MB Vectrex Console - Repair help needed

[Psycho Fox]

My Vectrex shows no signs of life when switched on. No sound, static or picture, nothing.

I've replaced the fuse in the plug but the fuse in the console looks intact.

Am I right in thinking this must be a power issue?

Any help is greatly appreciated as I'd love to get this old machine running again.

Here's a video of the unit showing the condition and a bit more info.

http://www.youtube.com/watch?v=dNzERiSy6ww

[dutchconsolefreak]

Here you have a link to the Vectrex service manual. Ofcourse you need a voltmeter to discover where the power distribution stops, must be close to/after the transformer since the whole system is dead. Good luck .

[Psycho Fox]

Here you have a link to the Vectrex service manual. Ofcourse you need a voltmeter to discover where the power distribution stops, must be close to/after the transformer since the whole system is dead. Good luck .

I've had the console switched on for 3 hours just to check it didn't power up as I've heard of these machines sometimes needing time to 'warm up'. After 3 hours the transformer casing was still cold. Not got a voltmeter so I'll re-solder a few joints and if that doesn't work it'll be for spares.

[nameless hero]

A voltmeter is so cheap...

[Psycho Fox]

Got a multimeter now and done some testing...

All continuity is good on caps and wires but when checking DC voltage I'm finding no power on either circuit board so I guess the transformer is dead.

Does anyone know what the issue with the transformer could be and if it can be fixed?

Also, can a modern transformer be fitted?

Many thanks!

[dutchconsolefreak]

You should check the AC voltage on the secundary side of the transformer before replacing it.



As you can see there is also the possibility the on/off/volume switch is at fault, or that other 'thing' in the (white) null line.
When you are sure the transformer is at fault, with google you can find that the type used is a 9-0-9 VAC. The primary voltage depends on where you live ofcourse.

[Jamtex]

Yes worth checking the fuse (use the diode or continuity tester of the multimeter, if dead then replace it), as well as power going into the transformer (if nothing then the fuse holder may be broken), by setting the transformer to VAC and measure between the two red wires (from the transformer to the switch) you should read a voltage of 18V, if you do then read to the board, if you are not getting voltage here then the switch may be faulty (if so you could bypass it by wiring the two red wires to the wire above it on the switch). If nothing then replace the transformer with a 9-0-9 transformer (also called a 18V centre tapped transformer) which can be picked up for not too much money (I've seen them as low as $4).

[Psycho Fox]

Many thanks! The fuse is ok and I've replaced it just to be sure but still nothing. To measure the AC voltage between the transformer and switch do I need to open up the metal shielding around the transformer?

[dutchconsolefreak]

I have never opened a Vectrex myself, but can't you just follow the wires to the on/off switch and measure from there?

[ASSEMbler]

All you need do is check for power from the transformer where it hits the board.

Power? Fix board
No power? Replace transformer.

[Psycho Fox]

No 18v from transformer (no volts at all) so the transformer must be dead. Is this the right replacement:

http://www.ebay.co.uk/itm/Power-Supp...item460304f4ac

It costs as much as I paid for the Vectrex! :)

[dutchconsolefreak]

That would be the correct one, although you can find them cheaper here and there.

[Psycho Fox]

Many thanks for those links - those are a much more reasonable price :)

One question, the Vectrex transformer has 6 wires in total coming out of it but the replacements only have 5, do you know if this will cause any problems?

[dutchconsolefreak]

The drawing in the service manual also shows only five wires, maybe the sixth wire is for grounding the transformer, or a second null line. You should be able to figure it out by following the wires from the original transformer.

[retro]

If in doubt, you need to make a judgment call as to whether you should be doing this. Vectrex is more than just a games console - if you don't know what you're doing (and, with no disrespect, your comments make me wonder), you could do yourself some damage poking around in there blindly.

As for parts sources, I've mentioned them before several times and in this very forum there should be a thread I made listing those sources. Take a look at it ;)