Game & Sound But No Picture

Question

Vectrex

The Vectrex is a vector based video game console that was developed by Western Technologies/Smith Engineering in 1982.

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Sir Adam @siradam

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crwdns2931729:0crwdne2931729:0: Kul 20, 2026

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Game & Sound But No Picture

*Update After Cleaning the pins of the J204 connector the screen emits a glow after turning the brightness up all the way and the tube on the back of the crt has a glow which did not happen before as seen in pictures.

*Edit Here are some photos of the power board. As far as I can tell none of the capacitors look damaged. I also took a picture of the board on the tube itself, not sure what that is called. Sorry for the weird angles but its the best I can do without removing the board.

I have a vectrex with game and sound both working but zero picture, no dot in the middle of the screen or anything. The only thing I have done to repair the vectrex was replace a fuse which brought back game & sound function. I am not very tech savvy and this is out of my league, any help is appreciated.

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score 0 · Answer 1 · 2026-03-21T13:00:28-07:00

oldturkey03 @oldturkey03

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crwdns2931729:0crwdne2931729:0: Kul 21, 2026

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@siradam as you already know this is a CRT (picture tube) that works with some pretty high and lethal voltages. You do want to make sure that you are utilizing the properly safety precautions before working on this. This "I am not very tech savvy and this is out of my league" is good to know. That means you are aware of needing somebody with some experience to fix that,

This sounds like an issue with the power board. There are multiple fuses that you will need to check. Check the capacitors for bulging and leaking as well. Do a visual inspection of your power board and post some well-focused, large images of that board with your Question. That way we can try and help you out. Adding images to an existing question

Do not poke around this without properly discharging the tube and the power capacitors!

Use the Vectrex Service Manual and start by reading the circuit description starting on page 8. It gives you a better understanding on how it works. Here is a CRT Safety Guide from Apple but it is the same for all CRT's. Use common sense and be careful!

@siradam ah, I see.

IC 303 is a LF347 Quad Amp IC (or TL084) here are the datasheets LF347 TL084 and this part should work.

IC 301 is a MC1408P8 DAC going to be trickier since it is considered obsolete. Mouser suggest this DAC0808LCN/NOPB as a replacement. Check {https://www.mouser.com/Compare/Alternate... |this site] for the comparison between those two parts. Definitely looks like a suitable replacement.

IC 302 is a 4052B analog multiplexer and looks like it's even harder to find than 301 :-) Here is the Cd4052b Mildatasheet that will help you to cross-reference items from either Digikey or Mouser (or anybody else) to find a replacement. this should work since it has almost identical characteristics. Just double check :-)

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Sorry, I did not see this until now, but yes I should have mentioned it was properly discharged before tinkering, And now that I think of it when it was discharged (after being turned on and tested awhile before) it did not show any spark, is that a possible clue as to what is wrong with it? I will try to take pictures as soon as I can.

crwdns2934271:0Kul 23, 2026crwdnd2934271:0 Sir Adam crwdne2934271:0

@siradam this "it did not show any spark" could be based on not having gotten charged up. That would once more lead me to the power board. Check the power board for the power rails to see if you are getting all the voltages needed.

crwdns2934271:0Kul 23, 2026crwdnd2934271:0 oldturkey03 crwdne2934271:0

@oldturkey03 I took some pictures of the board, if they aren't any good I can take more.

crwdns2934271:0Kul 24, 2026crwdnd2934271:0 Sir Adam crwdne2934271:0

@siradam what happened to your board:-)? Darn, the traces are quite wrinkled up. did it get cleaned with gasoline or anything else? I noticed a jumper wire on F103 instead of a fuse. Any reason for the mod. Same with tother fuses. Any reasons you removed those are were they just never connected on your board? IC101; did you change the thermal paste? looks a little crunchy too.

Which fuse did you replace?

First thing I would check are the wires that are on P204. Those are the ones in your picture#3 measure to see if you get the -5V +5v and -13V. For this issue the prime suspects are D106, D107, DZ102, C120, C121, and C122.

You okay with using a multimeter? Remember that two rails are - (negative) voltage rails, measure accordingly. Also, you have to do the measuring on a live circuit. That means there will be power on your board! Use extreme caution and do not touch anything with your bare hands and make sure the probes do not short anything out :-)

crwdns2934271:0Kul 24, 2026crwdnd2934271:0 oldturkey03 crwdne2934271:0

@oldturkey03 The board looked like that when I bought it, haha! The only thing I've done since getting it was replacing a 0.5A 125V slo blo fuse located in a contained box on the bottom of the system. And I never noticed the missing fuses either! I will try measuring the wires asap, thanks for your help so far!

crwdns2934271:0Kul 24, 2026crwdnd2934271:0 Sir Adam crwdne2934271:0

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Vectrex

Game & Sound But No Picture

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Update (04/23/26)

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