alortegac

Hi to all: I recently acquire (by chance) a G7401 Videopac console. After reading the IMPORT guide on the NEXTLEVEL website. I am no sure on what cable would be best for this console to work here in the USA. Question 1: should I purchase an 8pin to scart cable (original) then convert SCART to HDMI through an adapter? will this work? Question 2: would you suggest any other option? Also, I am assuming I will also need a power Voltage Converter Transformer to step up to 220v. Correct? Finally, any suggestions for a SWITCH replacement or alternative. Original feels mushy with no click, not sure it will work. thanks in advance for your help. Al

Battlezone?

Final Update: I replaced the 7805 this morning. I must have damaged the last one with heat or it was a dud. Eureka!!! Lesson: I should have followed occam’s razor principles on my troubleshooting. New Learnings: Thanks for showing me applications of Ohms law on resistive load testing. Thanks a lot for your help! Greatly appreciated.

The psu case/shell is definitely worth saving. My plan is one last repairing attempt. if I do not succeed, then there is one person interested in repurposing it. I will be happy to give it to him, since all people here are great! Best electronics has nice new psu’s at reasonable prices. I would probably buy one from them before risking my computer with a cheap newer psu’s 5V adapters. I see many of those on ebay, I would be cautious. I honestly do not know aliexpress specifically. My opinion, welcome to hear from others

All tests are to the same one Power supply. (?) not sure what you mean. Based on your comment, I am getting new 7805’s in the mail during the week to replace this one again ...:) will see what happens thanks a lot!

Ok, I repeated test 1 and measured at the 7805 pin 1 = 9.25 v pin 3 = 4.66 v Also measured transformer = 9.00 vac then I removed the “load” and measured: pin 1 = 10.79 V pin 3 = 5.2 V Transformer = 9.18 vac thanks again! Al

I apologize upfront for the "Mickey mouse" circuit I quickly but carefully put together for the test.....(I just did not want to do more soldering, etc. And could not find my proto board). In any case, I used 20x parallel sets of 75 ohms + 27 Ohm resistors series for the circuit. Also I included a Voltage meter display and, in the second video I included a led to the circuit. Interestingly, on my first measurement the power supply generated current of 0.544 A, but voltage display would die immediately after closing the circuit. On my second experiment, I got the same current readings and same thing with the display, but the led would remain on. Exactly how I see it when I tested it on the computer. Now, the question, what is wrong with the power supply? Would it be the 7805 (even though is new)? Or perhaps is the big capacitor? Or the Transformer? I would appreciate any input. Al IMG_4291.MOV IMG_4292.MOV

Yes, BillC, sorry for the dumb question. I realized that after posting then came back and edited. In any case, I do not have 100 Ohm, I only 220 ohm or 75 ohm. I was trying to calculate the number I would need and which value would be best to use. I was thinking 75ohm. thanks!!

Ahh!! Great! I will do that, I have resistors close to the value, I will calculate the conversion. thanks

Hi thanks for your input. The computer is currently 100% functional with any other of my several power supplies. This is my computer for my daily use and playing games.....works fine. I am just trying to repair its original power supply. This power supply came with the computer originally, it was in bad shape with bare wires on the din side, and not working at all. I replaced the 7805 regulator, I get 5V but still it appears no producing enough juice to get the computer to turn on, only the led. ---------------------------------------- Following up, on my previous tests: I tested voltage: 5.22 Volts I tested AC voltage at the Transformer: 9.25 AC I tested current with a simple circuit-led shown in pic: 0.003 A (is this a valid test??) The led is on but it does not show clearly on the pic. Thanks as always.

