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Peavey AMR 1600 VU lights problem
Old 19th February 2020
  #1
Peavey AMR 1600 VU lights problem

Hi!

I have a Peavey AMR 1600 console with a meter bridge problem.

After its been powered on for a while the VU lights starts to fade away and then comes back after a second. There is also a slight hum noise when that happends.

It gradually increases and occurs like every 10 minutes or so. I suspect i has to do with some kind of heat related issue.

It doesn't affect audio. No gaps. The hum noise is only apparent when there is no music playing.

Does anyone have any tips?

I really love the console. Its great sounding and a joy to work on.

Best regards
Fredrik Berg
Old 19th February 2020
  #2
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JohnRoberts's Avatar
 

I have no specific advice, but IIRC the meter bridge lamps are powered by the 12V power supply... odd to vary like that.

JR
Old 19th February 2020
  #3
Quote:
Originally Posted by JohnRoberts View Post
I have no specific advice, but IIRC the meter bridge lamps are powered by the 12V power supply... odd to vary like that.

JR
Thanks for taking your time to answer my question. If there somehow are problem with the 12V would i be possible to connect an extern 12V power supply just for the VU? Or could that damage something?

I have all the schematics that I got from you by email last year. Thanks again!

Best Regards
Fredrik
Old 20th February 2020
  #4
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JohnRoberts's Avatar
 

No problem but it may be something simple like loose wiring. Good luck

JR
Old 20th February 2020
  #5
Hi!

Some additional info.

When I bought the console all the lights were out. After checking that there was power I bought new lightbulbs. 12V 3W.

Now I'm thinking that maybe 3W is way to much and that i causing the problems.

Its a total of 18 VU lights.

Best Regards
Fredrik
Old 20th February 2020
  #6
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JohnRoberts's Avatar
 

Is this something that just started happening? Or was it misbehaving since you swapped the bulbs?

If I recall correctly each PS rail has a bicolor LED indication, green for all good, red for PS good but fuse open, and dark if PS rail down. Does the 12V LED dim or go out coincident with the lamps dimming.

I just looked at the 12V ps schematic and it does not have any fancy protection that would explain the behavior you see...

If 12V LED stays bright green while meter bridge lamps dim, check wiring.

JR
Old 20th February 2020
  #7
Quote:
Originally Posted by JohnRoberts View Post
Is this something that just started happening? Or was it misbehaving since you swapped the bulbs?

If I recall correctly each PS rail has a bicolor LED indication, green for all good, red for PS good but fuse open, and dark if PS rail down. Does the 12V LED dim or go out coincident with the lamps dimming.

I just looked at the 12V ps schematic and it does not have any fancy protection that would explain the behavior you see...

If 12V LED stays bright green while meter bridge lamps dim, check wiring.

JR
Hi!

All lights were broken when I bought the console.
So I dont know if this has happened before.

The led indicator is broken and taken out.
Actually its the phantom that was broken before I bought the console and the leds is on the same card.

I’m looking for a spare card.

I pulled the power to half the lights and its better now. I had 1 ”lights out” during an hour of mixing.

I’m gonna pull the rest except for the middle master VU and see if the problem dissapears completely. Then I know.

What is the recomended effect on those lights.

There was no information on the old broken ones that I replaced.

Best Regards
Fredrik
Old 21st February 2020
  #8
Hi!

So I did a session last night with only 9 Vu lights on and I didn't have any problem at all.

I think 3w is too much. I'm going to buy some other lamps, maybe leds.

Thanks for helping me. really appreciated.

Best regards
Fredrik
Old 21st February 2020
  #9
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JohnRoberts's Avatar
 

The stock AMR power supply does not have any thermal or current protection other than a standard fuse. I have no good explanation for the behavior you are seeing.

JR
Old 21st February 2020
  #10
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I think it would be a reasonable idea to go in with a magnifying glass and look to see if there are any cold or cracked solder joints, particularly in the power supply circuitry. A cracked solder joint can be thermally sensitive and make poor contact after it heats up, yet work fine when it is cold. Reflowing any that look slightly suspect might very well solve your problem (at least for a considerable time).
Old 21st February 2020
  #11
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JohnRoberts's Avatar
 

I am more suspicious of wiring between PS and meter bridge but who knows?

Pointless to argue about hypotheticals. I only know what it isn't (thermal shut down or current limiting).

JR
Old 21st February 2020
  #12
Quote:
Originally Posted by DrewE View Post
I think it would be a reasonable idea to go in with a magnifying glass and look to see if there are any cold or cracked solder joints, particularly in the power supply circuitry. A cracked solder joint can be thermally sensitive and make poor contact after it heats up, yet work fine when it is cold. Reflowing any that look slightly suspect might very well solve your problem (at least for a considerable time).
Its working right now, but I think its a good idea. The phantom-power card was broken. So maybe something happened to the other cards as well. I can do basic soldering and measuring but aren't that good with these things so I will try to get some electrician to check the PSU.

Thanks for helping me!


Quote:
Originally Posted by JohnRoberts View Post
I am more suspicious of wiring between PS and meter bridge but who knows?

Pointless to argue about hypotheticals. I only know what it isn't (thermal shut down or current limiting).

JR
I´m gonna check the wiring also. I'm glad the console is working right now.

Thanks!


Best Regards
Fredrik
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