:

Thank you A.J., you explain very clear to me and I appreciate it very much. The crystal only says that, sorry. I trust that you say my Atari is NTSC. I've tried it already. I've got 6 TV sets in my house, 1 PAL and 5 binorma (NTSC, PAL-N), one of the TV can be put to NTSC "forced mode" but the same noise appears. The only "pure" NTSC that I have is an old commodore monitor but it doesn't have an RF input, only A/V inputs. Now I'm going to make the A/V mod, that's my last hope. I've seen your mod and looks great but a little complicated to me, I don't know nothing about electronics. I think I'm going to make the Ben Heck' mod, it looks more easy to me. I thank you again for all your help!

Great app! My fav game