[Vectrex - Another one that has a missing -13v at cold start..]

That’s a good zener diode. The manual says 400 mW and that’s what I installed. 
One important thing I have learned when working on the Vectrex - replacing parts and de- and resoldering wires on the board may cause the vias not giving good contact anymore on the component side of the board although it looks good on the solder side (as we typically solder there). I believe it’s just due to the bad quality of these vintage boards.
Some traces are connected to the vias at component side. For example the trace between EP106 (where one wire comes from the switch) and C120. It happened to me that there was no good contact at EP106 (anymore) which caused an unstable system. Also found this issue on some capacitors I have replaced. So, you may want to double check your work and check on continuity between the parts especially on that -13V circuit. Maybe you have to solder the capacitor legs from both sides.

 

good luck and don’t give up 😁 My last Vectrex restoration took me 6 months and a lot of head scratches but at the end there were just missing contact issues (plus a faulty  IC401 and likely a diode).

[Vectrex - Another one that has a missing -13v at cold start..]

Hi kbj. I now found this phenomenon on 2 different Vectrex‘s and like you I was really clueless. All the voltages were good across the board. Just the -13V missing after a cold start. Found only -0,7V or so there. 
 

At the end of the day it seemed to be only related to a bunch of capacitors (C120,121,122) and a few diodes. The capacitors were already replaced, so I changed out the diodes D106, D107 and DZ102. 

 

That fixed the issue on both units. I cannot tell which diode was the culprit but I would put my money on a marginal working zener diode….

[no picture when cold start - missing -13VDC]

Obviously replacing the Diods helped to fix my missing -13VDC. Since then the screen always starts. Meanwhile I was also able to fix the vector issues. It has been caused by a faulty IC302. Maybe this chip contributed also to the other issue? I don’t know. I was nearly giving up but with some great help in the VCFED Vintage Gaming Forum I finally got my Vectrex up and running again 😊

[Vectrex won't display the game, only 3 lines.]

Try to replace IC302. This helped my Vectrex

[Vectrex won't display the game, only 3 lines.]

Hi Bailey7. I don’t have a solution for your issue but your screenshots look quite similar as what I get on my Vectrex since Saturday. Beside the other issue I described in my thread:
„no picture when cold start - missing -13VDC“

 

would you mind to have a look to my screenshot and compare? I am wondering whether “your” Vectrex was moved before it got its issue? That’s what I did on Saturday a few hours before it started to fail. If I understand correctly the games are working, so you can hear the game sound?

 

I am wondering whether there is somebody in this forum who knows the root cause. I did replace the 6522 on mine but it did not help

 

[no picture when cold start - missing -13VDC]

Thanks for helping me. But I am sure the switch is not causing the problem. When I recapped the system I also did clean up the switch and when turned on I can always measure continuity. When the unit (screen working or not) is on I can always measure ca. 10 VAC at EP104 and EP106 which tells me the switch is ok.

 

Yesterday I replaced D106, D107 and DZ102. Then I turned the unit on and let it run several hours without no problem. Then suddenly (in the middle of playing Vectorblade) the vectors got scrambled. It’s still the case also after replacing the 6522. Looks like now I got another fault🥵

 

There is currently no chance to get the screen up and running again. I can hear the sound of mine storm though.

 

[no picture when cold start - missing -13VDC]

Hi Vectrex experts,

 

I am Denis from Germany and I am a new Vectrex owner or better to say - I got the vec fever 😁

 

I hope there is somebody out there to help me out with this strange issue. Although i got no background in electronics I learned a lot in the last years by repairing a number of retro computers. Also difficult cases. After all these nice and interesting Commodore´s, Atari´s, Apple´s and IBM´s I have collected over 4 years I thought there could be nothing left which is even more exiting. Until I found my Vectrex.😘 I got it in a good condition although the calibration was far off. Tried to calibrate the unit but could not achieve a good result. So I decided to give myx vectrex a bit love and replaced all electrolytic and polystyrene capacitors. This went actually quite nicely without any issue. I made sure to replace them with the right type and put them in the right orientation. Double checked many times. But one issue happened to me though. I overseen that during the operation I bended C324 in such way that it got contact with the 5 VDC leg on the J204 connector when I put the plug on. I stupidly overseen it. So there was a short between +5VDC at the connector and the GND side of the capacitor. See photo attached.

 

When I tried to start up the vectrex the first time after the recap it did not start at all. Then I found that shortcut at J204 and fixed that. Maybe that caused my issue - I dont really know. But maybe not. Because since then the Unit always starts up and I can hear the sound from Mine Storm.

This tells me the logic is functioning. But there was no pcture coming up. Initially I thought the 6522 is the culprit because after replacing it the Vectrex worked as normal again. Furthermore I was able to calibrate it and now I got a very nice straight picture. But it only worked for 2 days or so. Then failed again. Sound but no picture.

 

This is still the current state. During troubleshooting I always found roughly 10 VAC at EP104 and EP106 (vs. EP105 or any GND contact). I always got -4,92VDC and +4,95VDC which looks good to me. But when there is no picture then -13VDC is missing. Actually I measure -30 mV or so. Now - when unplugging at J204 (-5V, +5V, GND, -13V from the Power supply) and starting up again I see -13VDC at the analog/power supply board. When plugging in at J204 again then I also get -13VDC at the digital board and I immediately get a picture on the screen. Like a magic self repair. 🤔 For 1-2 days only and then fails again. Believe it or not but starting the Power supply board when the digital board is disconnected and then reconnecting the digital board fixes temporarly the issue. Really strange. Because I espected a short between -13V and GND I already replaced all capacitors between -13VDC and GND one more time but without success. I replaced IC301 but no luck. It´s the only chip which uses the -13VDC. Also tested 2 different 6522 - same story. Looking on the schematic there are a number of diodes in the -13VDC circuit. Is there maybe a diode causing this temporarly issue? Can diodes fail in that way and then ressurect for a while?

 

Something prevents the power supply board to establish the -13VDC when the unit is not in use for a while. But it fixes somehow itself temporarly. Accidently i shorted -5VDC and GND when doing troubleshooting. This imediately brought back the -13VDC and the screen went on. Strange. I am really getting crazy about this issue.

 

Is there anybody having an idea what could cause my issue here?

 

I appreciate any little suggestion 😊

 

thanks

best regards

Denis