Pulsar repairs

[Paul C]

Hi everyone

Coming up to Village show time and my Pulsar 2 preset analogue desk has developed a fault.

One channel is giving out full 15V (input level), 2 channels are dead and luckily 9 are working fine.

I can get through show with 9 but wondered if anyone knows anywhere in somerset/devon area that might do repairs

or maybe point me towards what might be the problem. I did electronics degree but that was 40 yrs ago and I've forgotten the odd thing or two!!!

 

Thanks

[timsabre]

Are the faulty channels the same on both presets? Do the masters affect the faulty channels? Faulty sliders are most likely but not if on both presets.

[Don Allen]

If a channel is giving out full, the bottom end of the fader is not getting a common connection. Look for a dry joint or a faulty slider on the potentiometer.

 

Look at this older BR post Claening faders for some cleaning tips.

[patrick_keys]

You didn't mention which output sockets you're using to connect to the dimmers - but from memory the desks had 5 or 8-pin DIN and/or a larger single connector. Although it might not be the cause of your problem, it's not unknown for the soldering to fail around these connectors. Well worth taking a careful look at all of the solder joints on the board, and re-soldering any which look suspect. I found several dry joints on one of these years ago.

[themadhippy]

one other thing worth checking is the cable linking the desk to the dimmers,especially if there non pulsar dimmers as pulsars wiring convention is slightly diffrent to most others

[boatman]

Have you asked Pulsar for a circuit diagram? If they aren't willing to let you have one then this circuit will be pretty close to the guts of the Pulsar desk. Just needs a bit of creative interpretation.

[Paul C]

Thanks guys for suggestions and makes me realise I really should put more details in.

So:

All three problem channels behave same irrespective of preset and master / submaster positions.

 

Outputs in use are 8 pin din

 

Cables are as used before but go into a small box I constructed with 6 way mini desk for everyday use on it plus sockets for the Pulsar and Zero88 desks then hardwired to cables running to stage with 8x5A Anytronics and 4 x10A dimmer pack, can't remember make.

I have checked all my connections but will go through them again and then have a look at connections in the desk.

I'll take my magnifying lens and meter tomorrow and have a look at sockets as the full on channel is Chan 2 and that's pin 4 which is next to pin 1 +15v so could be a solder whisker or fault in socket.

Thanks for circuit diagram I'll have a look and see what I can check out.

[Don Allen]

If there are not too many connections, it may be quicker and easier to use some desoldering braid, remove solder from joint, then resolder. If it is an old joint, you may need to try getting some new fresh solder on the joint, before you can successfully desolder it.

 

This method picks up joints that are not quite faulty, but need improving.