alortegac

Thanks Stephen

It was thanks to Stephen!

Hello Stephen, Great news to report today. I first proceed with visual inspection of the circuit for shorts, cold joints, my not so good soldering, etc. Everything looked ok! Then, I removed 1 pin of R47, checked with meter, perfect 1M OMH. I reinserted it. Finally, I proceed with checking C55 (which I had not replaced yet, as we decided to first check 4013). I removed it, checked with capacitor meter.....NO READING. Check with meter, very low resistance....short! C55 WAS THE CULPRIT I replaced it with another 0.22 UF capacitor I had in my box of components, not quite the same cylindrical ceramic, but the same capacitance. I think a better one. My old 7800 is back from zombie land! and with best picture than ever. As I recap, I replaced S1, MJE210 (2 times), 7805, R53, C55, Zenner diode CR5 (3 times) and 1 4013 (now socketed). I really want to thank you for your help and patience. Many Thanks!! Alberto PS. I still have1 final question for you: How did you know the expected on/off high/low states of 4013? where can I learn how to inspect TIA, 6057 and 6532, etc? I have another light sixer sick console......that now I feel I can try to resuscitate, hopefully with more your help!. Perhaps matter for opening another topic, this console does weird things.....like overlapping images, changing letters in the screen, numbers, etc...weird, weird...stuff.

Hi Again, thanks for your follow up. Here are the new readings with the 4013 inserted in position. (The console still does not power up) SHOULD BE: ACTUAL READING Pin 1: Low ====== 0 volts Pin 2: High ======= 5.14 V Pin 3: High ====== 5.14 V Pin 4: Low ===== 5.08 V Pin 5: High ====== 4.21 V Pin 6: 0V === =====0V Pin 7: 0V (Supply Voltage) ===== 0V Pin 14: 4.7 - 5.2V (Zenner derived "5V" supply voltage) = ==== 5.14 V PIN 3 goes to LOW when I press S1 == OK The reading that is off is PIN 4. Please advise, Alberto

Removed R53 measuring only 511 not 560, OHM; I replaced it Removed Zenner was blown or shot, measuring 0 v both ways. I replaced it with a new one. Now we are back to 0 - 5.14V SHOULD BE: ACTUAL READING Pin 1: Low ====== =LOW (MINUS) -1.40 V. Pin 2: High ======= -10 mV LOW Pin 3: High ===== =5.14 V Pin 4: Low ===== 5.08 V HIGH Pin 5: High ======1.04 mV Pin 6: 0V === =====0V Pin 7: 0V (Supply Voltage) ===== 0V Pin 14: 4.7 - 5.2V (Zenner derived "5V" supply voltage) = ==== 5.14 V Note: I took all the readings without the IC being present as I socketed. I have a fresh 4013 ready to be placed when we find the problem and correct it.. Hope this is alright. Thanks for your help!! Alberto PIN 3 goes to liow when I press S1.

Stephen, This is my report: The logic states for the 4013 On/Off latch default "off" condition at main power on (not S1 controlled console power on) is 7805: Input:0v; G:0v; Output: 0v MJE210: E:13.2v; C: 0v B: 13.20v Q9: E:0v B:0v C:13.2v S1: 0.00v,0,0,0v (NOTE I DO NOT HAVE 4.99V anymore???) Pin 1: = 26.5 mV Pin 2: = 54 mV Pin 3: = -14 mV Pin 4: Low = 0V Pin 5: = 0V Pin 6: 0V = 0V Pin 7: 0V (Supply Voltage) = 0V Pin 14 = 2.5 mV ​​ I think R53 is open circuit because I am getting continuity when I test it. I am getting 0 to intermittent OHM readings from it.?? Any ideas? Thanks for your help!!