Attached are some images of the actual PS with the new 7805 in position U102. I inspected visually both sides of the board (fully disassembled), everything looks clean and traces do have continuity. I checked readings on resistors and diodes, they appear to be ok. The PS yields 5V, but as I said it does not appear to provide enough current to turn all computer's components on (no image)....only led turns on. For this reason, I am hesitant to do the "under load test" with the computer, is there any other way to check it? On pic 4586 and 4589, you can see there is an empty location for another regulator. Thermal compound was brushed in there at some point (?). I do not see this component being called on the schematics. I also cannot see it on the picture from the "poehland" article. I do not think it is missing anything there. Do you see anything? thanks for your time and curiosity,. Al

Yes, I replaced it with a new 7805 2A. I will check it under load and report back. In your experience, is it possible for the transformer to go bad? All diodes seem to be fine. I mean there are not too many components on this power supplies. thanks a lot!

Hi, I said it incorrectly, I did not try the power supply with other computers. I tried the computer with a working power supply. The computer is fully functional, and all the test passed with flying colors. I only tried the malfunctioning power supply once, after I verified polarity and voltage with multimeter was correct. I checked pin by pin, compared side by side with a working power supply. Everything appears correct. thanks for your comments, I may check it under load. Or just toss it....but maybe it is not worth risking the a computer over the power supply. i was mainly curious to know if it was possible to get weak power/voltage under load even after replacing the 7805. I suspected it since the led did turn on, but not the main components in the computer. thanks again! Al

Hi, quick question for the experts. I recently purchased an 800xl deck with its power supply. The PS came with bare wires on the din connector's side, which I have properly repaired and patched. I also opened it to replace the 7805 regulator. Everything looks ok. but still does not work properly. The power supply yields 5v ( I checked), and the computer's led turns on but it does not produce any image. I tested the PS with other computers with the same results. The power supply is probably not generating enough current. Is this possible? and, May you know any why? Also, I would appreciate your guidance to find the schematics. thanks a lot in advanced. thanks a lot!

Hi, I have a similar knob from one of this. Let me know if interested. Al

Iso of 1 working. ic to repair a Voice module. Also wondering if this IC can be programed. Any leads will appreciated. Thanks!

Thanks! Yes, I saw it. thanks a lot!

Question: Omega race only with roller set to joystick mode, right? I cannot get it to work in roller mode

Hi, I am ISO the IC on the title to repair a VOICE module. I have narrowed the issue to this CHIP. Any leads will be appreciated. thanks! Al

Is there one left? I will take it! If not, please sign me up for 1 of the next run. Please let me know payment instructions. thanks a lot!

Thanks it did work, greatly appreciated

Can someone tell me if Buck Rogers file in the thread will work with the FLash99? My Ti has an 32K extension pack. thanks!

Hi, Sorry for the delay, I never saw your message until today. I have a console that has the problem, voltage on an otherwise good power supply drops from 5.16v to ~4.76V causing random artifacts sometimes, not all the time, and not as severe. This console has the new 5V RAM and a new power switch installed very nicely. I have check VRAM test with the atarimax, funny sometimes it passed and sometimes it fails, randomly. I have also checked the RAM IC's with logic probe, one by one. All are working as they should, perfect readings. Finally, I checked continuity between RAM and VDP, all pins are good. I followed C5 troubleshooting guide to the dot and VDP test guide I found here in a different post. I will now check PIn 8 and 9 without IC's as you suggested. With IC's in, all are in high in the probe, reading ~4.76V with multi meter.

Hi, Requesting your assistance to troubleshoot a quiet Voice. I can only hear cracking sounds instead of the “words”. Like distorted words. i have replaced the amplifier with no change. I tested the speaker, it is good. i cleaned the slider potentiometer, but not sure on what are the correct ohms range. So I tried to go before the amplifier circuit to check if I was getting sound from the chip. I am not sure on how to test the main IC. I connected headphones right to the audio out pin 24 and ground, I could only hear the same faint cracking distortion sound whenever the voice should be speaking. is it possible the ic is bad? Somehow it appears to be working, but somewhere sound is being distorted or it is coming distorted from the ic. Thanks a lot in advance.