Hello Stephen, Happy new Year. Thanks for your response. Comments: About MJE210 in the "On" State console, definitely I blew the MJE210 by shortening it or something while probing to measure, this was the action that left the console in "ON STATE". However, a new MJE210 is inserted in the correct way now. I checked the datasheet several times. This is the link to the data sheet. https://www.fairchildsemi.com/datasheets/MJ/MJE210.pdf I will check the latch circuit per your instructions and report back. However, I will be able to get to it until the weekend, thanks for your patience and assistance. Alberto

Stephen, here some measurements. Console that would not turned Off (ON STATE): 7805: : Output: 4.81v G: 0v : Input:6.61v MJE210: E: 10.35v C:6.74v B:7.24v R56: 7.24v Q9: E:0v B:0v C:8.79v R56: 8.79v Zenner: Cathode: 4.97v Anode: 0v R53: 10.35 to 4.97v S1: 4.95v,0v,0v,4.95v R55: 10.35v 4013: PIN 1: 0v ; PIN 14: 4.96v THEN I replaced MJE210 and Q9 as we discussed, the console is dead again:; Measurements (OFF STATE): 7805: Input:0v; G:0v; Output: 0v MJE210: E:13.2v; C: 0v B: 13.20v Q9: E:0v B:0v C:13.2v S1: 4.00v,0,0,4.99v 4013: PIN 1: 0v, PIN 14: 4.99v R56: 13.20v Zenner: Cathode: 4.99v Anode: 0v I was able to take measurements on second WORKING 7800 console, these are the readings for comparison: ON STATE 7805: Input: 10.41, G:0v Output: 4.91v MJE210: E: 10.57v C: 10.46v B: 9.81v Q9: E:4.90 B: 6.22v C:0v S1: 4.63v,0,0,4.63v 4013: PIN 1: 4.50v PIN 14: 4.63v Zenner: Cathode: 4.63v Anode: 0v OFF STATE: 7805: I nput: 0v G:0v Ouput:0v MJE210: E: 13.11v C: 0v B:13.11v 4103: PIN 1: 0v PIN 14: 4.70v Q9: E: 0v B:0v C: 13.2V Thanks!

Stephen, Once again thank you for all you insight, Thanks for teaching me. I will follow due process and report back result. In the meantime, I wish you the best for this Holiday season.

Zenner is in the correct way, with the darker band in the same direction of the original, I was just saying in case it could have gotten damaged when the smell occurred, I will leave it alone as you suggested. Aside from my concern about being able to replace 4013 without damaging it or more or less work, I was asking about the on/off bypass because I read that this 4013 circuit resets the system so that the programs start up properly, so bypassing it may cause other issues. I have not seen those issues happening, so I was not sure. I will search for the CD4013 on ebay or such. I will let you know. Is there any difference in the CD4013B, or it is the same? Another thing that still bothers me is why the console was not working properly when I made it work the last time before the BOOM moment? Or it is something else in the circuit that can affect the function of the whole console. If you recalled, after replacing the zenner the first time around (before touching the MJE210/Q9), the console turned on and I was able to make few games to startup (none 2600's on 7800's and getting garbage). However, after a short period of time the console would die again. This happened twice with the new and the original 7805. But not now, the console works great, so I am ruling out the big capacitor, 7805, MJE210 (when I replace it again, I expect the same issue), Q9(when I replace it again), R53, zenner and new switch. thanks a lot!!

Thanks Stephen. I found this C55 on ebay. (I just want to have them just in case, as there is no Radio Shack around here anymore) http://www.ebay.com/itm/50pc-22uF-224-50V-20-Z5U-Axial-Capacitor-Ceramic-MLCC-KEMET-C410C224M5U5CA-/381218294136?hash=item58c2618978:g:5K0AAOSwpDdVIxik I will replace MJE210 and Q9 and do the measurements this Saturday and report back. Should I replace the zenner again too? Before I do all that, one more question: Will it be too bad if I just bypass all this circuit with a On/Off switch on the AC power points? I can do the power supply mod to a 2.1 MM round jack (to replace the original proprietary jack) and take the power from there to a On/Off Switch that I can install ion the side of console without affecting its looks that much. I am afraid if it is the 4013. I am not very experienced replacing chips. I do not know if I could find an original 4013. thanks a lot for your help..

Dauber, I did not think about that possibility before, thanks!! I must agree with you, signs come in many different ways.......but sometimes we just do not listen to them. I am very frustrated with this console.....but my friends from this forum will help me I am sure.

Ok, I will check with a multimeter to make sure, and replace the MJE210 again (I have the same exact part from Fairchild). I replaced Q9 once already, but I can do it again. I would like to know how to measure 4013 the right way, I mean where to place the multimeter terminals on the board. Perhaps I am not measuring things correctly there. BTW, I could not get to the on/off latching circuit using the link on your previous post. In another question, about C55. Do you know what I should buy? Thank you for your help!

Thank you both for your responses. Let me start with Crossbow, can you tell me which Capacitor I should buy? I checked and there several capacitors 0.22 uf ceramic axial options, what are the specs of C55? Stephen, It starts up immediately when I connect it the power source. The power button does not respond at all, ON or OFF. Just to be more specific in my process: The problem: The console was running and suddenly died. The first thing I did, was replacing the 7805, that did not correct the problem. Then I change the zenner and checked R53 was ok. I made the console work for a brief moment but not properly, I was not able to run any 2600 games and some 7800 would run the start up and the crash. Then the console would just shut itself off. So I then change the zenner for a new one again, and changed Q9. Result: it only run for a little bit with problems and then died again. Then I changed MJE210. Result: it only run for a little bit with the same problems and then died again. ( I have to admit, I am unsure I installed this one correctly, I tried to follow the schematics, but 50 / 50 change of error here). Even when bypassing MJE210, the console would turn on but with the same problems running games. Then I change the power button for the first time. and nothing, still dead. Then I decided to go back to the original 7805. and replaced all components again, including a new Q9, zenner and a new MJE210. Then BOOM! moment and smell, I think I might blew up the MJE210 while probing it. I replaced the button again, to make sure. Now is RUNNING GREAT, but cannot power it off or on using the button. But all games run great, video/sound/functions are ok, including, pause, reset and select.. Thanks for your help!!!

I have a similar situation with a 7800 that will not turn on...it was working and then it shut itself off and could not be restarted again....... By following other discussions, I replaced 7805, MJE210, Zenner diode, R53 and power button. After changing the zenner, I only made the console to turn on for a little while and then it shut itself off again. However, I was not able to get any 2600 game to display correctly, only 7800 games would start up sometimes. I thought maybe the new 7805 was not good, so I put the original one back. Well, now the strangest thing has happened, I connected it to the power and try to turn it on, an electronic smell, not burnt just a bit of smell....and BOOM! It working, I tested it for hours....and does work all functions all games,,7800's and 2600's.....BUT IT WILL NEVER POWER OFF. I replaced the power button again....and nothing. I have to unplug it to change games or re-start. From what I am reading above, perhaps MJE210 is open circuit(it got damaged again)...or 4013 is bad, or C55. I am lost now..... I am thinking to install an on/off switch, and be done with it,.....but I want to know what might have happed. Any help is welcome!

I have a similar situation with a 7800 that will not turn on...it was working and then it shut itself off and could not restart it again.......it was dead. By following this and other discussions, I replaced the 7805, MJE210, Q9, Zenner diode, R53 and power button. And the 7800 did not work consistently. I made the console to turn on for a little while and then it would shut itself off again..back to dead!. However, when on it was not working properly. I was not able to get any 2600 game to display correctly, only 7800 games would start up sometimes, and I was getting garbage in the screen... I thought maybe the new 7805 was not good, so I put back the original one. I replaced the MJE21, Q9 and the diode again. Well, now the strangest thing has happened, I connected it to the power and try to turn it on, an electronic smell, not burnt just a bit of smell....and BOOM! It is now working perfectly, I tested it for hours....and does work all functions all games, pause, reset , any 7800's and 2600's games. THERE is one problem though......it cannot be not turned off.....so I replace the power button again and nothing,,,,it just does not power OFF. ANY IDEAS will be appreciate it. thanks!!!